NATIONAL OPEN UNIVERSITY OF NIGERIA

UNIVERSITY VILLAGE, PLOT 91, CASDASTRAL ZONE, NNAMDI AZIKIWE EXPRESS WAY, JABI, ABUJA.
FACULTY OF SCIENCES
JULY 2017 EXAMINATION

COURSE CODE: BIO 303

COURSE TITLE: GENERAL CYTOLOGY (2 UNITS)

TIME ALLOWED: 2 Hours

INTRUCTION: ANSWER QUESTION ONE (COMPULSORY) AND ANY OTHER THREE QUESTIONS.

1. a. Define the following terms:

1. Cytogenetics; (1mark)
2. Cytology; (1mark) &
3. Genetics. (1mark)

          b. i. Mention the different types of Structural Chromosomal Variations.  (2marks)

          ii. Define each of the mentioned structural chromosomal variations.  (2marks)

          c. i. What is Numerical Chromosomal Variation? (2marks)

          ii. Mention the different types of numerical chromosomal variations. (1mark)

The diagram/image below shows the different parts of a modern day light microscope

4. State the function(s) of each labeled part of the  Microscope (6marks):

          e. State the feature & advantages of a Phase Contrast Microscope. (2marks)

          f. Indicate two advantages of an electron microscope. (2marks)

          g. Indicate two major disadvantages of an electron microscope. (2marks)

          h. Give any three (3) advantages of Fluorescence Microscope (3marks)

2. a. State the molecular composition of a cell. (2 ½  marks)

b. State five (5) functions/importance of protein in a living cell. (2½ marks)

c. List five (5) different types of Nucleic acids. (2 ½ marks)

d. Outline the roles of the different types of nucleic acids. (7 ½ marks)

3. a. Mention three (3) major control checkpoints which exist during the course of eukaryotic cell cycle. Elaborate on any one of these checkpoints. (5marks)

1. In a tabular form, make a brief comparism between RNA and Proteins. (10marks)

4. a. Outline the general cytogenetic procedures synonymous to all cytogenetic techniques. (4marks)

b. i. Define Karyotype. (2marks)

ii. After Karyotyping, what are the observable characteristics in the chromosomes? (4marks)

c. Enumerate the importance and applications of cytogenetics. (5marks)

5.  i. What is cellular differentiation? (8marks)

ii. List the four main stages of embryogenesis. (2marks)

iii.Write short note on  the word “Gastrulation”. (5marks)