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CEB601S - CELL BIOLOGY - 2ND OPP - JULY 2022 |
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NAMIBIA UNIVERSITY
OF SCIENCE AND TECHNOLOGY
FACULTY OF HEALTH, APPLIED SCIENCES AND NATURAL RESOURCES
DEPARTMENT OF NATURAL AND APPLIED SCIENCES
QUALIFICATION: BACHELOR OF SCIENCE (MAJOR AND MINOR)
QUALIFICATION CODE: 07BOSC
LEVEL: 6
COURSE CODE: CEB601S
COURSE NAME: CELL BIOLOGY
SESSION: JULY 2022
PAPER: THEORY
DURATION: 3 HOURS
MARKS: 100
EXAMINER
SECOND OPPORTUNITY QUESTION PAPER
DR LAMECH MWAPAGHA
MODERATOR | DOR JEYA KENNEDY
INSTRUCTIONS
Answer ALL the questions.
Write clearly and neatly.
Number the answers clearly.
All written work MUST be done in BLUE or BLACK ink.
PERMISSIBLE MATERIAL
Scientific Calculator
THIS QUESTION PAPER CONSISTS OF TEN (10) PAGES
(Including this front page)
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SECTION A: MULTIPLE CHOICE QUESTIONS
[20]
e There are 20 multiple choice questions in this section. Each question carries 1 mark.
e Answer ALL questions by selecting the LETTER with the correct answer.
1. Lysosomes can be expected to be present in large numbers in cells which;
A. are migrating
B. are actively dividing
C. carry out phagocytosis
D. replicate DNA
2. In lactose, the linkage is;
A. B-1-4 linkage
B. a-1-2 linkage
C. B-1-2 linkage
D . a-1-4 linkage
3. The stage of mitosis when chromosomes condense to form rod-shaped structures visible under the
microscope is called;
A. metaphase
B. telophase
C. prophase
D. anaphase
4. Cell surface receptors may be any of the following except;
A. G protein linked
B. enzymic receptors
C. single-pass transmembrane proteins for neurotransmitters
D. chemically-gated ion channels
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5. What are centrioles involved in?
A. cell division
B. lysosome formation
C. intracellular digestion
D. ribosome formation
6. Which of the following organelles and functions are NOT correctly related?
A. endoplasmic reticulum--photosynthesis
B. vacuoles--storage
C. lysosomes--enzymes
D . mitochondria--cellular respiration
7. The _____ surrounds the cell like a belt, preventing the passage of substances between the cells.
A. gap junction
B. desmosome
C. hemidesmosome
D. tight junction
8. Two molecules of acetyl-coenzyme A yields what energy rich molecules when metabolized via the
citric acid cycle?
A. 6 NADH + 2 FADH2 + 2 GTP
B. 3 NADH + 1 FADH2+ 1 GTP
C. 4NADH + 1FADH2 + 1 GTP
D. 3 NADH + 2 FADH2 +1 GTP
9. Which of the following deoxyoligonucleotides will hybridize with a DNA containing the sequence
(5')AGACTGGTC(3')?
A. (5')CTCATTGAG(3')
B. (5')GACCAGTCT(3')
C. (5')|GAGTCAACT(3')
D. (5')TCTGACCAG(3')
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10. Which of the following statements about the regulation of a metabolic pathway is correct?
A. Most metabolic pathways are regulated
B. Regulation of metabolic pathways always involves changing the amount of enzymes
C. Metabolic regulation always depends on control by hormones
D. Most metabolic pathways are not regulated
11. The mobile carrier protein that transports fructose to inside the cell using energy is
A. SGLT-1
B. GLUT-5
C. GLUT-2
D. All the above
12. Which of the following statements is FALSE?
A. Cell walls are found in plants but not in animals
B . Cell walls are found inside the plasma membrane of a cell
C, The main constituent of a primary cell wall is cellulose molecules
D . Secondary cell walls contain lignin, a substance that makes them stronger than primary cell walls
13. Migration of cancerous cells from the site of origin to other part of the body forming secondary
tumours is called;
A. proliferation
B diapedesis
C. metastasis
D . none of the above
14. Which of the following is a mismatch?
A. Polymerase — Taq polymerase
B . Template — double stranded DNA
C. Primer— oligonucleotide
D . Synthesis — 5’ to 3’ direction
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15. Which of the following apply to intercellular junctions?
A. The three major adhesive junctions of animal cells are adherens junctions, desmosomes and
hemidesmosomes
The junctional complexes of gastrointestinal enterocytes ensure that nutrients are only absorbed
through the spaces between the cells, which prevents them absorbing potentially harmful
substances
Desmosomes and hemidesmosomes connect epithelial cells to their basement membrane and
adjacent cells respectively
Gap junctions and plasmodesmata are homologous structures
16. Which of the following statements about the electron transport chain is correct?
A. The electron transport chain is made up of a chain of electron carriers with increasing redox
potential
. The electron transport chain is made up of a chain of electron carriers with decreasing electron
affinity
. The electron transport chain is made up of a chain of electron carriers with decreasing oxidising
power
. The electrons transferred from carrier to carrier in the electron transport chain gain energy
17. The chemical equation for photosynthesis;
A . 6CO2 + CgH120¢ --->using sunlight ---> 6H20 + 602
B. 6COz2 + 602 --->using sunlight ---> CgHi20¢6 + 6H20
C 6CO2 + 6H20 --->using sunlight ---> CgHi20¢ + 602
D . 602 + 6H20 --->using sunlight ---> C6H120¢6 + 6CO2
18. In which phase of the cell cycle is DNA replicated?
A. G1 phase
B . Sphase
G G2 phase
D . Mphase
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19. Which of the following statements about the reactions of glycolysis is correct?
A. In glycolysis glucose-6-phosphate is split into glyceraldehyde-3-phosphate and
dihydroxyacetone phosphate
In glycolysis fructose-6-phosphate is split into glyceraldehyde-3-phosphate and
dihydroxyacetone phosphate
In glycolysis glucose-6-phosphate is isomerized to fructose-1:6-bisphosphate.
In glycolysis fructose-1:6-bisphosphate is split into glyceraldehyde-3-phosphate and
dihydroxyacetone phosphate
20. Which statement about fatty acid metabolism.is true?
A. The product is pyruvate, which then enters the citric acid cycle
B. The product is acetyl-CoA, which then enters the citric acid cycle if there is a balance between
fat and carbohydrates
The product is a short fatty acyl-CoA, which is stored in the adipose tissue
The product is acetyl-CoA, which forms acetoacetate and D-3-hydroxybutyrate if there isa
balance between fat and carbohydrate
END OF SECTION A
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SECTION B
[80]
e There are FIVE (5) questions in this section. Answer all Questions.
Question 1
[16]
a) Briefly describe the following terms
(6)
|. Electron Affinity:
Il. = Atomic radius:
Ill. |§ Photobleaching:
IV. Electronegativity:
V. — Phototoxicity:
VI. lonization Energy:
b) Use your knowledge of atomic calculations to complete the following chart.
(6)
Element name | Symbol | #p* | #e | #n° | Charge
(atom or ion)
Argon
20
Potassium ion
39
19
K"!
19
sulphur ion
16 | -2
c) Calculate the field of view (@FOV) in um of a microscope with a field of view index (FVI) 20
and an objective magnification of X40.
(4)
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Question 2
[17]
a) Briefly describe the important players linked to cellular respiration
(6)
b) The glycolysis pathway is regulated by THREE (3) enzymes namely;
(3)
c) Briefly discuss the aerobic cellular respiration as a metabolic pathway that breaks down
glucose and produces ATP
(8)
Question 3
[15]
a) State FIVE (5) basic differences between the nuclear and mitochondrial DNA.
(5)
b) Draw the cyclic form of B—D-galactose
(4)
Obi
H—C—OH
HO-C—H
1d HO—C—H
CH5OH
c) With the aid of an amino acid generic structure draw a tripeptide
(6)
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Question 4
[18]
a) Discuss the Bicarbonate Buffer System in blood
(4)
b) Use a schematic energy diagram to show how enzymes speed-up reactions.
(4)
c) Briefly, delineate FIVE (5) factors that affect enzyme action.
(10)
Question5
[14]
a) Briefly describe the THREE (3) carrier proteins used in active transport.
(3)
b) Describe how Inositol triphosphate (IP3) and diacylglycerol (DAG): with the aid of
Phospholipase C enable signal transduction.
(6)
c) Describe the mechanism of action of Sarin nerve gas as a potent irreversible inhibitor.
(5)
END OF SECTION B
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