BIOCHEM C785 EXAM QUESTIONS WITH ANSWERS AND RATIONALE GRADED A+ ASSUARED SUCCESS

BIOCHEM C785 EXAM QUESTIONS WITH ANSWERS
AND RATIONALE GRADED A+ ASSUARED SUCCESS
What is the complementary sequence to 3’ ATG CGA ATA 5’?
(0/1 Points)
3’ TAT TCG CAT 5’
3’ TAC GCT TAT 5’
The correct answer is 3' TAT TCG CAT 5'. Remember complementary means “Matching
or Pairing” You have to remember to pay attention to your numbers as well as your
letters (A-T, G-C, 5'-3'). The correct answer is 3’ ATG CGA ATA 5’ (original sequence) 5’
TAC GCT TAT 3’ (complementary sequence) But we asked for it in the 3’ direction, so
mirror answer to give correct answer: 3’ TAT TCG CAT 5’ If you chose 3' TAC GCT TAT 5',
this is incorrect. Although the nucleotides are in the correct order, the 5' and 3' are in
the wrong place. DNA strands that are complementary run in opposite directions. This
means that if one strand starts with a 3', the the complementary strand must start with
a 5'. If none of the answer choices give the correct answer in 5' ---> 3', then you need to
write its mirror, which will run from 3' ---> 5'.
3’ GAT AGC ATA 5’
5’ ATA AGC GTA 3’
2
Which amino acid sequence would result from this Coding DNA
strand? 3’ ATG CAG ATA 5’?
(1/1 Points)
Tyr Val Tyr
Ile Gln Ile
Ile Asp Val
The correct answer is Ile Asp Val. We are starting at the coding strand, and have to
remember the relationship between coding DNA and mRNA. These two strands are non-
complementary and parallel. So we copy the coding strand , change T ---> U, and then
write the mRNA sequence: 3’ ATG CAG ATA 5’ coding 3’ AUG CAG AUA 5’ mRNAMirror by
changing orientation: 5’ AUA GAC GUA 3’ Read chart Ile Asp Val (chart is in direction of
5' ---> 3')
Leu His Lys
3
Which amino acid sequence would be made from this template DNA strand? 5’
TAT TAC CGA 3’?
(1/1 Points)
Tyr Tyr Arg
Ile Met Ala
Ser Val Ile
The correct answer is Ser Val Ile because 5’ TAT TAC CGA 3’ template is complementary
and antiparallel so 3’ AUA AUG GCU 5’ but it is in the wrong orientation, so mirror 5’
UCG GUA AUA 3’ and read the chart Ser Val Ile
Ser His Gln
4
Which of the following are the correct components for a PCR reaction? (1/1 Points)

dNTPs, Primer, RNA Polymerase, template RNA

,BIOCHEM C785 EXAM QUESTIONS WITH ANSWERS
AND RATIONALE GRADED A+ ASSUARED SUCCESS
dNTPs, Primer, DNA Polymerase, template DNA
The correct answer is dNTPs, Primer, DNA Polymerase, template DNA. Notice that all
components are about DNA. The Primer is even a DNA Primer.
ATP, Primer, mRNA polymerase; template mRNA
Acetyl CoA, RNA primer, DNA Ligase, Template phosphate
5
Assuming 100% reaction efficiency, how many DNA copies will be produced after 5 PCR c


16
32
The correct answer is 32. 2x2x2x2x2=32
64
10
6
Which of the following would represent a silent mutation if this is the original sequence:
(1/1 Points)

5’ AUC GGA ACA 3’
5' AUA GUA ACA 3'
The correct answer is 5' AUC GUA ACA 3' Ile Val
Thr 5’ AUG GUA ACA 3’
5’ AUC GCA ACA 3’
7
If the original coding sequence is 5’ CGA TAC TTC AGA 3’ and it is mutated to 5' CGA TAT
(1/1 Points)


Silent
The correct answer is silent mutation. The nucleotide sequence changes, but it codes for
the same amino acid. The coding sequence 5' TAC 3' corresponds to the mRNA
sequence 5' UAC 3' (Tyr), and the coding sequence 5' TAT 3' corresponds to the mRNA
sequence 5' UAU 3' (Tyr). Since the C changed to at T, this is a point mutation. If the
point mutation results in the same amino acid in the new sequence as in the original
sequence, the point mutation is a silent mutation.
Missense
Nonsense
Insertion
8
Huntington's is an autosomal dominant disorder. Which of the following chromosome pair



Option 1

, BIOCHEM C785 EXAM QUESTIONS WITH ANSWERS
AND RATIONALE GRADED A+ ASSUARED SUCCESS
The correct answer is Option 1 because an autosomal dominant disorder would be
inherited on numbered chromosomes, not sex chromosomes X or Y. Also, at least one
dominant allele (yellow box) needs to be present for the individual to have the dominant
disease.
Option 2
Option 3
Option 4
9
The pedigree below tracks Duchenne Muscular Dystrophy (DMD) through several generati
(1/1 Points)


Autosomal dominant
Autosomal recessive
X-linked Dominant
X- Linked recessive
The correct answer is X- linked recessive because parents (carriers) do not have it (II-5-
6) but a child does (III-5). You will get the same result if you consider parents (carriers)
(I-1-2), who do not have the trait, but a child does (II-3). A third option that gives the
same result (X-linked recessive) is by considering parents (carriers) who do not have the
trait (III-1-2), and their child does (IV-1). The pattern is recessive because the selected
parents are carriers, and it is X-linked because only males have the trait.
10
If you had a mother who is homozygous for a recessive disease, and a father who is a he
(1/1 Points)


0%
25%
50%
The correct answer is 50%. Homozygous recessive: aa Heterozygous: Aa When you see
"percentage" or "probability," think Punnett square. 50% of the children would be
expected to be Aa, and 50% of the children would be expected to be aa.
75%
100%
11
Which of the following describes an epigenetic change? (0/1 Points)

Denaturation of template DNA to facilitate primer annealing.
Increased methylation of the promoter region of a tumor suppressor gene in a
developing fetus.
Thymine dimer formation resulting from UV radiation.
Mismatch mutation caused by mistakes made by DNA Polymerase during replication.

The correct answer is "Increased methylation of the promoter region of a tumor suppressor gene in a develop