Page 54 - Biology - XII

VIVA VOCE

Q1. What does blastocoel has?
Ans. It has a fl uid to protect the inner cell mass.

Q2. Does the morula has less number of cells than blastula? How much/what is the number?
Ans. Yes. 16 blastomeres/cells.
Q3. What is the future of ‘foetus’ development in blastula?
Ans. Inner mass of cells attached to trophoblast layer.

Q4. Name the peripheral cells formed in blastula.
Ans. Trophoblast or trophoderm
Q5. What is cleavage?
Ans. A type of cell division that takes place in embryonic development is called cleavage.

Q6. What is blastula?
Ans. It is a 32-celled stage of embryo in mammals.

Q7. Which stage of embryonic development is blastula?
Ans. Second stage

Q8. Name the stage prior to blastula of the embryo.
Ans. Morula

Q9. How is morula diff erent from blastula?
Ans. Morula is solid structure (without cavity) and blastula is a structure with a cavity called blastocoel.
Q10. Mention the other name given to inner cell mass of blastula.
Ans. Trophoblast cells or cells of Rauber the point of attachment.

COMPETENCY BASED QUESTIONS

Multiple Choice Questions

Q1. The feature that diff erentiates morula from blastula is that blastula has
(a) trophoblast (b) blastocoel (c) inner cell mass (d) (a), (b), and (c)
Q2. The development of embryo in a human female takes place in

(a) oviduct (b) ovary (c) uterus (d) uterine cavity
Q3. Embryonic stages that develop in uterus of a human female after implantation/conceivement
is
(a) zygote (b) morula, Blastula
(c) morula, Blastula, Gastrula (d) embryo

Q4. Gastrula is the development stage of embryo that has
(a) more number of cells (b) cells reorganised as three germs layers

(b) (a) and (b) (d) solid structure

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