Monday, October 1, 2012

GRE Practice Test : Cytology - Plasma membrane

1. Steroid hormones have receptors predominantly on
a) cell surface
b) cytoplasm
c) both cell surface and cytoplasm
d) inside nucleus only

2. The major interaction responsible for stabilising plasma membrane
a)hydrophilic interactions
b)covalent bonds
c)ionic bonds
d)hydrophobic interactions

3. The organelles involved in protein transport
a)ER and Golgi
b)ER and mitochondria
c)Golgi and mitochondria
d) lysosomes and golgi

4. The role of carbohydrates in cell membrane
a) cell adhesion
b) cell-cell recognition
c) assisting transport across cell membrane
d) cell storage reserve

5. All hormones can cross plasma membrane except
a) Estrogen
b) insulin
c) progesterone
d) thyroxine

6. The major biomolecule responsible for selective uptake of materials across plasma membrane
a) Carbohydrate
b)protein
c) lipids
d)phospholipids

7. All the following substance pass through cell membrane except
a) O2
b)H2O
c)CO2
d)H+

8. At physiological pH increase in cholesterol level
a) increases fluidity
b)decreases fluidity
c) no change in fluidity
d) none of the above

9) The longer the fatty acid chain, fluidity of the lipid bi layer
a) increases
b)decreases
c) no change in fluidity
d) none of the above

10. The inner leaflets of erythrocytes has
a) sphingomyelin and phosphatidylcholine
b) phosphatidylserine and phosphatidylethanolamine.
c) sphingomyelin and phosphatidylserine
d) phosphatidyl serine and phosphatidylcholine

11. Lipid bi layer is
a) hydrophilic
b) hydrophobic
c) hydrophilic and hydrophobic
d) depends on the surrounding medium

12. Which of the following membrane has the largest amount of proteins
a) erythrocyte membrane
b) myelin sheath membrane
c) inner mitochondrial membrane
d) outer mitochondrial membrane

13. high lipid content is a characteristic of
a) erythrocyte membrane
b) myelin sheath membrane
c) inner mitochondrial membrane
d) outer mitochondrial membrane

14. The distribution of intrinsic proteins in the cell membrane is
a) symmetrical
b)assymetrical
c) random
d)uniform

15. In cell membrane, carbohydrates in glycoproteins or glycolipids are oriented
a) towards outside
b)towards inside
c) towards outside and inside
d)randomly distributed

16. The plasma membrane is impermeable to all molecules except
a) Glucose
b) ATP
c)rea
d)K+

17.  The erythrocyte glucose transporter is an example of
a)simple diffusion
b)active transport
c) facilitated diffusion
d)ion driven active transport

18. Which of the following transport induces conformational change in protein
a)simple diffusion
b)active transport
c) facilitated diffusion
d)ion driven active transport

19. Na+ glucose transporter is an example of
a) facilitated diffusion
b)ATP driven active transport
c)Symport
d)antiport

20. Clathrin coated pits are associated with
a) phagocytosis
b)pinocytosis
c)receptor mediated endocytosis
d)exocytosis
Answers
1. b) cytoplasm
2. d)hydrophobic interactions
3. a)ER and Golgi
4. b) cell-cell recognition
5. b) insulin
6. b)protein
7. d)H+
8. b)decreases fluidity
9. b)decreases
10.b) phosphatidylserine and phosphatidylethanolamine.
11.c) hydrophilic and hydrophobic
12.c) inner mitochondrial membrane
13. b) myelin sheath membrane
14. b)assymetrical
15. a) towards outside
16. c) urea
17. c) facilitated diffusion
18. c) facilitated diffusion
19. c)Symport
20. c)receptor mediated endocytosis



------------------------------------------ Best Wishes: Dr.Ehab Aboueladab, Tel:01007834123 Email:ehab10f@gmail.com,ehababoueladab@yahoo.com ------------------------------------------
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