Development from Zygote to Blastocyst

Q.

Which organ is first developed in the embryo?

Q. Which one of the following statements about morula in humans is correct?

1. It has almost equal quantity of cytoplasm as an uncleaved zygote but much more DNA
2. It has far less cytoplasm as well as less DNA than in an uncleaved zygote
3. It has more or less equal quantity of cytoplasm and DNA as in uncleaved zygote
4. It has more cytoplasm and more DNA than an uncleaved zygote

Q.

What are the inner cells of the blastocyst called?

Q. Select the correct explanation for the labels A, B, C and D.

1. A represents the fertilised zygote.
2. B represents the stage of morula formation.
3. C represents the blastocyst.
4. D represents the blastocyst implantation.

Q.

How long does it take to form a blastocyst?

Q.

Match the figures with the respective descriptions.

1. Daughter cells that are formed are known as blastomeres.
2. There is no growth phase between divisions during cleavage.
3. Mammalian blastula that contains two distinct cell lineages.
4. Inner cell mass becomes the embryo itself and trophoblast cells help implantation in the uterine wall.

1. i) $\Rightarrow$ 4, ii) $\Rightarrow$ 3, iii) $\Rightarrow$ 1, iv) $\Rightarrow$ 2

2. i) $\Rightarrow$ 3, ii) $\Rightarrow$ 4, iii) $\Rightarrow$ 2, iv) $\Rightarrow$ 1

3. i) $\Rightarrow$ 2, ii) $\Rightarrow$ 1, iii) $\Rightarrow$ 4, iv) $\Rightarrow$ 3

4. i) $\Rightarrow$ 4, ii) $\Rightarrow$ 2, iii) $\Rightarrow$ 1, iv) $\Rightarrow$ 3

Q.

State whether true or false:
In non-mammalian species, there is no inner cell mass. Instead, the blastula consists of just one cell layer.

1. True

2. False

Q.

A zygote is completely divided into two by a cleavage furrow. This type of cleavage is________

1. equatorial

2. meroblastic

3. radial

4. holoblastic

Q. Study the following statements and answer the question.

In the transport of ovum in the female reproductive system, a process known as ‘A’ occurs and the ‘B’ division starts as the zygote moves through the ‘C’ of the oviduct towards the ‘D’. Identify A, B, C and D.

1. A→Blastulation, B→Meiotic, C→Ampulla , D→Uterus
2. A→Parturition, B→Meiotic, C→Infundibulum, D→Uterus
3. A→Implantation, B→Mitotic, C→Fimbriae, D→ Ovary
4. A→Cleavage, B→ Mitotic, C→Isthmus, D→ Uterus

Q.

At the time of implantation, the human embryo is called:

1. embryo

2. blastocyst

3. zygote

4. foetus

Q.

State whether true or false:
In non-mammalian species, there is no inner cell mass. Instead, the blastula consists of just one cell layer.

1. True

2. False

Q. present in the blastocyst consist of stem cells that divide and differentiate to form the germ layers.

1. Trophoblast
2. Blastomeres
3. Morula
4. Inner cell mass

Q.

The embryonic period finishes at the end of -

1. 8 weeks

2. 4 weeks

3. 2 weeks

4. 12 weeks

Q. Gastrula is the embryonic stage in which

1. cleavage occurs
2. blastocoel forms
3. germinal layers form
4. villi form