exam 3 MC bio 151

Question 1

_______ mediate most of cell’s functions.
A. Carbohydrates
B. DNA
C. Lipids
D. Proteins
E. RNA

Answer 1

D. Proteins

Question 2

Redox reactions are best defined as gain or loss of
____.
A. Carbon
B. Electrons
C. Hydrogens
D. Oxygen

Answer 2

B. Electrons

Question 3

A mutant that manages to extract more energy out of
a glucose molecule is likely to ______.
A. Be targeted by other cells
B. Have greater fitness
C. Have chromosomal duplication
D. Have deleterious mutations
E. Gain other mutations

Answer 3

B. Have greater fitness

Question 4

Phosphorylation changes protein’s ______ and thus
affects function.
A. Activity
B. Binding
C. Conformation
D. Potential energy
E. Specificity

Answer 4

C. Conformation

Question 5

Energy coupling allows ______ reactions to occur
because they are coupled to ______ reactions.
A. Exergonic; endergonic
B. Endergonic; exergonic
C. Exothermic; endothermic
D. Endothermic; exothermic
E. Exergonic; endothermic

Answer 5

B. Endergonic; exergonic

Question 6

Allosteric regulators _______.
A. Are structurally similar to the substrate
B. Bind to enzyme’s active site
C. Bind and change the enzyme’s shape
D. Can be converted to noncompetitive inhibitor by
modest changes in the structure

Answer 6

C. Bind and change the enzyme’s shape

Question 7

Plasmodesmata are specialized ____ .
A. Tight junctions
B. Gap junctions
C. Cadherins
D. Desmosomes
E. Doesn’t need any of them

Answer 7

B. Gap junctions

Question 8

Which of the following motor proteins is important in
cilia and flagella?
A. Axoneme
B. Dynein
C. Kinesin
D. Myosin
E. Spoke
A. Proteoglycans

Answer 8

B. Dynein

Question 9

The best example of cells with ____ may be our
intestinal cells (or tissue).
A. Tight junctions
B. Gap junctions
C. Cadherins
D. Desmosomes
E. Doesn’t need any of them

Answer 9

A. Tight junctions

Question 10

Electron transport chain includes a non-protein
electron carrier called ____.
A. Citrate
B. FMN
C. Fe-S cluster
D. Pheophytin
E. Ubiquinone

Answer 10

E. Ubiquinone

Question 11

Which of the following term is NOT a cell signaling
method?
A. Cell-cell contact
B. Endocrine
C. Paracrine
D. Muscular
E. Neuronal

Answer 11

D. Muscular

Question 12

FADH2 transfer electrons to ___, and NADH transfer
electrons to ___
A. Complex I; complex II
B. Complex II; complex I
C. Complex I; complex III
D. Complex I & II; complex III
E. Complex I & III; complex IV

Answer 12

B. Complex II; complex I

Question 13

The electron transport chain transfers electron from
____.
A. Acetyl CoA to NADH
B. CO2 to ATP
C. FADH2 and NADH to O2
D. FADH2 and NADH to CO2
E. The intermembrane space to the mitochondrial matrix

Answer 13

FADH2 and NADH to O2

Question 14

Enzymes work by _____.
A. adding energy to a reaction
B. adding a phosphate group to a reactant
C. decreasing the potential energy difference
between reactant and product
D. increasing the potential energy difference
between reactant and product
E. promoting formation of the transition state

Answer 14

E. promoting formation of the transition state

Question 15

Competitive inhibitors ____.
A. Are structurally similar to the substrate
B. Bind to the active site on an enzyme
C. Bind and distort the enzyme’s shape
D. Can be converted to competitive inhibitor by
modest changes in the structure

Answer 15

B. Bind to the active site on an enzyme

Question 16

If an enzyme is operating at optimal pH and optimal
temperature, then how can the reaction rate be
further increased?
A. Add more substrate
B. Increase pH
C. Increase temperature
D. All of the above

Answer 16

A. Add more substrate

Question 17

Which of the following amino acid residues in a
protein cannot be phosphorylated?
A. Serine
B. Threonine
C. Tryptophan
D. Tyrosine

Answer 17

C. Tryptophan

Question 18

Which of the following is incorrect?
A. Complex sugars are carbohydrates.
B. All carbohydrates have the general formula
Cn(H2O)n.
C. Polysaccharides are polymers of simple sugars.
D. Carbohydrates have the most energy of all
macromolecules.
E. Simple sugars contain only carbon, oxygen, and
hydrogen atoms.

Answer 18

D. Carbohydrates have the most energy of all
macromolecules.

Question 19

The 10 steps of Glycolysis are nearly identical in all
species. What does this mean for evolution?
A. Glucose can be “deconstructed” in only one way
B. Glucose-metabolism enzymes were “collected”
through symbiosis
C. All species must have originated from one ancestral
cell
D. This is because of convergent evolution
E. This is an example of divergent evolution

Answer 19

C. All species must have originated from one ancestral
cell

Question 20

Which of the following is false about lysosomes?
Which of the following is false about lysosomes?
A. They contain 40+ enzymes
B. They have a pH = 5
C. They are damaged in Zellweger syndrome
D. They break-down phagocytosed material
E. They break-down damaged organelles

Answer 20

C. They are damaged in Zellweger syndrome

Question 21

A “three parent” baby has ____.
A. Two eggs + sperm nucleus
B. Two sperm nuclei + egg nucleus
C. A sperm + egg nucleus + egg without a nucleus
D. A woman slept with two different men but does
not know who the father is

Answer 21

C. A sperm + egg nucleus + egg without a nucleus

Question 22

Nucleolus should contain all of the following except__.
A. DNA
B. RNA
C. Lipids
D. Chromosome parts
E. Ribosomal proteins

Answer 22

C. Lipids

Question 23

. Which of the following is NOT an intermediate in
glycolysis?
A. Fructose-6-phosphate
B. Fructose-1,6-bisphosphate
C. Ribulose bisphosphate
D. 3-phosphoglycerate
E. Phosphoenolpyruvate

Answer 23

C. Ribulose bisphosphate

Question 24

24. Where is calcium stored?
    A. microtubules
    B. mitochondria
    C. centrioles
    D. rough endoplasmic reticulum
    E. smooth endoplasmic reticulum

Answer 24

E. smooth endoplasmic reticulum

Question 25

Which of the following metabolic pathways is central
to cellular metabolism in most cells?
A. The citric acid cycle
B. Glycolysis
C. Electron transport chain
D. Lipid degradation
E. Peptide synthesis

Answer 25

B. Glycolysis