Class-7 Science, Chapter-1 Nutrition in Plants, Additional exercises in line with NCERT book / CBSE Syllabus
Chapter 1
Nutrition in Plants
Additional Exercises
Exercises from textbook
Activities/Projects
Additional Exercises
Choose
the correct answer:
1- Minerals present in the
soil are absorbed by:
a. Roots
b. Leaves
c. Stem
d. Soil
2- A green pigment which helps
leaves to capture the energy of the sunlight:
a. Cytoplasm
b. Photosynthesis
c. Chlorophyll
d. carbon dioxide
3- Cotton-like thread spread on a piece of
bread is
a. Flour
b. Cotton
c. Fungi
d. Pollens
Match
the column
|
Column 1
|
Column II
|
|
Plants
|
Saprotrophs
|
|
Animals
|
Autotrophs
|
|
Pitcher Plant
|
Heterotrophs
|
|
Fungi
|
Insectivorous Plant
|
|
Lichens
|
Symbiotic relationship
|
|
Cuscuta
(Amarbel)
|
Parasitic Plants
|
Ans-
|
Column 1
|
Column II
|
|
Plants
|
Autotrophs
|
|
Animals
|
Heterotrophs
|
|
Pitcher Plant
|
Insectivorous Plant
|
|
Fungi
|
Saprotrophs
|
|
Lichens
|
Symbiotic relationship
|
|
Cuscuta
(Amarbel)
|
Parasitic Plants
|
Fill
in the blanks:
a. Leaves are the food factories of
plants.
b. The bodies of living
organisms are made of tiny units called cells.
c. Sun is the ultimate source of
energy for all living organisms.
d. The presence of starch in
leaves indicates the occurrence of photosynthesis.
e. carbohydrates are made up
of carbon, hydrogen and oxygen.
State
whether the following statements are true or false:
1. Algae can prepare their own
food by photosynthesis. True
2. plants can also synthesise
proteins and fats other than carbohydrates. True
Differentiate
between
Parasite and Saprotroph.
|
Parasite
|
Saprotroph
|
|
A parasite
takes its nutrition from the host plant which is alive.
|
A saprotroph
takes its nutrition from the dead or decaying matter.
|
|
Parasite
harms the host.
|
Saprotroph
does not harm and acts as a cleaning agent.
|
|
Example-
Cuscuta, tapeworm
|
Example- Bread
mould, other bacteria
|
Answer
the following questions:
Q1. What are nutrients?
Ans- Carbohydrates,
proteins, fats, vitamins and minerals are components of
food. these components of food are are necessary for our body and are
called nutrients.
Q2. Define nutrition. What are
the two modes of nutrition?
Ans- Nutrition is the mode
of taking food by an organism and its utilisation by the body.
Autotrophic
Nutrition-
It is the mode of nutrition in which organisms make food themselves from simple
substances.
Heterotrophic
Nutrition-
It is the mode of nutrition in which animals and other organisms take in
readymade food prepared by the plants.
Q3. Draw a labelled diagram
of stomata.
Q4. How does a pitcher plant
get its nutrition from an insect?
Ans- Pitcher plant has a
pitcher like structure, which is the modified part of the leaf. The apex of the
leaf forms a lid, which can open and close the mouth of the pitcher.
Inside the pitcher, there are hairs which are directed downwards. When an
insect lands in the pitcher, the lid closes and that trapped insect gets
entangled in the hair. The insect is digested by the digestive juices secreted
in the pitcher.
Q5. What is saprotrophic
nutrition? Give example.
Ans-
The mode of nutrition I. which organisim takes nutritients in solution form from
dead and decaying matter is called saprotrophic nutrition. For example fungi
growing on pickles, leather and clothes etc.
Q6. Explain symbiotic
relationship with an example.
Ans-
Some organisms live together ans share shelter and nutrients. This is
called symbiotic relationship.
Q7. For example, lichen is a
composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi
species in a mutualistic relationship.
Ans- Fungus provides shelter water and
Minerals to alga, in return, the alga provides food which is prepared by
photosynthesis.
Q8. How is the bacterium
Rhizobium useful to plants.
Ans- Plants need nitrogen in a soluble
form. The bacterium called rhizobium nitrogen and convert it into soluble form.
But rhizobium cannot make its own food. So it lives in the roots of gram,
moong, beans and other legumes and provides them with nitrogen. In return korma
the plants provide food and shelter to the bacteria. Have relationship this
association is a great significance for the farmers. They do not need to add
nitrogen fertilizers to the soil in which leguminous plants are grown.
Give
reason. Why?
Q1. The process of making of
food by plants is called Photosynthesis.
Ans- In plants, the
synthesis of food occurs in the presence of sunlight. Therefore it is called a
photosynthesis (photo means light; synthesis means to combine).
Q2. Life would be impossible
on the Earth in the absence of photosynthesis.
Ans- In the absence of
photosynthesis there would not be any food. The survival of almost all living
organisms directly or indirectly depends upon the food made by the plants.
Besides this, oxygen which is essential for all living organisms is
produced during photosynthesis. Therefore , in the absence of photosynthesis,
life would not be possible on the Earth.
Q3. You often see slimy,
green patches in ponds or in other stagnant water bodies.
Ans- Slimy, green patches
in ponds or other stagnant water bodies is formed by the growth of organisms
called algae. They contain chlorophyll, which gives them the green colour.
Q4. Farmers add fertilizers
rich in nitrogen to the soil.
Ans- Farmers add
fertilizers rich in nitrogen to the soil because in this way, the nitrogen
requirement of plants is fulfilled along with other constituents.
Q5. Bacteria present in soil
are useful to plants.
Ans- Certain bacteria
present in soil convert gaseous nitrogen into to a usable form and release it
into the soil. The soluble forms of nitrogen are absorbed by plants along with
water. plants use them for the synthesis of proteins and fats.
Q6. Cuscuta (Amarbel) is
called a parasite.
Ans- Cuscuta does not have
chlorophyll. It takes readymade food from the plant on which it is climbing
(host). Since it deprives its host of valuable nutrients, it is called a
parasite.
Exercises
from Textbook
Q. Why do organisms need to take food?
Ans- Organisms
need to take food for nutrition so that growth, development and repair and
maintenance of body takes place properly. Food also provide resistance to fight
against diseases and protection from infections.
Q.
Distinguish between parasite and saprotroph.
|
Parasite
|
Saprotroph
|
|
A parasite
takes its nutrition from the host plant which is alive.
|
A saprotroph
takes its nutrition from the dead or decaying matter.
|
|
Parasite
harms the host.
|
Saprotroph
does not harm and acts as a cleaning agent.
|
|
Example-
Cuscuta, tapeworm
|
Example- Bread
mould, other bacteria
|
Q.
How would you test the presence of starch in leaves?
Ans- Following
are the steps for the experiment to show the presence of starch in leaves:
1- Remove a green leaf from a plant which
is exposed to sunlight.
2- Boil the leaf in boiling water for 2
minutes. (stop enzymatic reaction)
3- Put the boiled leaf in boiling tube
containing alcohol (ethanol) and let it rest for 10 minutes in the beaker of
boiling watet {Extracts chlorophyll from the leaf}
4- Discard the alcohol and rinse the leaf
to remove traces of alcohol.
5- Take the leaf in a petridish and cover
it with iodine solution.
6- Leaf turns to blue-black. This show the
presence of starch in leaf.
Q.
Give a brief description of the process of synthesis of food in green plants.
Ans- Photosynthesis
is the process in which chlorophyll containing cells of leaves, in the presence of Sunlight, use carbon dioxide and water to synthesise
carbohydrates. this process can be
represented as an equation:
Show
with the help of a sketch that the plants are ultimate source of food.
Fill
in the blanks:
1- Green plants are called autotrophs
since they synthesise their own food.
2- The food synthesised by the plants is
stored as starch (carbohydrate).
3- In photosynthesis solar energy is
captured by the pigment called chlorophyll.
4- During photosynthesis plants take in carbon
dioxide and release oxygen.
Name
the following:
1- A
parasitic plant with yellow, slender and tubular stem.
Cuscuta
2- A plant that has both autotrophic and
heterotrophic mode of nutrition.
Pitcher Plant
3- The pores through which leaves exchange
gases.
Stomata
Tick
the correct answer:
1- Amarbel is an example of:
a. Autotroph
b. Parasite
c. Saprotroph
d. Host
2- The plant which traps and feeds on
insects is
a. Cuscuta
b. China rose
c. Pitcher plant
d. Rose
Match
the items given in column 1 with those in column 2
|
Column
1
|
Column
2
|
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Chlorophyll
|
Bacteria
|
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Nitrogen
|
Heterotrophs
|
|
Amarbel
|
Pitcher plant
|
|
Animals
|
Leaf
|
|
Insects
|
Parasite
|
Ans-
|
Column
1
|
Column
2
|
|
Chlorophyll
|
Leaf
|
|
Nitrogen
|
Bacteria
|
|
Amarbel
|
Pitcher plant
|
|
Animals
|
Heterotrophs
|
|
Insects
|
Parasite
|
Mark
“T” if the statement is true and
“F” if it is false:
1- Carbon dioxide is released during
photosynthesis. F
2- Plants which synthesise their food
themselves are called saprotrophs. F
3- The product of photosynthesis is not a
protein. T
4- Solar energy is converted into chemical
energy during photosynthesis. T
Choose
the correct option from the following:
·
Which part of
the plant takes in carbon dioxide from the air for Photosynthesis?
o
Root hair
o Stomata
o
Leaf veins
o
Sepals
Choose
the correct option from the following:
·
Plants take
carbon dioxide from the atmosphere mainly through their:
o
Roots
o
Stem
o
Flowers
o
Leaves
Extended
learning- Activities and Projects
1- Project
Take a potted plant with broad leaves. Take two strips of
black paper and cut out a small square in their centres. Cover a part of two
leaves with these papers and secured them with paper clips. Keep the plant in
the sunlight for 2-5 days. Observe the difference in the colour of the covered
and uncovered portions on the leaf. Perform iodine test on one leaf. Did the
two parts show any difference in results? Now take second leaf. Remove the
strip and expose the covered part to the sunlight for 2 to 3 days and do the
iodine test again. Describe your observations.
2- Visit a greenhouse if there is one near
your place. Observe how they raise
plants. Find out how they regulate the amount of light, water and carbon
dioxide to grow the plants.
3- Try growing a sweet potato just in
water. Describe your experiment and observations.
You can read more on the following website:
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Did
you know?
|
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Light is so
important to plants that their leaves grow in many patterns so as to catch
the most sunlight.
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