RBSE Solutions for Class 12 Biology Chapter 33 Embryonic Development in Man

Rajasthan Board RBSE Class 12 Biology Chapter 33 Embryonic Development in Man

RBSE Class 12 Biology Chapter 33 Multiple Choice Questions

Question 1.
How many cells are found in Morula?
(a) 4
(b) 8
(c) 16
(d) 32
Answer:
(c) 16

Question 2.
Which cavity is formed during gastrulation?
(a) Animal pole
(b) Vegetal pole
(c) Blastocoel
(d) Amniotic cavity
Answer:
(c) Blastocoel

Question 3.
Major parts of eyes are derived from which germinal layer?
(a) Ectoderm
(b) Mesoderm
(c) Endoderm
(d) None of the above
Answer:
(a) Ectoderm

Question 4.
Formation of Kidney takes place from which of the following germinal layer.
(a) Ectoderm
(b) Mesoderm
(c) Endoderm
(d) None of the above
Answer:
(b) Mesoderm

Question 5.
Which activity does not takes place during the first week of embryonic development of human?
(a) Implantation
(b) Formation of blastocoel
(c) Morula formation
(d) Formation of Primitive streak
Answer:
(d) Formation of Primitive streak

Question 6.
Development of heart completes during embryonic development of human in –
(a) First week
(b) Second week
(c) 3rd to 6th week
(d) 7th to 8th week
Answer:
(d) 7th to 8th week

RBSE Class 12 Biology Chapter 33 Very Short Answer Type Questions

Question 1.
What is Embryogenesis?
Answer:
The process of formation of the multicellular zygote from the single-celled zygote is called embryogenesis.

Question 2.
What kind of cell divisions take place during cleavage?
Answer:
Mitosis division but it is without growth phase.

Question 3.
What are blastomeres?
Answer:
The cells formed as a result of cleavage are called blastomeres.

Question 4.
How many blastomeres are found in morula?
Answer:
16 blastomeres.

Question 5.
What is derived from blastopore in a man?
Answer:
Anus.

RBSE Class 12 Biology Chapter 33 Short Answer Type Questions

Question 1.
How the formation of blastocyst takes place in Human?
Answer:
Blastulation:

• Formation of blastula/blastocyst from morula is known as blastulation.
• In human morula, the outer cuboidal cells become flattened when it reaches into the uterus.
• These flattened cells are called as Trophoblast, by which they adhere with uterine epithelium.
• Cleavage continued and a cluster of cells differentiates into two distinct groups, the epithelial-like trophoblast or nutritive cells surrounding the expanding cavity and inner cell mass of formative cells of the embryo.
• The cavity is called blastocoel and embryo is known as a blastocyst (a kind of blastula) in human.

Question 2.
Differentiate between blastulation and gastrulation?
Answer:

Blastulation	Gastrulation
It results in the formation	It results in the formation of blastula of the gastrula
Formation of Blastocoel	Formation of Gastrocoel
No opening is formed	Blastopore is formed

RBSE Class 12 Biology Chapter 33 Essay Type Questions

Question 1.
How and when the formation of blastocyst takes place?
Answer:
Blastulation:

• Formation of blastula/blastocyst from morula is known as blastulation.
• In human morula, the outer cuboidal cells become flattened when it reaches into the uterus.
• These flattened cells are called as Trophoblast, by which they adhere with uterine epithelium.
• Cleavage continued and a cluster of cells differentiates into two distinct groups, the epithelial-like trophoblast or nutritive cells surrounding the expanding cavity and inner cell mass of formative cells of the embryo.
• The cavity is called blastocoel and embryo is known as a blastocyst (a kind of blastula) in human.

Question 2.
Describe gastrulation in Man.
Answer:
Gastrulation:
During implantation, zona pellucida disappears and the trophoblast cells become giant-sized and aggressively invade the uterine tissue and make contact informing the placenta.

Inner cell mass at this time undergoes differentiation and a layer of very flat cells appear on the interior surface of the inner cell mass that forms future endoderm. The remaining dorsal inner cell mass is called epiblast, which is presumptive material for ectoderm and mesoderm.

Formation of three germinal layers from a single-layered blastocyst. The blastocoel gets obliterated & a new cavity called gastric or archenteron is formed. It is called a gastrula. The method by which blastula becomes or converted into gastrula is called Gastrulation.

The mesodermal cells soon involute through the primitive streak and diverge anteriorly and laterally, occupying a position between ectoderm and endoderm. Epiblast also contributes some cells to endoderm. The cells migrating to their future places by amoeboid movements.

Question 3.
A child born after seven months gestation period can survive. Explain How?
Answer:
Up to seven months of embryonic development, most of the vital body organs are formed and developed. This is the main region that embryo can survive.

RBSE Solutions for Class 12 Biology