Free Reproduction in Organisms Subjective Test 02 Practice Test - 7th grade 

Question 1

Give two examples of plants with winged seeds. [1 MARK]

SOLUTION

Solution : Each example: 0.5 Mark
 
Drumsticks and maple are two examples of plants which have winged seeds dispersed by wind.

Question 2

How is zygote formed in plants? What is the process called? [2 MARKS]
 

SOLUTION

Solution :

Each point: 1 Mark

After pollination,  male gamete present in the pollen grains moves into the ovules and fuses with the female gamete. The single cell resulting from this fusion is called a zygote. This process is called fertilization.

Question 3

Given below is a diagram representing a pistil. Identify the labeled parts.  [2 MARKS]  
 

SOLUTION

Solution :

Each point: 0.5 Mark

(i) Stigma
(ii) Style
(iii) Ovary
(iv) Ovules

Question 4

How are seeds dispersed by water? Give example.  [2 MARKS]

SOLUTION

Solution : Dispersal: 1 Mark
Example: 1 Mark

When the seeds of plants growing near water bodies, land up in water, they get transferred from one place to another along with the water currents. This is seed dispersal by water.
Seeds that are dispersed by water develop floating ability by forming spongy, fibrous coat.
Eg: Coconut

Question 5

Give some characteristics of seeds that are dispersed by air? Give example. [2 MARKS]

SOLUTION

Solution : Characteristics: 1 Mark
Example: 1 Mark

Seeds dispersed by wind have following characteristics
1. Small in size.
2. Light in weight.
3. Presence of wings. Eg., maple and drumstick.
4. Presence of hairy growths. Eg. grass and sunflower.

Question 6

Name and explain about the male and the female parts of a flower. [3 MARKS]

SOLUTION

Solution :

Naming: 1 Mark
Explanation: 2 Marks

Stamen is the male part of the flower while pistil is the female part of a flower.
Stamen consists of two parts - anther and filament. Anther produces pollen grains which contain the male gamete. Filament connects the anther to the flower.
A pistil consists of three parts - stigma, stile and ovary. Stigma receives the pollen grains while pollination. style connects the stigma to the ovary. Ovary contains ovule which houses the female gamete.

Question 7

What are spores? When are they formed? Give examples. [3 MARKS]

SOLUTION

Solution :

Each point: 1 Mark

A spore is an asexual reproductive body developed by an organism. It has a thick protective coating that protects it.
Spores are formed when the conditions are not favourable for the organism to reproduce. When favourable conditions return, the spore germinates to give rise to new individual organism.
Spores arethe means of reproduction in many fungi like the bread mould and plants like moss and ferns.

Question 8

Explain three methods of seed dispersal?  [3 MARKS]

SOLUTION

Solution :

Each point: 1 Mark

Seed dispersal occurs by the following agents:

1. Dispersal by wind - The seeds that are dispersed by wind are usually light in weight and have wing-like structures for efficient propagation. The stigma of these flowers have hair like structures. eg: maple.
2. Dispersal by water - This kind of dispersal occurs in aquatic plants and plants which grow near water bodies. eg: coconut seeds.
3. Dispersal by animals - Some seeds have spine-like structures on them. They get stuck on the fur of the animals and get spread to different places.

Question 9

Explain binary fission of amoeba with the help of a diagram.  [3 MARKS]

SOLUTION

Solution :

Explanation: 2 Mark
Diagram: 1 Mark

Amoeba is a single-celled organism. It begins the process of reproduction by the division of its nucleus into two nuclei. This is followed by division of its body into two, each part receiving a nucleus. Finally, two amoebae are produced from one parent amoeba. This type of asexual reproduction in which an animal reproduces by dividing into two individuals is called binary fission.

Question 10

State three main differences between asexual and sexual reproduction. [3 MARKS]
 

SOLUTION

Solution : Each point: 1 Mark

Asexual ReproductionSexual Reproduction(i) One parent is involved(i) Two parents are involved(ii) New generation is identical or true copy of their parent(ii) New born are similar to their parents(iii) It doesn't require the formation of gametes(iii) It requires the formation of gametes
 

Question 11

Mention three differences between self-pollination and cross-pollination. [3 MARKS]
 

SOLUTION

Solution : Each point: 1 Mark

Self PollinationCross Pollination(i) Transfer of pollen from the stamen to the pistil(i) Transfer of pollen from the stamen of one flower to the pistil of another flower ofof the same flowerthe same plant or different plants of the same kind(ii) External medium is not required(ii) External medium is required(iii) It occurs only in bisexual flowers(iii) It occurs in both unisexual and bisexual flowers
 

Question 12

Explain seed dispersal by bursting. Give two examples. [3 MARKS]

SOLUTION

Solution : Explanation: 1 Mark
Examples: 2 Marks

The transfer of seeds away from the parent plant is called seed dispersal.
Seeds can be dispersed by bursting of the fruit/pod. Due to high pressure while bursting, the seeds are scattered far from the parent plant.
Eg: castor and balsam.

Question 13

Write a short note on fertilization in plants.  [5 MARKS]

SOLUTION

Solution :

Each point: 1 Mark

1. After pollination, pollen grains from the stamen starts germinating on the stigma to give rise to pollen tubes.
2. The pollen tube grows through style to reach the ovule in the ovary.
3. As it reaches the ovule, the tip of the tube opens and releases the male gametes to fertilize the egg cell.
4. The fusion of the male and the female gamete results in the formation of zygote. The zygote develops into an embryo.
5. Fertilized ovary becomes a fruit and ovules develop into seeds.

Question 14

Write a short note on budding and fragmentation. Give examples of both. [5 MARKS]

SOLUTION

Solution :

Explanation: 3 Marks
Examples: 2 Marks

Budding - Budding is a method of asexual reproduction where a small outgrowth called bud is produced from the parent body. The bud grows and detaches from the parent body and gives rise to a whole new organism. This mode of reproduction is seen in yeast.
Fragmentation - Fragmentation is the process in which the body of the organism gets cut into smaller fragments. Each fragment gives rise to a new individual. This process is observed in simpler organisms like spirogyra.

Question 15

Mention five features of asexual reproduction. [5 MARKS]
 

SOLUTION

Solution :

Each point: 1 Mark

1. Only one parent is involved.
2. It is quicker than sexual reproduction.
3. No gametes are formed.
4. It does not involve fertilization.
5. There is no variation. Newly developed individuals are identical to their parents.

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