Cleavage refers to the division of cells in the early embryo and it is a characteristic term for embryology. After cleavage, fertilization follows where the transfer is triggered with an activation of cyclin-dependent kinase complex. Many species have their zygotes undergo rapid cell cycles having no significant overall growth. It produces a cluster of cells of the same size as that of the origins zygote. Different cells which are obtained as a result of the cleavage are called Blastomeres and these form a compact mass known as Morula. The cleavage biology ends with the formation of the Blastula.
Cleavage in biology or cleavage in zoology is the same as explained in the above paragraph. The two categories of cleavage depend on the amount of yolk present in the egg and those are holoblastic, where total or entire cleavage takes place and the second one is meroblastic cleavage also known as partial cleavage. Meroblastic cleavage takes place in the presence of a large amount of yolk in the fertilized egg cell and its two types are discoidal and superficial cleavage. Vegetal pole is the pole of the egg where the highest concentration of yolk is present and its opposite is known as animal pole.
The three types of cleavage are determinate cleavage, indeterminate and holoblastic cleavage. Holoblastic cleavage can be further divided into bilateral, radial, rotational and spiral.
Below are some of the samples for Cleavage Biology MCQs for NEET 2020
1. Meroblastic Cleavage is another name for which of these
(a) Equal holoblastic
(b) Unequal holoblastic
2. Which type of Cleavage is found in Insects?
3. Discoidal and Superficial Cleavages belong to which type of Cleavage?
(a) Unequal holoblastic
(b) Equal holoblastic
(c) Both (a) and (b)
4. When the first Cleavage furrow divides the Zygote completely into two, it is
(a) Meroblastic cleavage
(b) Radial cleavage
(c) Equatorial cleavage
(d) Holoblastic cleavage
5. The only system in Humans which is derived from all the three Germ layers is
(a) Nervous system
(b) Respiratory system
(c) Digestive system
(d) Excretory system
6. The process by which fertilized egg divides is known as
7. When an unfertilized egg is pricked with a micro needle, what happens?
(a) It will transform into a tadpole at a faster rate
(b) It starts dividing
(c) It will remain undivided
(d) It will die immediately
8. How many cells are there in a freshly unfertilized egg of hen?
(a) One cell
(b) 1,000 cells
(c) 100 cells
(d) 10,000 cells
9. A 16 celled stage of egg completes how many Cleavages?
10. The spindle in determinate Cleavage is situated
11. How many hours after fertilization, the zygote undergoes a series of Mitotic divisions to form Blastomeres?
(a) 10 hours
(b) 5 hours
(c) 15 hours
(d) 30 hours
12. An outer envelope of cells in the Blastocyst is called
(c) Animal pole
(d) Anembryonic pole
13. Implantation occurs after how many days of Fertilization?
(a) 2 days
(b) 4 days
(c) 10 days
(d) 7 days
14. Which of the following is correct during Cleavage?
(a) Embryo size decreases
(b) Cell’s size decreases
(c) Cell’s size increases
(d) Embryo size increases
15. In mammalian egg, Cleavage is
(a) Discoidal meroblastic
(b) Unequal holoblastic
(c) Equal holoblastic
(d) Superficial meroblastic
16. In an egg, the Cleavage type can be determined by
(a) Sperm’s shape and size
(b) Location and size of the nucleus
(c) Distribution and amount of yolk
(d) Number of egg membranes
17. What’s true about the Cleavage in fertilized eggs of Humans?
(a) It starts in the fallopian tube
(b) It starts when egg reaches the uterus
(c) It is meroblastic
(d) It is identical to normal mitosis
18. How is the division of Meroblastic Cleavage?