Category: Class7

Heat Class 7 Extra Questions Science Chapter 4

Heat Class 7 Science Extra Questions Very Short Answer Type

Class 7 Science Chapter 4 Extra Questions Question 1.
In a mercury thermometer, the level of mercury rises when its bulb comes in contact with a hot object. What is the reason for this rise in the level of mercury? [HOTSl
Answer:
As the temperature increases, then expansion in mercury takes place which leads to the rise in the level of mercury in thermometer.

Class 7 Science Chapter 4 Heat Extra Questions Question 2.
Shopkeepers selling ice blocks usually cover them with jute sacks. Explain why. [NCERT Exemplar; HOTS]
Answer:
As we know that jute sacks is thermal insulators, it helps ice not to be melt immediately. So, shopkeepers used to cover ice blocks with jute sacks.

Heat Class 7 Extra Questions And Answers Question 3.
The radiators in cars are painted black. Explain why. [HOTS]
Answer:
Since, the black bodies are better radiators, so due to this reason, radiators in cars are painted black.

Ncert Solutions For Class 7 Science Chapter 4 Extra Questions Question 4.
To keep her soup warm, Paheli wrapped the container in which it was kept with a woollen clothes. Can she apply the same method to keep a glass of cold drink cool? Give reason for your Answer: [NCERT Exemplar; HOTS]
Answer:
Yes, she can apply the same method to keep a glass of cold drink cool because wool is a thermal insulator, and it cannot allow to heat pass through it.

Heat And Temperature Class 7 Questions And Answers Question 5.
A laboratory thermometer A is kept 7 cm away on the side of the flame while a similar thermometer B is kept 7 cm above the flame of a candle as shown in figure. Which of the thermometers A or Swill show a greater rise in temperature? Give reason for your answer: [NCERT Exemplar]

Answer:
Thermometer B will show a greater rise in temperature because heated air above the candle rises immediatly and increase the temperature of bulb of thermometer B quite greater than A.

Heat Class 7 Questions And Answers Question 6.
While constructing a house in a coastal area, in which direction should the windows preferably face and why?
Answer:
Window should preferably towards the sea beach so that the sea breeze coming from sea keeps the house cool during the day time.

Class 7 Science Chapter 4 Extra Questions And Answers Question 7.
A circular metal loop is heated at point O as shown in figure. [NCERT Exemplar]

(a) In which direction, would heat flow in the loop?
(b) In which order, the pins at points P, Q and R fixed with the help of wax fall if points O, P, Q and R are equidistant from each other?
Answer:
(a) Heat will flow in both the directions from O to P and from O to R.
(b) First of all pin at P and R will fall simultaneously after that pin at Q will fall.

Heat Questions And Answers For Class 7 Question 8.
The mercury does not fall or rise in a clinical thermometer when taken out of the mouth. Explain why.
Answer:
Because of the kink present in the thermometer, the mercury does not fall or rise.

Ncert Class 7 Science Chapter 4 Extra Questions Question 9.
If a pan is removed from the fire, then why does it cool down?
Answer:
When a pan is removed from the fire, it loses heat to the surroundings by radiation and it cools down.

Heat Chapter Class 7 Questions And Answers Question 10.
Name the mode of transfer of heat in which medium is not required.
Answer:
Radiation is the mode of transfer of heat in which medium is not required.

Class 7 Science Ch 4 Extra Questions Question 11.
It is preferred to use two thin blankets rather than one thick blanket. Explain the reason. [HOTS]
Answer:
In case of two thin blankets, there is an air gap which does not allow heat pass out from the body and it is not as such as in case of one thick blanket.

Class 7 Science Chapter 4 Extra Question Answer Question 12.
Why is it advised not to hold the thermometer by its bulb while reading it?
Answer:
It is advised not to hold the thermometer bulb while reading it as the level of mercury increases from the actual reading by our body temperature.

Class 7 Science Heat Extra Questions Question 13.
Briefly mention one application of kink in the clinical thermometer.
Answer:
The clinical thermometer consists of kink which prevents the mercury level from falling on its own.

Heat Class 7 Worksheet With Answers Question 14.
Explain how do we find out how hot an object really is.
Answer:
By using thermometer, we can measure the degree of hotness of a body.

Ncert Solutions For Class 7 Science Chapter 4 Heat Extra Questions Question 15.
Is the body temperature of every person 37°C?
Answer:
No, the body temperature of every person is not 37°C. It is an average temperature. It could be slightly higher or slightly lower.

Question 16.
How can we measure the temperature of other object rather than human body?
Answer:
Temperature of other object is measured with laboratory thermometer because clinical thermometer is not suitable for higher temperature.

Question 17.
How does the heat travel in air?
Answer:
Heat travels in air through convection.

Question 18.
We are advised to use an umbrella when you go out in the sun. Comment.
Answer:
We use an umbrella to protect us from heat coming from the sun in the form of radiation.

Question 19.
You may have noticed that a few sharp jerks are given to clinical thermometer before using it. Why is it done so? [NCERT Exemplar; HOTS]
Answer:
Jerks are given to clinical thermometer before using it to settle down the mercury level below normal temperature so that the measurement taken of a body be accurate.

Heat Class 7 Science Extra Questions Short Answer Type

Question 1.
The handle of a pressure cooker is covered with the thick plastic. Explain why.
Answer:
As we know that plastic is a bad conductor of heat due to which the heat from the cooker does not flow to its handle and we can hold it easily.
So, this is a reason because of which the handle of a pressure cooker is covered with the thick plastic.

Question 2.
Differentiate between two modes of transfer of heat, i.e. convection and conduction.
Answer:
Difference between convection and conduction

Conduction	Convection
The mode of transfer of heat from the hotter part material to its colder part or from a hot material to a cold material in contact with it without the movement of material as a whole. So, this phenomenon is known as conduction	The mode of transfer of heat from the hotter part of a fluid to its colder parts by the movement of liquid itself. So, this phenomenon is known as convection.
In all the solids, heat is transferred by the process of conduction	In all the liquids and gases, heat is transferred by the process of convection

Question 3.
While reading a clinical thermometer, what precautions should we take?
Answer:
Reading a Clinical Thermometer

There are following steps to read the temperature on a thermometer.
Step I
Firstly, wash the thermometer with an antiseptic solution and if in case, the antiseptic solution is not available, then wash it with a clean water.
Step II
Gently, hold the thermometer tube in your hand and give it a jerk in such a way that the mercury thread in the thermometer tube falls below the reading of 35°C.
Step III
Now, put the bulb of the thermometer under the tongue of the patient for about one minute. Then take out the thermometer from patient’s mouth.
Step IV
In order to read the temperature, hold the thermometer horizontally in your hand and rotate it slowly. When we see a magnified image of the mercury thread in its tube, then a position will come. Now, read the temperature on thermometer tube in level with the top of the mercury thread.

Precautions while Reading the Thermometer

A clinical thermometer should not be used for any object other than the human body. There are some following precautions which are to be observed while reading a clinical thermometer.

1. Wash the clinical thermometer before and after using preferably with an antiseptic solution.
2. Be ensure that the mercury level before using the clinical thermometer should be below 35°C.
3. The clinical thermometer should be read by keeping the level of mercury along the line of sight.
4. While reading the clinical thermometer, it should never be held by the bulb.
5. The clinical thermometer should be carefully handled.

Question 4.
Observe the picture given in figure. Water is being boiled in a pan of wide base.

(a) Which position P or T will feel warmer?
(b) Fill up the boxes P and T to indicate the mode of flow of heat to the hand.
Answer:
(a) As in the given diagram, position P will feel warmer because of heat, air rises.
(b) The flow of heat to P is a convection process and flow of heat to T is radiation.

Question 5.
For setting curd, a small amount of curd is added to warm milk. The microbes present in the curd help in setting if the temperature of the mixture remains approximately between 35°C to 40°C. At places where room temperature remains much below the range, setting of curd becomes difficult. Suggest a way to set curd in such a situation.[NCERT Exemplar; HOTS]
Answer:
For the setting of curd where temperature is below room temperature, the container in which curd is to be made must be kept in a thermally insulated cover or it can be wrapped with wool or jute sacks so that temperature is maintained for the setting of curd.

Question 6.
State the limitation of clinical thermometer.
Answer:
The clinical thermometer cannot be used for measuring the temperature of any object more than 42°C (i.e. more than the body temperature). If it kept in the sun or near a flame, then this clinical thermometer can be break.

Question 7.
Explain in brief, why we wear dark coloured clothes in winter and light coloured clothes in summer.
Answer:
We wear dark coloured clothes in winter to keep us warm as they absorb all the heat radiation coming from the sun whereas light coloured clothes reflect most of the heat radiation coming from the sun that falls on them and therefore we feel more comfortable wearing them in the summer.

Question 8.
Explain the reason for the shiny reflectors of room heaters.
Answer:
Since, the shiny surface absorbs very little heat due to which the reflectors reflect all the heat which makes the room heaters more effective. So, due to this reason, room heaters have shiny reflectors.

Question 9.
Describe the effects of heat.
Answer:
The effects of heat are
(i) When an object is heated, then it becomes hotter and may get expand. So, in this heat may change the state of the body like ice can also get change into the water.
(ii) Heat sometimes acts as a catalyst to speed up the chemical reaction.
(iii) Heat can even kill the bacteria as well.

Question 10.
The freezer is located at the top of the refrigerator. Explain why.
Answer:
The freezer is located at the top of the refrigerator. It is because the air inside and around the compartments of freezer gets cool and move downwards and on the other side, the lesser cool air moves upward to get cooled.
So, as a result of this, convection of heat are setup in the air and the tower section of the . refrigerator also gets cooled faster. .

Question 11.
Instead of water explain the reason, why do the mercury is used in the thermometer?
Answer:
Due to following reasons, mercury is used in the thermometers instead of water

1. When the thermometer breaks, the mercury can be easily collected.
2. Mercury can has more expansion than the water.
3. Also, mercury do not stick on the walls of thermometer like water.

Question 12.
Explain the reason for the general fitting of air conditioner at higher level on the wall of the room.
Answer:
As a fact that warm air is much lighter than the cold air, so being heavier the cold air from air conditioner moves downwards while the hot air moves upwards at the lower level and gets cooled and come downwards once again. So, due to this convection of heat are set in the air and room gets warmer faster.

Question 13.
Briefly explain, why do the kites and eagles fly without flapping their wings.
Answer:
As it is a fact that the hot air during the day time surrounds the land gradually and rises up, due to which a convection air of heat develops. So, kites and eagles start moving along this rising current of heat without flapping the wings to fly high up in the sky.

Question 14.
In the arrangements A and B as shown in figure, pins P and Q are fixed to a metal loop and an iron rod with the help of wax. In which case are both the pins likely to fall at different times? Explain.

Answer:
As in the given figures A and B, in case A P and Q got equal heat, so pin fix at P and Q in case of a fall simultaneously.
But in case of B pin at point P falls first than after pin at Q will fall as because heat received at P is greater than Q at the same time.

Question 15.
At a camp site there are tents of two shades. One made with black fabric and the other with white fabric. Which one will you prefer for resting on a hot summer afternoon? Give reason for your choice. Would you like to prefer the same tent during winter? [HOTS]
Answer:
We will prefer white fabric tent in case of summer because it reflects all the radiations from the sun and keeps us cool inside the tent.
But in ease of winter, we should not use white fabric tent, we should use black fabric tent as it absorbs all colours of light from the sun and keeps us warm inside the tent.

Question 16.
Briefly explain the maximum and minimum thermometers.
Answer:
Maximum and minimum thermometers are the special thermometers which automatically record the maximum and minimum temperature of the day. The maximum and minimum temperature of the last day reported in weather reports in TV and newspapers are measured by the maximum and minimum thermometers.

Question 17.
Explain the reason for serving of tea in China clay cup and plates.
Answer:
Tea is generally served in China clay cup and plates because China clay is a bad conductor of heat which do not allow the heat to pass through it and hence keep the tea hot.

Question 18.
Describe briefly about the direction of the convection current during ventilation.
Answer:
Since, with the help of ventilators, warm air being higher get rises up and leaves the room. Even the fresh air enters the room from outside through the doors and windows.

Question 19.
Explain the reason for wrapping of ice in gunny bags.
Answer:
Since, we know that gunny bags consist of number of fine pores which are filled with air. As air is a bad conductor of heat, so due to this reason, it does not allow the external heat to move inside and melts the ice.

Question 20.
Mention any two examples each of insulators as well as of conductors.
Answer:
Copper and aluminium are the examples of conductors which allow the heat to pass through them. While wood and plastic are the examples of insulators which do not allow the heat to pass through them.

Question 21.
The clinical thermometer is not used to measure high temperature. Why?
Answer:
Clinical thermometer has the range 35°C to 42°C. If we use it to measure high temperature, it may break and mercury present in the clinical thermometer is harmful. So, we cannot use clinical thermometer to measure high temperature.

Heat Class 7 Science Extra Questions Long Answer Type

Question 1.
Explain the differences between heat and temperature.
Answer:
The differences between heat and temperature are given as below

Heat	Temperature
It is a form of energy which flows from one body to another when there is a difference in temperature between the objects.	It is the thermal condition of a body that indicates whether or not and in which direction, heat will flow from one body to the other.
It is equal to the sum of internal energies of the molecules of a body.	It is proportional to average kinetic energy of the molecules of the body.
As a heat between two bodies, total amount of heat of two bodies remains unchanged.	As a conclusion of exchange of heat between two bodies, sum of their temperatures before and after exchange is not same.
SI unit of heat is joule (J).	SI unit of temperature is kelvin (K).

Question 2.
Explain the reason for the following statement, “When heat is applied at the bottom of the water vessel, then
it gets heated more quickly than when it is heated at the top.” [HOTS]
Answer:
The particles of water become more lighter and rise up in the middle. Due to this, the cold particles of water which are heavier come down along the sides of the vessel. So, the convection currents of heat are setup and water becomes hot. The moment, when the heat is applied at the top, then the water present in the upper portion becomes hot and these hot water molecules get fixed over the surface. Since, water is a bad conductor of heat, due to which water present at the lower end (or bottom) of the vessel remains.

Question 3.
Prove with the help of an experiment that heat radiation can travel through vacuum.
Answer:
First of all, take a flat bottom flask and fix a rubber stopper having two holes in the mouth of the flask. Shift a thermometer through one hole and a glass tube with stopper through the other hole. Now, with the help of a vacuum pump, remove the air from the flask and try to record the temperature from the thermometer. Put a flask in the bright sunlight and we will observe that the thermometer records a rise in temperature. So, on this basis, we can say that this experiment proves that the heat radiation can travel through vacuum.

Question 4.
On last Monday, Pankaj was dealing immense cough and cold. Besides this, he was suffering from a great headache. So, he decided to take a leave on that day so that he could take some rest at his home. After one hour he thought to check his fever through a clinical thermometer, so before using it, he washed it and started shaking it very fastly in his hand, so that the mercury level of thermometer gets reduced. At the same time, his elder brother Vishwas scold him and suggested him to shake the thermometer slowly.
(a) State some precautionary measures while checking the fever through a clinical thermometer.
(b) Mention the values showed by the elder brother of Pankaj (i.e. Vishwas). [Value Based Question]
Answer:
(a) The following precautionary measures while checking the fever through a clinical thermometer are
(i) While reading the clinical thermometer, it should never be held by the bulb.
(ii) The clinical thermometer should be washed properly (before and after use).
(b) The values showed by the elder brother of Pankaj, Vishwas, are concern towards the way of using the clinical thermometer and the importance of money as well.

Question 5.
Last Sunday, Pooja on her week off entered in her kitchen to cook rice for her family in lunch time. The moment she put fry pan on the gas stove and lighted it through the matchstick, all of sudden her 5 years small daughter entered into the kitchen and tends to touch the hot fry pan. At the same time, Pooja saw her and pushed her away from the hot fry pan. In this way, she saved her child.
(a) Explain why do the fry pan are provided with the plastic handles?
(b) Mention the values represented by Pooja here towards her 5 years small daughter. [Value Based Question]
Answer:
(a) As we know that plastic is a bad conductor of heat which does not allow the heat to pass through itself. So, heat from the fry pan does not flow to the handle due to which we can hold it easily. So that’s why, the fry pans are provided with the plastic handles.
(b) The value showed by Pooja here is a great concern and careness towards her five years old small daughter.

Question 6.
Describe in detail about the occurrence of oceanic currents.
Answer:
Since, it is a fact that the water present in the ocean (near the equator) is heated by the sun to a very higher temperature than the water near the poles of the earth. It is due to the falling of the sun rays perpendicularly in the equatorial region. So, in the equatorial region, the ocean water expands and becomes lighter.

While on the other side, the water in the polar region remains cold and heavy. It leads to the flow of convection currents of heat of warm water from the equator towards the poles.

Heat of the cold water flow from the poles towards the equator just below the surface of ocean. So, these types of currents are known as oceanic currents.

Heat Class 7 Science Extra Questions Miscellaneous

Multiple Choice Questions

Question 1.
A marble tile would feel cold as compared to a wooden tile on a winter morning because the marble tile
(a) is a better conductor of heat than the wooden tile
(b) is polished while wooden tile is not polished
(c) reflects more heat than wooden tile
(d) is a poor conductor of heat than the wooden tile
Answer:
(a) is a better conductor of heat than the wooden tile

Question 2.
A beggar wrapped himself with a few layers of newspaper on a cold winter night. This helped him to keep himself warm because [NCERT Exemplar]
(a) friction between the layers of newspaper produces heat
(b) air trapped between the layers of newspaper is a bad conductor of heat
(c) newspaper is a conductor of heat
(d) newspaper is at a higher temperature than the temperature of the surroundings
Answer:
(b) air trapped between the layers of newspaper is a bad conductor of heat

Question 3.
Heat always flows
(a) from a colder object to a hotter object
(b) from a hotter object to a colder object
(c) in both the directions
(d) None of the above
Answer:
(b) from a hotter object to a colder object

Question 4.
Paheli and Boojho measured their body temperature. Paheli found her to be 98.6°F and Boojho recorded 37°C. Which of the following statements is true?
(a) Paheli has a higher body temperature than Boojho.
(b) Paheli has a lower body temperature than Boojho.
(c) Both have normal body temperature.
(d) Both are suffering from fever.
Answer:
(c) These two temperatures are different scales but their actual values are equal.

Question 5.
Boojho has three thermometers as shown in figure. He wants to measure the temperature of his body and that of boiling water. Which thermometer(s) should he choose? [NCERT Exemplar]

(a) Thermometers (i) and (iii) for measuring body temperature and (ii) for measuring the temperature of boiling water
(b) Thermometer (i) for measuring temperature of both
(c) Thermometer (ii) for measuring temperature of both
(d) Thermometer (iii) for measuring temperature of both
Answer:
(a) Thermometers (i) and (iii) are clinical thermometer and (ii) is laboratory thermometer.

Question 6.
Four arrangements to measure temperature of ice in beaker with laboratory thermometer are shown in figure (a, b, c, d). Which one of them shows the correct arrangement for accurate measurement of temperature?

Answer:
(a) Thermometer (a) has been put in correct way to measure the temperature.

Question 7.

Figure (a, b, c, d) shows the reading of four different thermometers. Indicate which of the reading shows the normal human body temperature?

Answer:
(c) As we know that normal body temperature is 37°C. So, correct option is (c). .

Question 8.
Figure (a, b, c, d) shows a student reading of a doctor’s thermometer. Which of the figure indicates the correct method of reading temperature? [NCERT Exemplar]

Answer:
(a) In first case, eyes of student are in level of the thermometer, so it is correct way to measure temperature using clinical thermometer.

Fill in the Blanks

Question 1.
Temperature is the measure of …….. of an object.
Answer:
Fill in the Blanks
hotness

Question 2.
The thermometer used to measure human body temperature is called …….. thermometer.
Answer:
clinical

Question 3.
The normal temperature of human body is …….. °C.
Answer:
37

Question 4.
A …… near the bulb of a clinical thermometer prevents mercury level from falling of its own.
Answer:
kink

Question 5.
In ……. generally, the heat is transferred by the process of conduction.
Answer:
solids

Question 6.
The water and air are …… conductors of heat.
Answer:
poor

Question 7.
In coastal areas, cold air flows in the day from sea to land. It is called …….
Answer:
sea breeze

Question 8.
When we come out in the sun, we feel ……..
Answer:
warm

Question 9.
All hot bodies radiate ……..
Answer:
heat

Question 10.
Wool is a ……. conductor of heat.
Answer:
poor

True/False

Question 1.
Our sense of touch about hotness or coldness is not always reliable.
Answer:
True

Question 2.
Normal temperature of human body is 98.6°C.
Answer:
False, it is because the normal temperature of human body is 37°C.

Question 3.
In all cases, heat flows from a hotter object to a colder object.
Answer:
True

Question 4.
Water at higher temperature feels more hot.
Answer:
True

Question 5.
Marking on clinical thermometer is from 0°C to 100°C.
Answer:
False, it is because the markings on the clinical thermometer is from 35°C to 100°C.

Question 6.
Shining thread in thermometer is the column of mercury.
Answer:
True

Question 7.
The materials which allow heat to pass through them easily are called conductors.
Answer:
True

Question 8.
Water and air are good conductors of heat.
Answer:
False, it is because water and air are the poor conductors of heat.

Match the Columns

Question 1.
Match the Column I with Column II.

Column 1	Column II
(a) Conduction	(i) Wood, plastic, wool, air, water
(b) Convection	(ii) Requires no medium
(c) Radiation	(iii) Solids
(d) Conductors	(iv) Metals
(e)Insulators	(v) Liquids

Answer:
(a)-(ii). (b)-(v), (c)-(ii), (d)-(iv), (e)-(i)

Question 2.
Match the Column I with Column II.

Column 1	Column II
(a) Land breeze	(i) Night
(b) Sea breeze	(ii) A device to measure the degree of hotness
(c) Dark coloured surfaces	(iii) Poor absorbers of heat
(d) Light coloured surfaces	(iv) Good absorbers of heat
Thermometer	(v) Day time

Answers:
(a)-(i), (b)-(v), (c)-(iv), (d)-(iii), (e)-(ii)

Extra Questions for Class 7 Science

Nutrition in Animals Class 7 Extra Questions Science Chapter 2

Nutrition in Animals Class 7 Science Extra Questions Very Short Answer Type

Nutrition In Animals Class 7 Extra Questions And Answers Question 1.
What is the total number of teeth in an adult human?
Answer:
In an adult human, there are total 32 teeth.

Class 7 Science Chapter 2 Extra Questions Question 2.
Name the parts of the alimentary canal where
(a) water gets absorbed from undigested food
(b) digested food gets absorbed
(c) taste of the food is perceived
(d) bile juice is produced [NCERT Exemplar]
Answer:
(a) large intestine
(b) small intestine
(c) tongue
(d) liver

Ncert Solutions For Class 7 Science Chapter 2 Extra Questions Question 3.
Identify the location of salivary gland.
Answer:
Salivary gland is present in the buccal cavity and it secretes saliva.

Nutrition In Animals Class 7 Extra Questions With Answers Question 4.
You were blindfolded and asked to identify the drinks provided in two different glasses. You could identify drink A as lime juice and B as bitter gourd juice. How could you do it inspite of being blindfolded? [NCERT Exemplar; HOTS]
Answer:
Inspite of being blindfolded, one could identify two different drinks with the help of taste buds present in the tongue.

Class 7 Science Chapter 2 Extra Questions Answers Question 5.
We should not eat hurriedly. Give reason.
Answer:
We should not eat hurriedly because if we ingest food in hurry or we talk or laugh while eating we experience hiccups, coughing or choking sensation.

Class 7 Science Chapter 2 Extra Question Answer Question 6.
Name the secretions of stomach which digest food.
Answer:
The inner lining of stomach secretes mucous hydrochloric acid and digestive juices.

Class 7 Science Chapter 2 Important Questions Question 7.
Explain the role of mucus secreted by stomach.
Answer:
The function of mucus is to protect the lining of stomach from the action of hydrochloric acid secreted by stomach lining.

Class 7 Science Ch 2 Extra Questions Question 8.
The long structure of small intestine is accommodated in small space within our body. Comment. [HOTS]
Answer:
The small intestine is about 7.5 metre long It is accommodated in a coiled form inside our body.

Ncert Class 7 Science Chapter 2 Extra Questions Question 9.
Suggest the organ of digestive system where the digestive juices from liver and pancreas is poured.
Answer:
The digestive juices from liver and pancreas is poured into small intestine which helps in complete digestion and absorption of food.

Nutrition In Animals Class 7 Worksheet With Answers Question 10.
From which organ of digestive system, the undigested faecal matter is removed?
Answer:
The undigested faecal matter is removed through the anus by the process called egestion.

Nutrition In Animals Class 7 Questions And Answers Question 11.
Mention the position of the rumen in ruminants.
Answer:
The rumen is the sac-like structure which is present between small intestine and large intestine in ruminants.

Ch 2 Science Class 7 Extra Questions Question 12.
What is assimilation?
Answer:
The process by which absorbed food is taken by body cells and is used for energy, growth and repair is called assimilation.

Science Ch 2 Class 7 Extra Questions Question 13.
Describe alimentary canal briefly.
Answer:
Alimentary canal is the tube running from mouth to anus of human and animals here digestion and absorption of food take place.

Extra Questions For Class 7 Science Ch 2 Question 14.
Name the simple forms of carbohydrates, fats and proteins.
Answer:
The food components and their simple forms are carbohydrates (glucose), fatty (fats) acids and glycerol, proteins (amino acids).

Chapter 2 Science Class 7 Extra Questions Question 15.
Write the shape of stomach.
Answer:
The shape of stomach is like flattened U-shaped.

Class 7 Nutrition In Animals Extra Questions Question 16.
Discuss the role of hydrochloric acid secreted by gastric glands.
Answer:
It helps in the breakdown of food particles. It creates an acidic environment which facilitates the action

Nutrition in Animals Class 7 Science Extra Questions Short Answer Type

Question 1.
With the help of labelled diagram show the gradual decay of tooth.
Answer:
Sweets and Tooth Decay The tooth is covered by white, hard outer covering of tooth called Enamel enamel below which dentine is present. It is similar to bone which Pulp cavity (with nerves and blood vessels) protects the pulp cavity having nerves and blood vessels. Bacteria are Gum present in our mouth but they are not harmful to us. However, if we do not clean our teeth and mouth after eating, many harmful bacteria also begin to live and grow in it. These bacteria breakdown the sugars present from the leftover food and release acids. The acids gradually damage the tooth. This is called tooth decay.

Therefore, tooth decay is defined as the process of rotting of tooth and formation of cavity or holes in it which leads to the toothache.
When the holes or cavity reaches to the pulp cavity, it causes pain. If these cavities are not treated on time it causes severe toothache and may result in tooth loss.

Tooth decay can be prevented by adapting following measures.
(i) One should rinse and clean its teeth thoroughly after every Pulp cavity meal.
(ii) We should clean our teeth with the help of datun or brush Gradual decaying of human tooth and toothpaste, twice a day.
(iii) We should use dental floss which is a special strong thread. It is moved between two teeth to take out
trapped food particles.
(iv) Dirty fingers or unwashed objects must be avoided to put in the mouth.
(v) We should avoid the use of sweets, chocolates, toffees, ice-cream, etc. Much use of cold drink should also be avoided.”

Question 2.
Name the various components of food and their simpler forms.
Answer:
The various components of food and their simpler forms are

Components of food	Simpler form
Carbohydrate	Glucose
Fats	Fatty acids and glycerol
Proteins	Amino acids
Vitamins	Vitamins
Minerals and water	Minerals and water

Question 3.
‘A’ got her gall bladder removed surgically as she was diagnosed with stones in her gall bladder. After the surgery, she faced problems in digestion of certain food items when consumed in bulk. Can you tell which kind of food items would they be and why? [NCERT Exemplar; HOTS]
Answer:
After surgical removal of gall bladder, ‘A’ would face problems in digestion of fat and fatty substances when consumed in bulk. This is because the bile juice stored in the gall bladder helps in digestion of fats.

Question 4.
Discuss the various associated glands of digestive system and their role in digestion.
Answer:
The various associated glands of digestive system and their role in digestion are as follows

1. Salivary gland digestion of starch in mouth.
2. Liver secretes bile juices which help in the digestion of fats.
3. Pancreas secretes pancreatic juices which act on carbohydrate, fats and proteins and change them into simpler compounds.

Question 5.
Boojho took some grains of boiled rice in test tube ‘A’ and Paheli took boiled and chewed rice in test tube ‘S’. Both of them poured 1-2 drops of iodine solution into the test tube and observed the colour change. What colour change would they have observed? Give reasons for your Answer: [NCERT Exemplar; HOTS]
Answer:
In test tube A, blue black colour appeared because of presence of starch.
In test tube 6, colour of iodine will not change because of digestion of starch into sugars by the action of saliva in our mouth.

Question 6.
Mention the different steps of nutrition in animals.

Question 7.
List the preventive measures that one should adopt for avoiding tooth decay.
Answer:
Sweets and Tooth Decay The tooth is covered by white, hard outer covering of tooth called Enamel enamel below which dentine is present. It is similar to bone which Pulp cavity (with nerves and blood vessels) protects the pulp cavity having nerves and blood vessels. Bacteria are Gum present in our mouth but they are not harmful to us. However, if we do not clean our teeth and mouth after eating, many harmful bacteria also begin to live and grow in it. These bacteria breakdown the sugars present from the leftover food and release acids. The acids gradually damage the tooth. This is called tooth decay.

Therefore, tooth decay is defined as the process of rotting of tooth and formation of cavity or holes in it which leads to the toothache.
When the holes or cavity reaches to the pulp cavity, it causes pain. If these cavities are not treated on time it causes severe toothache and may result in tooth loss.

Tooth decay can be prevented by adapting following measures.
(i) One should rinse and clean its teeth thoroughly after every Pulp cavity meal.
(ii) We should clean our teeth with the help of datun or brush Gradual decaying of human tooth and toothpaste, twice a day.
(iii) We should use dental floss which is a special strong thread. It is moved between two teeth to take out
trapped food particles.
(iv) Dirty fingers or unwashed objects must be avoided to put in the mouth.
(v) We should avoid the use of sweets, chocolates, toffees, ice-cream, etc. Much use of cold drink should also be avoided.”

Question 8.
Write the difference between milk teeth and permanent teeth.
Answer:
The difference between milk teeth and permanent teeth are

Milk teeth	Permanent teeth
They grow during infancy, i.e. when one is small baby.	They grow at the age of 6-8 years.
They are also called as temporary teeth because these are lost at the age of 6-8 years.	They do not fall till the old age.
They can be replaced by permanent teeth.	If these teeth fall down no new teeth arises on its place.

Question 9.
Complete the following table, from the options given below:
(Scraping, chewing, siphoning, capturing and swallowing, sponging, sucking, etc.)

Name of animal	Kind of animal	Mode of feeding
Snail
Ant
Eagle
Humming bird
Lice
Mosquito
Butterfly
Housefly

Answer:
The complete table is

Name of animal	Kind of food	Mode of feeding
Snail	Leaves and insects	Scraping
Ant	Food particles	Chewing
Eagle	Small animals	Capturing and swallowing
Humming bird	Nectar of flower	Sucking
Lice	Blood	Sucking
Mosquito	Blood	Sucking
Butterfly	Nactar of flower	Siphoning
Housefly	All most everything	Sponging

Question 10.
Briefly describe the mechanism of producing hiccups while we take food in hurry.

Question 11.
Boojho and Paheli were eating their food hurriedly so that they could go out and play during the recess. Suddenly, Boojho started coughing violently. Think of the reasons, why he was coughing and discuss with your friends?
[NCERT Exemplar; HOTS]
Answer:
Sometimes when we eat hurriedly, talks or laughs while eating, the flap-like valve (called epiglottis) which closes the passage of windpipe remains open. Therefore, the food may enter into the windpipe. Coughing helps to clear the passage and returns the food particle back to the foodpipe.

Question 12.
Gastric glands in stomach release hydrochloric acid, enzyme pepsin and mucus. What will happen if mucus is not secreted by the gastric glands?
Answer:
Mucus protects the inner lining of stomach form the action of hydrochloric acid and enzyme pepsin. If mucus is not released, it will lead to erosion of inner lining of stomach leading to acidity and ulcers.

Question 13.
Choose the odd one out from each group and give reasons.
(a) liver, salivary gland, starch, gall bladder
(b) stomach, liver, pancreas, salivary gland
(c) tongue, absorption, taste, swallow
(d) oesophagus, small intestine, large intestine, rectum [NCERT Exemplar]
Answer:
(a) Starch, because rest all are glands and starch is a type of carbohydrate.
(b) Stomach, because rest all are digestive glands and stomach is a digestive organ.
(c) Tongue, because rest all are digestive processes and tongue is a part of digestive system.
(d) Small intestine, because it carriers the process of digestion and rest are not involved in digestion.

Question 14.
Following statements describe the five steps in animal nutrition. Read each statement and give one word for each statement. Write the terms that describe each process.
(a) Transportation of absorbed food to different parts of body and their utilisation.
(b) Breaking of complex food substances into simpler and soluble substances.
(c) Removal of undigested and unabsorbed solid residues of food from the body.
(d) Taking food into the body.
(e) Transport of digested and soluble food from the intestine to blood vessels.[NCERT Exemplar]
Answer:
(a) Assimilation
(b) Digestion
(c) Egestion
(d) Ingestion
(e) Absorption

Question 15.
Small intestine in herbivores is longer than in carnivores. Do you agree? Support your Answer:
Answer:
Yes, carnivores animals cannot digest cellulose, hence they have a shorter small intestine. In herbivores, digestion of cellulose takes a longer time. Hence, herbivores need a longer small intestine to allow complete digestion of cellulose.

Question 16.
Draw a neat and clean diagram of Amoeba showing the correct location of the following components : nucleus, vacuole, pseudopodia.
Answer:

Question 17.
Draw the labelled diagram of tongue showing different region for taste buds.
Answer:
Refer to figure on page 17.

Question 18.
Ruminants such as cows and buffaloes swallow their food hurriedly and then sit restfully and chew their food. Give reason. [NCERT Examplar; HOTS]
Answer:
Ruminants such as cows and buffaloes swallow their food hurriedly and store it in a part of the stomach called rumen. The cellulose of the food is digested here by the action of certain bacteria which are not present in humans. Later, this partially digested food is returned to the buccal cavity of the animals in small lumps and animal chews it to complete the process of digestion. This process is called rumination.

Question 19.
Discuss the position and number of molars in buccal cavity.
Answer:
Molars are very large teeth which are present behind the premolar, towards the back of our mouth. They are only present in the permanent set of teeth and are 6 in each jaw.

Question 20.
Name the three digestive glands in our body.
Answer:
The three digestive glands are

1. liver
2. Pancreas
3. Salivary glands

Question 21.
The swallowed food moves downwards in the alimentary canal. Explain.
Answer:
The swallowed food moves downwards in the alimentary canal because of the atternate relaxation contraction movement of muscles in the wall of foodpipe called peristalsis.

Question 22.
Explain how assimilation is different from absorption.
Answer:
The process by which nutrients from the digested food are absorbed by the body is called absorption whereas the process by which the absorbed nutrients are utilised by the body for providing energy is called assimilation.

Question 23.
Food moves in the opposite direction during vomiting. How?
Answer:
The intense pressure is formed in the stomach when the food is not accepted by the stomach. The content in the stomach is then pushed back. This returned content is expelled out from the mouth in the form of vomiting.

Question 24.
Briefly explain, why animals like cow cannot chew their food properly at the time they take it in.
Answer:
Animals like cow cannot chew their food properly due to the presence of cellulose in their diet. At the time they take in food, the food is moistend and is sent for cellulose digestion and softening in rumen.

Question 25.
Is there any role of liver in digestion of fats? Explain.
Answer:
Yes, liver produces bile which has bile salts. These salts break large fat molecules to fine droplets. These fine droplets are further converted into fatty acids and glycerol.

Question 26.
Cellulose rich food substances are good source of roughage in human beings. Justify. [HOTS]
Answer:
Cellulose rich food substances are good source of roughage in human beings. It is because the cellulose digesting bacteria are not present in the body of human beings due to which human beings cannot digest cellulose (present in plant foods).

Question 27.
Recall and name the main organs of the digestive system in our body.
Answer:
The different organs of the alimentary canal are as follows :

1. Mouth and mouth cavity
2. Oesophagus
3. Stomach
4. Small intestine
5. Large intestine
6. Anus

Question 28.
Alimentary canal is different from digestive system. Comment.
Answer:
Alimentary canal is a long, muscular coiled tube. It is also known as digestive tract. The alimentary canal with its associated glands constitute the digestive system. These glands are salivary glands, liver and pancreas.

Question 29.
Windpipe runs adjacent to the foodpipe. What will happen if food particles enter the windpipe? Explain.
Answer:
The windpipe carries air from the nostrils to the lungs. It runs adjacent to the foodpipe. If, by chance, food particles enter the windpipe, we feel choked, get hiccups or cough.

Question 30.
Explain how is small intestine designed to absorb digested food.
Answer:
The finger-like projections called villi are present in the inner walls of the small intestine. The villi increase the surface area. The large surface area of small intestine helps in the rapid absorption of the digested food.

Nutrition in Animals Class 7 Science Extra Questions Long Answer Type

Question 1.
Label the given figure as directed below in A to D and give the name of each type of teeth.
(a) The cutting and biting teeth as A
(b) The piercing and tearing teeth as B
(c) The grinding and chewing teeth as C
(d) The grinding teeth present only in adult as D

Answer:

Question 2.
Briefly describe the process of digestion in Amoeba with the help of labelled diagram. [NCERT Examplar]
Answer:
Feeding and Digestion in Amoeba

Amoeba is a microscopic single celled organism, which is found in pond water. It is a very simple animal and cannot be seen by naked eyes. Amoeba has a cell membrane, a rounded dense nucleus and many small bubble-like vacuoles in its cytoplasm. These vacuoles are of two types, i.e. food vacuole and contractile vacuole. Food vacuole contains food surrounded by water while contractile vacuole contains liquid or water and controls water regulation activity in Amoeba. Its shape is not fixed, i.e. it constantly changes its shape and position. The body of Amoeba has finger-like projections, called pseudopodia or false feet. It captures food and helps in locomotion of Amoeba.

The food of Amoeba are microscopic organisms like tiny plants and animals present in pond water. When Amoeba senses its food, it pushes out pseudopodia around the food particle and engulfs it. The two pseudopodia join around the food particle and trap the food particle with a little water forming vacuole around food, thus the food gets trapped. Digestive juices present inside the vacuole, acts on the food and break it into simpler substances. This digested food is then absorbed and is used for growth, maintenance and multiplication of Amoeba. The undigested food residue is expelled outside by the vacuole. The basic process of digestion of food and release of energy is as similar to the other organisms.

Question 3.
Label the following parts of above figure and name them.
(a) The largest gland in our body.
(b) The organ where protein digestion starts.
(c) The organ that releases digestive juice into the small intestine.
(d) The organ where bile juice gets stored. [NCERT Examplar]

Answer:

Question 4.
Little Rishi (student of class VI) was watching his favourite cartoon serial on television. Suddenly he got hiccups. His elder brother Shubham who was sitting near by him gave him a glass of water and suggested not to eat too fast in a hurry. Little Rishi got confused as he had heard that ‘hicki’ comes when someone remembers. He asked his father. His father smiled and explained him that it is only a myth. He also explained him the proper scientific reason behind it.
(a) What is hiccup?
(b) Why do we get hiccup?
(c) What are the values shown by Rishi? [Value Based Question]
Answer:
(a) Hiccup is a choking sensation that produces a characteristic gulping sound repeatedly. It is called ‘hicki’ in our local language.
(b) Sometimes, when we eat too fast in a hurry or talk too much or laugh while eating, then a little of windpipe remains open due to which food particles may enter the windpipe. It may result in a choking sensation called hiccups.
(c) He is sincere and curious to know about the things at an early age.

Question 5.
Jaya returned from school and found that grandmother was scolding her maid, Rani as she did not come yesterday. The maid told that his son was passing watery stools frequently that’s why she didn’t come. Jaya’s mother who was listening the discussion came to them and told Rani not to come for coming 3-4 days. She also suggested her to give his son a solution of sugar and salt in clean water, many times a day for fast recovery. Jaya was surprised. She rushed to her mother and asked the scientific reason for it. Her mother smiled and explained her the importance of this solution.
(a) Name the term used to describe the condition in which a person passes out watery stools.
(b) Name the solution of sugar and salt in water. Why is it given to a person suffering from diarrhoea?
(c) What are the values shown by Jaya? [Value Based Question]
Answer:
(a) Diarrhoea.
(b) Oral Rehydration Solution (ORS). It is given to a person suffering from diarrhoea to prevent the dehydration.
(c) She is sincere, curious and has interest in science.

Question 6.
Read the following passage carefully and answer the questions that follow it.
Bile juice is stored in a sac called, gall bladder, located near its organ of secretion, liver. The gall bladder releases the bile juice into the small intestine whenever food reaches there. Though bile juice is devoid of any digestive enzymes, it is required for the digestion of fats. The fats cannot be digested easily because they are insoluble in water and are present as large globules. Bile juice breaks down big fat droplets into smaller droplets. These are then easily digested by the enzymes released from the pancreas
(a) Which organ secretes the bile juice?
(b) Why is digestion of fats difficult as compared to that of other nutrients?
(c) How does bile juice help in digestion of that of other nutrients?
(d) Where is the digestion of fat completed?
(e) Does bile juice digest fat completely? [NCERT Exemplar]
Answer:
(a) Bile juice is secreted by liver.
(b) Digestion of fats is difficult as compared to that of other nutrients because of insolubility of fat in water.
(c) Bile juice helps in digestion of fat by breaking down big fat droplets into smaller droplet.
(d) Digestion of fat is completed in small intestine.
(e) No, fat is not completely digested by bile juice.

Question 7.
Define oral rehydration solution and when it is given to the patient? How can you prepare ORS at home?
Answer:
Oral rehydration solution is the solution of sugar and salt in a particular ratio in the clean water. When a person passes out watery stools frequently, the disease is called diarrhoea. In this condition there is a loss of water and salt from the body of a person.

This is called dehydration which may be fatal if not cured at proper time. In order to prevent dehydration, the person or patient should be given ORS. ORS makes up the loss of water and salts in the body and sugar provides energy which helps in the recovery of disease. It should be given to a patient suffering from diarrhoea at a regular interval.

At home the ORS can be prepared by dissolving a teaspoonful of sugar and pinch of salt in a glass of clean water. The water used for preparing ORS should be first boiled and then cooled so that all the microorganisms or harmful bacteria may be killed.

Question 8.
Open your mouth, look into a mirror and try to count the different types of teeth of teeth in your mouth. Compare them with figure 2.3 on page 13 of your NCERT textbook. Record your observations in the table below: [NCERT Exemplar]

Type of teeth	Number of teeth
	In my mouth	In the figure
Incisors
Canines
Premolars
Molars

(a) Did you observe any difference in the number of teeth? If yes, could you identify which type of teeth showed the difference?
(b) Compare the number and type of teeth in an adult (say your parents or cousins who have reached the age of 25-30 or more). Note your observation.
Answer:

Type of teeth	Number of teeth
	In my mouth	In the figure
Incisors	4	4
Canines	8	8
Premolars	8	8
Molars	8	12

(a) Yes, the difference has been observed in the number of molars.
(b) The number and type of teeth varries in an adult as compared to the child. Children have 28 teeth in their mouth.There are only four molars in each jaw.
While, adults have 32 teeth in their mouth which means six molars in each jaw.

Question 9.
Explain how the digestion of cellulose occurs in grass eating animals.
Answer:
Digestion in Grass-Eating Animals

The herbivorous animals such as cow, buffaloes, etc eat grass. These animals quickly swallow the grass and store it in a part of stomach called rumen. The food is not chewed completely. Rumen possess cellulose digesting bacteria which breakdown the food by fermentation. This partially digested food or grass present in the rumen of cow is called cud.

This cud is brought back into the mouth of the cow from the rumen into small lumps and animal chews it again. This process is called rumination and animals are called ruminants.
When this cud is thoroughly chewed in the mouth of the cow, it is swallowed again. This time the chewed cud does not go back to rumen but enter into the other compartments of cow’s stomach and then into the small intestine for complete digestion and absorption of food. The cellulose digesting bacteria are not present in the body of human being, therefore human beings and other carnivore cannot digest cellulose present in plant food items.

Nutrition in Animals Class 7 Science Extra Questions Miscellaneous

Multiple Choice Questions

Question 1.
Hydrochloric acid is secreted by
(a) linings of small intestine
(b) inner lining of stomach
(c) pancreas
(d) lining of liver
Answer:
(b) inner lining of stomach

Question 2.
Which of the following pair of teeth differ in structure but are similar in function? [NCERT Exemplar]
(a) Canines and incisors
(b) Molars and premolars
(c) Incisors and molars
(d) Premolars and canines
Answer:
(b) Molars and premolars

Question 3.
The swallowed food moves downwards in the alimentary canal because of [NCERT Exemplar]
(a) force provided by the muscular tongue
(b) the flow of water taken with the food
(c) gravitational pull
(d) the contraction of muscles in the wall of foodpipe
Answer:
(d) the contraction of muscles in the wall of foodpipe

Question 4.
The acid present in the stomach
(a) kills the harmful bacteria that may enter along with the food
(b) protects the stomach lining from harmful substances
(c) digests starch into simpler sugars
(d) makes the medium alkaline
Answer:
(a) kills the harmful bacteria that may enter along with the food

Question 5.
The simplest form of protein is
(a) fatty acids
(b) glucose
(c) glycerol
(d) amino acids
Answer:
(d) amino acids

Question 6.
The finger-like outgrowths of Amoeba helps to ingest food. However, the finger-like outgrowths of human intestine helps to [NCERT Exemplar]
(a) digest the fatty food substances
(b) make the food soluble
(c) absorb the digested food
(d) absorb the undigested food
Answer:
(c) absorb the digested food

Question 7.
The false feet of Amoeba are used for [NCERT Exemplar]
(a) movement only
(b) capture of food only
(c) capture of food and movement
(d) exchange of gases only
Answer:
(c) capture of food and movement

Question 8.
Read the following statements with reference to the villi of small intestine.
(i) They have very thin walls.
(ii) They have a network of thin and small blood vessels close to the surface.
(iii) They have small pores through which food can easily pass.
(iv) They are finger-like projections.
Identify those statements which enable the villi to absorb digested food.
(a) (i), (ii) and (iv)
(b) (ii), (iii) and (iv)
(c) (iii) and (iv)
(d) (i) and (iv)
Answer:
(c) (iii) and (iv)

Question 9.
The absorption of nutrients or food components in its simpler form takes place in
(a) blood vessels of small intestine wall
(b) large intestine wall
(c) gall bladder
(d) liver
Answer:
(a) blood vessels of small intestine wall

Question 10.
The enzymes present in the saliva convert [NCERT Exemplar]
(a) fats into fatty acids and glycerol
(b) starch into simple sugars
(c) proteins into amino acids
(d) complex sugars into simple sugars
Answer:
(b) starch into simple sugars

Question 11.
Cud is the name given to the food of ruminants which is [NCERT Exemplar]
(a) swallowed and undigested
(b) swallowed and partially digested
(c) properly chewed and partially digested
(d) properly chewed and completely digested
Answer:
(b) swallowed and partially digested

Question 12.
Cellulose rich food substances are good sources of roughage in human beings because [NCERT Exemplar]
(a) human beings do not have cellulose: digesting enzymes
(b) cellulose gets absorbed in the human blood and converts into fibres
(c) the cellulose digesting bacteria convert cellulose into fibres
(d) cellulose breaks down into smaller components which are egested as roughage
Answer:
(a) human beings do not have cellulose: digesting enzymes

Question 13.
If, by chance, food particles enter the windpipe, we feel
(a) hiccups and cough
(b) yawning
(c) sleep
(d) None of these
Answer:
(a) hiccups and cough

Question 14.
The tip or front of tongue taste
(a) sour
(b) bitter
(c) salt and sweet
(d) All of these
Answer:
(c) salt and sweet

Question 15.
Dentine protects which part of human teeth?
(a) Enamel
(b) Pulp cavity
(c) Gums
(d) Dental cavity
Answer:
(b) Pulp cavity

Question 16.
The finger-like projection presents on the inner lining of small intestine is called
(a) villi
(b) stomach
(c) rumen
(d) diarrhoea
Answer:
(a) villi

Fill in the Blanks

Question 1.
……. is the process of taking food inside the body.
Answer:
Ingestion

Question 2.
….. is the simplest form of carbohydrate.
Answer:
Glucose

Question 3.
The process of breakdown of complex food material into …… is called …….
Answer:
simpler form, digestion

Question 4.
Amoeba digests its food inside ………
Answer:
food vacuole

Question 5.
……. teeth replaces the milk teeth.
Answer:
Permanent

Question 6.
…… is the long tube-like structure which
Answer:
Alimentary canal

Question 7.
Large intestine absorbs ….. and …… from undigested food.
Answer:
water, salts

Question 8.
Animals are …….
Answer:
heterotrophic

Question 9.
Cud chewing animals are called ……..
Answer:
ruminants

Question 10.
Four kinds of teeth present in human are ……, …….., …….. and ……..
Answer:
incisor, cannines, premolar, molar

True/False

Question 1.
Oesophagus is also called as foodpipe.
Answer:
True

Question 2.
Simplest form of fat is sugars and glucose.
Answer:
False, simplest form of fat is fatty acid and glycerol.

Question 3.
Ruminant can digest cellulose (carbohydrate).
Answer:
True

Question 4.
Canines are used for grinding of food.
Answer:
False, canines are used for piercing and tearing the food.

Question 5.
Amoeba is a microscopic, single celled animal.
Answer:
True

Question 6.
The nutrition in Amoeba takes place by pseudopodia.
Answer:
True

Question 7.
Egestion is the process of removing waste food or undigested food through anus.
Answer:
True

Question 8.
Diarrhoea can be treated by only giving water to the patient.
Answer:
False, diarrhoea can be treated by giving a solution of sugar and salt in the clean water for several times in a day. This solution is called ORS.

Question 9.
Source of energy for living being is food.
Answer:
True

Question 10.
The digestion of starch only takes place in the stomach
Answer:
False, digestion of starch normally begins in the mouth where it is broken down into smaller sugar molecules, glucose. Additional breakdown of starch occurs in the small intestine.

Match the Columns

Question 1.
Match the Column I with Column II. [NCERT Examplar]

Column 1	Column II
(a) Rectum	(i) Mucus
(b) Gallbladder	(ii) Villi
(c) Stomach	(iii) Taste buds
(d) Tongue	(iv)Faecus
(e) Small intestine	(v) Bile juice

Answers:
(a)-(v), (b)-(vi), (c)-(i), (d)-(vii), (e)-(ii), (f)-(iv), (g)-(iii)

Question 2.
Match the Column I with Column II.

Column 1	Column II
(a) Amoeba	(i) ORS
(b) Incisors	(ii) Bile juice storage
(c) Diarrhoea	(iii) Release of faecus
(d) Fat	(iv) Cud chewing animals
(e) Gall bladder	(v) Pseudopodia
(f) Ruminants	(vi) Cutting and biting
(g) Anus	(vi) Fatty Acid and Glycerol

Answers:
(a)-(iii), (b)-(i), (c)-(iv), (d)-(ii)

Extra Questions for Class 7 Science

Nutrition in Plants Class 7 Extra Questions Science Chapter 1

Nutrition in Plants Class 7 Science Extra Questions Very Short Answer Type

Class 7 Science Chapter 1 Extra Question Answer Question 1.
Potato and ginger are both underground parts that store food. Where is the food prepared in these plants? [NCERT Exemplar]
Anwer:
In both the plants, shoot system and leaves are above ground. They prepare food through photosynthesis and transport it to the underground part for storage.

Nutrition In Plants Class 7 Extra Questions With Answers Question 2.
Plants prepare their food using a different mode of nutrition than us. What is it?
Answer:
The mode of nutrition in plant is autotrophic, i.e. they synthesise their own food.

Class 7 Science Chapter 1 Extra Questions Question 3.
Photosynthesis requires chlorophyll and a few other raw materials. Add the missing raw materials to the list given below:
Water, minerals, (a) …… (b) …….
Answer:
(a) Sunlight
(b) Carbon dioxide

Ncert Solutions For Class 7 Science Chapter 1 Extra Questions Question 4.
The tiny openings present on the leaf surface. What are they called?
Answer:
Stomata are the tiny pores present on the surface of leaves through which gaseous exchange takes place in plants.

Nutrition In Plants For Class 7 Questions With Answers Question 5.
What is the function of guard cells of stomata?
Answer:
Guard cells help in controlling the opening and closing of stomata for gaseous exchange.

Nutrition In Plants For Class 7 Worksheet With Answers Question 6.
Which parts of the plant are called food factories of the plant?
Answer:
Leaves are referred to as food factories of plants. This is because, leaves synthesise food by the process of photosynthesis.

Ncert Class 7 Science Chapter 1 Extra Questions Question 7.
A carbohydrate is produced by plants as food source. It is constituted from which molecules?
Answer:
Carbohydrates are composed of carbon, hydrogen and oxygen.

Class 7 Science Ch 1 Extra Questions Question 8.
Why do some plants feed on insects?
Answer:
Insectivorous plants grow in soil which lack nitrogen, therefore they eat insects to fulfill their need of nitrogen.

Chapter 1 Science Class 7 Extra Questions Question 9.
Define parasites.
Answer:
Parasites they are those organisms which grow on other plants or animals for their food, e.g. Cuscuta.

Nutrition In Plants Class 7 Questions And Answers Question 10.
Name the bacteria that can fix atmospheric nitrogen.
Answer:
Rhizobium is the bacterium which can fix atmospheric nitrogen.

Science Class 7 Chapter 1 Extra Questions Question 11.
Except plants, why can’t other living organisms prepare their food using CO₂, water and minerals? [HOTS]
Answer:
Our body does not contain chlorophyll for absorbing solar energy which is necessary for preparing food using air, water, etc.

Nutrition In Plants For Class 7 Notes Questions And Answers Question 12.
A leguminous plant can restore the soil’s concentration of mineral nutrients. Can you give examples of some such plants?
Answer:
Plants such as gram, pulses and beans are leguminous.

Extra Questions For Class 7 Science Nutrition In Plants Question 13.
Algae are green in colour. Why?
Answer:
Algae contain chlorophyll which imparts green colour to them.

Class 7th Science Chapter 1 Extra Questions Question 14.
what do you understand by nutrition?
Answer:
The process of utilising nutrients like carbohydrates, proteins, fats, etc., to generate energy is called nutrition.

Ch 1 Science Class 7 Extra Questions Question 15.
Fungus can be harmful and useful. Give an example showing both of these traits of fungus.
Answer:
Fungus produces antibiotics like penicillin used to treat diseases and fungus can also harm us by causing fungal infections on skin and hair.

Extra Questions For Class 7 Science Chapter 1 Question 16.
A unique feature in leaves allows them to prepare the food while other parts of plants cannot. Write the possible reason for this. [HOTS]
Answer:
Leaves contain chlorophyll which is essential for food preparation and is absent in other parts of plant.

Class 7 Chapter 1 Science Extra Questions Question 17.
Algae and fungi form a unique association sharing benefits from each other. What is the name of association between them?
Answer:
Lichens.

Class 7 Nutrition In Plants Extra Questions Question 18.
In a plant, photosynthesis occurs in a part other than leaf. Name that plant and the part where photosynthesis occurs.
Answer:
Cactus, the part where photosynthesis occurs are stem and branches which are green.

Nutrition In Plants Question Answer Question 19.
Why is Cuscuta, categorised as a parasite?
Answer:
Cuscuta derives its nutrition using an association where it deprives its host of all valuable nutrients and absorbs them itself. Hence, it is called a parasitic plant.

Extra Questions Of Chapter Nutrition In Plants Class 7 Question 20.
Plant cannot use the nitrogen present in the soil directly. Why?
Answer:
Plants can use nitrogen only in soluble form while in soil nitrogen is present in inorganic form.

Question 21.
Why are insectivorous plants called partial heterotrophs?
Answer:
Insectivorous plants are autotrophs, i.e. they prepare their own food. They are partial heterotrophs as they eat insects for obtaining nitrogen.

Question 22.
What is the stored food form in sunflower seeds?
Answer:
In sunflower seeds, glucose is stored in the form of oils (fats).

Question 23.
What do you understand by saprotrophic mode of nutrition?
Answer:
The mode of nutrition in which organisms take their nutrients from dead and decaying matter is called saprotrophic mode of nutrition.

Question 24.
A mutually beneficial relationship that occurs between two plants. It is known by what name? Give an example.
Answer:
Symbiosis is the mutually benefitting association between two plants, e.g. lichens.

Question 25.
For testing the presence of starch in leaves, a boiled leaf is used. Why?
Answer:
Boiling the leaf remove chlorophyll/green colour from the leaves.

Question 26.
Mosquitoes, bed bugs, lice and leeches suck our blood. Can they be called as parasites? [HOTS]
Answer:
Yes, these animals/insects are parasites as they harm the hosts while they suck blood.

Question 27.
Insectivorous plants have one or the other specialised organs to catch their prey. What is that organ?
Answer:
Leaves of insectivorous plants catches the prey.

Question 28.
Farmers spread manure of fertilisers in the field or in gardens, etc. Why are these added to the soil?
Answer:
Plants absorb mineral nutrients from soil. Thus, declining their concentration in soil fertilisers and manures enhance or add these essential nutrients back in soil.

Question 29.
A cell is formed of many sub-components. Identify different constituents of the cell. Are animal and plant cells similar?
Answer:
A cell contains nucleus, cytoplasm, vacuole, cell organelles like chloroplast, mitochondria, etc. No, animal cells are different from plant cells.

Question 30.
A goat eats away all the leaves of a small plant (balsam). However, in a few days, new leaves could be seen sprouting in the plant again. How did the plant survive without leaves? [NCERT Exemplar; HOTS]
Answer:
The plant of balsam survived on the food stored in the stem and roots.

Nutrition in Plants Class 7 Science Extra Questions Short Answer Type

Question 1.
Different modes of nutrition has been observed in plants. What are they? Give example of each.
Answer:
Plants show two major modes of nutrition, i.e.
(i) Autotrophs are those which can synthesise their own food.
(ii) Heterotrophs are those which are dependent on other plants and animals for their food. They are of following types:
(a) Parasites, e.g. Cuscuta
(b) Saprotrophs, e.g. fungi.

Question 2.
Sunlight, chlorophyll, carbon dioxide, water and minerals are raw materials essential for photosynthesis. Do you know where they are available? Fill in the blanks with the appropriate raw materials.
(a) Available in the plant: ………
(b) Available in the soil: ………
(c) Available in the air: ………
(d) Available during day : ……… [NCERT Exemplar]
Answer:
(a) Available in the plant: chlorophyll
(b) Available in the soil : water, minerals
(c) Available in the air : carbon dioxide
(d) Available during day : sunlight

Question 3.
Plants are considered an essential part of earth as they keep a check on lot of process occurring all over. What would happen if all the green plants are wiped from earth? [HOTS]
Answer:
Green plants are the source of energy for all the living organisms so that they can perform their normal functions. If all green plants and trees disappear, all the organism depending on them for food and shelter will also die.

The lack of gaseous exchange will lead to increase in amount of CO₂, causing death in humans and other animals also. The cycle of life will gradually disappear.

Question 4.
Autotrophs and heterotrophs are two different organisms with distinct modes of nutrition state. How are they different from each other?
Answer:
The difference between autotrophs and heterotrophs are as follows:

Autotrophs	Heterotrophs
They can prepare their own food.	They cannot prepare their own food.
Autotrophs take simple inorganic substances and change it into complex organic food, e.g. green plants.	They take in complex food and breakdown it into simple compounds, e.g. all animals, fungi and non-green plants.

Question 5.
Wheat dough if left in the open, after a few days, starts to emit a foul smell and becomes unfit for use. Give reason. [NCERT Exemplar; HOTS]
Answer:
Carbohydrates in wheat dough encourage the growth of yeast and other saprophytic fungi which breakdown carbohydrates into simpler compounds like CO₂ and alcohol and emit a foul smell.

Question 6.
What are the various raw materials for photosynthesis?
Answer:
Plants utilise carbon dioxide from air and water and minerals are derived from soil (through roots) as raw material for photosynthesis. Besides these chlorophyll present in green leaf is necessary for the process and sunlight is the source of energy which is converted into chemical energy during the process of photosynthesis.

Question 7.
Observe the given figure and label the following terms given in the box. Stomatal opening, guard cell

Answer:
Labelled figure is given below:

Question 8.
Nitrogen is an essential nutrient for plants growth. But farmers who cultivate pulses as crops like green gram, bengal gram, black gram, etc., do not apply nitrogenous fertilisers during t cultivation. Why? [NCERT Exemplar; HOTS]
Answer:
Roots of pulses (leguminous plants) have a symbiotic association with a bacterium called Rhizobium. This bacteria convert gaseous nitrogen of air into water soluble nitrogen compounds and give them to the leguminous plants for their growth. Hence, farmers need not use nitrogenous fertilisers.

Question 9.
Pooja is worried about her new shoes which she wore on special occassions that they were spoiled by fungus during rainy season. Is she right to worry, if yes, then tell why does fungi suddenly appears during the rainy season? [HOTS]
Answer:
Yes, the fungi reproduces by spores which are generally present in the air and grow on any article that are left in hot and humid weather for a long time. During rainy season they land on wet and warm things and begin to germinate and grow.

Question 10.
In what unique manner does a pitcher plant derive its nutrition?
Answer:
Nepenthes or pitcher plant modifies its leaf axis into a long tubular pitcher to form a pitfall trap. Inside the pitcher sticky liquid is present. When any insect comes in contact with the leaf, the lid present on it is closed and insect is trapped. The liquid contains digestive enzymes which slowly digest the trapped insects.

Question 11.
Water and minerals are absorbed by the roots and then transported to leaves. How?
Answer:
Water and minerals are transported to the leaves by the vessels which run like pipes throughout the root, stem, branches and the leaves. These vessels are xylem and phloem, forming a continuous path or passage for the nutrients to make them reach the leaf.

Question 12.
Some plants have deep red, violet or brown coloured leaves. Can these leaves perform the photosynthesis process? [HOTS]
Answer:
Yes, plants having deep red, violet or brown coloured leaves can also carry out photosynthesis because they contain chlorophyll. But their green colour of chlorophyll is masked by the large amount of all other coloured pigments.

Question 13.
If plant has a requirement for nitrogen, then from where will they obtain it?
Answer:
Soil contains nitrogen in the form that is not usable by plants. Bacteria like Rhizobium converts nitrogen into soluble form that can be easily used by plants. So, if plant has a requirement for nitrogen, then it will obtain that which the help of bacteria.

Question 14.
In the absence of photosynthesis, life would be impossible on earth. Is it true or false?
Answer:
True, because photosynthesis is important for the existence of life on the earth. Photosynthesis is important process as it is provides food to all living organisms and maintains CO₂ – O₂ balance of nature.

Nutrition in Plants Class 7 Science Extra Questions Long Answer Type

Question 1.
Describe the process by which plants prepare their food using different raw materials.
Answer:
The process by which green plants can prepare their own food is called photosynthesis. Green plants possess chlorophyll in their leaf and utilises carbon dioxide (from air) water, minerals (from soil, through root) as raw material and sunlight as source of energy and convert light energy into chemical energy. The food thus synthesised is in the form of starch (carbohydrate). The overall reaction for photosynthesis can be given as follows:

Question 2.
Describe the method for replinishing the soils with minerals and other essential constituents used by plants growing in those soil by farmers.
Answer:
Replenishment of Nutrients in Soil

Crops require a lot of nitrogen to make proteins. After the harvest, the soil becomes deficient in nitrogen. Plants cannot use the nitrogen gas available in atmosphere directly. Action of certain bacteria can convert this nitrogen into form readily used by plants. Rhizobium bacteria live in the root nodules of leguminous plants. These bacteria take nitrogen gas from the atmosphere and convert it into water soluble nitrogen compounds making it available to the leguminous plants for their growth.

In return, leguminous plants provide food and shelter to the bacteria as Rhizobium cannot prepare its food. They, thus have a symbiotic relationship. This association is very important for the farmers, as they do not need to add nitrogen fertilisers to the soil in which leguminous plants are grown.

Question 3.
Harish went to visit his grandfather in village where he saw that his grandfather’s field of wheat are infected with fungus but no one is aware of this. Harish rushed to his grandfather’s side and told him that the field have been infected with fungi. He should use an antifungal agent in his fields to stop this infection.
(a) What is fungus?
(b) Can fungus only cause diseases or can it be helpful also?
(c) What values are shown by Harish? [Value Based Question]
Answer:
(a) Fungus are saprophytic organisms usually present as spores in atmosphere which can germinate on any substrate in optimal conditions.
(b) Fungus are also useful in that they produce many antibiotics which can cure different types of infections like penicillin.
(c) Harish is sincere, curious and knowledgeable with a keen sense of applying it where necessary.

Question 4.
Wild animals like tiger, wolf, lion and leopard do not eat plants. Does this mean that they can survive without plants? Can you provide a suitable explanation? [HOTS]
Answer:
Animals like tiger, wolf, lion and leopard are carnivores and do not eat plants. They hunt and eat herbivorous animals like deer, gaur, bison, zebra, giraffe, etc., which are dependent on plants for food.

If there are no plants, herbivorous animals will not survive and ultimately animals like tiger, wolf, lion and leopard will have nothing to eat.

Question 5.
Asha went to visit her grandfather in his village. He was having a serious discussion with his fellow members regarding the productivity level of crops for present year. They all were worried about how to increase the productivity of crop Asha listened to this and then suggested to the group that the reason may be decreased level of minerals in soil.
She told her grandfather to plant crops like pulses, gram, beans, etc., for a year then follow with regular crops. This will increase the crop productivity?
(a) What will you name the process suggested by Asha? Why is there decrease in crop productivity?
(b) What are noted benefits of this process? Will the results be as what Asha expressed?
(c) What values are shown by Asha? [Value Based Question]
Answer:
(a) This process is known as crop rotation. All the plants/crops grown in soil use the minerals present in soil for their own use. This continuous usage depletes the concentration of mineral in soil.
(b) After growing leguminous plants, the mineral content of soil is restored and enriched to new level. Yes, the benefit of leguminous plant is the re-enrichment of soil minerals.
(c) Asha is observant, sincere and interested in applying her knowledge to situations.

Nutrition in Plants Class 7 Science Extra Questions Miscellaneous

Multiple Choice Questions

Question 1.
Organisms which prepare food for themselves using simple naturally available raw materials are referred to as [NCERT Exemplar]
(a) heterotrophs
(b) autotrophs
(c) parasites
(d) saprophytes
Answer:
(b) autotrophs

Question 2.
In the process of photosynthesis, which of the following energy conversions occur?
(a) Solar energy is changed into chemical energy.
(b) Solar energy is changed into mechanical energy.
(c) Bioenergy is converted into chemical energy.
(d) Chemical energy is changed into light energy.
Answer:
(a) Solar energy is changed into chemical energy.

Question 3.
The raw material used by plants during photosynthesis
(a) N₂ and O₂
(b) O₂, H₂ and CO₂
(c) CO₂ and water
(d) water and minerals
Answer:
(c) CO₂ and water

Question 4.
Which of the following statements is/are correct?
(i) All green plants can prepare their own food.
(ii) Most animals are autotrophs.
(iii) Carbon dioxide is not required for photosynthesis.
(iv) Oxygen is liberated during photosynthesis.
choose the correct answer from the options below: [NCERT Examplar]
(a) (i) and (iv)
(b) only (ii)
(c) (ii) and (iii)
(d) (i) and (ii)
Answer:
(a)  (i) and (iv) are correct statements and (ii) and (iii) are incorrect. Because (ii) animals are heterotrophs and (iii) CO₂ is necessary for photosynthesis. Green plants prepare their own food from CO₂ and H₂O.

Question 5.
The symbiotic association is seen in which of the following?
(a) Lichens
(b) Algae
(c) Fungi
(d) Bacteria
Answer:
(a) Lichens

Question 6.
Pitcher plant traps insects because it
(a) is a heterotroph
(b) grows in soils which lack in nitrogen
(c) does not have chlorophyll
(d) has a digestive system like human beings
Answer:
(b) grows in soils which lack in nitrogen

Question 7.
Insectivorous plant among the following is
(a) lichen
(b) Cuscuta
(c) pitcher plant
(d) bread mould
Answer:
(c) pitcher plant

Question 8.
In the plant of cactus leaves are modified into
(a) branches
(b) spines
(c) leaf vein
(d) pitcher
Answer:
(b) spines

Question 9.
If iodine is dropped on the boiled leaf it gives blue-black colour due to the presence of
(a) starch
(b) protein
(c) fat
(d) vitamin
Answer:
(a) starch

Question 10.
When we observe the lower surface of a leaf through a magnifying lens, we see numerous small openings. Which of the following is the term given to such openings
(a) Stomata
(b) Lamina
(c) Midrib
(d) Veins
Answer:
(a) Stomata

Question 11.
Two organisms are good friends and live together. One provide? shelter, water and nutrients while the other prepares and provides food. Such an association of organisms is termed as
(a) saprophyte
(b) parasite
(c) autotroph
(d) symbiosis
Answer:
(d) symbiosis

Question 12.
In the process of photosynthesis, plants
(a) take O₂ and release CO₂
(b) take CO₂ and release O₂
(c) take and release O₂
(d) take O₂ and release water
Answer:
(b) take CO₂ and release O₂

Question 13.
Which of the following raw material is available in the air for photosynthesis? [NCERT Exemplar]
(a) Oxygen
(b) Carbon dioxide
(c) Nitrogen
(d) Hydrogen
Answer:
(b) Carbon dioxide

Question 14.
The ultimate source of food on earth is
(a) plants
(b) sunlight
(c) animals
(d) proteins
Answer:
(a) plants

Question 15.
Farmers use manure and fertilisers to
(a) replenish plant
(b) replenish soil
(c) replenish air
(d) replenish fungi
Answer:
(b) replenish soil

Fill in the Blanks

Question 1.
The association where two participating plants mutually benefit each other is called …….
Answer:
symbiosis

Question 2.
……. plants derive their nutrient from dead and decaying animals or plants.
Answer:
Saprophytic

Question 3.
The openings present on the surface of leaves are protected by cells called …….
Answer:
guard cells

Question 4.
Leaves are called the ……. of plants.
Answer:
food factory

Question 5.
All green plants possess ……. in their leaves.
Answer:
chlorophyll

Question 6.
Cuscuta is a ……. plant.
Answer:
parasitic

Question 7.
The plants that provide nutrition to the parasitic plant are called …….
Answer:
host

True/False

Question 1.
Food is necessary for plants only.
Answer:
False, food is necessary for all the living organisms as all of them grow and require maintenance from time to time

Question 2.
Animals are heterotrophs.
Answer:
True

Question 3.
Cells are called building block of a body.
Answer:
True

Question 4.
Chlorophyll is present in an animal cell.
Answer:
False, chlorophyll is present in leaf of plants not in animal cells.

Question 5.
Fungi are green plants that can synthesise their own food.
Answer:
False, fungi are not green and they are not classified as plants. They are saprophytic organisms which derive nutrition from dead and decaying matter.

Question 6.
Pitcher plant eats insects.
Answer:
True

Question 7.
Lichen is a saprophytic plant.
Answer:
False, lichen is a symbiotic association between an alga and a fungi. It is not a plant.

Question 8.
Rhizobium can fix atmospheric nitrogen into nitrogen compound.
Answer:
True

Match the Columns

Question 1.
Match the Column I with Column II.

Answers:
1. (a) – (iv), (b) – (iii), (c) – (v), (d) – (vii), (e) – (i), (f) – (x), (g) – (ii), (h) – (vi), (i) – (viii), (j) – (ix)

Extra Questions for Class 7 Science