Nutrition in Plants

Fill in the blanks:

(a) Green plants are called _ autotrophs __ since they synthesize their own food.

(b) The foods synthesized by the plants are stored as starch .

(c) In photosynthesis solar energy is captured by the pigment called ___ chlorophyll

(d) During photosynthesis plants take in ____CO2________ and release _ O2

Name the following:

(i) A parasitic plant with yellow, slender, tubular stem.------- Cascuta

(ii) A plant that has both autotrophic and heterotrophic mode of nutrition.--------- Insectivorous plants

(iii) The pores through which leaves exchange gases. ------- Stomata

(iv) A plant that has both autotrophic as well as heterotrophic mode of nutrition. --- Pitcher plant.

(v) An organism that live is an association of an alga and a fungus ---------- lichen

(vi) Amarbel is an example of: ----parasites

(vii) The plant which traps and feeds on insects is----- pitcher plant

Match the items in column I with those in column II:

Chlorophyll --- Leaf.

Nitrogen Bacteria.

Amarbel Parasite.

Animals Heterotrophs.

Insects Pitcher Plant

What is Nutrients?

Food is essential for all living organisms. 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.

How humans and animals are are directly or indirectly dependent on plants.

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.

Why do we need food ?

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.

What is food ?

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.

What is Nutrition?

Nutrition is the sum of all including taking food by an organism and its utilization by the body.

The mode of nutrition in which organisms make food themselves from simple substances is

called autotrophic nutrition. Ex plants.

The mode of nutrition in which organisms take in ready made food prepared by the plants

called heterotrophic nutrition. Ex animals

Whether food is made in all parts of a plant or only in certain parts?

Only certain part plant like leaves having green pigment chlorophyll. so Leaves are called the food factories of

plants.

Besides leaves, photosynthesis also takes place in other green parts of the plant in green stems and green

branches. The desert plants have scale- or spine-like leaves to reduce loss of water by transpiration. These

plants have green stems which carry out photosynthesis.

How do plants obtain the raw materials from the surroundings?

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

How do the raw materials transport them to the food factories of the plants?

Plants have pipe-like vessels to transport water and nutrients from the soil. The vessels are

made of special cells, forming the vascular tissue. The vascular tissue for the transport of water and nutrients in

the plant is called the xylem. The vascular tissue for the transport of water and nutrients in the plant is called

the xylem. Thus, xylem and phloem transport substances in plants

What is cell ?

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

What is the cell membrane?

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.

What is tissue ?

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.

What are the main requirements of photo synthesis?

Chlorophyll, sunlight, carbon dioxide and water are necessary to carry out the process of

Photosynthesis.

Explain the process of Photosynthesis?

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

Carbon dioxide + water ---------sunlight/chlorophyll--Carbohydrate + oxygen

Here the carbohydrates ultimately get converted into starch

How would you test the presence of starch on leaves?

Put 2-3 drops of dilute iodine solution on the leaves. Appearance of a blue-black colour indicates presence of

starch in the leaves.

Why are leaves called the food factories of plants? Explain.

Leaves are called the food factories of plants due to following functions

Green leaves have all the raw materials neccessary to carry the process of photosynthesis.

They have chlorophyll (green pigment) which captures the energy of sunlight.

Leaves consist of tiny pores called stomata on their surface.

Carbon dioxide from air is taken in through stomata.

Water and minerals are absorbed by the roots from the soil and transported to the leaves by vessels.

Why sun is called the ultimate source of energy for all living organisms?

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.

Why algae are green in colour?

Algae contain chlorophyll which gives them the green colour. It can also prepare their own food by

photosynthesis.

What are the main components presents in carbohydrates?

The main components presents in carbohydrates are carbon, hydrogen and oxygen.

From where do the plants obtain nitrogen?

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

What is parasitic nutrition?

The mode of by which parasitic organism get and synthesize their food is called parasitic nutrition. Example

Cucuta It does not have chlorophyll It takes readymade food from the plant

on which it is climbing. The plant on which it climbs is called a host.

How Pitcher plants get their nutrition?

There are a 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 Pitcher plant

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.

Why does the pitcher plant feed on insects though it is green?

The pitcher plant does not get all the required nutrients especially those of nitrogen from the soil, hence it

feeds on insects.

What is saprotrophic nutrition? What is the mode of nutrition in fungi?

This mode of nutrition in which organisms take in nutrients in solution form from dead and decaying matter is

called saprotrophic nutrition. Plants which use saprotrophic mode of

nutrition are called saprotrophs. Example Fungi that secrete digestive juices on the dead

and decaying matter and convert it into a solution. Then they absorb the nutrients from it.

How do fungi appear suddenly during the rainy season?

Air generally consists of fungal spores. When these spores come in contact with warm things they germinate

and grow. During rainy season, there are more chances of things getting wet.

Hence, fungi appear more in rainy season.

What do you under stand by symbiotic relationship present in some organism?

Some organisms live together and share shelter and nutrients. This is called symbiotic relationship . E.g. an

alga, and a fungus live together fungus provides shelter, water and

Minerals to the alga and, in return, the alga provides food which it prepares by photosynthesis.

What is Symbiosis?

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.

How nutrients are replenished in soil?

Nutrients are replenished in soil by following ways

1.By spreading manure or fertilizers that contain nutrients such as nitrogen in the fields

2.By The bacterium Rhizobium that can take atmospheric nitrogen and convert it into a soluble form.

How do leguminous plants help replenishing soil fertility?

Rhizobium cannot make its own food. So it lives in the roots of gram, peas, moong beans

and other legumes and provides them with nitrogen. In return, the plants provide food and

shelter to the bacteria

Distinguish between a parasite and a saprotrophs

Parasite

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.

saprotrophs

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.

Why algae are green in colour?

Algae are green in colour as they contain chlorophyll which gives them the green colour. Algae can also

prepare their own food by photosynthesis. Slimy, green patches in ponds or in other stagnant water bodies are

algae.

class 7 - Science - Ch1 - Nutrition in Plants

Nutrition in Plants Q1: Why do organisms need to take food? Answer: All organisms take food and utilise it to get energy for the growth and maintenance of their bodies. Q2: Why do plants use the nitrogen present in soil? How is this nitrogen replenished in the soil? Answer: Plants cannot absorb nitrogen in gas form; they need it in soluble form. Therefore, they use the nitrogen present in soil to prepare proteins. Atmospheric nitrogen is fixed in soil by nitrogen-fixing bacteria such as Rhizobium,which live in the root nodules of leguminous plants such as gram, peas, beans, etc. In return, the plants provide food and shelter to the bacteria. Q3: Define nutrition. Answer: Nutrition is the process in which an organism consumes food, which is then utilized by the body. Q4: Distinguish between a parasite and a saprotroph. Answer: Organisms derive nutrition from the body of other living organisms (host) are parasites.E.g. Cuscata (amar bel)

Organisms which organisms derive nutrition from dead and decaying organisms are called saprotrophs.E.g. Mushrooms

Q5: Why do plants need nitrogen? Answer: Plants need nitrogen to synthesize proteins. Q6: What are insectivorous plants? Give an example. Answer: Insect-eating plants are known as insectivorous plants. Example: pitcher plant. Q7: Choose the correct option from the following: Which part of the plant gets carbon dioxide from the air for photosynthesis. (a) root hair (b) stomata (c) leaf veins (d) sepals Answer : Stomata Q8: Lichens is a composite of which two organisms? What type of nutrition relationship exists here? Answer: Two partners are Algae and Fungi. They exhibit symbiotic relationship. The fungus provides shelter, water and minerals to the alga and, in return, the alga provides food which it prepares by

photosynthesis. Q9: Choose the right option. Green plants are: a) herbivores b) autotrophs c) hetrotrophs d) omnivores Answer: Autotrophs (Note: Here Green plants are mentioned. Non Plants (both green + non-green) together are autotrophs and hetrotrophs.) Q10: Define Photosynthesis. Answer: The process of preparing food with the help of water, carbon dioxide, sunlight and chlorophyll in plants is called photosynthesis.

Chlorophyll component present in leaves, in the presence of sunlight, converts Water and Carbon Dioxide into food.

CBSE Class 7 - Science - Ch1 - Nutrition in Plants (MCQs)

Nutrition in Plants

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(MCQs) Q1: Green plants are: (a) herbivores (b) autotrophs (c) hetrotrophs (d) omnivores

Q2: The tiny pores present in the leaves of the plants for exchange of gases are called _____ (a) Stomata (b) Tracheae (c) Chloroplast (d) Spiracles Q3: Rhizobium is an example of (a) Symbiosis (b) Parasites (c) Insectivorous (d) none of these Q4: Which part of the plant gets carbon dioxide from the air for photosynthesis? (a) root hair (b) stomata (c) leaf veins (d) sepals Q5: Iodine used to detect presence of starch. It gives starch (a) red colour (b) green colour (c) blue-black colour (d) colourless appearance Q6(NCERT): Amarbel (Cuscuta) is an example of: (a) autotroph (b) parasite (c) saprotroph (d) host Q7(NCERT): The plant which traps and feeds on insects is: (a) cuscuta (b) china rose (c) pitcher plant (d) rose Q8: Green plants use which of the following to prepare food? (a) Carnon DiOxide (b) Sunlight (c) Water (d) All of these

Q9: Which of the following statements is NOT true? (a) Heterotrophs cannot prepare their own food. (b) Dodder is an example of parasite. (c) Saprophytes are green. (d) Pulses and Beans are legumes. Q10: The main function of a leaf is: (a) To prepare food (b) To prevent disease (c) To support the plant (d) To give a proper shape

Answer: 1: (b) autotrophs 2: (a) Stomata 3: (a) Symbiosis 4: (b) stomata 5: (c) blue-black colour 6: (b) parasite 7: (c) pitcher plant 8: (d) All of these 9: (c) Saprophytes are green. 10: (a) To prepare food