Fertilization

Q.

Explain what is porogamy , mesogamy and chalazogamy with suitable diagram.

Q.

Give functions of Umbilical cord.

Q. Give the advantages of seed formation for plant.

Q.

How does the embryo get nourishment?

Q.

Distinguish between pollination and fertilisation. Mention the site and product of fertilisation in a flower. Draw a neat, labelled diagram of a pistil showing pollen tube growth and its entry into the ovule.

Q.

One of the following processes does not lead to the formation of clones. This is :
(a) fission
(b) fertilisation
(c) fragmentation
(d) tissue culture

Q.

Where does fertilization occurs in human females?

1. Uterus

2. Cervix

3. Oviduct

4. None of these

Q.

What is external fertilization? The following diagram shows life cycle of a frog. Identify A, B , C and D in the diagram. [3 MARKS]

Q.

In what ways is fertilisation in a plant :
(a) similar to fertilisation in a human?
(b) different from fertilisation in a human?

Q.

The number of chromosomes in parents and offsprings of a particular species remains constant due to :
(a) doubling of chromosomes after zygote formation
(b) the halving of chromosomes during gamete formation
(c) doubling of chromosomes after gamete formation
(d) the halving of chromosomes after gamete formation

Q.

External fertilisation can occur both in water and on land.

1. True
2. False

Q.

The advantage that internal fertilisation has over external fertilisation is that in internal fertilisation :
(a) new off-springs are exactly like the parent
(b) production of large numbers of gametes is unnecessary
(c) copulation and fusion of gametes is passive
(d) fewer individuals are produced

Q.

(a) Explain the term 'fertilisation'.
(b) Give some examples of different modes of fertilisation in nature ?
(c) What type of fertilisation takes place in (i) fish, and (ii) birds ?

Q.

The length of pollen tube depends on the distance between

1. Pollen grain and upper surface of stigma

2. Pollen grain on upper surface of stigma and ovule

3. Pollen grain in anther and upper surface of stigma

4. Upper surface of stigma and lower part of style

Q.

Which part/organ of the female reproductive system serves as the

(i) Site for implantation of the zygote

(ii) Site of fertilization.

Q. (a) Fertilisation in humans can occur only once in a month. Why ?
(b) What is the scientific name of (i) womb, and (ii) birth canal ?

Q.

What is umbilical cord?

Q.

What is the process of fertilization?

Q.

Fish and frog perform internal fertilization.

1. True
2. False

Q. Which one of the following best describes the function of the umbilical cord ? It :
(a) feeds the embryo with digested substances.
(b) conveys nutrients and wastes to and from the embryo respectively
(c) removes waste matter from the embryo to the mother's blood.
(d) supplies oxygenated blood from the mother to the embryo.

Q. Fertilisation results immediately in the formation of :
(a) a zygote
(b) an embryo
(c) a placenta
(d) a foetus

Q.

In humans, fertilization takes place in-

Q.

Select odd one out giving reasons:
Embryo, zygote, larva, foetus.

Q.

What are haploid cells?

Q. state the significance of variation that occurs during sexual reproduction

Q.

The germ cell A produced by a person X is round in shape and it fuses with another germ cell B having a long tail and produced by a person Y. The fusion of A and B produces a new cell C. The cell C divides repeatedly and grows inside the organ D of person X to form E in which the body features of the unborn baby are not much developed. E grows further to form F in which the various body features of the unborn baby (like hands, legs, head, eyes, and ears, etc.) can be identified. F grows further and ultimately forms a baby. What are A, B, C, E and F ? Out of the two persons X and Y, which one is male and which one female?

Q.

The fusion of ovum and sperm is called _________.

Q.

When a fertilised egg E formed in the oviduct of a human female divide repeatedly to form an embryo, the embryo gets implanted in the thick and soft lining of the uterus. After this, a disc-like special tissue T develops between the uterus wall and embryo through which all the requirements of the developing embryo (and foetus) are met from the mother's body. The embryo is connected to the tissue T through a string like structure S.
(a) What is the other name of fertilised egg cell E?
(b) What is the name of tissue T?
(c) Name the string-like structure S.
(d) Name two substances which pass from mother's blood to embryo through tissue T and, one type of substance which passes from embryo to mother's blood.
(e) What happens to S when the baby is born? Why?

Q.

Internal fertilisation does not occur in ______ and ______.

1. humans

2. fish

3. frogs

4. cows

Q. Fertilisation leads to the formation of

1. seed
2. embryo
3. zygote
4. fruit