Sample MCQs

Question 1

Which of the following is not a membrane bounded compartment in eukaryotic cells?
A) nucleus
B) mitochondria
C) lysosome
D) ribosome
E) chloroplast

Answer 1

D) ribosome

Question 2

Ganglioside GM2 is:
A) A sphingolipid
B) A glycerophospholipid
C) A sterol
D) A lipid composed of several isoprenoid groups
E) None of the above

Answer 2

A) A sphingolipid

Question 3

Which of the following lipids is more common in the exoplasmic than the cytosolic leaflet (face) of the eukaryotic plasma membrane?
A) Cholesterol
B) Phosphatidylserine
C) Phosphatidylethanolamine
D) Phosphatidylcholine
E) None of the above

Answer 3

D) Phosphatidylcholine

Question 4

Which of the following is a typical resting membrane potential of an animal cell (cytosol relative to extracellular space)?
A) -70 mV
B) +50 mV
C) -70 kV
D) -10 mV
E) 0 mV

Answer 4

A) -70 mV

Question 5

A pure lipid bilayer is permeable to which of the following?
A) O2
B) Glucose
C) K+
D) Ca++
E) Amino acids

Answer 5

A) O2

Question 6

Ion channels transport ions across membranes by
A) Active Transport
B) Facilitated Diffusion
C) Secondary Active Transport
D) Passive Diffusion
E) Hydrolysis of ATP

Answer 6

B) Facilitated Diffusion

Question 7

Which of the following ions is at a higher concentration inside the cell than outside?
A) K+
B) Na+
C) Ca++
D) Cl-
E) None of the above

Answer 7

A) K+

Question 8

P-class ATP-powered pumps transport protons in order to acidify:
A) the inner membrane space of mitochondria
B) lysosomes
C) the stomach
D) peroxisomes
E) None of the above

Answer 8

C) the stomach

Question 9

Members of the ABC superfamily of ATP-powered pumps transport:
A) drugs
B) amino acids
C) sugars
D) all of the above
E) none of the above

Answer 9

D) all of the above

Question 10

Which of the following is not a member of the ABC superfamily of ATP-powered pumps?
A) E. coli histidine permease
B) The multi drug resistance protein
C) Cystic fibrosis transmembrane regulator (CFTR)
D) Aquaporin
E) E. coli vitamin B12 importer

Answer 10

D) Aquaporin

Question 11

In an actin filament undergoing “threadmilling” in vitro at a steady state conditions:
A) There is no hydrolysis of ATP
B) ADP bound actin is added at the plus end
C) ADP bound actin is lost at the plus end
D) ATP bound actin is found at the plus end
E) ATP bound actin is found at the minus end

Answer 11

C) ADP bound actin is lost at the plus end

Question 12

Which of the following does NOT bind to actin filaments (F-actin)?
A) Myosin
B) Dynein
C) The Arp2/3 complex
D) Alpha-actinin
E) Spectrin

Answer 12

B) Dynein

Question 13

Hutchison-Gilford progeria syndrome is caused by mutations in:
A) An actin-binding protein
B) myosin II
C) An intermediate filament protein
D) beta-tubulin
E) A microtubule motor protein

Answer 13

C) An intermediate filament protein

Question 14

Which of the following statements about microtubules is FALSE?
A) Microtubules are polymers
B) Microtubules don’t have an intrinsic polarity
C) Microtubules undergo threadmilling
D) Microtubules exhibit dynamic instability
E) Microtubules are built up from dimers of alpha and beta-tubulin

Answer 14

B) Microtubules don’t have an intrinsic polarity

Question 15

Which of the following statements about translocation of proteins across the endoplasmic reticulum in higher eukaryotes is TRUE?
A) It occurs predominantly post-translationally
B) It occurs predominantly co-translationally
C) It occurs by passive diffusion
D) It occurs after protein folding is complete
E) None of the above statements is true

Answer 15

B) It occurs predominantly co-translationally

Question 16

Of the four categories of integral membrane proteins which has multiple transmembrane domains?
A) Type I
B) Type II
C) Type III
D) Type IV
E) All of the above

Answer 16

D) Type IV

Question 17

Folding of mitochondrial matrix proteins occurs in which cellular compartment?
A) cytosol
B) intermembrane space of the mitochondria
C) the matrix of the mitochondria
D) the lumen of the ER
E) None of the above

Answer 17

C) the matrix of the mitochondria

Question 18

The targeting sequence for transport of proteins to the mitochondrial matrix is recognized by:
A) The import receptor Tom 20/22
B) The general import pore Tom 40
C) The chaperone protein Hsc70
D) SRP
E) Tim 23/27

Answer 18

A) The import receptor Tom 20/22

Question 19

Which of the following proteins could (probably) pass through the nuclear pore by passive diffusion?
A) A 20 kDa protein
B) A 90 kDa protein
C) A 300 kDa protein
D) Both A and B
E) None of these proteins

Answer 19

A) A 20 kDa protein

Question 20

Which of the following statements is FALSE?
A) Ran plays a role in nuclear import but not in nuclear export
B) The nuclear pore complex has a greater molecular weight than a ribosome
C) Exportins and importins are related in their amino acid sequence (homologous)
D) One type of nuclear localization (import) signal contains basic amino acids
E) The proteins that make up the nuclear pore complex are called nucleoporins

Answer 20

A) Ran plays a role in nuclear import but not in nuclear export