Free Nutrition in Plants Subjective Test 01 Practice Test - 7th grade 

The green colour in autotrophic plants is due to a green pigment called chlorophyll. It harnesses sunlight necessary for photosynthesis.

Classification: 1 Mark each

Based on their mode of nutrition, plants can be classified as either autotrophic or heterotrophic.

Autotrophs are plants which produce their own food from sunlight, carbon dioxide, and water by performing photosynthesis. Examples: all green plants.

Heterotrophic plants are those that derive their nutrition from autotrophs or other organisms. Example: mistletoe. 

Definition: 1 Mark 
Equation: 1 Mark

The process by which plants produce their own food using sunlight, water, carbon dioxide and minerals in the soil is termed as photosynthesis. 
Equation:

Definition: 1 Mark
Examples: 1 Mark

Plants which consume insects to meet their energy requirements are called insectivorous plants.
Examples: Nepenthes/pitcher plant and Venus fly trap.

Definition: 1 Mark
Examples: 1 Mark

Heterotrophs are organisms which depend on other organisms or dead organic matter for their food sources. This type of nutrition is said to be the heterotrophic mode of nutrition.
Examples: Indian pipe, venus flytrap

Each point: 1 Mark

1. All organism require food to survive.
2. Organisms need food to produce energy for various metabolic and physiological activities.
3. It also provides nutrients for protection against diseases.

Definition: 1 Mark
Necessity: 1 Mark
Modes of nutrition: 1 Mark

The process by which organisms take in food and utilize it is called as nutrition.
We need nutrients because they give us energy, and energy is needed for any organism to work, grow and reproduce.
The two modes of nutrition are:
1. Autotrophic
2. Heterotrophic

Each point: 1 Mark

(i)  All green plants can prepare their own food – Correct.
(ii) Most animals are autotrophs – Incorrect because animals are heterotrophs as they are directly or indirectly dependent on plants for food.
(iii) Carbon dioxide is not required for photosynthesis – Incorrect because $C{O}_2$ is essential for photosynthesis.

Definition: 1 Mark
Food: 1 Mark
Examples: 1 Mark

The organisms which obtain their nutrition from dead and decaying organic matter are called saprophytes. Fungi are examples of saprophytes. These organisms extend their mycelium and secrete enzymes to digest the decaying matter. They secrete digestive juices (enzymes) like cellulases, proteases, and lipases onto dead and decaying matter to digest it and then absorb nutrients from it. 
Examples: mushroom, bread mold, etc.

Definition: 1 Mark
Opening mechanism: 1 Mark
Function: 1 Mark

Stomata are minute apertures found typically on the outer leaf skin layer, also known as the epidermis. Stomatal opening is guarded by two bean-shaped cells called
guard cells. When guard cells are turgid i.e. filled with water, the stomatal pore opens and when guard cells lose water and become flaccid, the stomatal pore closes.
Their main function is to allow diffusion of gases such as carbon dioxide, water vapour, and oxygen.

Differences: 1 Mark each

$\begin{array}{ccc}\text{S.No.}& \text{Autotrophs}& \text{Heterotrophs}\\ 1& \text{They produce their own food through photosynthesis}.& \text{They depend on autotrophs for nutrition.}\\ 2& \text{They are usually green plants that contain chloroplasts.}& \text{They are non-green plants that do not contain chloroplasts.}\\ 3& \text{They depend on solar energy.}& \text{They do not directly depend on solar energy.}\\ \text{Examples:}& \text{All green plants}& \text{All animals}\end{array}$

Adaptations: 1 Mark each
Name of plants like cacti: 1 Mark

Any two: 
1. Cacti have their leaves reduced to spines to prevent water loss.
2. By storing carbon dioxide during the night and closing their stomata in the morning, they also prevent water loss.
3. The fleshy succulent stems store water and food.
4. They have very efficient roots that go very deep into the soil to get enough water.

Plants like cacti are called xerophytes.

Explanation: 2 Marks
Examples + reason: 1.5 Mark each

Parasitic mode of nutrition is where an organism (parasite) lives on the body surface or inside the body of another type of organism (host). The parasite obtains nutrition directly from the body of the host and in turn harm the host. This type of nutrition comes under heterotrophic nutrition.

Examples
Cuscuta: It is a parasitic plant which develops special roots called haustoria. They are non-green and they derive nourishment by using their haustoria to gain access to the food and water conducting tissues of the host plant.
Mistletoe is also a parasitic plant which derives nourishment by gaining access to the vascular tissue of the host plant. Similar to that in Cuscuta.

Each Name and category: 1 Mark

 

1. Green plants prepare their own food by a process called photosynthesis.
2. Glucose is prepared by using raw materials like carbon dioxide and water in the presence of sunlight and chlorophyll. As a byproduct oxygen is also produced. 
3. The oxygen produced is released into the air which is consumed by other living beings for their survival. 
Equation: