Deck 18: Genetic Information

Question 1

The replisome consists of all of the following proteins except _________.

A) DNA polymerase
B) DNA topoisomerase
C) Primase
D) Catabolic gene activator protein
E) Helicase

Answer 1

D

Question 2

The experiment that demonstrated the mechanism whereby DNA is synthesized was performed by

A) Avery, MacLeod and McCarty
B) Watson and Crick
C) Linus Pauling
D) Meselson and Stahl
E) Maurice Wilkins

Answer 2

D

Question 3

The _____ are enzymes that catalyze the unwinding of duplex DNA.

A) Topoisomerases
B) Helicases
C) Ligases
D) Primases
E) Unwindases

Answer 3

B

Question 4

SSB are

A) A series of nucleases that degrade RNA primers
B) Substrates for DNA ligase
C) Proteins that bind to single-stranded DNA
D) Enzymes that catalyze Okazaki fragment formation
E) Molecules that bind to DNA

Question 5

The background rate of spontaneous mutations is approximately ________ mutations per gene per million gametes

A) 0.01 to 0.1
B) 0.1 to 1
C) 1 to 10
D) 10 to 100
E) None of the above are correct

Question 6

DNA polymerase $\beta$ is believed to be involved in

A) Eukaryotic DNA repair
B) Mitochondrial DNA replication
C) Chloroplast DNA replication
D) Prokaryotic DNA synthesis
E) Chloroplast DNA repair

Question 7

Mutations are caused by all of the following except ________.

A) Depurinations
B) Radiation
C) Viruses
D) Oxidative Damage
E) None of the above are correct

Question 8

DNA molecules are copied or replicated by a _______ mechanism.

A) Conservative
B) Semiconservative
C) Dispersive
D) More than one answer is correct
E) All of the above are correct

Question 9

The tangling of DNA strands during replication is prevented by _________.

A) Topoisomerases
B) Helicases
C) Ligases
D) Primases
E) Unwindases

Question 10

The rate of DNA synthesis in eukaryotes is approximately_________ nucleotides per ________ per replication fork.

A) 10/ second
B) 50 / second
C) 100 / second
D) 50 / minute
E) 100/ minute

Question 11

In the eukaryotic cell cycle the M(itosis) phase occurs after the ______ phase.

A) G_o
B) G₁
C) G₂
D) S
E) None of the above is correct

Question 12

_______ is a form of intermicrobial DNA transfer that occurs when bacteriophage
Inadvertently serve as carriers of bacterial DNA to the recipient cell.

A) Transposition
B) Conjugation
C) Transformation
D) Transduction
E) Recombination

Question 13

The initiation of transcription involves the binding of RNA polymerase to a specific sequence called a __________.

A) Delta repeat
B) Consensus sequence
C) Promoter
D) Primer
E) Long terminal repeat

Question 14

All of the following gene products are coded for by constitutive genes except ______.

A) Histone
B) Aconitase
C) Pyruvate dehydrogenase
D) Lactose
E) rRNA

Question 15

The reassortment of DNA sequences is called

A) Duplication
B) Replication
C) Recombination
D) Decoding
Reconstitution

Question 16

_______ are tumors that arise in connective tissue.

A) Lymphomas
B) Leukemias
C) Carcinomas
D) Sarcomas
E) None of the above is correct

Question 17

______ is a protooncogene that codes for a GTP-binding protein.

A) Sis
B) Src
C) Jun
D) Myc
E) None of the above is correct

Question 18

______ is a protooncogene that codes for platelet-derived growth factor.

A) Sis
B) Src
C) Jun
D) Myc
E) None of the above is correct

Question 19

_______ is a product of a delayed response gene.

A) Cyclin
B) Jun
C) Fos
D) AP-1
E) Myc

Question 20

______ is an enzyme that catalyzes a critical step in replicative transposition.

A) Unwindase
B) Replicase
C) Resolvase
D) Primase
E) Catabolic gene activation protein

Question 21

_______ catalyzes the transcription of the precursor of the tRNAs and 5S rRNA.

A) RNA polymerase I
B) RNA polymerase II
C) RNA polymerase III
D) RNA directed DNA polymerase
E) None of the above is correct

Question 22

DNA transposition can cause gene ______.

A) Duplication
B) Deletion
C) Transcription
D) Both A and B are correct
E) All of the above are correct

Question 23

Many promoters for RNA polymerase II contain a consensus sequence call the _______.

A) CAAT box
B) GC box
C) Pribnow box
D) TATA box
E) Okazaki box

Question 24

Place the following steps of general recombination in chronological order
I) DNA ligase seals the cut ends
Ii) A second series of DNA strand cuts occurs opposite the first crossover strands
Iii) Two homologous DNA molecules become paired
Iv) DNA polymerase fills any gaps and DNA ligase seals the cut strands
V) Two of the DNA strands are cleaved
Vi) The two strand segments cross over

A) i, iii, v, iv, ii, vi
B) iii, iv, vi, i, vi, iii
C) iv, ii, v, i, ii, iv
D) iii, v, vi, i, ii, iv
E) v, vi, i, ii, iv, iii

Question 25

Most of the carcinogenic effects of radiation are believed to be the result of _______.

A) Viruses
B) Transposition
C) ROS
D) Transduction
E) Alkylation

Question 26

DNA is synthesized in which of the following directions

A) In the 5' $\rightarrow$ 3' direction on the leading strand and 3' $\rightarrow$ 5' direction on the lagging strand
B) In the 3' $\rightarrow$ 5" direction on the leading strand and the 5' $\rightarrow$ 3' direction on the lagging strand
C) In the 5' $\rightarrow$ 3' direction on both DNA strands
D) The direction differs depending on the genes being duplicated
E) None of the above is correct

Question 27

All of the following play a role in DNA repair except ________.

A) Light
B) PR enzyme
C) Ribozymes
D) Endonuclease
E) Pol I

Question 28

In the absence of its inducer the lac operon remains repressed because of the binding of lac repressor to the _______.

A) Promoter
B) Regulatory gene
C) Catabolic gene activator protein
D) Operator
E) CAP site

Question 29

Eukaryotic gene expression is affected by all of the following except ______.

A) RNA processing
B) Translational control
C) ) Gene rearrangements
D) Transcriptional control
E) None of the above is correct

Question 30

The majority of genetic variations arise from

A) Mutations
B) Genetic recombination
C) Base deletion
D) Tautomerism
E) Both A and B are correct

Question 31

Topoisomerases

A) Join DNA strands together
B) Prevent tangling of DNA strands
C) Relieve torque in replicating DNA
D) Change the supercoiling of DNA
E) All of the above are correct

Question 32

Type II topoisomerases

A) Produce double stranded breaks in DNA
B) Replicate only the lagging strand
C) Replicate only the leading strand
D) Relieve torque ahead of the replicating machinery
E) Both A and B are correct

Question 33

In higher eukaryotes replication begins with the

A) Origin of replication complex (ORC)
B) Assembly of pre-initiation replication complex (preRC)
C) Recruiting of the MCM complex to the replication site
D) Stabilizing of the DNA strands by replication protein A (RPA)
E) Attachment of DNA polymerase $\delta$ to each DNA strand

Question 34

Light-induced repair will correct which of the following mutations

A) Deamination of adenine
B) Reversion of thymine dimers
C) Tautomerism of uracil
D) Removal of nucleotides
E) Breaks in the phosphodiester linkage

Question 35

In nucleotide excision repair

A) Single bases are removed and replaced
B) Bulky lesions are removed
C) Thymine dimers are replaced
D) Gaps are repaired by DNA polymerase
E) Nucleotides are removed and new ones inserted

Question 36

Insertion of viral DNA into a host cell's genome is an example of

A) Transformation
B) Transduction
C) Conjugation
D) Site specific recombination
E) Myosis

Question 37

Genomic libraries are produced by

A) Colony hybridization techniques
B) Polymerase chain reactions
C) Electroporation
D) Shotgun cloning
E) Cosmids

Question 38

Homology modeling facilitates

A) Protein structure prediction
B) Open reading frames synthesis
C) Stop codons deletion
D) Protein function
E) Start codon initiation

Question 39

Protooncogenes are

A) Normal genes that code for transcription factors
B) Normal genes that if mutated can promote carcinogenesis
C) Tumor suppressor genes
D) Growth factor receptor genes
E) All of the above are correct

Question 40

An exonuclease is an enzyme that

A) Depolymerizes RNA only
B) Polymerizes DNA and RNA
C) Removes nucleotides from the end of a polynucleotide strand
D) Add nucleotides to the end of a polynucleotide strand
E) Depolymerizes DNA only

Question 41

Repair of DNA by the SOS system has a major disadvantage

A) Repair is slow
B) Repair is error prone
C) Repair cannot replace missing nucleotide sequences
D) Frequently fragments the DNA chain
E) C and D

Question 42

A difference between prokaryotic and eukaryotic DNA polymerases is:

A) Polymerizes DNA from opposite ends of the DNA chain
B) Eukaryotic DNA polymerases do not remove RNA primers
C) Prokaryotic polymerases work with both DNA and RNA chains
D) Prokaryotic DNA polymerases do not require an RNA primer
E) There are no differences

Question 43

The average natural mutation rate for plants and animals is one mutation per ______
Genes/generation.

A) 10,000
B) 50,000
C) 100,000
D) 1,000,000

Question 44

____________ repair occurs only on a strand actively being transcribed,

A) Mismatch repair
B) Transcription coupling repair
C) Replication slippage
D) DNA
E) RNA

Question 45

__________ corrects replication proofreading errors.

A) Mismatch repair
B) Transcription coupling repair
C) Reading repair
D) Transcription coupling repair factor
E) Isomerase repair factor

Question 46

What is a replication fork?

Question 47

What is an Okazaki fragment?

Question 48

What is mismatch repair?

Question 49

What is an insertional element?

Question 50

What is a cosmid?

Question 51

What is a riboswitch?

Question 52

How does negative supercoiling promote the initiation of replication?

Question 53

Mustard gas is an extremely toxic substance that severely damages lung tissue. In small amounts, mustard gas is a mutagen and carcinogen. Considering that mustard gas is a bifunctional alkylating agent, explain how it mutates genes and impacts DNA replication.

Question 54

Indicate what types of mutation that ROS causes.

Question 55

What types of mutations are caused by small alkylating agents?

Question 56

What type of mutations would nitrous acid cause?

Question 57

How can viruses cause mutations?

Question 58

Explain the significance of "jumping genes."

Question 59

Describe two forms of genetic recombination. What functions do they fulfill?

Question 60

Within cells, cytosine slowly converts to uracil. What type of mutation would this lead to? What impact would the same modification have if it occurred at the RNA or gene product level?

Question 61

A correlation has been found among species between life span and efficiency of DNA repair systems. Suggest a reason why this is so.

Question 62

Describe the advantages for organisms to arrange genes in operons.

Question 63

Many genes generate different products depending on the type of the cell expressing the gene. How is this phenomenon accomplished?

Question 64

RNA molecules are more reactive than DNA molecules explain.

Question 65

Although genetic variation is required for species to adapt to changes in their environment, most genetic changes are detrimental. Explain why mutations are rarely beneficial.

Question 66

During certain stages of development, the requirement for certain gene products may require gene amplification. What purpose does gene amplification serve?

Question 67

There appears to be insufficient genetic material to direct all the activities of certain types of eukaryotic cell. Provide one example whereby genetic recombination is used to solve this problem.

Question 68

Adjacent pyrimidine bases in DNA form dimers with high efficiency after exposure to UV light. If these dimers are not repaired, skin cancers can result. Melanin is a natural sunscreen produced by melanocytes, a type of skin cell, when the skin is exposed to sunlight. Individuals who spend long periods over many years developing a tan eventually acquire thick and highly wrinkled skin. Such individuals are also at high risk for skin cancer. Can you explain, in general terms why these phenomena are related?

Question 69

Phorbol esters have been observed to reduce the transcription of AP-1 genes. Explain how this process could occur. What are the consequences of AP-1 transcription? What role does intermittent exposure to phorbol esters have on an individual's health?

Question 70

Because of overuse of antibiotics and/or weakened government surveillance of infectious disease, several diseases that had been thought to be no longer a threat to human health are rapidly becoming unmanageable (e.g. antibiotic resistant tuberculosis). Superbugs (microorganisms that are resistant to almost all known antibiotics) have also been detected. How did this circumstance arise? What will happen if the process continues?

Question 71

Explain the difference between the potential effects on an individual organism of errors made during the replication and those made during transcription.

Question 72

Explain how a reverse transcriptase activity within a cell can result in gene amplification.

Question 73

It was originally thought that the DNA polymerase machinery moves along the DNA in the manner analogous to a train on a track. Current evidence indicates that the polymerizing machinery is instead stationary, and DNA strands are pumped through the complex. What advantages does this stationary machinery have?

Question 74

Determine the magnitude of amplification of a single DNA molecule that can be attained with PCR during five cycles.