Bio 181 Unit 3

Question 1

A protein’s activity can be affected by post-translational modifications like phosphorylation

Answer 1

TRUE

Question 2

Because of how small regulatory RNAs work, injecting small double-stranded RNA molecules that match part of a gene’s mRNA will cause increased expression of the gene

Answer 2

FALSE

Question 3

A sample of RNA has 20% guanine (G) bases. What percentage of the RNA sample has uracil bases?

Answer 3

It cannot be determined (DNA can be)

Question 4

What is a DNA sequence? (not a protein)

Answer 4

The promoter

Question 5

A mutation in a gene’s silencer results in the gene being expressed when it normally would not be . What is an explanation for this result?

Answer 5

The mutation prevents a protein from binding to the sequence

Question 6

What does a gene’s promoter do in gene expression?

Answer 6

Signals the starting point for transcription by binding RNA polymerase

Question 7

What are the results of mRNA processing?

Answer 7

Addition of a 5’ cap and a poly-A tail/splicing of introns

Question 8

In transcription, what binds to the promoter region of a gene?

Answer 8

RNA polymerase

Question 9

What is the role of tRNA during translation?

Answer 9

It carries amino acids to the ribosome

Question 10

What happens if a stop codon appears early in a sequence?

Answer 10

The RNA sequence will be shortened and the protein will not be functional

Question 11

What happens at the end of the elongation phase in translation?

Answer 11

A stop codon is encountered

Question 12

Which molecule is directly involved in the negative regulation of gene transcription?

Answer 12

Repressor

Question 13

In eukaryotes, which of the following occurs at the transcriptional level of gene expression regulation

Answer 13

Chromatin remodeling

Question 14

What does an operon do in bacterial gene regulation?

Answer 14

It enables the simultaneous regulation of multiple genes

Question 15

When does mRNA splicing occur?

Answer 15

post-transcription

Question 16

What would happen if a mutation in an enhancer region might affect gene expression?

Answer 16

It could reduce the gene’s transcription levels

Question 17

Alternative splicing of mRNA allows cells to:

Answer 17

Create multiple isoforms from a single gene

Question 17

A point mutation that changes a single nucleotide but does not alter the amino acid sequence is known as:

Answer 17

A silent mutation

Question 18

What is a misense mutation?

Answer 18

Not a silent mutation; ex: hydrophobic to hydophillic (substitution)

Question 19

What is a frameshift mutation?

Answer 19

Deletion or addition one or two nucleotides (can be more) in the exon

Question 20

What is a nonsense mutation?

Answer 20

Early stop codon (substitution)

Question 21

Epigenetic modifications (like DNA methylation) differ from mutations because they:

Answer 21

Can be reversed and do not alter the sequence itself

Question 22

A mutation that prevents RNA polymerase from binding to the promoter region would result in:

Answer 22

Reduced transcription of the gene

Question 23

In eukaryotes, what occurs after transcription but before translation?

Answer 23

An addition of a 5’ cap and a poly-A tail to the mRNA

Question 24

Which direction is RNA made?

Answer 24

5' to 3'

Question 25

Which RNA molecule is directly involved in translation by carrying amino acids to the ribosome

Answer 25

tRNA

Question 26

In eukaryotes, what occurs during transcriptional regulation?

Answer 26

The binding of transcription factors to enhancer or silencer sequences

Question 27

What process directly follows transcription in eukaryotes?

Answer 27

mRNA processing including splicing and addition of 5' cap and poly-A tail

Question 28

If a mutation occurs in a gene's enhancer region, leading to reduced gene expression, what does it affect?

Answer 28

the ability of transcription factors to increase transcription levels

Question 29

What end is the phosphate group attached to on DNA?

Answer 29

The 5' end

Question 30

If complementary base pairing were prevented within a cell, what processes would be directly affected?

Answer 30

transcription and translation

Question 31

DNA is read which direction?

Answer 31

3' to 5'

Question 32

RNA is made from which direction

Answer 32

5' to 3' (N to C)

Question 33

What must be present for a gene to be transcribed?

Answer 33

RNA polymerase,

Question 34

Where are snRNAs found?

Answer 34

the nuclei of eukaryotes

Question 35

How are liver cells and muscle cells different in the same organism?

Answer 35

the mRNA is alternatively spliced in muscle and liver cells

Question 36

What environment is transferrin transcribed in in a cell?

Answer 36

A low iron environment, lets iron into a cell

Question 37

What environment is ferritin transcribed in in a cell?

Answer 37

A high iron environment, the protein binds to the receptor

Question 38

When looking at a transcription model with tRNA adding bases to the RNA molecule being transcribed, where do you look to see the next amino acid sequence to be added?

Answer 38

The coding strand has the same amino acid that will be added to the RNA

Question 39

In the transferrin/ferritan model, what will happen when iron levels are low?

Answer 39

Transferrin receptor mRNA will be translated

Question 40

In transferrin/ferritan model, what will happen when iron levels are high?

Answer 40

Ferritan mRNA will be translated

Question 41

Ribosomes catalyze the formation of:

Answer 41

peptide bonds

Question 42

What is the path of a tRNA?

Answer 42

A site to P site to E site then leaves the ribosome

Question 43

What must be present for a gene to be transcribed?

Answer 43

RNA polymerase and transcription factors bound to the gene's promoter

Question 44

What is a DNA sequence

Answer 44

enhancer, promoter, silencer, and the gene itself

Question 45

What happens if RNA polymerase cannot function?

Answer 45

RNA synthesis will immediately stop and protein synthesis will eventually stop

Question 46

What kind of transcription factor binds to an enhancer?

Answer 46

Regulatory transcription factors

Question 47

What kind of transcription factor binds to a silencer

Answer 47

General transcription factors

Question 48

Why do different cells in your body perform different things?

Answer 48

Different cells express different genes but all have the same DNA

Question 49

Because of the naturally-existing regulation mechanisms of the cell, injecting double-stranded RNA (dsRNA) into a cell has the effect of:

Answer 49

Silencing the expression of a gene