REA MCAT Multiple Choice Q's Exam-
Graded A
D. Enzymes are proteins that act as catalysts. Carbohydrates are not proteins, and
therefore cannot be enzymes. - ANS-Enzymes are:
a. proteins
b. catalysts
c. carbohydrates
d. both proteins and catalysts
B. Organisms control the activity of enzymes by changing or blocking active sites.
Location and amount of enzymes may be controlled through feedback. Types of
enzymes are determined genetically and cannot be altered. - ANS-Organisms can
control all of the following EXCEPT:
a. location of enzymes
b. type of enzymes
c. amount of enzymes
d. activity of enzymes
C. In feedback inhibition the flow of metabolites is often regulated by controlling the
activity of key enzymes in a pathway. Usually, the first enzyme in a metabolic pathway
is controlled by the end product of the pathway. - ANS-In feedback inhibition of
metabolic pathways, which are controlled directly?
a. end pdts
b. metabolites
c. enzymes
d. precursor molecules
B. Glycolysis is the series of metabolic reactions by which glucose is converted to
pyruvate (a 3-C sugar) with the concurrent formation of ATP. Glycolysis occurs in the
cytoplasm of the cell and for this process the presence of oxygen is unnecessary. -
ANS-Glycolysis does NOT:
a. occur in the cytoplasm
b. require oxygen
c. produce ATP
d. break down glucose
D. NADH is converted to NAD during oxidative phosphorylation, which yields 3 ATP. -
ANS-In the Krebs Cycle, all of the following occur EXCEPT:
a. oxidation of succinate
b. formation of FADH2
, c. formation of NADH
d. transformation of NADH to NAD
D. The aerobic production of ATP involves the Krebs cycle and the oxidation of glucose.
The anaerobic production of ATP takes place during glycolysis. The citric acid cycle
produces 34 ATP's and the oxidation of glucose produces 2. This makes the total
number of ATP's produced during aerobic processes 36. Glycolysis yields 2 ATP's. The
net ratio of aerobic ATP to anaerobic ATP is 36:2, which reduces to 18:1. - ANS-The
ratio of ATP produced aerobically to anaerobically by the oxidation of one molecule of
glucose is
a. 2:1
b. 1:2
c. 1:18
d. 18:1
A. Cytosine normally binds to guanine and uracil normally binds to adenine. A
conversion of cytosine to uracil would lead to a conversion of guanine to adenine in the
complementary strand. Thus a CG to AU event has occurred. - ANS-Nitrous acid
converts cytosine to uracil by deamination. This type of conversion in one DNA strand
would lead to a change in the complementary base in the other strand to
a. adenine
b. cytosine
c. thymine
d. guanine
D. Viruses do not have any membranes because they have no need to take in or expel
material. Viruses lack all metabolic machinery and do not produce ATP because they do
not perform energy requiring processes. Viruses do possess either DNA or RNA, but
cannot independently reproduce. They must rely on host cells for reproductive
machinery and components. - ANS-Viruses differ from living organisms because
a. viruses possess no bounding membrane
b. viruses lack all metabolic machinery
c. viruses lack all reproductive machinery
d. all of the above
A. In moderate viruses the phage DNA is incorporated directly into the host
chromosome, and thus replicates only when the host does. RNA retroviruses may
induce tumors. Most viruses, with the exception of moderate ones, cause immediate
lysis of infected bacteria. Viruses may contain either DNA or RNA, not both. - ANS-
Moderate viruses may
a. replace DNA only when the host replicates
b. induce tumors
c. cause immediate lysis of infected bacteria
d. have both DNA and RNA
Graded A
D. Enzymes are proteins that act as catalysts. Carbohydrates are not proteins, and
therefore cannot be enzymes. - ANS-Enzymes are:
a. proteins
b. catalysts
c. carbohydrates
d. both proteins and catalysts
B. Organisms control the activity of enzymes by changing or blocking active sites.
Location and amount of enzymes may be controlled through feedback. Types of
enzymes are determined genetically and cannot be altered. - ANS-Organisms can
control all of the following EXCEPT:
a. location of enzymes
b. type of enzymes
c. amount of enzymes
d. activity of enzymes
C. In feedback inhibition the flow of metabolites is often regulated by controlling the
activity of key enzymes in a pathway. Usually, the first enzyme in a metabolic pathway
is controlled by the end product of the pathway. - ANS-In feedback inhibition of
metabolic pathways, which are controlled directly?
a. end pdts
b. metabolites
c. enzymes
d. precursor molecules
B. Glycolysis is the series of metabolic reactions by which glucose is converted to
pyruvate (a 3-C sugar) with the concurrent formation of ATP. Glycolysis occurs in the
cytoplasm of the cell and for this process the presence of oxygen is unnecessary. -
ANS-Glycolysis does NOT:
a. occur in the cytoplasm
b. require oxygen
c. produce ATP
d. break down glucose
D. NADH is converted to NAD during oxidative phosphorylation, which yields 3 ATP. -
ANS-In the Krebs Cycle, all of the following occur EXCEPT:
a. oxidation of succinate
b. formation of FADH2
, c. formation of NADH
d. transformation of NADH to NAD
D. The aerobic production of ATP involves the Krebs cycle and the oxidation of glucose.
The anaerobic production of ATP takes place during glycolysis. The citric acid cycle
produces 34 ATP's and the oxidation of glucose produces 2. This makes the total
number of ATP's produced during aerobic processes 36. Glycolysis yields 2 ATP's. The
net ratio of aerobic ATP to anaerobic ATP is 36:2, which reduces to 18:1. - ANS-The
ratio of ATP produced aerobically to anaerobically by the oxidation of one molecule of
glucose is
a. 2:1
b. 1:2
c. 1:18
d. 18:1
A. Cytosine normally binds to guanine and uracil normally binds to adenine. A
conversion of cytosine to uracil would lead to a conversion of guanine to adenine in the
complementary strand. Thus a CG to AU event has occurred. - ANS-Nitrous acid
converts cytosine to uracil by deamination. This type of conversion in one DNA strand
would lead to a change in the complementary base in the other strand to
a. adenine
b. cytosine
c. thymine
d. guanine
D. Viruses do not have any membranes because they have no need to take in or expel
material. Viruses lack all metabolic machinery and do not produce ATP because they do
not perform energy requiring processes. Viruses do possess either DNA or RNA, but
cannot independently reproduce. They must rely on host cells for reproductive
machinery and components. - ANS-Viruses differ from living organisms because
a. viruses possess no bounding membrane
b. viruses lack all metabolic machinery
c. viruses lack all reproductive machinery
d. all of the above
A. In moderate viruses the phage DNA is incorporated directly into the host
chromosome, and thus replicates only when the host does. RNA retroviruses may
induce tumors. Most viruses, with the exception of moderate ones, cause immediate
lysis of infected bacteria. Viruses may contain either DNA or RNA, not both. - ANS-
Moderate viruses may
a. replace DNA only when the host replicates
b. induce tumors
c. cause immediate lysis of infected bacteria
d. have both DNA and RNA
