Final Review - Biochemistry Flashcards
1
Q
Where does the synthesis of fatty
acids take place in a eukaryotic cell?
A
Cytoplasm
2
Q
What is the type of enzyme that catalyzes the
hydrolysis of triglycerides to yield free fatty acids and
glycerol?
A
Lipase
3
Q
The activation of a fatty acid to acyl adenylate
requires the equivalent of how many ATP?
A
2
4
Q
Which molecule is not required in the activation
and transport of a fatty acid into the mitochondria?
A
NADH
5
Q
Which of the following is not a co-
substrate in the beta-oxidation of a
fatty acid?
A
NADPH
6
Q
The beta-oxidation of a C24 fatty acid would
yield how many molecules of acetyl-CoA?
A
12
7
Q
he beta-oxidation of a C18 fatty acid would yield
how many molecules of (i) NADH and (ii) FADH2?
A
8 NADH, 8 FADH2
8
Q
beta-oxidation of a cis-
unsaturated fatty acid requires what
additional enzyme?
A
isomerase
9
Q
What are the three major ketone
bodies produced in the body?
A
acetoacetate, acetone and beta-hydroxybutyrate
10
Q
The activation of acetyl CoA to malonyl CoA in
fatty acid synthesis requires what two molecules?
A
ATP and CO2
11
Q
Fatty acid synthase can only synthesize
___(i)___ fatty acids up to ___(ii)___ carbons long.
A
(i) saturated (ii) 16
12
Q
Amino acids generated from the breakdown of
digested dietary proteins, or the degradation of
cellular proteins can be:
A
- used for synthesis of new proteins
- used for energy
13
Q
Can amino acids be stored for later use like fats and carbs?
A
No they cannot
14
Q
The first step in the degradation of amino acids is
the transfer of the ___(i)___ to alpha-ketoglutarate by
a(n) ___(ii)___.
A
i) amino group (ii) aminotransferase
15
Q
In uricotelic organisms, like
birds, excess ammonia is excreted
as:
A
uric acid
16
Q
In the first step of the urea cycle, bicarbonate
(HCO3-) and NH4+ are converted to ________
A
carbamoyl phosphate
17
Q
Where do the 2 nitrogen atoms in urea come from?
A
NH4
aspartate
18
Q
An amino acid is found to be broken down to form
acetyl CoA. What would be the best classification of
this amino acid?
A
ketogenic
19
Q
Nitrogen can be fixed from N2 to
NH3 by _____.
A
the Haber-Bosch process
some bacteria and archaea
20
Q
Can nitrogen be fixed by plants?
A
No
21
Q
Approximately how many ATP molecules are
required to biologically fix one N2 to two NH3?
A
16
22
Q
Nitrogen is incorporated into amino acids by
specific aminotransferases. What cofactor do
aminotransferases contain?
A
PLP (pyridoxal phosphate)
23
Q
If DNA was replicated conservatively, how many different DNA
bands would have appeared in the CsCl gradient after centrifugation
in the Meselson-Stahl experiment after one round of replication?
A
2
24
Q
Which of the following is not an
enzyme involved in DNA replication?
A
DNA synthase
25
Which of the following statements is true
regarding how DNA is synthesized during DNA
replication?
a. The leading strand is synthesized continuously, while the lagging
strand is synthesized in short fragments.
b. The lagging strand is synthesized continuously, while the leading
strand is synthesized in short fragments.
c. Both the leading and lagging strands are synthesized continuously.
d. Both the leading and lagging strands are synthesized in short
fragments.
e. DNA polymerase synthesizes the leading strand in the 5’ 3’
direction and synthesizes the lagging strand in the 3’ 5’ direction.
a. The leading strand is synthesized continuously, while the lagging
strand is synthesized in short fragments.
26
What are the short fragments on the lagging strand called?
Okazaki fragments
27
How are okazaki fragments joined together?
DNA ligase
28
T/F DNA replication is semi-discontinuous
True
29
Which of the following below are involved in
stabilizing the single strands of the separated DNA
double helix?
single stranded binding proteins
30
The error rate in the selection efficiency (tendency
to choose the correct nucleotide initially) of DNA
polymerase is approximately ________.
1 in 10^4-10^5
31
Which of the DNA polymerases
| have 3’ to 5’ exonuclease activity?
DNA Polymerase III
32
What is the product of the
spontaneous deamination of
cytosine?
Uracil
33
```
Which of the following can result
in DNA damage?
a. errors in replication
b. reaction with reactive oxygen species
c. exposure to ultraviolet radiation
d. exposure to ionizing radiation
e. All of the above can result in DNA damage
```
e. All of the above can result in DNA damage
34
Name the sources of DNA Damage:
- Errors in replication
- Reactive Oxygen Species
- Alkylating Agents
- Deamination
- Ultraviolet Radiation
- Other Ionizing Radiation
35
```
Which class of RNA molecules
would be considered the most
diverse?
a. mRNA
b. rRNA
c. tRNA
d. All of the types of RNA molecules are equally diverse.
```
a. mRNA
36
Which subunit of RNA polymerase functions to
recognize the consensus sequence required for the
initiation of transcription?
Sigma
37
What subunit helps to find the promoter sequence in transcription?
the omega subunit
38
What is the promoter sequence?
The site where transcription begins
39
Name common promoters and consensus sequences:
- pribnow box: (-10 site) - TATAAT
| - 35 sequence
40
Which of the following statements is FALSE
regarding the comparison of transcription in
prokaryotes and eukaryotes?
a. Eukaryotic mRNA transcripts are often monocistronic while prokaryotic
transcripts can be polycistronic.
b. Virtually all types of eukaryotic RNA undergo further processing while
only tRNA and rRNA in prokaryotes undergo further processing.
c. In prokaryotes, transcription and translation both occur in the cytoplasm,
while in eukaryotes, transcription and translation both occur in the nucleus.
d. In prokaryotes, translation can begin before transcription has finished,
while in eukaryotes, transcription and translation are temporally separated.
e. None of the above statements is false.
In prokaryotes, transcription and translation both occur in the cytoplasm,
while in eukaryotes, transcription and translation both occur in the nucleus.
This is false because translation occurs in the cytoplasm, not the nucleus
41
What are the 2 main types of termination
- Factor Independent Termination
| - Factor Dependent Termination
42
```
Which below is a requirement
for proper splicing of Group 1
introns?
a. a splicesome
b. a free guanosine or guanine nucleotide
c. snRNPs
d. snRNAs
e. Group I introns require all of the above
```
b. a free guanosine or guanine nucleotide
43
The equivalent of how many ATP are required to
attach the correct amino acid to the proper tRNA
molecule?
c. 2
44
If the mRNA codon reads 5’ CGU 3’, what would
| be the anticodon on the proper tRNA molecule?
5’ ACG 3’
45
Which of the following below are
required for the initiation of
translation?
IF2
| initiation factor
46
```
In an amine group, which atom
is capable of serving as a hydrogen
bond donor?a. nitrogen
b. carbon
c. oxygen
d. hydrogen
e. more than one of the above
```
Hydrogen
47
If the pH in a solution increases
from 7 to 8, how does [H+] in the
solution change?
b. the [H+] decreases by a factor of 10
This is because the lower the number the more H+ ions are present
48
The pKa of a weak acid is 5.75. What would be
the ratio of the acid to conjugate base (HA/A-) in a
solution buffered at a pH of 7.20?
0.035 : 1
49
```
Which of the following amino
acid side chains (at pH = 7) is
characterized incorrectly?
a. cysteine = polar, uncharged
b. valine = nonpolar
c. glutamate = positively charged
d. tyrosine = polar, uncharged
e. leucine = nonpolar
```
c. glutamate = positively charged
50
What would be the overall
charge on the amino acid tyrosine
at pH = 5?
0
51
The bonds in a polypeptide backbone can be
identified as either the phi ( ), psi ( ) or peptide bond.
About which bonds is rotation allowed?
a. only the phi ( ) bond
b. only the psi ( ) bond
c. only the peptide bond
d. only the phi ( ) and psi ( ) bonds
e. Rotation is allowed about the phi ( ), psi ( ) and peptide bonds.
d. only the phi ( ) and psi ( ) bonds
52
Which of the following describes
or is an example of protein
secondary structure?
a. the sequence of amino acids linked by peptide bonds
b. interactions between the side chains of amino acids
c. the interaction between multiple, folded polypeptide chains
d. alpha helices and beta sheets
e. disulfide bonds formed between cysteine side chains
d. alpha helices and beta sheets
53
The enzyme succinate dehydrogenase contains a
tightly bound molecule of FAD. The molecule of FAD
would be best identified as a(n) _________.
a. prosthetic group
b. cosubstrate
c. essential metal ion
d. apoenzyme
e. antioxidant
a. prosthetic group
54
The value of Km for an enzyme
describes __________.
a. the amount of product formed/time/mg enzyme
b. the number of reactions catalyzed per second
c. the maximal velocity of an enzyme
d. the substrate concentration required for an enzyme to catalyze
reactions at ½ the maximal rate
d. the substrate concentration required for an enzyme to catalyze
reactions at ½ the maximal rate
55
The cleavage of trypsinogen converts the enzyme
to the active form, trypsin. This type of regulation
would best be described as _________.
regulation via proteolysis
56
What does chymotrypsin do?
protease specific for peptide bonds on carboxyl-
terminal side of large aromatic, hydrophobic amino acids (typically
Phe, Trp, Tyr)
57
The phosphodiester bond that forms between
nucleotides of DNA or RNA results from attack of the
__________.
c. 3’ OH on the 5’ phosphate
58
What types of linkages are
found between glucose monomers
in amylopectin?
d. -1,4 and -1,6
59
What would be the best
classification for steroid hormones
such as testosterone?
isoprenoid
60
The sodium-calcium exchanger is an integral
membrane protein that couples the downhill
flow of Na+ ions INTO the cell while pumping
Ca2+ ions against the concentration gradient
OUT of the cell. The sodium-calcium exchanger
is an example of what type of protein?
antiporter
61
The initiation of the insulin signal transduction
pathway includes insulin binding to the receptor on
the extra cellular side, followed by ___________.
cross phosphorylation of the tyrosine residues on the intracellular
side of the receptor
62
Define Kinase:
enzymes that phosphorylate a substrate
| using ATP
63
Define cAMP:
regulates the activities of other proteins (ex.
| protein kinase A).
64
Define function of Adenylyl cyclase
converts ATP to cAMP (second
| messenger).
65
A reaction that is
nonspontaneous at standard
conditions _______.
) may be spontaneous at particular nonstandard conditions
66
The conversion of CO2 to CH2O
| is a __________.
4 electron reduction
67
In glycolysis, the conversion of glyceraldehyde-3-
phosphate to 1,3-bisphosphoglycerate is catalyzed by
what type of enzyme?
c. dehydrogenase
68
What are the (net) products of
glycolysis (per molecule of
glucose)?
2 pyruvate, 2 ATP, 2 NADH
69
In gluconeogenesis, how many steps are required
| to convert pyruvate to phosphoenolpyruvate?
2 steps
pyruvate --> oxaloacetate --> phosphoenol pyruvate
70
Lactate can be transported from muscle
tissue to the liver where the reactions of
gluconeogenesis can convert it back into
glucose to then be transported back to the
muscle in order to generate ATP via the
reactions of glycolysis. This process is called
the ________.
Cori cycle
71
Which TCA cycle reaction
generates ATP via substrate level
phosphorylation?
succinyl CoA succinate
72
Which of the following is not a cofactor,
cosubstrate or substrate for Complex I in the
mitochondrial electron transport chain?
a. NADH
b. FADH2
c. FMN
d. Fe-S clusters
e. All of the above are either cofactors, cosubstrates or substrates for
Complex I.
b. FADH2
73
```
Complex IV of the electron transport chain
oxidizes ___(i)___ and reduces ___(ii)___.
```
a. (i) cytochrome c (ii) O2
74
In the light dependent reactions,
| the ultimate electron donor is
H2O
75
The fixation of 1 molecule of CO2 via the
| Calvin cycle requires how many ATP and NADPH?
b. 3 ATP; 2 NADPH
76
Both glycogen synthase and glycogen
phosphorylase are regulated via phosphorylation.
If the phosphorylation of glycogen
phosphorylase increases the activity of the
enzyme, how would you predict phosphorylation
would regulate glycogen synthase?
a. Phosphorylation would lower the activity of glycogen synthase.
77
In addition to being used in biosynthetic pathways
| within the cell, where else is NADPH required?
c. regeneration of reduced glutathione
