Genetics not on exams but final

C

Keto-enol tautomerization of G makes it pair with: (put actual answer)

A

T
G
C

G

Keto-enol tautomerization of T makes it pair with: (use actual answer)

A
T
G
C

a

What can be said about AT and GT pairs?

AT is a Watson-Crick pair, and GT is a wobble pair

AT is a wobble pair, and GT is a Watson-Crick pair

They are both Watson-Crick pairs

They are both wobble pairs

d

Chromosomal DNA replication in living cells can best be described as:

conservative and unidirectional

conservative and bidirectional

semiconservative and unidirectional

semiconservative and bidirectional

b

DNA polymerase from the prokaryote Thermus aquaticus lacks the proofreading activity. This activity is also known as:

5'-to-3' exonuclease activity

3'-to-5' exonuclease activity

5'-to-3' polymerase activity

3'-to-5' polymerase activity

a

Compared to a DNA polymerase that DOES have proofreading activity, how will DNA polymerase from T. aquaticus compare in replication accuracy?

T. aquaticus polymerase will make MORE mistakes

T. aquaticus polymerase will make LESS mistakes

Polymerase accuracy is comparable whether or not it has proofreading activity

Since T. aquaticus is a prokaryote, it does NOT have DNA as its genetic material

b

When telomerase extends the telomeres, it synthesizes _____ while using _____ as a template.

DNA, DNA

DNA, RNA

RNA, RNA

RNA, DNA

T

T or F. DNA polymerases require primer, while RNA polymerases do not.

a

In prokaryotes, the RNA polymerase holoenzyme contains 

the core enzyme and the Sigma factor

the core enzyme only

the Sigma factor only

T

T or F. RNA molecules are synthesized in the 5’ to 3’ direction.

c

In the backbone of an RNA molecule, the previous and consecutive ribonucleotides are held together by a(n) _____________ bond.

Ester

Hydrogen

Phosphodiester

Ionic

a

In prokaryotes, the Sigma factor is necessary for

a. recognition of promoter elements

b. elongation of the RNA chain

c. termination of the RNA chain

d. maximum translation of the gene

b

How many different types of RNA polymerase holoenzymes can a bacterial cell have?

One

As many as there are different Sigma factors

As many as there are different types of ribosomes

a

Which type of RNA is translated into proteins?

mRNA

tRNA

rRNA

All of the above

c

Suppose RNA polymerase needs to insert a G nucleotide into the growing RNA chain. Which nucleotide will RNA polymerase choose?

GMP

GDP

GTP

c

Suppose you have an RNA molecule with the sequence 5'-UUAAAGGGG-3'. How many ATP molecules were directly needed to synthesize this RNA?

One

Two

Three

Four

Nine

b

During initiation of transcription in prokaryotes, which of the following binds first to the promoter?

The RNA polymerase core enzyme

The Sigma factor

TATA binding protein (TBP)

f

T or F. In prokaryotes, the RNA polymerase core enzyme + Sigma factor stay together throughout the entirety of transcription elongation

b

During transcription, what is the difference between the coding DNA strand and the non-template DNA strand?

These are two complementary DNA strands

This is the same DNA strand

c

If the sequence of the coding DNA strand is 5'-ATTGCGAATCT-3', what is the sequence of the RNA transcript?

5'-UTTGCGUUTCT-3'

3'-UTTGCGUUTCT-5'

5'-AUUGCGAAUCU-3'

3'-AUUGCGAAUCU-5'

c

If the sequence of the non-coding DNA strand is 5'-ATGCGCCAGTT-3', what is the sequence of the RNA transcript?

5'-AUGCGCCAGUU-3'

3'-AUGCGCCAGUU-5'

5'-AACUGGCGCAU-3'

3'-AACTGGCGCAT-3'

a

If the sequence of the RNA is 5'-AUUGCCGUAAU-3', what is the sequence of the non-template DNA strand?

5'-ATTGCCGTAAT-3'

3'-ATTGCCGTAAT-5'

5'-TAACGGCATTA-3'

3'-TAACGGCATTA-5'

T

T or F. In prokaryotes, Rho-independent transcription termination requires the formation of an RNA “hairpin”, in which RNA-RNA base-pairing competes with RNA-DNA base-pairing and destabilizes the RNA-DNA hybrid in the transcription “bubble”.

c

The prokaryotic Rho factor can be best described as

Nuclease

Polymerase

Helicase

t

T or F. A bacterial operon contains more than one protein-coding gene and is transcribed into a single polycistronic mRNA.

c

During mRNA transcription initiation in eukaryotes, general transcription factors help recruit _____ to the promoter.

DNA polymerase

Reverse transcriptase

RNA polymerase II

DNA primase

c

In eukaryotes, the mRNA transcription initiation complex typically binds DNA at the ___ region via the ___ protein.

Pribnow box; Sigma factor

rut (Rho utilization site); Rho factor

TATA box; TBP

d

In eukaryotes, precursor mRNA (pre-mRNA) molecules are processed in the

Ribosomes

Golgi bodies

Cytoplasm

Nucleus

All of the above

d

A mature eukaryotic mRNA has a ______, which is connected through a ______

3' cap; 5' to 3' triphosphate linkage

3' cap; 5' to 5' triphosphate linkage

5' cap; 5' to 3' triphosphate linkage

5' cap; 5' to 5' triphosphate linkage

c

The poly(A) tail of an mRNA

a. keeps the coding sequence from being degraded

b. is not coded for in the DNA template

c. all of the above

b

Suppose there is a gene called “bicycle”. The pre-mRNA of this gene contains four exons:

Exon 1 = “frame”
Exon 2 = “disc brakes”
Exon 3 = “V-brakes”
Exon 4 = “wheels”

Suppose you want to customize this “bicycle” to have only “disc brakes”, but not "V-brakes". Which mature mRNA splice product would achieve this purpose?

NOTE: A bicycle is defined as having a frame, wheels, and brakes.

a. Ex1-Ex2-Ex3-Ex4

b. Ex1-Ex2-Ex4

c. Ex1-Ex3-Ex4

d. Ex1-Ex4

T

T or F. In the question above, all introns are removed from the mature mRNA, regardless of how many exons are kept.

a

Which amino acids are more soluble in water (i.e. more hydrophilic)?

Neutral polar

Neutral non-polar

c

Which amino acids are called “acidic”?

neutral polar

neutral non-polar

negatively charged

positively charged

a

A peptide bond forms between the _____ group of one amino acid and the _____ group of another amino acid.

amino, carboxyl

carboxyl, phosphate

amino, amino

carboxyl, carboxyl

a

The order of amino acids in the polypeptide chain is called the ______________ structure. 

primary

secondary

tertiary

quaternary

e

How many different 3-letter codons are possible if the “alphabet” contains 4 letters (A, U, G, C)?

3

4

12

20

64

b

The genetic code is called “degenerate” because

a. a single codon usually specifies several different amino acids

b. a single amino acid is usually specified by several different codons

t

T or F. mRNA is translated in the 5’-to-3’ direction.

d

What kind of linkage connects an amino acid to the corresponding tRNA?

Amino group to 5’ end linkage

Amino group to 3’ end linkage

Carboxyl group to 5’ end linkage

Carboxyl group to 3’ end linkage

c

In prokaryotes, translation initiation begins when the small ribosomal subunit recognizes the

Kozak sequence

5' cap of the mRNA

Shine-Dalgarno sequence

3' UTR of the mRNA

a

Proteins are synthesized in the ________ to __________ direction.

N-terminal to C-terminal

C-terminal to N-terminal

Either (a) or (b), depending on the protein

c

Which codon serves as the START codon in the vast majority of cases?

5'-UGA-3'

5'-GGA-3'

5'-AUG-3'

b

Which amino acid serves as the first amino acid during translation in bacteria?

Methionine (Met)

N-formyl-Methionine (fMet)

Arginine (R)

Asparagine (Asp)

d

Consider an mRNA molecule with the following sequence: 5’-AUGUUUCCGUGA-3’. This mRNA will be translated into a protein of what length? (The reading frame starts with the first nucleotide.)

1 amino acid in length

2 amino acids in length

3 amino acids in length

4 amino acids in length

d

During initiation of translation, the start codon will be in the ____ site of the ribosome, and the codon for the next amino acid will be in the ____ site of the ribosome.

A, E

E, A

P, E

P, A

a

Suppose you have a mRNA molecule with the following tRNA anticodon located in the P site of the ribosome. Which codon corresponds to the E site of the ribosome

5'-CUA-3'

5'-UAG-3'

5’-ACG-3’

5’-CGU-3’

d

Suppose you have a mRNA molecule with the following tRNA anticodon located in the P site of the ribosome. A tRNA with which anticodon will be located in the A site of the ribosome?

5'-CUA-3'

5’-UAG-3’

5’-ACG-3’

5’-CGU-3’

c

Suppose you have a mRNA molecule with the following tRNA anticodon located in the P site of the ribosome. How many amino acids are attached to the tRNA in the P site of the ribosome?

Zero

One

More than one

d

Suppose that in the P site of the ribosome, you have a tRNA attached to two amino acids (AA1 and AA2) as follows:
AA1 – AA2 – tRNA

a. What kind of bond connects AA1 and AA2 here?

b. Phosphodiester bond between 3’ of AA1 and 5’ of AA2

c. Phosphodiester bond between 5’ of AA1 and 3’ of AA2

d. Peptide bond between the amino group of AA1 and the carboxyl group of AA2

e. Peptide bond between the carboxyl group of AA1 and the amino group of AA2

a

Suppose that in the P site of the ribosome, you have a tRNA attached to two amino acids (AA1 and AA2) as follows:
AA1 – AA2 – tRNA

What is the orientation of the N- and C-termini?

a. N – AA1 – AA2 – C

b. C – AA1 – AA2 – N

c. N – AA1 – AA2 – N

d. C – AA1 – AA2 – C

d

During translation elongation, a single tRNA could recognize more than one codon because of

a. Wobble pairing between the 3’ position of the codon and the 3’ position of the anticodon

b. Wobble pairing between the 5’ position of the codon and the 5’ position of the anticodon

c. Wobble pairing between the 5’ position of the codon and the 3’ position of the anticodon

d. Wobble pairing between the 3’ position of the codon and the 5’ position of the anticodon

c

When does translation terminate?

a. When the ribosome reaches the end of the mRNA

b. When the ribosome reaches a tyrosine codon

c. When the ribosome reaches a stop codon

d. When the polypeptide chain folds into an alpha helix

c

One of the three stop codons has the sequence 5’-UGA-3’. What is the sequence of the anticodon loop of the corresponding stop tRNA?

5’-ACU-3’

3’-ACU-5’

There is no such thing as “stop tRNA”

a

A missense mutation

a. causes an amino acid substitution

b. creates a stop codon

c. causes a frameshift

d. prevents initiation of translation

e. prevents termination of translation

T

T or F. A neutral missense mutation is a mutation that changes a codon for one amino acid to a codon for another amino acid with similar properties.

b

An A nucleotide is mutated to a C nucleotide. This is an example of ______.

Transition Transversion

b

Deamination of cytosine converts it to

5-methyl cytosine

uracil

adenine

guanine

c

Deamination of adenine converts it to

guanine

cytosine

inosine

N⁶-methyladenine

C

In its keto form, G will usually pair with which of the following? (actual answer)

A
T
G
C

A

In its imino form, C pairs with which of the following? (actual answer)

A
T
G
C

c

Which of the following is a source of spontaneous mutations?

UV radiation

Intercalating agents

DNA polymerase errors

X-ray radiation

d

Treating cells with an intercalating agent can induce which type of DNA mutation?

Missense mutation

Silent mutation

Neutral mutation

Frameshift mutation

Nonsense mutation

c

Suppose the wild-type protein sequence is:

Ser-Gln-Lys-Phe-Thr.

Which of the following mutant proteins occurred as a result of a DNA
mutation caused by an intercalating agent?

a. Ser-Gln-Arg-Phe-Thr

b. Ser-Gln-Glu-Phe-Thr

c. Ser-Gln-Glu-Ile-Tyr

c

During DNA replication, proofreading allows for the removal of incorrect nucleotides. This repair mechanism is based on which enzymatic function of DNA polymerase?

3’ to 5’ endonuclease activity

5’ to 3’ endonuclease activity

3’ to 5’ exonuclease activity

5’ to 3’ exonuclease activity

b

Photolyase is an enzyme that can break up UV-induced TT dimers. This process is called “light repair” because

TT dimers are formed during exposure to light

Photolyase is activated by light

b

Nucleotide excision repair (NER) is known as the “dark repair” mechanism. This is because

This mechanism requires dark conditions for its activation

This mechanism does not require light for its activation

b

A trait known as Xeroderma Pigmentosum (XP) is

a. A human disease characterized by reduced production of melanin, which is a skin pigment

b. A human disease that can be caused by mutations in the nucleotide excision repair (NER) system

c. An autosomal recessive trait caused by mutations in the photolyase gene

d. An infection caused by bacteria with defects in the photolyase gene

c

Under conditions of extreme DNA damage, prokaryotes will use which of the following DNA polymerases to replicate damaged DNA?

DNA Pol I

DNA Pol III

DNA Pol V

T

T or F. One negative side-effect of using low-fidelity (non-proofreading) DNA polymerases for DNA synthesis is that they make DNA replication mistakes even when using a perfectly normal DNA template strand, causing unnecessary mutations. Therefore, cells activate such DNA polymerases only in situations of extreme DNA damage, such as during the bacterial SOS response.

c

DNA mutations can be caused by mistakes during DNA replication. Suppose that during replication of a perfectly normal DNA template strand, a regular high-fidelity DNA polymerase makes a mistake by inserting G opposite T, and this mistake goes unnoticed by DNA polymerase’s proofreading activity. After the fact, what is one way in which the cell might still know whether this GT mismatch should be an AT pair or a GC pair?

a. The cell has no way of telling which pair it should be; it simply assumes that each GT mismatch should be corrected by mutating G to A to make it an AT pair

b. The cell has no way of telling which pair it should be; it simply assumes that each GT mismatch should be corrected by mutating T to C to make it a GC pair

c. The cell methylates some adenines in the old DNA template strand to distinguish it from the newly synthesized DNA strand; the cell will conclude that the correct base is on the methylated strand (T)

a

Mutations in which genes would be most detrimental to an organism?

Genes responsible for DNA repair

Genes responsible for melanin production

Genes responsible for fingernail growth

b

Which of the following is a palindromic double-stranded DNA sequence (only one DNA strand is shown)?

GCTTCG

GGATCC
GGGTTT
ATGTAG

a

Which of the following enzymes will recognize and cut double-stranded palindromic DNA sequences

Restriction endonucleases

Telomerases

DNA polymerases

RNA polymerases

d

Suppose a linear double-stranded DNA molecule has 2 sites recognized by the restriction endonuclease BamHI. How many DNA fragments will be generated after cutting it with BamHI?

0

1

2

3

4

c

Suppose a circular double-stranded DNA molecule has 2 sites recognized by the restriction endonuclease BamHI. How many DNA fragments will be generated after cutting it with BamHI?

0

1

2

3

4

c

Suppose you have a circular double-stranded DNA molecule with a single recognition site for BamHI. You cut the DNA with BamHI and get a linear DNA molecule. How can you make this DNA circular again?

By using DNA polymerase + dNTPs

By using RNA polymerase + NTPs

By using DNA ligase + ATP

By using BamHI + ATP

c

Ethidium bromide, a chemical often used in the lab to visualize DNA on a gel, is an example of a(n)

Deaminating agent

Alkylating agent

Intercalating agent

Hydroxylating agent

b

During gel electrophoresis, the ____ fragments will run fastest through the gel.

Larger

Smaller

All fragments will run at the same speed

c

Suppose you set up a polymerase chain reaction (PCR). You add template DNA, primers, dNTPs, and magnesium. Which DNA polymerase can be used without having to replenish it in the test tube after each PCR cycle?

E. coli DNA polymerase

Human DNA polymerase

T. aquaticus DNA polymerase

S. cerevisiae DNA polymerase

b

In Sanger sequencing, what ensures chain termination during DNA synthesis?

dNTPs

ddNTPs

NTPs

Adenosine monophosphate (AMP)

a

What is used by some bacteria as a defense system against bacteriophages?

CRISPR-Cas

Innate immunity

B-cell antibodies

RNase E

a

Suppose a normal (euploid) cell has 17 chromosomes. What’s the ploidy of the cell?

a. Haploid

b. diploid

c. triploid

d. polyploid

b

Which of the following determines the correct segregation of X and Y chromosomes during meiosis I in humans (male):

a. lack of homology between X and Y

b. Presence of “pseudoautosomal” (PAR) regions shared by X and Y

c. the presence of the SRY gene

e

Red-green color blindness is an X-linked recessive trait. A man and wife, both with normal vision have a color-blind daughter. What genetic situation caused this?

a. man and wife both carriers

b. the man is not the biological father

c. mother is a carrier

d. both a and b

e. both b and c

d

Genes A and B are on the same chromosome and are 20 mu apart. What is the probability that the cross AB//ab x AB//ab will produce offspring with the genotypes Ab//Ab?

a. 0.20

b. 0.10

c. 0.16

d. 0.01

b

The sheep-goat hybrid is

a. fertile because he is a diploid

b. sterile because he is an allodiploid

c. sterile because he is a triploid

a

When a fruit fly with the karyotype XXY produces gametes, it is more likley to produce gametes of the following karyotypes

a. XY and X

b. XX and Y

c. XY and Y

d. YY and X

a

Which of the following population will exhibit the largest heritability of a quantitative trait

a. a genetically diverse population in a uniform environment

b. the same genetically diverse population as above, but in non-uniform environment

c. a genetically identical true-breeding population in a non-uniform environment

b

Incorporation of the next deoxyribonucleotide into the newly synthesized DNA strand requires energy. This energy is directly supplied by

a. ATP

b. The incoming nucleotide itself

c. The triphosphate of the previously incorporated nucleotide

b

proofreading activity of a DNA polymerase refers to its

a. 5-3 exonuclease activity

b. 3-5 exonuclease activity

c. double-stranded endonuclease activity

a

Consider the following template DNA strand: 5’-GTTTTTAAAC-3’. How many ATP molecules are needed to synthesize an RNA transcript on this template

a. 5

b. 3

c. 1

d. 0

c

In prokaryotes, what enzyme does the Rho factor have?

a. DNA polymerase

b. RNA polymerase

c. Helicase

d. Exonuclease