Ch 14: Gene Expression

Question 1

Which of the following is a stop codon?

Answer 1

UGA

Question 2

Which of the following is not a post-translational modification that might be required of a protein before it becomes functional in a cell?

Answer 2

All of the listed responses are post-translational modifications required of some proteins.

Question 3

Which binding site on a ribosome holds a tRNA attached to a growing polypeptide chain?

Answer 3

P site

Question 4

Which of the following is true of RNA processing?

Answer 4

Assemblies of protein and small RNAs, called spliceosomes, may catalyze splicing.

Question 5

The type of mutation responsible for sickle-cell anemia is __________.

Answer 5

both a point mutation and a nucleotide-pair substitution

Question 6

Which of the following is not transcribed from DNA?

Answer 6

Promoter

Question 7

Which of the following is true of transcription factors?

Answer 7

All of the listed responses are correct.

Question 8

A nucleotide deletion early in the coding sequence of a gene would most likely result in __________.

Answer 8

All of the listed choices are correct.

Question 9

Transcription involves the transfer of information from __________.

Answer 9

DNA to RNA

Question 10

Transfer RNA binds to what?

Answer 10

its specific amino acid in the active site of an aminoacyl-tRNA synthetase

Question 11

A stretch of bacterial DNA 600 nucleotides long can code at most for a polypeptide of how many amino acids?

Answer 11

200

Question 12

RNA polymerase moves along which strand of DNA and elongates RNA in which direction?

Answer 12

moves along the template strand of DNA, elongating an RNA molecule in a 5′ → 3′ direction

Question 13

A ribozyme is __________.

Answer 13

an RNA molecule that functions as an enzyme

Question 14

A series of studies on mutants of Neurospora identified three classes of mutants that needed arginine added to minimal media in order to grow. The production of arginine includes the following steps: precursor → ornithine → citrulline → arginine. What nutrient(s) have to be supplied to the mutants that had a defective enzyme for the ornithine → citrulline step in order to grow?

Answer 14

Citrulline

Question 15

Which of the following is not part of the translation initiation complex?

Answer 15

TATA box

Question 16

A signal peptide is __________.

Answer 16

the first 20 or so amino acids of a protein destined for a membrane location or for secretion from the cell

Question 17

How is the template strand for a particular gene determined?

Answer 17

It is established by the presence of the promoter.

Question 18

If the 5′ → 3′ nucleotide sequence on the nontemplate DNA strand is CAT, what is the corresponding codon on mRNA?

Answer 18

CAU

Question 19

Which enzyme synthesizes tRNA?

Answer 19

RNA polymerase

Question 20

The energy required for assembly of a polypeptide by a ribosome comes directly from __________.

Answer 20

GTP

Question 21

There are how many types of bacterial RNA polymerase?

Answer 21

One

Question 22

Which of the following is transcribed and then translated to form a protein product?

Answer 22

A gene for a transcription factor

Question 23

Which of the following is not involved in the formation of a eukaryotic transcription initiation complex?

Answer 23

Small RNA molecules

Question 24

Which of the following would not be found in a bacterial cell?

Answer 24

Small RNAs in spliceosome

Question 25

Which of the following individuals was the first to suggest that genes dictate phenotypes through enzymes?

Answer 25

Archibald Garrod

Question 26

Holds the tRNA that carries the growing polypeptide chain

Answer 26

P site

Question 27

The three stages of translation

Answer 27

- Initiation - Elongation - Termination

Question 28

elongation factors occurs in what three steps:

Answer 28

codon recognition, peptide bond formation, and translocation

Question 29

Polypeptides destined for the ER or for secretion are marked by a _______, which targets the protein to the ER

Answer 29

signal peptide

Question 30

Binds to the signal peptide

Answer 30

signal-recognition particle (SRP)

Question 31

Holds the tRNA that carries the next amino acid to be added to the chain

Answer 31

A site

Question 32

The exit site, where discharged tRNA’s leave the ribosome

Answer 32

E site

Question 33

Can eukaryotes use coupled transcription and translation at the same time? Why or Why not?

Answer 33

No. Because eukaryotes have transcription happen in the nucleus and translation happens in the cytoplasm

Question 34

Changes in the genetic material of a cell

Answer 34

Mutations

Question 35

Are frame shift or point mutations worse?

Answer 35

Frame shift mutations

Question 36

Chemical changes in just one nucleotide pair of a gene

Answer 36

Point mutations

Question 37

have no effect on the amino acid produced by a codon because of redundancy in the genetic code

Answer 37

Silent mutations

Question 38

change one amino acid to another

Answer 38

Missense mutations

Question 39

change an amino acid codon into a stop codon, nearly always leading to a nonfunctional protein

Answer 39

Nonsense mutations

Question 40

an Insertion or deletion of nucleotides that may alter the reading frame of the genetic message (changes the whole thing)

Answer 40

frameshift mutation

Question 41

physical or chemical agents that can cause mutations

Answer 41

Mutagens

Question 42

– A discrete unit of inheritance – A region of specific nucleotide sequence in a chromosome – A DNA sequence that codes for a specific polypeptide chain

Answer 42

Gene

Question 43

an infectious particle consisting of little more than genes packaged into a protein coat

Answer 43

virus

Question 44

may consist of either – Double- or single-stranded DNA, or – Double- or single-stranded RNA

Answer 44

Viral genomes

Question 45

a phage replicative cycle that culminates in the death of the host cell and produces new phages and lyses (breaks open) the host’s cell wall, releasing the progeny viruses

Answer 45

lytic cycle

Question 46

replicates the phage genome without destroying the host

Answer 46

lysogenic cycle

Question 47

Phage DNA is often identified as foreign and cut up by ____?

Answer 47

restriction enzymes

Question 48

system consists of clustered regularly interspaced short palindromic repeats and nuclease enzymes called Cas, CRISPR-associated proteins

Answer 48

CRISPR-Cas

Question 49

the major medical tool for preventing viral infections, a harmless derivative of a pathogen that stimulates the immune system to mount defenses against the harmful pathogen

Answer 49

Vaccines

Question 50

general outbreak

Answer 50

epidemic

Question 51

global epidemic

Answer 51

pandemic

Question 52

Proteins that are known to be infectious and appear to cause a number of degenerative brain diseases in various animal species. They can be transmitted in food and act very slowly, with an incubation period of at least 10 years. They are also virtually indestructable

Answer 52

prions

Question 53

the study of fossils

Answer 53

Paleontology

Question 54

a process in which individuals with favorable inherited traits are more likely to survive and reproduce

Answer 54

Natural selection

Question 55

Descent with modification by natural selection explains three broad observations about nature

Answer 55

- The unity of life - The diversity of life - The ways that organisms are suited for life in their environments