Biology 151
Fall 2008 – Prof. Hart
Midterm Exam #4 --- 40 Questions worth 2.5 points each
Correct answers shown in BOLD after each question
1) What is the pattern of inheritance of the disease outlined in the pedigree above?
B) autosomal recessive
2) Which of the following BEST represents the genotype of the person indicated with an arrow in the pedigree
above?
A) aa
3) A Hershey-Chase experiment was performed on a virus containing 3 different macromolecules
(Molecules A, B & C). Which molecule(s) could be the genetic information of this virus?
Molecule A was located at the bottom of the test tube (where the bacteria pellet). This indicates that it entered
the bacterial cells therefore it is the genetic material.
4) DNA replication…
D) uses each strand of a DNA molecule as a template for the creation of a new strand.
5) Some chemotherapeutic drugs combat cancer by using…
B) molecules similar to normal nucleosides that are chemically altered/blocked on the 3’ carbon.
6) Okazaki fragments are formed during DNA synthesis because:
C) DNA Polymerase can only make DNA in one direction 5' to 3'
7) What enzyme catalyzes the unwinding of a DNA double helix?
A) helicase
8) Here are the results of a Meselson-Stahl experiment on Martian DNA:
Based on these results, we would conclude that Martian DNA was synthesized…
This question related to the banding pattern of heavy (N 15) vs. light (N14) DNA centrifuged in a CsCl gradient.
Both in class and in the animation I showed, you were asked to predict the banding pattern of DNA that is
semi-conservatively, conservatively or dispersively replicated. Depending on which exam version you received,
the banding pattern of Martian DNA was either conservatively or dispersively replicated.
9) The directions for each amino acid in a polypeptide are indicated by a codon that consists of ____3____
nucleotide(s) in an RNA molecule.
10) A point mutation in a gene sometimes produces a protein that is WAY too short. What is the name of this
type of problem?
B) nonsense mutation
1
11) Which of the following enzymes catalyzes the linking together of ribonucleotides to form a single-stranded
RNA molecule?
A) RNA polymerase
12) Which one of the following occurs when RNA polymerase attaches to the promoter DNA?
D) initiation of transcription
13) Which one of the following does NOT happen to eukaryotic messenger RNA?
E) Introns are added to the RNA.
14) Which of the following is/are required for translation to occur?
A) sources of energy (ATP or GTP molecules)
B) a small and large ribosomal subunit
C) tRNA attached to an amino acid
D) mRNA molecule
E) All of the choices are required for translation to occur.
15) Which one of the following BEST describes events in translation in the right order?
C) small ribosomal subunit binds mRNA → peptide bond formed → empty tRNA in E site → termination factor
binds
16) Consider the following sentence: "The dog did not eat." Which one of the following variations of this
sentence is most like a missense mutation?
D) The doe did not eat.
17) If one nucleic acid is changed to another in a section of DNA, it is called a __ point ___ mutation.
18) Which of the following is FALSE regarding the life cycle of HIV?
B) RNA polymerase converts viral RNA into viral DNA.
19) Which of the following is FALSE about a tRNA molecule?
D) It is important during transcription.
20) If one strand of DNA has the base sequence AAGCAA, the complementary strand of RNA has which of the
following sequences?
A) UUCGUU
21) The structural genes in the lac operon of E. coli are _transcribed _ when the repressor is bound to lactose.
22) A single cell, the zygote, can develop into an entirely new organism with many different specialized cells.
The animation shown in class demonstrated this by showing…
A) ...how cells of the endoderm, mesoderm and ectoderm differentiate into different tissues/organs.
23) Which one of the following is FALSE?
B) Tight DNA packing tends to promote gene expression.
24) Enhancers are…
C) the site on DNA to which activated transcription factors bind.
25) Which of the following permits a single gene to code for more than one protein?
B) alternative RNA splicing
26) Which is FALSE about spliceosomes?
D) They work along side ribosomes in the cytoplasm to produce fully functional proteins.
27) What is a prophage?
2
B) It is a phage that has inserted its genes into the circular chromosome of its bacterial host.
2nd base
U
DNA:
C
A
G
UUU
UUC
U
UUA
UUG
(Phe/F)
(Phe/F)
(Leu/L)
(Leu/L)
UCU
UCC
UCA
UCG
(Ser/S)
(Ser/S)
(Ser/S)
(Ser/S)
UAU
UAC
UAA
UAG
(Tyr/Y)
(Tyr/Y)
Ochre
Amber
UGU
UGC
UGA
UGG
(Cys/C)
(Cys/C)
Opal
(Trp/W)
CUU
CUC
C
CUA
CUG
1st
base
AUU
AUC
A
AUA
AUG
(Leu/L)
(Leu/L)
(Leu/L)
(Leu/L)
CCU
CCC
CCA
CCG
(Pro/P)
(Pro/P)
(Pro/P)
(Pro/P)
CAU
CAC
CAA
CAG
(His/H)
(His/H)
(Gln/Q)
(Gln/Q)
CGU
CGC
CGA
CGG
(Arg/R)
(Arg/R)
(Arg/R)
(Arg/R)
(Ile/I)
(Ile/I)
(Ile/I)
(Met/M)
ACU
ACC
ACA
ACG
(Thr/T)
(Thr/T)
(Thr/T)
(Thr/T)
AAU
AAC
AAA
AAG
(Asn/N)
(Asn/N)
(Lys/K)
(Lys/K)
AGU
AGC
AGA
AGG
(Ser/S)
(Ser/S)
(Arg/R)
(Arg/R)
GUU
GUC
G
GUA
GUG
(Val/V)
(Val/V)
(Val/V)
(Val/V)
GCU
GCC
GCA
GCG
(Ala/A)
(Ala/A)
(Ala/A)
(Ala/A)
GAU
GAC
GAA
GAG
(Asp/D)
(Asp/D)
(Glu/E)
(Glu/E)
GGU
GGC
GGA
GGG
(Gly/G)
(Gly/G)
(Gly/G)
(Gly/G)
Transcribe the gene below and then translate it. Use the genetic code shown above.
AGGTACCTACGGGATACAATTGTTCTACT
28) This protein (above) has ______ amino acids.
A) 5
29) The first amino acid in this protein is ________ while the fourth amino acid is ________.
C) Met / Leu
DNA:
Here is the same piece of DNA, but with a mutation (underlined) in it:
AGGTACCTACGGGATACAATGTGTTCTACT
30) How many amino acids are in this MUTANT protein?
B) 8
31) What do we call this type of mutation?
D) frameshift
32) Which of the following does NOT contribute to normal cells becoming cancerous?
D) p53 protein turning on genes involved in stopping the cell cycle
33) The development of colon cancer occurs slowly, as it does in many cancers.
B) more than one somatic mutation must occur.
34) In a signal-transduction pathway, a ligand binds to a receptor protein which tells cytoplasmic proteins to…
B) go to the nucleus and activate expression of certain genes.
MATCH the following genes with the mechanism by which they contribute to the development of cancer.
3
35) Telomerase gene = Mutations in this gene give a cell an almost endless life-span – since chromosomes are
allowed to be replicated indefinitely.
36) genes from Human Papilloma Virus = Tends to insert into key cell cycle genes, inactivating them.
37) Ras genes = When mutated, can over-stimulate the cell cycle, even in the absence of a growth factor.
38) BRCA1 = Mutations in this gene can be inherited, significantly increasing someone’s cancer risk.
39) In RNA interference,
B) RiSC complex, bound to a single strand of RNA, cuts mRNA molecules.
40) When a hormone influences gene expression, this occurs….
C) translationally.
4