NIOS Class 10 Science Worksheet 24 Questions Answers – Reproduction

This Worksheet 24 contains questions based on Chapter 24 Reproduction complete answers.

This post explains the answers of questions given in the worksheet including explanation, diagrams. These solutions will help you complete your assignments and TMA also.

 

Reproduction Worksheet 24 Solution

Q1. List three distinguishing features between sexual and asexual types of reproduction.

Answer

Basis	Asexual reproduction	Sexual reproduction
Number of parents	Only one parent is involved	Two parents (male and female) are involved.
Gametes	No formation and fusion of gametes	Male and female gametes are formed and fused to form zygote
Nature of offspring	Offsprings are exact copies of parent	Offsprings have variations

 

Q2. Mention the role of gametes and zygote in sexually reproducing organisms. Write the importance of reproduction.

Answer

Role of gametes

i.   These are sex cells. Male gametes are sperms and female gametes are egg.

ii.   They carry genetic information from both parents.

iii.   Male gametes and female gametes fuse to form zygote.

iv.  A new individual is produced after fusion or fertilization of gametes.

Role of zygote

i.     The zygote is formed by fusion of gametes.

ii.   It is the first cell of a new organism.

iii. The zygote divides repeatedly to form an embryo.

iv The embryo develops into an individual.

Importance of Reproduction

i.    It ensures the continuity of species.

ii.   It helps in the survival of living organisms on the earth.

iii. It maintains the balance of life in nature.

iv.   It allows transfer of characters form parents to offspring.

v.    It is a basic life process.

 

Q3. Define pollination? How does it occur in plants? How does pollination lead to fertilisation?

Answer

Pollination: - It is the process of transfer of pollen grains from the anther to the stigma of a flower. The process is carried by agents like wind, insects, water etc.

Process of Pollination

Pollination occurs in two ways – (i) Self-pollination (ii) Cross pollination

(i)       Self-pollination: - The transfer of pollens from the same flower falls on its own stigma.

(ii)      Cross pollination: - The transfer of pollens from the flower falls on stigma of another flower of the same species.

Pollination to Fertilization

After pollination, the pollen grains reach the stigma of the flower where it germinates and forms a pollen tube. This pollen tube grows through the style towards the ovary. The male nucleus travels through the pollen tube and reaches the ovule (female gametes).

Inside the ovule, the male nucleus fuses with the female nucleus fuses with the female nucleus. This fusion is called fertilization.

After fertilization, the fertilized ovule develops into a seed which can grow into a new plant.

 

Q4. Identify A,B and C in the given diagram and write their functions.

Answer

Q5. Draw a labelled diagram of female reproductive organs. Write the functions of the following parts in human female reproductive system:

(i)        Ovary (ii) Oviduct (iii) Uterus (iv) Fallopian tube

Answer

Functions of female reproductive organs

(A)   Ovary: - It produces ova or eggs. It secretes female hormones like oestrogen and progesterone.

(B)    Oviduct: - It carries eggs from the ovary to the uterus.

(C)    Uterus: - The womb where the embryo develops into a foetus. It provides nutrition and protection to the developing baby.

(D)   Fallopian tube: - It transports the egg form the ovary to uterus. The fertilization occurs here.

 

 

Q6. Give one function of testes and vas deferens, in human male reproductive system. List in a sequence the events that lead to the birth of a new individual.

Answer

Function of testes: - They produce sperms (male gametes)

Function of vas deferens: - It transports sperms from testes to the ejaculatory duct.

Sequence of events that lead to the birth of a new individual

i.    Formation of gametes- sperms in testes and ovum in ovary

ii.   Fertilization: - Fusion of sperm and ovum in the fallopian tube.

iii.   Zygote formation: - First cell formed after fertilization.

iv.  Cell division: - Zygote divides to form embryo.

v.    Implantation: - Embryo gets embedded in uterine wall.

vi.  Foetus development: - Embryo develops into foetus in uterus.

vii.    Birth :-  A developed child is born.

 

Q7. State the role of hormones related to reproduction. List out the influence and function of each of the following:

i.        FSH

ii.     LH

iii.   Estrogen

iv.   Testosterone

v.       Oxytocin

Answer

Reproduction in human is controlled by different hormones. These hormones regulate the growth of sex organs, formation of gametes, development of secondary sexual characters, pregnancy and child birth.

Functions of hormones

    1. FSH (Follicle stimulating hormone): - It helps in the maturation of eggs in females and also helps in sperm formation in males.

    2. LH (Luteinising Hormone) :- It helps in the release of the egg form the ovary and also supports hormone secretion.

    3. Estrogen :- It is the female hormone that helps in the development of female secondary sexual characters like breast development and controls menstrual cycle.

    4. Testosterone: - It is male hormone that helps in the development of male secondary sexual characters like deep voice, facial hairs and muscle growth and supports sperm formation.

    5. Oxytocin: - This hormone causes uterine contraction during childbirth and helps in the delivery of the baby.

 

Q8. Mention the physiological changes that arise at puberty in girls and boys and also list out two psychological changes experienced by adolescents.

Answer

Puberty is the stage when a child’s body changes into an adult. This stage is capable of reproduction. During puberty, following physiological changes occur in both girls and boys.

Physiological changes in girls at puberty

i.    Development of breasts

ii.   Menstruation cycle starts

iii.    Maturation of ovaries and release of eggs

iv.  Growth of pubic and underarm hair

v.    Rapid increase in height and weight

Physiological changes in boys at puberty

i.     Maturation of testes and sperm formation

ii.   Growth of facial hair, pubic and underarm hair

iii.  Muscle development

iv. Rapid growth and height

Psychological changes in adolescents

i.     Mood swings and emotional sensitivity

ii.   Increase of self-consciousness and concern about appearance

 

Q9. Write three methods of contraception. State two advantages of using such preventive methods.

Answer

Contraception means the method used to prevent pregnancy. These methods help in family planning land allow people to decide the size and timing of family.

There are different types of contraceptive methods.

i.     Condoms: - prevent sperms from reaching the egg

ii.    IUCD (copper -T) – Prevent implantation of embryo in the uterus.

iii.   Oral contraceptive pills :- Prevent ovulation process

 

Q10. Expand the abbreviations HIV and AIDS. Is AIDS an infectious disease? List any four modes of spreading AIDS. How it can be prevented?

Answer

HIV – Human Immunodeficiency Virus

AIDS – Acquired  Immunodeficiency Syndrome

Yes, AIDS is an infectious disease because it spreads from one person to another through specific modes of transmission.

Modes of spreading AIDS/HIV

i.     Unprotected sexual contact with an infected person.

ii.    Transfusion of infected blood

iii.  Use of infected needles and syringes

iv.  From infected mother to child during pregnancy

Prevention of AIDS

i.   Safe sex practices and use of condoms

ii. Have one faithful partner

iii.Use sterilized needles and syringes

iv.Test blood before transfusion

v.   Proper medical care of HIV infected pregnant woman