AP Board 7th Class Science Solutions 3rd Lesson Nutrition in Organisms

SCERT AP 7th Class Science Study Material Pdf 3rd Lesson Nutrition in Organisms Textbook Questions and Answers.

AP State Syllabus 7th Class Science 3rd Lesson Questions and Answers Nutrition in Organisms

7th Class Science 3rd Lesson Nutrition in Organisms Textbook Questions and Answers

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I. Fill in the blanks.

1. During photosynthesis ________ gas is released.
2. The tiny pores present on the surface of the leaves are __________
3. ____________ is the outermost layer of teeth.
Answer:
1. oxygen
2. stomata
3. Enamel

II. Choose the correct answer.

1. Muscular tubular structure that connects pharynx with Stomach
a) Duodenum
b) Buccal cavity
c) Oesophagus
d) Rectum
Answer:
c) Oesophagus

2. Non insectivorous plant,
a) Drosera
b) Nepenthes
c) Utricularia
d) Dodder
Answer:
d) Dodder

3. The green colour pigment in the leaf
a) chloroplast
b) stomata
c) chlorophyll
d) all the above
Answer:
c) chlorophyll

III. Matching

A) Autotrophs	1. Mushroom
B) Saprophytes	2. Mango plant
C) Parasite	3. Food vacuole
D) Holozoic	4. Intestinal worms
E) Amoeba	5. Man
	6. Egestion

Answer:

A) Autotrophs	2. Mango plant
B) Saprophytes	1. Mushroom
C) Parasite	4. Intestinal worms
D) Holozoic	5. Man
E) Amoeba	3. Food vacuole

IV. Answer the following questions.

Question 1.
Distinguish between autotrophic and heterotrophic nutrition.
Answer:

Autotrophic nutrition	Heterotrophic nutrition
1. The mode of nutrition in which organisms make food by them selves is called autotrophic nutrition	1. The mode of nutrition in which organisms depend on other organisms for food is called Heterotrophic nutrition
2. Organisms that perform autotro phic nutrition are called autotrophs.	2. Organisms that perform heterotrophic nutrition are called heterotrophs.
3. They need carbon dioxide, water and sunlight to prepare their own food.	3. They don’t need these materials as they feed on other organisms for food.
4. They are green in colour due to the presence of a colouring pigment called chlorophyll.	4. They don’t have chlorophyll.
5. Ex: Plants	5. Ex: Animals

Question 2.
What is Photosynthesis? Write its word equation.
Answer:
The process by which green plants make their own food from carbon dioxide and water by using light energy in the presence of chlorophyll is called Photosynthesis.

Question 3.
Describe different types of teeth and their functions.
Answer:
There are four different types of teeth in our human beings.

1. Incisors :
The four front teeth in both the upper and lower jaws are called incisors. Thus there are eight incisors in the oral cavity. They have sharp incisal edge. Their primary function is to cut food.

2. Canines :
They are behind and adjacent to the lateral incisors on both the jaws. There are four canines in the oral cavity. They have single sharpcusp. Their main function is to tear food.

3. Premolars :
These teeth are located behind and adjacent to the canines. There are two premolars on the upper jaw and also two premolars on the lower jaw on either side of the mouth. Thus there are eight premolars in the oral cavity.These teeth can have 3-4 cusps. They are designed to crush food.

4. Molars :
The most posterior teeth in the mouth are the molars. There are 12 molars in the permanent dentition.They have broader and flatter surfaces with 4-5 cusps. They are designed to grind food.

Question 4.
What happens if leaves of a green plant are coated with green paint?
Answer:

1. If the leaves of a green plant are coated with green paint, then stomata present on the surface of the leaf will get blocked.
2. As a result exchange of gases will be affected.
3. So, plant may not get sufficient amount of carbon dioxide for photosynthesis and oxygen for respiration.
4. oreover, paint over the leaf prevents the reaching of sunlight to the leaf.
5. As a result plant will not be able to perform photosynthesis and respiration, gradually it leads to its death.

Question 5.
What questions will you ask a doctor to know about gastritis?
Answer:

1. What is gastritis?
2. What are the reasons for gastritis?
3. How can it be prevented?
4. Is there any relation between gastritis and life style?
5. Are there any home remedies to get relief from gastritis?
6. What is the treatment for gastritis?

Question 6.
How can you prove that the leaves other than green also carry out photo synthesis? (Activity – 2)
Answer:
Aim: To know whether leaves other than green perform photosynthesis or not.

What you need:
Red or brown coloured leaves, dropper; test tube, iodine solution, water.

What to do:
Take few Red or brown coloured leaves, add few drops of water and mash them to make a paste, collect the extract by squeezing the paste (pulp). Take 5-6 drops of this extract into a test tube. Also add two drops of iodine solution. Note your observations.

What do you see:
The colour of the leaf extract turns blue black.

What do you learn:
This shows the presence of starch in the leaves, confirming that red or brown coloured leaves also perform photosynthesis.

These non-green leaves also have chlorophyll. The large amount of red, brown and other pigments mask the green colour. So photosynthesis takes place in these leaves also.

Question 7.
Draw a neat labelled diagram of human digestive system.
Answer:

Question 8.
Draw a flow chart showing nutrition in amoeba.
Answer:

Question 9.
How will you appreciate the role of saprophytes in cleaning of the earth surface?
Answer:

1. Saprophytes grow on dead and decaying matter.
2. They secrete digestive juices on it, convert it into a solution and then absorb the nutrients from it.
3. During this process they decompose them and mix them with the soil.
4. In this Way they help in cleaning the earth surface by removing the dead and decaying matter.
5. This process help in recycling the nutrients too.
6. Thus they are doing a great service to the entire living world.

Question 10.
What precautions will you take to keep your digestive system healthy?
Answer:
To keep my digestive system healthy, I will

1. take simple and balanced diet
2. drink sufficient quantity of water.
3. brush my teeth regularly.
4. prefer natural foods.
5. avoid Junk foods and cool drinks.
6. never smoke.
7. never consume alcohol.
8. never chew tobacco and tobacco products.
9. do moderate exercises regularly.
10. take fibre rich food.

7th Class Science 3rd Lesson Nutrition in Organisms InText Questions and Answers

7th Class Science Textbook Page No. 37

Question 1.
My mother prepares food for me. Who prepares food for animals?
Answer:

1. Animals cannot make food.
2. They depend on other plants and animals for food.

Question 2.
How do animals get their food?
Answer:
Animals get their food from plants and animals.

Question 3.
Plant is a living thing. What is the food for it?
Answer:
Plants also need food, such as glucose, carbohydrates, minerals etc.

Question 4.
How do they get their food?
Answer:

1. Plants prepare their food by using photosynthesis.
2. Some plants get their food from other plants and animals.

Question 5.
What is the food for mushrooms?
Answer:
Mushrooms get their food from dead and decaying matter.

Question 6.
Even you might have got the same doubts?
Answer:
Yes.

Question 7.
Is the nutrition in plants same as in animals?
Answer:
No.

Question 8.
We eat food daily. But plants are not eating food then how are they living?
Answer:
Plants are able to live as they make their food themselves.

7th Class Science Textbook Page No. 38

Question 9.
How can the green plants prepare their own food?
Answer:
Green plants make their own food from carbon dioxide and water by using light energy in the presence of chlorophyll. This process is called photosynthesis.

7th Class Science Textbook Page No. 39

Question 10.
In which part of the plant, does photosynthesis takes place?
Answer:
The synthesis of food occurs in all green parts of plant body. For Ex : leaves.

Question 11.
How do the raw materials required for photosynthesis reach there?
Answer:

1. Plants get carbon dioxide from air through stomata in leaves.
2. Water obsorbed by the roots are transported to the leaves through the stem.
3. Chlorophyll captures the energy of the sunlight.

Question 12.
Do they perform photosynthesis?
Answer:
Yes, the plants with red and brown coloured leaves make their food in the process of photosynthesis.

7th Class Science Textbook Page No. 40

Question 13.
What is the importance of sunlight in photosynthesis?
Answer:

1. Sunlight is the source of energy in the process of photosynthesis.
2. The solar energy is captured by the leaves and stored in the plant in the form of food.
3. If there is no sunlight starch cannot be prepared in plants.

Question 14.
Plants get water from the soil through their roots. How does this water reach the leaves from the roots? What path does it follow?
Answer:

1. Water absorbed by the roots are transported to the leaves through the stem.
2. It follows the path from roots to leaves via stem.

7th Class Science Textbook Page No. 41

Question 15.
How do carbondioxide enters the leaves?
Answer:
Carbondioxide from air is entered the leaves through stomata which are present in the surface of the leaf.

Question 16.
How do oxygen comes out of the leaves?
Answer:
Through the stomata, oxygen produced in photosynthesis goes out of the leaves.

Question 17.
Where do these substances (starch, fats and proteins) come from?
Answer:
Plants produce sugar first, which is converted to starch and then other compounds like fats and proteins.

7th Class Science Textbook Page No. 42

Question 18.
There are some plants which do not have chlorophyll. How do they get their food?
Answer:

1. Organisms which do not have chlorophyll, cannot synthesis their food. They are heterotrophs.
2. Heterotrophic nutrition is of different types basing on how they obtain their food from other organisms.
3. Some plants depends on dead and decaying matter and some on other plants.

Question 19.
How do they (mushrooms) get their food?
Answer:

1. Mushrooms grow on dead and decaying matter.
2. They secrete digestive juices on it convert it into a solution and then absorb the nutrients from it.
3. This type of nutrition is called saprophytic nutrition.

Question 20.
A rat died at Pullaiah’s house. What happens to the body after few days? Do you find any traces of its body after a month? Where did that body go?
Answer:

1. Saprotrophs like fungi and bacteria will grow on the dead body of the rat, after a few days.
2. We cannot find any traces (except strong bones) of the dead body of rat, after a month.
3. The decomposed body of the rat is mixed with the soil.

Question 21.
How does Cuscuta survive? From where does it get nutrition?
Answer:

1. Cuscuta take readymade food from the plant on which it is climbing.
2. It develops special roots called haustoria, which penetrate into the tissues of the host plant and absorb food materials from them.

7th Class Science Textbook Page No. 43

Question 22.
How do animals take their food?
Answer:

1. Animals obtain their food from other organisms.
   Ex : Cow eats grass, cat drinks milk, dog eats meat.
2. They take the food in the form of solid or liquid.

Question 23.
Where do they digest it?
Answer:

1. Animals take food into the body for digestion.
2. Digestion occurs inside the body.

7th Class Science Textbook Page No. 44

Question 24.
What do you understand from Sabiha observations?
Answer:
Holozoic nutrition is the mode of heterotrophic nutrition in which the food is taken in solid or liquid form from the outside and is digested inside the body.

Question 25.
How do Amoeba takes its food?
Answer:

1. Amoeba has many small bubbles – like vacuoles in its cytoplasm.
2. Amoeba pushes out one or more finger – like projections called pseudopodia for movement and capture of food.
3. Food vacuole forms around the captured food.
4. Food get digested in it, absorbed into the cytoplasm and assimilates.
5. Finally, undigested food is sent out by opening this vacuole out at the body surface.

Question 26.
Is the nutrition in human beings also holozoic?
Answer:
Yes. The nutrition in human beings also holozoic.

7th Class Science Textbook Page No. 45

Question 27.
Have you ever wondered what happens to the food inside the body?
Answer:
Seeing the food that went into the body being digested, I was very surprised.

Question 28.
Do you have any structures like vacuole in our body?
Answer:
No.

Question 29.
Where do the food eaten by us go?
Answer:

1. We take food in the form of solids or liquids.
2. It goes to the digestive system, which is consisting of the alimentary canal and digestive glands.
3. Food get’s digested in the digestive system.
4. Digested food is absorbed by the blood.
5. Blood transports digestive food to different parts of the body for assimilation.
6. Undigested food will be ejected out of the body.

Question 30.
What change does the food undergo inside the mouth?
Answer:

1. We chew the food with the teeth and break it down mechanically into small pieces.
2. Carbohydrates are digested in the mouth.
3. Food also mixed with saliva and thrown into the stomach.

7th Class Science Textbook Page No. 46

Question 31.
How many kinds of teeth could you find?
Answer:
Four types of teeth.

Question 32.
Which teeth do you use for biting and cutting and which one for tearing?
Answer:

1. Teeth which are located at front side of the mouth are used for biting and cutting. (These are called incisors.)
2. Canines are used for tearing, which are located behind incisors.

Question 33.
Have you noticed formation of new teeth in the mouth of small children? Do all the teeth, wfiich sprouted first, remain forever?
Answer:

1. Yes. f have noticed that the formation of new teeth in the mouth of small children.
2. The teeth which sprouted first do not remain forever.

Question 34.
Do you know how does tooth decay happens?
Answer:
When food remains stuck in teeth, bacteria feed on them. As a result, lactic acid is produced, which causes the destruction of enamel and it leaves toothache.

7th Class Science Textbook Page No. 47

Question 35.
How does acid come into contact with teeth?
Answer:
When food remains stuck in teeth, bacteria feed on them. Bacteria produce lactic acid. This acid come to contact with teeth.

Question 36.
Do you now realise the importance of cleaning your teeth after food?
Answer:
Yes. It is very important. If we do not clean odr teeth properly after food, some food material will stuck in between teeth and causes tooth decay.

Think & Respond

7th Class Science Textbook Page No. 39

Question 1.
Testing tiie starch in the leaf directly with iodine had certain problems. To obtain results successfully think and discuss regarding this with your teacher.
Answer:

1. Leaves are green in colour.
2. When iodine solution is put on a leaf, it should turn blue if starch is present.
3. However, the green colour of the leaf disguises the blue colour.
4. More over cuticle present on the leaf hardly allows the iodine to reach he starch present in side the leaf.

7th Class Science Textbook Page No. 47

Question 2.
Which habit should be practised for the health of teeth? Why?
Answer:

1. Brush teeth twice a day with fluoride tooth paste.
2. Use dental floss to clean between your teeth.
3. Change your tooth brush every 3 months.
4. Cut down on how often you have sugary foods like chocolates, sweets and cool drinks. Visit dentist regularly.

The above habits should practise for healthy teeth. Because, if we do not clean our teeth and mouth after eating, many harmful bacteria begin to live and grow in mouth. These bacteria breakdown the sugars present from left over food and release acids. These acids gradually damage teeth and causes severe toothache.

Activities and Projects

Question 1.
Designer leaves making select any broad-leaved potte d plant. Cut a card board with a design of your choice and seal the selected leaf with the card board. Let the plant stand under the sun for a week then remove the card board. You will get designer leaves plant. Try to make more leaves with designs and display your plant but don’t forget to present your writeup.
Answer:

I have selected a potted plant with broad leaves.

I cut a design of my name first letter on a card board.

I sealed the selected leaf with the card board.

I kept this plant under the sun for a week.

Then I remove card board.

I surprised to see the design of my name first letter on the leaf.

Question 2.
Collect small plants, or the branches or other parts of big plants from your locality and classify them into autotrophs, parasites, saprophytes and symbionts. With the help of your teacher, preserve them in the form of specimens in the biology laboratory of your school.
Answer:
I have collected the following plants and classified them in to following categories.

Autotrophs:
Neem, mango, hibiscus, Paddy

Parasites:
Cuscuta, loranthus.

Saprophytes:
Mush rooms, Moulds Symbionts: Red gram, beans,

I preserved these specimens in the biology laboratory of our school.

Activities

Activity – 1

Question 1.
Fill the following table basing on your own observations and information collected from elders.

Answer:

Name of the organism	Prepare own food/ Depend on other organisms for food	Inference (Autotroph/ Heterotroph)
1. Mango tree	Prepares own food	Autotroph
2. Cat	Depends on other organisms	Heterotroph
3. Rose plant	Prepares own food	Autotroph
4. Mushroom	Depends on other organisms	Heterotroph
5. Leech	Depends on other organisms	Heterotroph
6. Goat	Depends on other organisms	Heterotroph
7. Human beings	Depends on other organisms	Heterotroph

→ Are all plants Autotrophs?
Answer:
No.

→ What kind of nutrition is seen in mushrooms?
Answer:
Heterotrophic nutrition (Saphrophytic).

→ What kind of nutrition is seen in animals?
Answer:
Heterotrophic (Parasitic, Holozoic).

7th Class Science Textbook Page No : 38 (Autotrophic Nutrition – Photosynthesis)

Question 2.
Anu said plants also prepare their food same as we prepare boiled rice.
Comparative table prepared by her was given below. Study the table and answer the questions.

	Preparation of Boiled Rice	Preparation of food by green plants
Raw materials	Rice, Water	Carbon dioxide, water
Source of energy	Fire from stove	Sunlight
Happens in	Vessel/cooker	Chloroplast in green parts
Finally forms	Boiled rice	Glucose/Carbohydrates

→ What are the raw materials required for the preparation of food by green plants?
Answer:
Carbondioxide, water.

→ Which gas is taken by plants during this process?
Answer:
Carbondioxide.

→ Name the food material formed in plants?
Answer:
Glucose / Carbohydrates.

→ What do you conclude from the above information?
Answer:
Plants prepare their own food.

Activity – 3

Question 3.
How do you prove that the sunlight is essential for photosynthesis?
Answer:
Aim: To know the importance of light in photosynthesis.

What you need :
Two potted plants, dropper, test tube, iodine solution, water.

What to do:
Take two potted plants of the same kind. Keep one in the dark (or in a black box) for 72 hours and the other in the sunlight. Perform iodine test with the Leaf extracts of both the plants as you did in activity-2. Note your observations.

What do you see :
The colour of the leaf extract of first plant does not change. The colour of the leaf extract of second plant turns blue black.

What do you learn :
This shows the presence of starch in the leaves of plant kept in the sunlight indicating the occurrence of photosynthesis. There is no starch in the leaves of the plant kept in the dark. This confirms that sunlight is essential for photosynthesis.

Activity – 4

Question 4.
How do you conduct an activity to show the saprotrophic nutrition in bread moulds?
Answer:
Aim:
To observe the saprotrophic nutrition ih bread mould.

What you need:
Piece of bread, water, a container and a hand lens.

What to do:
Take a piece of Bread, in a container. Sprinkle some water and close the container. Open the container after few days and observe. (Use mask and gloves while doing this activity).

What do you see:
You will see cotton-like threads spread on the piece of bread and bread size is decreased.

What do you learn:
These thread-like structures are some sort of plants called Fungi. They don’t have chlorophyll so they obtain their food from dead and decaying matter.

Activity – 5

Question 5.
Wash your hands. Look into the mirror and count your teeth. Use your index finger to feel the teeth. How many kinds of teeth could you find? Take a piece of an apple, sugar cane or bread and eat it. Which teeth do you use for biting and cutting and which one for tearing?

Also find out the ones that are used for chewing and grinding? Compare your observations with the given picture and fill the table.

(Note: The picture of teeth on lower jaw was given here. The number and type of teeth on the upper jaw is same as on the lower jaw.)

→ What do you find?
Answer:
I found different types of teeth in my mouth.

→ How many teeth do you have? Is it equal to the number given in the picture?
Answer:
I have 28 teeth. No, in the figure there are 32 teeth. But 1 have only 28 teeth.

→ Which teeth are absent?
Answer:
I have no (wisdom teeth). 4 molars are absent in my mouth.

Activity – 6

Question 6.
How does acid damage our teeth? Prove with an activity.
Answer:
Aim : To know the process of tooth decay.

What you need :
Marbles, dilute hydrochloric acid and test tube.

What to do:
Put a few small pieces of marble in dilute hydrochloric acid. Examine after awhile.

What do you see :
Acid reacts with marble and dissolves it.

What do you learn :
The enamel, which is a calcium compound, reacts with acid and gets destroyed in the same way a marble reacts with hydrochloric acid.

When food remains stuck in teeth, bacteria feed on them. As a result, lactic acid is produced, which causes the destruction of enamel.