Exam 2

Question 1

Central Doggma

Answer 1

refers to as transcription and translation, DNA replication

Question 2

What is the aim for transcription and translation?

Answer 2

protein synthesis, which we know as expression of the genes

Question 3

Why do genes need to be expressed?

Answer 3

so organism can function

Question 4

What is DNA polymerase

Answer 4

enzyme responsible for duplicating DNA material material before a cell “commits to the vision”

Question 5

Transcription is

Answer 5

RNA synthesis

Question 6

Translation is

Answer 6

protein synthesis

Question 7

What causes spontaneous mutations

Answer 7

DNA polymerase introducing changes in the sequence of DNA while copying DNA

Question 8

Are spontaneous mutations corrected?

Answer 8

no

Question 9

Are spontaneous mutations inherited?

Answer 9

no

Question 10

Why can we have a change in nucleotide sequence, but the protein structure remains the same?

Answer 10

bc we have multiple codons that specify the same amino acid

Question 11

What is a silent mutation?

Answer 11

a change in the nucleotide sequence, however the protein structure remains the same

Question 12

What is a missense mutation?

Answer 12

a change in a nucleotide that reults in a change in the amino acid sequence; results in a faulty protein

Question 13

What is a nonsense mutation?

Answer 13

STOP codon that appears prematurely in DNA sequence; resulting in incomplete/nonfunctional protein

Question 14

What is a frameshift mutation?

Answer 14

insertion/removal of a letter, thus changing the message

Question 15

Why is a template important for a cell fixing errors?

Answer 15

repair mechanisms need to see which is nonmutated strand and which is the mutated strand

Question 16

A spontaneous mutation usually originates as an error in?

Answer 16

DNA transcription

Question 17

When do spontaneous mutations occur?

Answer 17

in DNA replication when DNA polymerase incorporates the wrong nucleotide

Question 18

Are there mutations in RNA during transcription? Why or why not?

Answer 18

yes, but they are not relevant, as they are not permanent, bc RNA is a temporal structure that carries out its job and is then degraded

Question 19

What are the two types of detections of mutation?

Answer 19

positive and negative

Question 20

How does positive selection detect mutations?

Answer 20

by selecting a mutant and rejecting a nonmutant
-looks for bacteria that have gained traits you are able to select

Question 21

How does negative selection detect mutations?

Answer 21

by looking for strains/mutant cells that have lost a function
-(most common)

Question 22

What is an auxotroph?

Answer 22

a mutant that has lost capacity to generate media
-only in complete media

Question 23

What is the Ames test?

Answer 23

test used as the first screening to determine how bad of a mutagen a chemical agent is

Question 24

How does the Ames test work?

Answer 24

tests the cells that regain the capacity to xyz
-aka it reverses the mutation

Question 25

What is horizontal gene transfer?

Answer 25

genes are only transferred from donor to recipient; when DNA is transferred, it will incorporate into the chromosome of the host cell of the recipient cell(recombination cell)

Question 26

If a mutation occurs in a noncoding region, will it be affected?

Answer 26

no

Question 27

What are base analogs?

Answer 27

looks like a base, but is not a nucleotide

Question 28

What does an alkylating agent do?

Answer 28

cross links nucleotides

Question 29

What does an intercalating agent do?

Answer 29

inserts itself between nucleotides

Question 30

What did Beadle and Tatum do?

Answer 30

used ionizing radiation to create mutants on fungi using x rays

Question 30

Explain the process of Beadle and Tatum's experiments.

Answer 30

they did two lines of experiments, which included the same colony being grown on minimal and complete media, and looked for colonies able to grow on minimal media

Question 31

How do ribosomes know there are three segments that need to be translated?

Answer 31

there is a sequence that precedes each of the three sequences

Question 32

Shine Delgarno is exclusive to

Answer 32

prokaryotes only

Question 33

Where does translation start?

Answer 33

at the starting codon AUG, which occurs in the cytoplasm

Question 34

Mistakes and errors will modify the structure of the DNA, but why would a cell want to repair those mutations?

Answer 34

it must maintain the integrity of the genetic information

Question 35

What is the problem the repair mechanisms have?

Answer 35

they need to distinguish which strand of DNA is the mutated one, and which one is the unmutated one

Question 36

Mismatch occurs

Answer 36

right after replication recognizes it, removes it, and corrects it

Question 37

How does nucleotide excision repair work?

Answer 37

detects extortion of DNA structure, and cuts out the chunk of DNA strand, then, the DNA polymerase will replace since the complementary strand is in tact

Question 38

How does photoreactivation work?

Answer 38

photoligase identifies extortion in DNA and breaks covalent bond via light that links dimers

Question 39

How does direct repair work?

Answer 39

photolyase repairs without replacing any nucleotides