LESSON: NUTRITION IN PLANTS - Eureka plus 7th science Solution
I. 1. a saprophyte 2. autotrophic 3. chlorophyll 4. starch 5. photosynthesis 6. fix nitrogen
II. 1. X 2. X 3. ✓ 4. X 5. X 6. X
III. 1. The process by which an organism obtains substances that provide energy, help in growth and maintain the body is called nutrition.
2. No. Birds are heterotrophs.
3. Living organisms that feed on other living organisms are known as heterotrophs.
4. Fungi are saprophytes.
5. Chloroplasts contain the green pigment called chlorophyll.
6. Yes. The leaves of plants such as crotons appear red because the green chlorophyll in such plants is masked by a red pigment.
7. Oxygen is produced during the process of photosynthesis.
8. Rhizobium bacteria live in the roots of plants such as beans, peas and grams.
9. Mistletoe is a 'Partial parasitic plant.
10. Food made by the leaves is transported to all parts of the plants through phloem tubes.
IV. 1. Autotrophs: Autotrophs are the organisms that make their own food by using simple substances from their surroundings. Examples: most plants, unicellular algae and some bacteria.
Heterotrophs: All organisms that obtain nutrition by feeding on other living organisms are called heterotrophic organisms. Examples: animals
2. Carbon dioxide + Water--- ---> Glucose (sugar) + Oxygen.
3. Total parasitic plants : Plants that do not have chlorophyll and obtain food and water from other plants are called total parasitic plants. For example, Cuscuta plant.
Partial parasitic plants : They grow on trees such as mango and teak. They have chlorophyll and makes some of their food, but depend on the host plant for water and certain nutrients. For example, Mistletoe plant.
4. Growing a crop such as beans, after growing a crop such as wheat, in order to increase the fertility of the soil is called rotation of crops.
5. Some plants depend on other plants for food and water. Such plants are called parasitic plants. For example, Cuscuta.
6. Lichens are formed by the association of an alga and a fungus, and sometimes a photosynthesising bacterium. The organisms help each other to live.
VI 1. Leaves help a plant to make its food by a process called photosynthesis. During photosynthesis, light energy is converted into chemical energy. In this process, water and carbon dioxide combine to form sugar and oxygen.
2. The saprophyte (fungus) grows on organic matter. It secretes digestive juices which break down organic matter into simple substances and convert it into a solution. The saprophyte absorbs the solution and obtains nutrition.
3. The roots of bean plants contain certain bacteria called Rhizobium. These bacteria convert nitrogen gas from air into water-soluble nitrogenous substances, which are used by the plants to make proteins.
4. Parasitic plants depend on other living plants for food and water. A parasitic plant damages the host plant. Saprophytes are organisms that obtain nutrition from dead organic matter.
5. Boil some water in a container and place a leaf in it for about 3 minutes.
Remove the leaf from the boiling water and place it in a test tube and pour enough alcohol (ethanol or rectified spirit) to cover the leaf.
Place the test tube in boiling water and let the alcohol boil.
Stop boiling the alcohol when the leaf has turned completely colourless.
Wash the leaf with tap water. Lay the leaf on a clean dish and pour some dilute iodine solution on it.
A bluish colour will develop on the leaf. Iodine reacts with starch to give a bluish colour. This proves that starch is present in the leaves.
6. Chlorophyll is the green pigment present in the chloroplasts of leaves. They trap energy from sunlight and use it to make food for the plant. Some plants have leaves that do not appear green. These leaves also have chlorophyll. The chlorophyll in such leaves is masked by pigments of different colors.
Higher Order Thinking Skills
1. The leaf is exposed to sunlight.
2. The chlorophyll in the leaf cells absorbs the sunlight.
3. Air enters the stomata and carbon dioxide is taken into the leaf cells.
4. Energy-rich sugar molecules are formed.
5. Oxygen is formed and released through the stomata. 6. Excess sugar is converted to starch.
LESSON 2-NUTRITION IN ANIMALS
1. small, Simple molecules 2. Small intestine 3.Amylase
4. Fatty Acid 5.Only Fats 6. Carbon dioxide, water, energy
7. Cellular respiration 8. Amino acids
II. 1.e, 2.d 3.a 4.b, 5.c
III 1. Pancreatic juice 2. Blood 3. Amylase 4. Liver 5. Glands in the inner walls of the stomach
6. Amino acids 7. Mucus 8. Pancreas
IV. 1, Digestion is the process through which the body converts useful substances in the food into simple substances. It takes place with the help of certain enzymes secreted by various organs of the digestive system.
2. Organs of the human digestive system are mouth, oesophagus, stomach, liver, pancreas, small intestine and large intestine.
3. Incisors are the four front teeth which are used to bite or cut food into smaller pieces. The canines are the tearing teeth present, one each on either side of the incisors, on each jaw.
4. Saliva is a digestive juice. It contains amylase that breaks down carbohydrates into sugar.
5. The inner walls of the small intestine have finger-like projections called villi. These villi are richly supplied with blood vessels. They increase the surface area for absorption of useful substances.
6. Complex fat molecules present in the food items such as butter, oil, milk and meat are broken into simple fatty acids in the small intestine.
V. 1. Food items such as wheat, potato and rice contain a carbohydrate called starch. A starch molecule is made up of several hundred glucose molecules linked together. It is a very large molecule and therefore the body cannot use it. The amylase secreted by the saliva in the mouth starts breaking down the carbohydrates. The pancreatic juice helps in further breaking down of carbohydrates into simple glucose molecules in the small intestine. The body uses glucose to obtain energy.
2. Proteins present in food items such as pulses, milk, meat and fish are complex substances. Each protein molecule is made up of many small amino acid molecules. The digestion of proteins starts in the stomach where the digestive juice called pepsin is present. The digestion of proteins is completed in the small intestine where the pancreatic juice breaks down proteins into amino acids. The body uses amino acids to grow and repair injured tissue.
3. The blood carries the glucose obtained from the digested food to every cell of the body. The glucose is broken down inside the cell in the presence of oxygen. During this process, the chemical energy present in the glucose is released along with carbon dioxide and water. This process is known as cellular respiration. This is how cells obtain energy and use it to perform different functions.
4. Ruminants have a four-chambered stomach. The first chamber is called the rumen. These herbivores eat quickly and store large amounts of grass in the rumen which contains millions of microbes and a large amount of saliva. The microbes begin to break down the food in the rumen. The animal now regurgitates the contents of the rumen back into the mouth several times to chew on it. The additional chewing helps in breaking down the cellulose contents further. From the rumen, the contents pass into the other two chambers before it reaches the fourth chamber. In these chambers, the hydrochloric acid and the gastric juices digest the proteins.
5. Amoeba lives in freshwater puddles and ponds and feeds mostly on remains of plants.
Nutrition in Amoeba involves the following:
• Ingestion: Amoeba senses a food particle, moves towards it and engulfs it.
Digestion: A food vacuole is formed around the engulfed food particle containing digestive juices, which break down the food particle into simple substances.
Assimilation: Amoeba uses these substances.
Egestion: The undigested portion is removed from the body.
Higher Order Thinking Skills
I. 1.The carbohydrate in the chapati is broken down into sugar by the saliva. Hence it tastes sweet when chewed for a long time.
2. Digestion is completed in small intestine, and the absorption of the nutrients by the blood vessels happens here. Therefore, smal intestine is richly supplied with blood vessels.
3. Vegetables and fruits contain a lot of fibre. This helps in moving the undigested food to the anus. Thus it cleans the digestive system. |
4. Mammals such as whales have teeth which help in biting and chewing their food. These animals are called fitter feeders as they have to strain their food from water.
II. 1.The moth feeds on nectar from flowers.
2. ‘No, the moth may collect nectar from different types of flowers.
3. The moth has a straw-like mouth part that helps in sucking nectar.
4. Bees and butterflies have similar straw-like mouth parts to suck nectar from flowers.
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Class7 Chapter 03. Plants fiber and fabric
A Tick the correct options:
1. Which of the following is not a natural fibre?
(a) cotton (b) rayon √ (c) silk (d) wool
2. Lohi is the breed of
(a) cow (b) silk moth (c) sheep √ (d) buffalo
4. Sheep are sheared in season
(a) summer √ (b) spring (c) autumn Ö (d) winter
3. How many weeks are required for the eggs of silk moth to hatch? See book
(a) one (b) two √ (c) three (d) four
6. Which of the following silk is produced when raw silk is twisted?
(a) spun (b) coloured (c) thrown √ (d) mooga
5. What do we call the silky covering spun by the silkworm for its protection?
(a) moth (b) larvae (c) pupa (d) cocoon√
B. Fill in the blanks:
1. Alpaca is generally found in South America.
2. Silk and wool fibres are obtained from animals.
3. Silk is obtained from cocoons of silkworm.
4. Natural fibres are obtained from plants and animals.
6. The fewer the burrs, the better is the wool.
7. The eggs are warmed to a suitable temperature in an oven
8. During the period of spinning of its cocoon, a silkworm is transformed into Pupa.
C. State whether the following statements are True (T) or False (F).
Rewrite the false statements correctly:
1. Silk is obtained from cocoons of silkworms. (T)
2. The process of washing the fleece of sheep to remove dust, dirt, sweat and grease is
called shearing. False Scouring.
3. The rearing of silkworms for obtaining silk is called sericulture. T
4. The damaged or waste cocoons are used to produce raw silk. F Spun silk
D. Very Short Answer Questions:
1. What is the process of removing the burrs from fleece called?
2. Name any two breeds of sheep found in India.
Ans. Merino ,Lohi
3. Name the process of removing hair from the body of a sheep.
4. Name the sheep which is found in Gujarat and whose wool is used in hosiery.
6. Which country leads the world in silk production?
5. What is the process of taking out threads from the cocoon called?
Ans. reeling the silk
7. Name two wool-yielding animals.
Ans. Sheep, goat, yak and camel.
E. Short Answer Type-I Questions:
1. What is meant by rearing of sheep?
Ans. The raising and breeding of domestic sheep is called rearing of sheep.
Sheep are raised principally for their meat (lamb and mutton), milk (sheep's milk), and
2. What is throwing?
Ans. Throwing is the process of twisting and doubling the single raw silk fibres into
usable thread after reeling and cleaning.
3. Why does shearing not hurt the sheep?
Ans. Shearing doesn't usually hurt a sheep. It's just like getting a haircut.
4. What is meant by scouring?
Ans. The sheared skin with hair is thoroughly washed in tanks to remove grease, dust
and dirt. This is called scouring.
5. What is cocoon?
Ans. A cocoon is a soft covering that an insect spin with silky thread to protect itself.
F. Short Answer Type-| Questions:
1. What is meant by selective breeding? What is its purpose?
Ans. Selective breeding is a kind of artificial selection in which two different kind of
breed are crossed to develop new organisms with desirable characteristics. For example
native breeds (female) crossed with exotic breed (male).
2. What is silk? How do we get silk from cocoon?
Ans. Silk is a kind of animal which are soft and lustrous.
The cocoons are kept under the sun or boiled or exposed to steam. The silk fibres
3. (a) What are raw silk and spun silk?
(b) On burning silk, it gives out the smell of burning hair. Give reason.
Ans. (a) Silk fibre obtain from cocoon and twisted to make stronger thread is called raw
silk. Silk fibre obtain from damaged cocoon is called spun silk.
(b) On burning silk gives out the smell of burning hair as it is made up of protein
4. With the help of a flow chart only, describe the life cycle of a silkworm.
5. (a) What is sorter's disease?
Ans. People working in wool industry sometimes they get infected by a bacterium called
anthrax, which causes a fatal blood disease called sorter’s disease
(b) Name two Indian breeds of sheep and also mention the quality of wool produced.
Ans. (i) Deccani sheep breed - low grade fibres, mostly used for the manufacturing rough
(ii) Gaddi Sheep Breed - wool is fine and lustrous and it is used for manufacturing of
high quality kulu shawls and blankets.
6. (a) Why do wool yielding animals have a thick coat of hair on their bodies?
Ans. wool yielding animals have a thick coat of hair on their bodies so that sheep can
withstand with cold weather.
(b) The process of removing hair from the body of sheep is called shearing. Why is
shearing done in summers?
Ans. Sheep are usually found in hilly and cold region. Shearing of sheep done in
summers because sheep can survive without their protective coat of hair.
G. Long Answer Questions:
1. Write the various steps involved in the production of silk cloth from silk moth.
Ans. a. Incubation: The silk moth eggs are warmed to a temperature suitable for
hatching. This is known as incubation.
b. Rearing: After hatching, the silkworms are fed on mulberry leaves for six weeks, and
the worms eat almost continuously and increase in size.
c. Spinning: Branches of trees or shrubs are placed in their rearing houses. The worms
climb these branches and make their cocoons out of one continuous thread.
d. Reeling: The cocoons are first boiled or treated in ovens, killing the insects by heat.
The silk fibre is then obtained from the cocoons by a delicate process known as reeling.
This fibre woven into cloth.
2. Describe the process of wool production.
Ans. The different processes involved in wool production are shearing, scouring, grading,
dyeing, and drying.
Shearing: The process of removal of the fleece from an animal is called shearing.
Scouring: The sheared hair is washed properly to remove dirt, dust, and grease. The
process of removing dirt, dust, and grease from the sheared hair is called scouring.
Grading : the wool is sorted on the basis of length, colour, texture
Dyeing: As the natural colour of fleece is white, brown, or black, the sheared wool is
dyed in different colours.
Drying : In this process, containers of wool are put through rollers to squeeze out as
much water as possible. Then the wool is weighed and packed into bales. The bales are
transported to the mills where they are processed further for making cloth
3. Discuss various varieties of natural silk.
Ans. Eri silk – it may be white or brick-red ;
Muga silk - golden-yellow silk thread which is very attractive and strong.
Mulberry silk – it contributes to around 90 percent of the world silk production.
Tasar silk - copperish colour mainly used for furnishings and interiors.
H. HOTS (Higher Order Thinking Skills) Questions:
1. How is selective breeding advantageous for us?
Ans. selective breeding increase the production by selecting best variety of animals.
2. Why are animal activists against the silk production?
Ans. Animal activists are against the present process of getting silk from the cocoon
because in this process the pupa are killed in a cruel way by boiling them in water.
E. Short Answer Type-I Questions:
1. What is the function of saliva?
Ans: The digestive functions of saliva include moistening food, and helping to create a
food bolus, so it can be swallowed easily.
Saliva contains the enzyme amylase, also called ptyalin, which is capable of breaking
down starch into simpler sugars such as maltose and dextrin that can be further broken
down in the small intestine
2. What is ingestion?
Ans: The process of taking food inside our mouth is known as ingestion.
3. What is chyme?
Ans: Partially digested food formed by the action of gastric juice in the stomach is called
4. What happens to the undigested food in the body?
Ans: The undigested food passes to large intestine.Some water is absorbed and the semi
solid waste (feces) is egested through anus.
5. What do you understand by the term assimilation?
Ans: The process of producing energy from the absorbed food is known as assimilation
6. Where is liver located? Give its function.
Ans:liver lies in front of stomach. Liver secrate bile that is stored in gall bladder. It make
the digestion of fat faster.
Note: Bile juice contains no digestive enzymes, yet it is important for digestion. Bile juice
has bile pigments such as bilirubin and biliverdin. These break down large fat globules
into smaller globules so that the pancreatic enzymes can easily act on them. This process
is known as emulsification of fats.
F. Short Answer Type-Il Questions:
1. Why we cannot breathe and swallow at the same time?
Ans: Every time we swallow, the epiglottis closes the wind pipe .If we breathe and
swallow at the same time, food or water enters wind pipe and we chock and cough.
2. In what substances carbohydrates, proteins and fats get converted into after
Ans: in small intestine Carbohydrates get converted into sugars. Proteins get converted
into amino acids. Fats get converted into fatty acids and glycerol.
3. What are the functions performed by tongue?
Ans: tongue helps in process of chewing by pushing the food towards the teeth. It also
help to mix the food with saliva.
4. Which part of the alimentary canals involved in (a) chewing of food (b) killing of
bacteria (C) absorption of food (d) formation of faeces?
Ans: (a) chewing of food – Mouth (b) killing of bacteria – stomach (C) absorption of
food – small intestine (d) formation of faeces – large intestine
5. Different types of teeth in our jaws have different functions, but they all work together
to chew the food.
Ans: Different types of teeth in our jaws have different functions
(i) Incisors :- They help us in biting and cutting the food.
(ii) Canines : - They help us in piercing and tearing the pieces of meat.
(iii) Premolars:- They assist the molars by holding the food with their cusps and also
(iv) Molars : - They help us in chewing and grinding the food so that it can be swallowed
(b) What do we learn from our teeth that have different functions?
Ans: If we work united we will do any impossible work .
G. Long Answer Questions:
1. Briefly describe nutrition in Amoeba with the help of diagrams.
Ans: Amoeba takes in food by forming temporary finger-like projections called
pseudopodia. The pseudopodia fuse over the food particle forming a food vacuole. The
digestive enzymes from the surrounding cytoplasm enter into the food vacuole and
breakdown the food into small, water soluble molecules by chemical reactions. The
digested food from the food vacuole spreads into the whole of Amoeba cell and gets
absorbed in the cytoplasm. A part of absorbed food is used to obtain energy through
respiration and some is used for the growth of Amoeba cell. The undigested part of the
food is moved to the surface of Amoeba cell and egested (thrown out) by the rupture of
2. Describe the process of digestion in ruminants.
Ans: The stomach of a ruminant is divided into four chambers. As soon as the ruminant
swallows the food, it enters the first chamber called rumen where it gets partially
digested (converted to cud). From here, the food enters the second chamber from where
it again reaches the mouth for rumination, which is thorough chewing. The food is again
swallowed, and now it enters the third and the fourth chamber for digestion. From here,
it enters the small intestine for the absorption of nutrients.
3. What are liver and pancreas? Write their functions in detail.
Ans: liver and pancreas are organ that help in digestion of food.
Live produce bile juice that breaks down fats and stores some vitamins and minerals.
The pancreas has two main functions: an exocrine function that helps in digestion and
an endocrine function that regulates blood sugar.
Liver is the largest gland of the body. It is a reddish-brown gland situated on the right side of the upper part of the
Functions of liver are as follows:
(i) To secrete bile juice which helps in the emulsification of fats present in the food.
(ii) Detoxification- Conversion of toxic substances into non-toxic forms like conversion
of ammonia to urea which gets excreted in the urine.
(iii) Clearing the blood from drugs and other harmful substances.
(iv) Conversion of excess glucose into glycogen for storage (glycogen can later be
converted back to glucose to energy when body is in short of nutrients)
Pancreas is a organ located in the upper abdomen and adjacent to the small
intestine. It performs two main kind of functions in the body:
(i) Exocrine function: It helps in the digestion of food. It produces various enzymes such
as amylase, lipase and trypsin which helps to digest carbohydrate, fats and proteins
(ii) Endocrine function: It produces hormonal insulin and glucagon which regulate the
level of sugar present in the blood
H. HOTS (Higher Order Thinking Skills) Questions:
1. The bacteria present on uncleaned teeth convert the sugar in food into a substance 'X'
which causes tooth decay. Name the substance 'X'. Which part of the teeth does it affect?
Ans: Substance X is lactic acid which is formed in the mouth after we eat food
containing sugar. it affect enamel.
[ Note : Lactic acid lowers the pH in the mouth making it acidic. Our tooth enamel is
made up of calcium phosphate, which is the hardest material in our body, but even it
starts getting corroded when the pH in the mouth is lower than 5.5(Acidic)]
2. How is ruminant's stomach different from humans?
Ans: The stomach of a ruminant is divided into four chambers they are rumen,
reticulum, omasum, and abomasum. Human stomach is a single organ.
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Class7 Chapter 01 Nutrition in plants and Animals Cordova Science
A (Tick) the correct options:
1. Rhizobium bacteria live in the root nodules of plant
(a) wheat (b) rice (c) barley (d) peaÖ
2. Plants store food as
(a) cellulose (b) sugar (c) glucose (d) starchÖ
3. Which of the following is an insectivorous plant?
(a) Cucuta (b) DroseraÖ (c) mistletoe (d) lichen
4. The mode of nutrition shown by Cuscuta is
(a) parasiticÖ (b) symbiotic (c) saprophyte (d) autotrophic
5. On adding iodine solution, starch
(a) turns blue blackÖ (b) turns green (C) remains colourless (d) turns red
6. We keep healthy potted plant in a dark room for some days to the leaves
(a) decolourise (b) defragment (c) destarchÖ (d) deprotein
7. The portion of leaf that is not exposed to sunlight, will not make
(a) fats (b) protein (c) glucose Ö (d) starch
B.Fill in the blanks:
1. Rhizobium bacteria provide --nitrogen---- to the leguminous plants.
2. Green plants make their food by the process of photosynthesis.
3. Stomata are surrounded by guard cells.
4. Cuscuta is a -Total--- parasite.
5. The roots of saprophytes contain organisms called ….symbionts
C. Very Short Answer Questions:
1. Name any two heterotrophs.
2. Name any two insectivorous plants.
Ans: Venus flytrap, pitcher plants, butterworts, sundews
3. Name the pores through which leaves exchange gases.
4. Name one plant in which photosynthesis occurs in plant part other than leaves. Name
the plant part.
Ans: cactus in it's stem
5. What are the two main modes of nutrition in plants?
Ans: Autotropic and heterotrophic
6. Name the green pigment present in the leaves.
D. Short Answer Type-l Questions:
1. What are autotrophs?
Ans: Organism prepare own food like green plants
2. Why is Cuscuta called parasite?
Ans: Cuscuta is called parasite as it draw nutrition from host.
3. In which form, do plants need nitrogen?
Ans: Plants absorb nitrogen from the soil in the form of nitrate (NO3−) and ammonium
4. Why are leaves of a plant green in colour?
Ans: leaves of a plant are green in colour due to presence of chlorophyll.
5. Why do some plants feed on insects?
Ans: some plants feed on insects to get nitrogenous compound from which they make
6. Define photosynthesis.
Ans: Photosynthesis is the food making process of green plant using CO2 and water in
the presence of sunlight
E. Short Answer Type-ll Questions:
1. How can we decolorized a leaf? What will you conclude when white patches do not
turn blue black adding iodine solution?
Ans: Leaf of green plant heated in a test tube containing alcohol in water bath to
decolorize. if white patches do not turn blue black adding iodine solution showing
absence of starch
2. What is saprotrophic mode of nutrition? Give one example.
Ans: The mode of nutrition in which organism derive nutrients from dead and decaying
organic matter. Eg. Mushroom.
Saprophytes breakdown organic matter by secreting digestive juice into it. Then they
absorb what they need from the digested matter.
3. How does the pitcher plant catch its food?
Ans : Pitcher plants have leaves that look like pitchers. The lid of the pitcher closes when
an insect lands on the pitcher. The trapped insect slides down the wall of the pitcher and
is digested inside it.
4. Algae and fungi live together in lichens.
(a) What is this association called? (b) What value can we learn from this association in
Ans: The fungus provides minerals and water to the alga. The alga supplies the fungus
with food that it manufactures.
(a) Symbiotic relationship (b) We live with other in mutual benefit take help and give
5. Discuss the importance of photosynthesis.
Ans: Photosynthesis helps green plant to prepare glucose. Photosynthesis use CO2 and
release O2 and thus balance the oxygen and carbon dioxide level in atmosphere. Water
vapor released during photosynthesis also help in formation of cloud and bring rain.
F. Long Answer Questions:
1. Write an experiment to show that sunlight is necessary for photosynthesis.
Ans: cover a part of a leaf of a potted plant with black paper. Use paper clips to fix the
paper on both sides of the leaf
Make sure the plant get enough sunlight Pluck the leaf and take off the paper after two
Heat the leaf in alcohol, as in the previous activity, and test for starch. Only the part of
the leaf which was exposed to sunlight will turn blue-black. This shows that sunlight is
necessary for photosynthesis.
2. How do Rhizobium bacteria and leguminous plants help each other in survival?
Ans: Plant provide shelter to Rhizobium bacteria and Rhizobium bacteria provide nitrogenous compound that plants required to make plants protein.
G. HOTS (Higher Order Thinking Skills) Questions:
1. What will happen if plant leaves are devoid of stomata?
Ans: if plant leaves are devoid of stomata there is no exchange of gases like O2 and CO2
. Plants cannot perform photosynthesis
2. What will happen if all the plants disappear from the earth?
Ans: Food chain unbalance and no life exist.
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