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Biology 141 – General Biology
Fall 2013 – Dr. Carey – Exam 4
Name______________________________
Part I – Multiple Choice – 1 pt. each.
1.
How many mRNA codons are necessary to produce a protein containing 120
amino acids? A) 40 B) 60 C) 120 D) 240 E) 360
2.
How many DNA bases are necessary to produce a protein containing 120 amino
acids? _______ (Use the choices in question 1)
3.
How many tRNA molecules are necessary to produce a protein containing 120
amino acids? _______ (Use the choices in question 1)
4.
Hershey and Chase labeled viruses with radioactive P and S. Their results led to
the conclusion that: A) the nucleus controls the cell B) one gene codes for one
enzyme C) the genetic material is protein D) enzymes are proteins
E) the genetic material is DNA
5.
Free nucleotides can be attached to a growing nucleic acid chain: A) at either
end B) at any point in the chain C) only in ribosomes D) only at the 5’ end
E) only at the 3’ end
6.
A certain section of DNA has the base sequence AGCCTATAG. The
complementary sequence formed during transcription is: A) TCGGATATC
B) AGCCTATAG C) UCGGAUAUC D) AGCCUAUAG
E) TCGGUTUTC
7.
Using the choices in question 6, what would be the complimentary sequence
formed during replication? ________
8.
To begin the process of translation, mRNA will first bind with: A) a large
ribosome subunit B) an appropriate tRNA C) a DNA transcript D) a small
ribosome subunit E) RNA polymerase
9.
We have a codon with the base sequence CGA. The DNA sequence that
produced it was: A) CGA B) GCT C) CGU D) GCU E) CGT
10.
Corepressors are molecules that: A) attach to operators B) attach to promoters
C) activate repressors D) inactivate repressors E) slow down rates of translation
11.
Operon theory is a well supported theory for transcription control in: A)
humans B) prokaryotic cells C) lower animals D) plants E) more than one
of the above
12.
Which of the following does not contain base codes that could be used in the
production of a protein? A) operator B) structural gene C) cistron
D) operon E) exon
13.
If 20% of the nucleotides in a DNA molecule are adenosine, what percent are
cytosine? A) 20 B) 30 C) 40 D) 60 E) 80 F) there is not enough
information to answer the question
14.
If 20% of the nucleotides in an RNA molecule are adenosine, what percent are
cytosine? ______ (Use the choices in question 13)
15.
In a DNA molecule, guanine binds to its normal complementary base with ____
hydrogen bonds. A) 1 B) 2 C) 3 D) 4 E) 5
16.
All else being equal, the most efficient method of controlling gene expression
would be to control:
A) replication B) translation C) transcription
D) protein function E) RNA production F) none of the above
17.
In controlling gene expression, which mechanism is not used by prokaryotes?
________ (Use the choices in question 16)
Part II – Fill-in – 1 pt. each bank.
1.
____________________________ was the person who discovered that pairs of
DNA bases come in equal concentrations. Prior to this discovery it was thought
that all 4 bases had equal concentrations. This earlier data led many to believe
that, chemically, genes were _____________________ in nature, because only
this substance seemed to possess the necessary ___________________ in
structure to be able influence all the different characters in living things.
2.
Of the 64 codons possible, ___________________ of them are called stop
codons. Which amino acid do these stop codons specify? _________________.
Of the 64, _______________________ codon(s) is(are) start codons. Which
amino acid is specified by a start codon? ___________________________.
3.
To keep the two chains of a DNA molecule parallel, one large
____________________ base must be paired with one small
____________________ base across the middle. This large base/small base
pairing occurs normally in DNA, but also occurs with a point mutation type
known as a(n) ________________________. Actually the 2 chains of DNA are
more appropriately described as ____________________ to each other, because,
though they are parallel, they are opposite in ____________________________.
Part III – True-false – 1 pt. each.
1.
A point mutation will cause at least one amino acid change in the protein it codes
for.
2.
The structure drawn at right could be a schematic representation of uracil.
3.
A frameshift mutation could potentially change all of the amino acids in a protein.
4.
DNA is replicated in a conservative manner.
5.
In order for a eukaryotic messenger to be translated, the exons must first be
removed from it.
6.
A single codon may specify more than one amino acid.
8.
A single amino acid may be specified by more than one codon.
9.
It is possible for 70% of the nucleotides in a DNA molecule to be cytosine.
10.
It is possible for 70% of the nucleotides in an RNA molecule to be cytosine.
Part IV – Short answer – pts as indicated.
1.
Define: (3 pts each)
A. regulator gene
B. translocation
C. codon
D. Okazaki fragment
E. “A” site on a ribosome
F. frameshift mutation
2.
Describe Griffith’s work that led him to the notion of bacterial transformation.
(13 pts)
3.
Draw and label an operon containing all 3 possible functional regions. Describe
the function of each part. (12 pts)
4.
Draw a representation of a tRNA molecule. Give the function of each major
binding site on it. (10 pts)
5.
List 3 chemical or structural differences between RNA and DNA. (9 pts)