Description

BZYCT 133 BSCG ignou assignment 2024

Course : BSCG
Session 2024
Submission date : This assignment is valid from 1st January, 2024 to 31st December, 2024.

1. a) Write two important differences between scales of reptiles and fishes.
b) Explain keratinization in terrestrial vertebrates.
(5)
(5)
2. a) Mention the two types of endoskeletal structures found in vertebrates.
What is the difference between their ground matrix?
b) Fill in the blanks in the following sentences by selecting an appropriate
word from those given in the parenthesis after each sentence:
i) The skeleton of the head is known as ……………………. (vertebral
column, pelvic girdle, skull).
ii) Cranium encloses and protects the ……………………… (eye, heart,
brain).
iii) The brain within the cranium is in contact with the spinal cord
through ………………………… an aperture found at the hind end of
the cranium (fenestra ovalis, foramen magnum, external nares).
iv) The vertebra with concavity infront and convexity behind is called
…………………. type (amphicoelous, procoelous, opisthocoelous).
v) The bone humerus of the upper arm articulates with the pectoral
girdle at ……………………… cavity (glenoid, acetabulum,
zygapophysis).
vi) Radio-ulna, a composite bone is found in ……..…………….. (rabbit,
bat, frog).

BZYCT 133 BSCG ignou assignment 2024

3. a) Describe the structure of the respiratory system of cartilaginous fishes and
state how it differs from that of bony fishes.
b) Briefly discuss the mechanism of pulmonary respiration in frog. How is it
different from reptilian mechanism of respiration?
(5)
(5)
4. a) Write short note on the general structure of heart wall.
b) Name different stages in the evolution of heart.
(5)
(5)
5. Draw a well labeled diagram of the internal structures of ovary and describe the
structures present in it.
(10)
6. List at least three stages in gene expression that can be regulated to result in
differentiated cell types? Explain any one of them with the help of an example.

BZYCT 133 BSCG ignou assignment 2024

7. Mark the following statements as ‘True’ or ‘False’:
i) During development cells move by extending their cell processes in all
directions without any polarity.
(10)
4
ii) The cytoskeleton of the cell is actively involved in cell movement and cell
shape change.
iii) Cadherin on one cell binds strongly to similar cadherins molecules on
other cells.
iv) Integrins are cell adhesion molecules that attach cells to other cells at the
apical region.
v) Permissive interaction involves gene expression in the induced cell.
vi) Morphogens are paracrine signalling molecules.
vii) In apoptosis the cell organelles are delivered to lysosomes and the cell
contents are spilled out.
viii) Cell death by necrosis indicates that cell has undergone a toxic reaction.
ix) Optic cup is induced to form the retinal layers by reciprocal induction from
the lens.
x) Pattern formation is the result of morphogenesis.
8. a) Briefly describe the spermiogenesis process.
b) What are the major differences in the development and differentiation of
an egg and a sperm?
(5)
(5)
9. Describe the process of neurulation in chick. (10)
10. a) How is the placenta formed? What are its functions?
b) Draw a flow chart to show how the three germinal layers are derived from
the zygote.