Development from Zygote to Blastocyst
- It has almost equal quantity of cytoplasm as an uncleaved zygote but much more DNA
- It has far less cytoplasm as well as less DNA than in an uncleaved zygote
- It has more or less equal quantity of cytoplasm and DNA as in uncleaved zygote
- It has more cytoplasm and more DNA than an uncleaved zygote
State whether true or false:
In non-mammalian species, there is no inner cell mass. Instead, the blastula consists of just one cell layer.
Cleavage in the fertilised egg of humans
Starts in uterus
Starts when egg is in fallopian tube
Match the figures with the respective descriptions.
- Daughter cells that are formed are known as blastomeres.
- There is no growth phase between divisions during cleavage.
- Mammalian blastula that contains two distinct cell lineages.
- Inner cell mass becomes the embryo itself and trophoblast cells help implantation in the uterine wall.
i)➡ b, ii)➡ a, iii)➡ d, iv) ➡ c
i)➡ d, ii)➡ b, iii)➡ a, iv) ➡ c
i)➡ c, ii)➡ d, iii)➡ b, iv) ➡ a
i)➡ d , ii)➡ c, iii)➡ a, iv) ➡ b
Morula differs from the blastula in the
Absence of cavity
Presence of cavity
Absence of yolk
None of these
- 4-8 cells
- 8-16 cells
- 24-30 cells
- 60-72 cells
At the time of implantation, the human embryo is called:
The embryo at the 16-celled stage is known as
A represents the fertilised zygote.
B represents the stage of morula formation.
C represents the blastocyst.
D represents the blastocyst implantation.
Morula is a developmental stage___________
between the zygote and blastocyst
between the blastocyst and gastrula
between implantation and parturition
after the implantation