Class VII, NCERT (CBSE) Science
CHAPTER 1, NUTRITION IN PLANTS
Textbook Exercise Solution
Q.1: Why do organisms need to take food?
Ans: Food is required by all living organisms mainly for four reasons or purposes:
(1) Food helps a living organism to grow. If enough food is not given or if, the food given is not of right kind, the organism will not have proper growth.
(2) Another important function of food is to provide energy which is required for any living organism for movements and other activities.
(3) Food is also needed by living organisms for replacement and repairing of their damaged parts.
(4) Food provide us the power to fight against infections and diseases.
Q.2: Distinguish between a parasite and a saprotroph.
Ans:
Parasite | Saprotroph |
1. A parasite takes readymade food from the organism on which it feeds. 2. They feed on a living organism. 3. The organism on which it feeds is called host. 4. It deprives the host of valuable nutrients. | 1. They secrete the digestive juices on the matter they live and convert it into a solution and then absorb it. 2. They feed on dead and decaying organism. 3. They do not feed on a living organism. 4. There is no host at all. |
Q.3: How would you test the presence of starch on leaves?
Ans: The presence of starch on leaves can be tested by Iodine Test. Iodine turns starch solution blue.
Q.4: Give a brief description of the process of synthesis of food in green plants.
Ans: Leaves have a green pigment called chlorophyll. In presence of sunlight, they use carbon dioxide and water to synthesize carbohydrate. During this process oxygen is released. The carbohydrates ultimately get converted into starch.
Carbon dioxide from air is taken through stomata. Water and minera;ls are absorbed by roots and transported to leaves.
Q.6: Fill in the blanks:
(a) Green plants are called __________ since they synthesize their own food.
(b) The foods synthesized by the plants are stored as __________.
(c) In photosynthesis solar energy is captured by the pigment called _________.
(d) During photosynthesis plants take in ____________ and release _________.
Ans: (a) autotrophs (b) starch (c) chlorophyll (d) carbon dioxide, oxygen.
Q.7: Name the following:
(i) A parasitic plant with yellow, slender, tubular stem.
(ii) A plant that has both autotrophic and heterotrophic mode of nutrition.
(iii) The pores through which leaves exchange gases.
Ans: (i) Cascuta (ii) Insectivorous plants (iii) Stomata.
Q.8: Tick the correct answer:
(a) Amarbel is an example of -
(i) Autotroph
(ii) Parasite
(iii) Saprotroph
(iv) Host
(b) The plant which taps and feeds on insects is -
(i) Cuscuta
(ii) China rose
(iii) Pitcher plant
(iv) Rose
Ans: (a) Parasite (b) Pitcher Plant.
Q.9: Match the items in column I with those in column II:
Column I | Column II |
Chlorophyll Nitrogen Amarbel Animals Insects | Bacteria Heterotrophs Pitcher Plant Leaf Parasite |
Ans: Chlorophyll ---– Leaf. Nitrogen ––– Bacteria. Amarbel ––– Parasite.
Animals ––– Heterotrophs. Insects ––– Pitcher Plant.
Q.10: Mark “T” if the statement is true and “F” if it is false:
(i) Carbon dioxide is released during photosynthesis.
(ii) Plants which synthesize their food themselves are called saprotroph.
(iii) The product of photosynthesis is not a protein.
(iv) Solar energy is converted into chemical energy during photosynthesis.
Ans: (i) F (ii) F (iii) T (iv) T.
Q.11: Choose the correct option in the following:
Which part of the plant gets carbon dioxide from the air for photosynthesis?
(i) Root hair (ii) Stomata (iii) Leaf veins (iv) Sepals.
Ans: (ii) Stomata
Q.12: Which is the correct option in the following:
Plants take carbon dioxide from the atmosphere mainly through their -
(i) Roots (ii) Stem (iii) Flowers (iv) Leaves.
Ans: (iv) Leaves.
EXTRASCORE
(Additional Important Questions-Answers)
Q.1: Define: (a) Parasites and (b) Total Parasites (c) Partial Parasites
Ans: (a) Parasites - The organisms which depend on other living organismsfor their food are called parasites. For example, cascuta, tapeworm, liver fluke etc. There are two types of parasites: Total parasite and Partial parasite.
(b) Total Parasites - The parasites which depend for both food and shelter on the host are called total parasites. For example, liver fluke, tape worm.
(c) Partial Parasites - Those parasites which depend only for food on the host are called partial parasites. For example, mosquito, lice etc.
Q.2: What is Symbiosis? What is Symbiotic relationship?
Ans: Symbiosis - It is the type of nutrition in which two different kinds of depend on each other for their nutrition. In this both the organisms are benefitted by each other e.g., lichen. In this one alga and one fungus live together and remain in symbiotic relationship.
Symbiotic Relationship - Some organisms live together and share shelter and nutrients. This type of relationship is called symbiotic relationship.
Q.3: Fill in the blanks:
(i) All organisms take ________ and utilize it to get energy for growth and the maintenance of their bodies.
(ii) Green plants synthesize their food themselves by the process of __________ they are called ________.
(iii) ________ energy is stored by the leaves with the help of chlorophyll.
(iv) ________ derive nutrition from dead, decaying matter.
(v) Plants like cascuta takes food from __________ plant.
(vi) All animals are categorized as ________.
(vii) ________ is produced and ________ is utilized during photosynthesis.
Ans: (i) food (ii) photosynthesis, autotrophs (iii) Solar (iv) Fungi / saprotroph (v) host (vi) Heterotrophs (vii) oxygen, carbon dioxide
Q.4: What is the mode of nutrition in fungi?
Ans: Fungi secrete digestive juices on dead and decaying matter and convert it into a solution. Then they absorb nutrients from it. This mode of nutrition in which organisms take in nutrients in solution form from dead and decaying matter is called saprotrophic nutrition.
Q.5: Choose the true (T) and false (F) statements:
1) Food is essential for all living beings.
2) Leaves are the food factories of plant.
3) Water comes into leaves through stomata in the form of vapours.
4) Plants utilize the carbon dioxide dissolved in the water absorbed by the roots for photosynthesis.
5) The sun is the ultimate source of energy for all living organisms.
6) Algae are saprotrophs.
7) Cascuta is a parasite.
8) Saprotrophs take their food in solution form from dead and decaying matter.
9) Insectivorous plants are partial Heterotrophs.
10) Plants take atmospheric nitrogen stomata and utilize a nutrient.
11) Pitcher plant is an insectivorous plant.
12) Many fungi are saprotroph.
13) ‘Leaves’ of a plant is called its food factory.
14) Insectivorous plants eat insects to fulfill their needs of energy.
Ans: 1.-T 2.-F 3.-F 4.-F 5.-T 6.-F 7.-T 8.-T 9.-T 10.-F 11.-T 12.-T 13.-T 14.-F
Class VII, CBSE (NCERT) Science
CHAPTER 2, NUTRITION IN ANIMALS
Textbook Exercise Solution
Q.1: Fill in the blanks:
(a) The main steps of digestion in humans are _________ and ___________.
(b) The largest gland in the human body is _________.
(c) The stomach releases hydrochloric acid and ______ juices which act on food.
(d) The inner wall of the smaller intestine has many finger-like outgrowths called _________.
(e) Amoeba digests its food in the ____________.
Ans: (a) buccal cavity, oesophagus, stomach, small intestine and large intestine (b) liver (c) digestive juices (d) villi (e) food vacuole.
Q.2: Mark ‘T’ if the statement is true and ‘F’ if it is false:
(a) Digestion of starch starts in the stomach.
(b) The tongue helps in mixing food with saliva.
(c) The gall bladder temporarily stores bile.
(d) The ruminants bring back swallowed grass into their mouth and chew it for sometime.
Ans: (a) F (b) T (c) T (d) T
Q.3: Choose the correct option:
(a) Fat is completely digested in the
(i) stomach (ii) mouth (iii) small intestine (iv) large intestine
(b) Water from the undigested food is absorbed in the
(i) stomach (ii) food pipe (iii) small intestine (iv) large intestine
Ans: (a) – (iii). (b) – (iv).
Q.4: Match the terms of column I with those given in the column II:
Column I | Column II |
Food components Carbohydrates Proteins Fats | Products of digestion Fatty acids and glycerol Sugar Amino acids |
Ans: Carbohydrates => Sugar. Proteins => Amino acids. Fats => Fatty acids and glycerol.
Q.5: What are villi ? What is their location and function ?
Ans: The inner wall of the small intestine has thousands finger-like outgrowths called villi.
These are found in small intestine. The villi increase the surface area for absorption of food.
Q.6: Where is the bile produced ? Which component of the food does it digest ?
Ans: Bile is produced in liver and is stored in a sac called the gall bladder.
The bile plays an important role in the digestion of fats.
Q.7: Name the type of carbohydrates that can be digested by ruminants but not by humans. Give the reasons also.
Ans: Cellulose is the carbohydrate that can be digested by ruminants. Ruminants have large sac like structure between the small intestine and large intestine. The cellulose of the food is digested by the action of certain bacteria which are not present in human beings.
Q.8: Why do we get instant energy from glucose ?
Ans: Because glucose easily breakdown in the cell with the help of oxygen and give carbon dioxide, water and energy.
Q.9: Which part of the digestive canal is involved in:
(i) absorption of food __________.
(ii) chewing of food __________.
(iii) killing of bacteria _________.
(iv) complete digestion of food ___________.
(v) formation of faeces ____________.
Ans: (i) small intestine. (ii) mouth. (iii) stomach (iv) small intestine. (v) large intestine.
Q.10: Write one similarity and one difference between the nutrition in amoeba and human beings.
Ans:
Similarity: During the digestion of food, in amoeba digestive juices are secreted into the food vacuole. They act on the food and break it into simpler substances. In human being, the inner walls of stomach and the small intestine also secrete the digestive juices. The digestive juices convert complex substances of food to simpler ones.
Difference: Amoeba feeds on some microscopic organisms. When it senses food, it pushes out pseudopodia around the food particle. The food is trapped in a food vacuole. Human beings take food through the mouth, digest and utilize it. The food is gradually digested as food travels through the variouscompartments.
Q.11: Match the items of column I with suitable items of column II.
Column I | Column II |
(a) salivary gland (b) stomach (c) liver (d) rectum (e) small intestine (f) large intestine | (i) bile juice secretion (ii) storage of undigested food (iii) saliva secretion (iv) acid release (v) digestion is completed (vi) absorption of water (vii) release of faeces |
Ans: (a)–(iii). (b)–(iv). (c)–(i). (d)–(ii). (e)–(v). (f)–(vi).
Q.13: Can we survive only on raw, leafy vegetables / grass? Discuss.
Ans: We know that including all animals, fungi, many bacteria, non-green plants and human being do not possess the ability to synthesize their own food. Therefore depend upon autotrophs for their food supply either directly or indirectly. The green plants (leafy vegetables / grass) trap solar energy and manufacture their food in the form of glucose. So, leafy vegetables and grass can provide sufficient energy required for the survival of human being.
Class 7, CBSE (NCERT) Science | Chapter-2, Nutrition in Animals | Sample Questions-Answers and More [Read]
CHAPTER 3, FIBRE TO FABRIC
Textbook Exercise Solution
Q.1: You must be familiar with following nursery rhymes:
(i) ‘Baa baa black sheep, have you any wool’.
(ii) ‘Marry had a little lamb, whose fleece was white as snow’.
Answer the following -
(a) Which parts of the black sheep have wool?
(b) What is meant by the white fleece of the lamb?
Ans: (a) The hairy skin called fleece have wool in black sheep.
(b) White fleece means the hairy skin which is white in colour.
Q.2: The silkworm is (a) a caterpillar, (b) a larva. Choose the correct option.
(i) a (ii) b (iii) Both a and b (iv) neither a nor b.
Ans: (iii)
Q.3: Which of the following does not yield wool?
(i) yak (ii) camel (iii) goat (iv) woolly dog.
Ans: (iv)
Q.4: What is meant by the following terms?
(i) Rearing
(ii) Shearing
(iii) Sericulture.
Ans:
Rearing - Rearing of animals means taking care of economically useful animals by managing their breeding, feeding, medical care etc. for obtaining one or more of their product useful for human beings e.g., apiculture,sericulture.
Shearing - The process of removing the fleece of the ship along with thin layer of skin is called shearing.
Sericulture - The rearing of silk worms for obtaining silk is called sericulture.
Q.5: Given below is a sequence of steps in the processing of wool. Which are the missing steps? Add them.
Shearing, _____________, sorting, ________, __________.
Ans: Shearing, scouring, sorting, picking out of burrs, colouring, rolling.
Q.7: Out of the following which are the two terms related to silk production:sericulture, floriculture, moriculture, apiculture, silviculture.
Ans: Sericulture, Moriculture.
Q.8: Match the following:
Column I | Column II |
1. Scouring 2. Mulberry leaves 3. Yak 4. Cocoon | (a) Yields silk fibers. (b) Wool yielding animal (c) Food of silkworm (d) Reeling (e) Cleaning sheared skin. |
Ans: 1-e, 2-c, 3-b, 4-a
.EXTRASCORE
(Additional Important Questions-Answers)
Q.1: Choose the correct option from the given options:
(i) Which among the following is an animal fiber?
a. jute
b. cotton
c. polyester
d. silk
(ii) Wool can be obtained from:
a. sheep
b. goat
c. yak
d. all above
(iii) Which is not related with silk industry?
a. sericulture
b. moriculture
c. apiculture
d. reeling
(iv) Silk is derived from
a. cocoon
b. pupa
c. egg
d. moth
(v) Which is not a variety of silk?
a. Tassar
b. Mooga
c. Ruby
d. Kosa
Ans: (i)d (ii)d (iii)c (iv)a (v)c
Q.2: State whether true (T) or false (F):
(i) Wool and silk are the animal fibers.
(ii) Silk is obtained from the fleece of sheep.
(iii) Pashmina shawls woven from the wool obtained from the under fur of Kashmiri goats.
(iv) Silk moth spins the silk fibers.
(v) Silk fiber is chemically a protein.
(vi) The most common silk moth is the mulberry silk moth.
(vii) For reeling of silk cocoon is boiled.
(viii) The hair of sheep is termed as fleece.
(ix) In India mostly sheep are reared for getting wool.
(x) Marwari is the name of a breed of sheep.
Ans: (i) T (ii) F (iii) T (iv) F (v) T (vi) T (vii) T (viii) T (ix) T (x) T
Class VII Science (CBSE Board)
Chapter 4, HEAT
NCERT Science Textbook Exercise (Solved)
Q.1: State similarities and differences between the laboratory and clinicalthermometer.
Ans: Similarities:
1. Both consist of a long, narrow, uniform glass tube.
2. Both have a bulb containing mercury at the end of the tube.
3. Both are marked with Celsius scale on the glass tube.
Differences:
1. A clinical thermometer reads temperature from 35OC to 42OC, while a laboratory thermometer ranges between
–10OC to 110OC.
2. Clinical thermometer has a kink near the bulb while there is no kink in laboratory thermometer.
Q.2: Give two examples each of conductors and insulators of heat.
Ans:
Conductors of heat: copper, iron.
Insulators: wood, paper, plastic.
Q.3: Fill in the blanks:
(a) The hotness of an object is determined by its _____________.
(b) Temperature of boiling water can not be measured by a _________thermometer.
(c) Temperature is measured in degree ___________.
(d) No medium is required for transfer of heat by the process of _______.
(e) A cold steel spoon is dipped in a cup of hot milk. It transfers heat to its other end by the process of _________.
(f) Clothes of __________ colours absorb heat better than clothes of light colours.
Ans: (a) temperature, (b) Celsius, (c) conduction, (d) clinical, (e) radiation, (f) dark
Q.4: Match the following:
(i) Land breeze blows during (ii) Sea breeze blows during (iii) Dark coloured clothes are preferred during (iv) Light coloured clothes are preferred during | (a) Summer (b) Winter (c) Day (d) Night |
Ans: (i) - d, (ii) - c, (iii) - b, (iv) - a.
Q.5: Discuss why wearing more layers of clothing during winter keeps us warmer than wearing just one thick piece of clothing.
Ans: Wearing more layers of clothing during winter keeps us warmer than wearing just one thick piece of clothing because of the air trapped between two layers of clothes. This layer prevents the flow of the heat from our body to the cold surroundings and keeps our body relatively warmer.
Q.7: In places of hot climate it is advised that outer walls of houses be painted white. Explain.
Ans: It is because the white colour reflects most of the heat that falls on it. Hence, the outer walls of the houses in the places of hot climate are advised to paint with white colour so that most of the heat falling on these walls would be reflected which will help in keeping the houses cool.
Q.8: One liter of water at 30OC is mixed with one liter of water at 50OC. The temperature of the mixture will be:
(a) 80OC (b) more than 50OC but less than 80OC
(c) 20OC (d) between 30OC and 50OC
Ans: (d)
Q.9: An iron ball at 40OC is dropped in a mug containing water at 40OC. The heat will
(a) flow from iron ball to water
(b) not flow from iron ball to water or from water to iron ball.
(c) flow from water to iron ball.
(d) increase the temperature of both.
Ans: (b)
Q.10: A wooden spoon is dipped in a cup of ice cream. Its other end
(a) becomes cold by the process of conduction.
(b) becomes cold by the process convection.
(c) becomes cold by the process of radiation.
(d) does not become cold.
Ans: (d)
Q.11: Stainless steel pans are usually provided with copper bottoms. The reason for this could be that
(a) copper bottom makes the pan more durable.
(b) such pans appear colourful.
(c) copper is better conductor of heat than the stainless steel.
(d) copper is easier to clean than the stainless steel
Ans-c
Chapter 4, HEAT
EXTRASCORE Study Material
(Additional Important Questions)
Q.1: Give the names of any three kinds of thermometers.
Ans: Clinical thermometer, Laboratorythermometer, and Maximum-minimumthermometer.
Q.2: Which metal is used in the bulb ofthermometer?
Ans: Mercury.
Q.3: What is the unit of temperature?
Ans: SI unit of temperature is Kelvin (K). Other units are Celsius and Farenhite.
Q.4: What is the range of clinical thermometer?
Ans: 35OC to 42OC.
Q.5: By which method we get heat from the sun?
Ans: Radiation.
Q.6: What kind of cloth we prefer in summer?
Ans: Light coloured clothes.
Q.7: What are conductors?
Ans: The materials which allow heat to pass through them.
Q.8: State whether following statements are true or false:
a. Our sense of touch about hotness or coldness is not always reliable.
b. Normal temperature of human body is 98.6OC.
c. In all cases heat flows from a hotter object to a colder object.
d. Water at higher temperature feels hotter.
e. Marking on clinical thermometer is from 0OC to 100OC.
f. Shinning thread in thermometer is the column of mercury.
g. The materials which allow heat to pass through them easily are called conductors.
h. Water and air are good conductors of heat.
i. Woolen clothes keep us warm during winter.
j. The maximum and minimum temperature of the day is measured by a laboratory thermometer.
k. Celsius is the SI unit of temperature.
l. Conduction is the method of transfer of heat in gases.
Ans: a - T. b - F. c - T. d - T. e - F. f - T. g - T. h - F. i - T. j - F. k - F. l - F.
Q.9: Fill in the blanks:
(i) Temperature is the measure of _________ of an object.
(ii) The thermometer used to measure human body temperature is called __________thermometer.
(iii) The normal temperature of human body is ___________OC.
(iv) A ___________ near the bulb of a clinical thermometer prevents mercury level from falling of its own.
(v) The water and air are ___________ conductors of heat.
(vi) All hot bodies radiate ______________.
(vii) Wool is a ____________ conductor of heat.
Ans: (i) hotness. (ii) clinical. (iii) 37. (iv) kink. (v) poor. (vi) heat. (vii) poor.
