Science Chapter 1 - Nutrition in
Plants
Class- 7
NCERT Important Questions
Short Answer Type Questions
Question 1. What is Nutrients?
Answer: Carbohydrates,
proteins, fats, vitamins and minerals are components of food. The chemical
substance present in components of food is necessary for our body and is called
nutrients.
Question 2. How humans
and animals are directly or indirectly dependent on plants.
Answer: All living
organisms require food. Plants can make their food themselves but animals
including humans cannot. They get it from plants or animals that eat plants.
Thus, humans and animals are directly or indirectly dependent on plants.
Question 3. What is food?
Answer: Food is the
source of energy and every cell of an organism gets energy by the breakdown of
glucose. The cells use this energy to carry out vital activities of life.
Question 4. Why do we
need food?
Answer: Living organisms need food to build their
bodies, to grow, to repair damaged parts of their bodies and provide the energy
to carry out life processes.
Question 5. How do plants
obtain the raw materials from the surroundings?
Answer:
* Water and minerals present in the
soil are absorbed by the roots and transported to the leaves.
* Carbon dioxide from air is taken in
through the tiny pores present on the surface of the leaves. Such pores are
called stomata. These pores are surrounded by ‘guard cells’.
Question 6. What is cell?
Answer:
* The bodies of living organisms are
made of tiny units called cells therefore Cell are called the building blocks
of living organism. Cells can be seen only under the microscope.
* Some organisms are made of only one
cell. They are called Unicellular Ex. Amoeba, Paramecium etc.
* Living organism made up of many cells
are called Multi cellular like man, tree etc.
Question 7. What is the
cell membrane?
Answer:
* The cell is enclosed by a thin outer
boundary, called the cell membrane
* Most cells have a distinct, centrally
located spherical structure called the nucleus
* The nucleus is surrounded by a
jelly-like substance called cytoplasm.
Question 8. What is
tissue?
Answer: A tissue is a
group of cells that perform specialized function in an organism. For example,
the vascular tissue for the transport of water and nutrients in the plant is
called the xylem.
Question 9. What are the
main requirements of photo synthesis?
Answer: Chlorophyll,
sunlight, carbon dioxide and water are necessary to carry out the process of
Photosynthesis.
Question 10. Explain the
process of Photosynthesis?
Answer:
* Carbon dioxide from air is taken in
through stomata.
* Chlorophyll helps leaves to capture
the energy of the sunlight. This energy
is used to synthesize (prepare) food from carbon dioxide and water.
* Since the synthesis of food occurs in
the presence of sunlight, it is called photosynthesis.
Question 11. Why sun is
called the ultimate source of energy for all living organisms?
Answer: The solar
energy is captured by the leaves and stored in the plant in the form of
food. and this in turn use by other
organism to get food to obtain energy.
Thus, sun is the ultimate source of energy for all living organisms.
Question 12. Why algae
are green in colour?
Answer: Algae contain
chlorophyll which gives them the green colour. It can also prepare their own food by photosynthesis.
Question 13. What are the
main components presents in carbohydrates?
Answer: The main
components present in carbohydrates are carbon, hydrogen and oxygen.
Question 14:
Differentiate between nutrients and nutrition.
Answer:
* Carbohydrates, proteins, fats,
vitamins and minerals are essential components of food, these components are
called nutrients
* Nutrition is the mode of taking food
by an organism and its utilisation by the body.
Question 15:
Differentiate between autotrophs and heterotrophs.
Answer:
* Green plants are called autotrophs as
they prepare their own food from simple substances
* Animals and most other organisms are
called heterotrophs as they take in ready-made food prepared by the plants.
Question 16: Explain the
food factory of plants.
Answer: Leaves are
called food factory of plants, as the synthesis of food takes place in leaves
of plants. Water and minerals present in soil are absorbed by roots and
transported to leaves via stem. Carbon dioxide from air is taken in through
tiny pores on surface of leaves called stomata.
Question 17: How water
and minerals are transported to leaves from roots?
Answer:
There
are vessels inside a plant which run like pipes throughout the root, stem
branches and leaves, by going through these vessels water and minerals are
transported to leaves from roots.
Question 18: Draw a
labelled diagram of cell showing nucleus and cytoplasm.
Question 19: Define
chlorophyll .
Answer: Chlorophyll is
the green colour pigment which helps leaves to capture energy from sunlight to
carry out the food making process of plants by the leaves.
Question 20: Explain the
role of chlorophyll in the process of
photosynthesis.
Answer: Chlorophyll is
the green colour pigment which helps leaves to capture energy from sunlight to
carry out the food making process of plants by the leaves. It is the green
photosynthesis pigment which provides energy necessary for photosynthesis.
Question 21: Define
photosynthesis along with the equation for the same.
Answer: Photosynthesis
is the food manufacturing process of green plants containing chlorophyll, in
presence of sunlight, with the help of carbon dioxide and water to synthesise
carbohydrates. The equation for the process is as follow:
Carbon
dioxide + water —> carbohydrate +
Oxygen
Question 22: What is the
function of stomata in leaf of a plant?
Answer: Stomata are the
tiny pores present on the surface of leaves which helps in exchange of gases,
the pores in stomata are surrounded by guard cells.
Question 23: Why do we
need food?
Answer: Living
organisms need food to build their bodies, to grow, to repair damaged parts of
their bodies and provide with energy to carry out life processes.
Question 24 : Draw a labelled diagram showing the process
of photosynthesis.
Question 25. What is so special about the leaves
that they can synthesis food but other parts of the plant cannot?
Answer: The leaves have a green pigment called chlorophyll.
It helps leaves to capture the energy of the sunlight. This energy is used to
synthesis (prepare) food from carbon dioxide and water.
Question 26: What is the
cell membrane?
Answer: The cell is
enclosed by a thin outer boundary, called the cell membrane. Many cells have a distinct, centrally located
spherical structure called the nucleus. The nucleus is surrounded by a
jelly-like substance called cytoplasm.
Question 27: What are the
main requirements of photosynthesis?
Answer: Chlorophyll,
sunlight, carbon dioxide and water are necessary to carry out the process of
Photosynthesis.
Question 28: Why colours
of algae are green?
Answer: Algae contain
chlorophyll which gives them green colour and because of chlorophyll . it can also prepare their own food by
photosynthesis.
Question 29: What are the
main components presents in carbohydrates?
Answer: The main
components presents in carbohydrates are carbon, hydrogen and oxygen.
Question 30: From where
do the plants obtain nitrogen?
Answer: Soil has
certain bacteria that convert gaseous nitrogen into a usable form and release
it into the soil. These soluble forms are absorbed by the plants along with
water. By adding fertilizers rich in nitrogen to the soil farmers also made
nitrogen available for plants.
Question 31: Define
insectivorous plants along with examples.
Answer: There are few
plants which can trap insects and digest them. Such plants may be green or of
some other colour. Such insect-eating plants are called insectivorous plants.
Example: Venus Flytrap and Pitcher plant.
Question 32: Explain how
Pitcher plants get their nutrition?
Answer: When an insect
lands in the pitcher, the lid closes and the trapped insect gets entangled into
the hair. The insect is digested by the digestive juices secreted in the
pitcher.
Question 33. What are insectivorous plants?
Answer: Insect-eating
plants such as pitcher plant are called insectivorous plants.
Question 34. What do you mean by nutrition?
Answer: Nutrition is the mode of taking food by an organism
and its utilization by the body.
Question 35. Why photosynthesis is named so?
Answer: Since the synthesis of food occurs in the presence
of sunlight, it is called photosynthesis (Photo: light; synthesis: to combine).
Question 36. What are called autotrophs?
Answer: Organisms able to make food themselves from simple
substances are called autotrophs.
Question 37. What are heterotrophs?
Answer: Animals and most other organisms take in ready-made
food prepared by the plants. They are called heterotrophs (heteros = other).
Question 38. What are stomata?
Answer: Tiny pores are present on the surface of the leaves
which helps in exchange of gases. Such pores are called stomata.
Question 39. What Is heterotrophic nutrition?
Answer: Heterotrophic nutrition is the mode of nutrition in
which organisms depend upon other organisms to survive.
Question 40. What are nutrients?
Answer: Carbohydrates, proteins, fats, vitamins and minerals
are components of food. These components of food are called nutrients.
Question 41. What Is chlorophyll?
Answer: A green pigment present in all green plants which
helps leaves to capture the energy of the sunlight is called chlorophyll.
Question 42. Where and in what conditions do
fungi grow?
Answer: Fungi grow on pickles, leather, clothes and other
articles that are left in hot and humid weather for long time.
Question 43. How do fungi grow and develop?
Answer: The fungal spores are generally present in the air.
When they land on wet and warm things they germinate and grow.
Question 44. Why algae are green in colour?
Answer: They contain chlorophyll which gives them the green
colour. Algae can also prepare their own food by photosynthesis.
Question 45. What are the raw materials required
for photosynthesis?
Answer: Chlorophyll, sunlight, carbon dioxide and water are
necessary to carry out the process of photosynthesis.
Question 46. Do insectivorous plants perform
photosynthesis?
Answer: Insectivorous plants got leaves therefore they can
photosynthesis, which means they can prepare their food in the presence of
sunlight.
Question 47. What are algae?
Answer: We often see slimy, green patches in ponds or in
other stagnant water bodies. These are generally formed by the growth of
organisms called algae.
Question 48. Why do organisms need to take food?
Answer: The food enables living organisms to build their
bodies, to grow, to repair damaged parts of their bodies and provide the energy
to carry out life processes.
Question 49. Why plants such as pitcher plant do
not get all the required nutrients from the soil in which they grow?
Answer: Plants such as pitcher plant do not get all the
required nutrients from the soil in which they grow because they are deficient
in nutrients such as nitrogen.
Question 50. What is Cuscuta?
Answer:
* Cuscuta is a parasitic plant. It is yellow tubular
structures twining around the stem and branches.
* It does not have chlorophyll. It takes readymade food from
the plant on which it is climbing.
Question 51. What is the role of rhizobium
bacteria in leguminous plant?
Answer: The bacterium called Rhizobium present in leguminous
plant can take atmospheric nitrogen and convert it into a soluble form. Thus
help in nitrogen fixation.
Question 52. Some plants have deep red, violet
or brown leaves. Do these leaves also carry out photosynthesis?
Answer: The leaves other than green also have chlorophyll.
The large amount of red, brown and other pigments mask the green colour.
Photosynthesis takes place in these leaves also.
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