CBSE Class 10 Science Important Questions Chapter 8 How Do Organisms Reproduce Part 5

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5 Marks Questions

1. Describe triples fusion in plants? Where does it occur? Draw a neat and clean well labeled diagram to support your answer.

Ans. After pollination, the pollen grains germinate n the stigma by producting pollen tube. This pollen tube is formed from inner wall of the pollen grain. It penetrates the stigma and passes through the style and enters the ovule through an opening called male gamete it releases two male gametes in the embryo sac. One male gamete fuses with egg cells and second fuses with two polar nuclei. The fusion of one male gamete with the egg cells is called syngamy. The fusion of second male gamete with two polar nuclei is called triple fusion. This process occurs in ovary.

Triples fusion in plants

Triples Fusion in Plants

Triples fusion in plants

2. Draw a well labeled diagram of female reproductive system and mention its parts.

Female reproductive system

Female Reproductive System

Female reproductive system

Ans. a) A pair of ovaries – ovaries produces ova and female sex hormone. One egg is produced every month by one of the ovaries. Ova are picked up by the funnel shaped fallopian tubes.

b) Fallopian tubes – There are two fallopian tubes. It carries ova from ovary to the uterus. Fertilization occurs in fallopian tubes.

c) Uterus – Pear shaped hollow muscular organ. Fertilized ovum remains attached to the uterus wall.

d) Vagina – It is a narrow muscular tube. Its upper end is connected to the cervix of the uterus and lower end opens outside through an opening. It is a place for copulation.

3. Draw a well labeled diagram of male reproductive system and describe its parts.

Male reproductive system and describe its parts.

Male Reproductive System and Describe Its Parts.

Male reproductive system and describe its parts.

Ans. a) A pair of testes – Each testis produces sperms and male sex hormone called testosterone. Testes are present in small pouch called scrotum.

b) Epididymis – It is a long coiled tube. The head is connected with testis and tail is connected with vas deferens

c) Vas deferens – It is a long tube which begins from the tail of epididymis Urethra – It receives the vas deferens from both the testes. It opens outside through penis. It carries both sperms and urine.

4. Differentiate between asexual and sexual reproduction.

Ans.

Asexual and Sexual Reproduction
Asexual and sexual reproduction

Asexual reproduction

Sexual Reproduction

Only one parent is involved

Two parents are involved

Offspring resembles exactly with the parent

Organisms do not resemble exactly, but certain features of both the parents

Cell divides mitotically

Mitosis and meiosis both divisions are involved.

Gametes are not produced

Gametes are produced

Not fertilization

Fertilisation of gametes

Organisms produced have less adoptability

Organism produced has more adaptability

Variations are absent

Variations are present

5. What is the need of population control?

Ans. Overpopulation leads to a number of problems like –

a) Unemployment – More number of people means more jobs and if sufficient numbers of jobs are not available, it leads to unemployment.

b) Poverty – If there are more persons and the income is less, it becomes poorer with the addition of every child.

c) Food supply – If the population increases and the food production does not increase; this will lead to shortage of food supply.

d) Hygienic condition – more people in small area generally make the condition unhygienic for survival

e) Educational problem – It becomes difficult for the government to provide education to all

f) Housing problem – It also creates housing problem.

g) Pollution – More pollution with increasing population.

h) Decrease in natural resources – More people will decrease the natural resources quickly.

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