CH13

Question 1

The principle of transformation was first demonstrated by which of the following individuals or groups of individuals?

Answer 1

Griffith

Question 2

A complex consisting of a single mRNA molecule with several ribosomes is called a

Answer 2

polysome.

Question 3

When an F plasmid integrates into the host chromosome, the strain is referred to as

Answer 3

Hfr.

Question 4

When bacterial genes are transferred to another bacterium by a virus, it is called

Answer 4

transduction.

Question 5

Which of the following types of mutation may play an important role in driving evolution because they are often nonlethal and, therefore, remain in the gene pool?

Answer 5

missense

Question 6

_______ are strains that are unable to grow on a minimal medium that supports growth of the wild type strain but are able to grow on the minimal medium if one or more nutritional supplements are added.

Answer 6

Auxotrophs

Question 7

________ molecules deliver amino acids to ribosomes during translation.

Answer 7

Transfer RNA (tRNA)

Question 8

Transfer of genetic information via direct cell-cell contact is called

Answer 8

conjugation.

Question 9

The Ames test

Answer 9

is used to measure the mutagenicity of chemicals.

Question 10

The strand of DNA for a particular gene that is copied by the RNA polymerase to form mRNA is called the __________ strand.

Answer 10

template

Question 11

When a DNA molecule is replicated, the daughter molecules contain one strand of parental DNA and one strand of newly synthesized DNA; this is called __________ replication.

Answer 11

semiconservative

Question 12

When a recipient cell acquires a piece of naked DNA from the environment, it is called

Answer 12

transformation.

Question 13

You have taken E. coli strain A, which has its own plasmids, and mixed it with E. coli B strain without plasmids. E. coli B cells now have plasmids but, in addition, they also carry some genes from E. coli A strain. An explanation for this:

Answer 13

some F+ E. coli A cells became Hfr cells.

Question 14

Which of the following is not a termination codon?
UGA
AUG
UAA
UAG

Answer 14

AUG

Question 15

The region at which the RNA polymerase binds is the __________ region.

Answer 15

promoter

Question 16

The portion of the tRNA molecule that binds to the codon on the mRNA is called the

Answer 16

anticodon.

Question 17

After an F+ × F- mating, the donor is __________ and the recipient is __________.

Answer 17

F+; F+

Question 18

If 20% of nucleotides in the DNA of a particular organism contain thymine, estimate the percentage of cytosine that is present in the DNA.

Answer 18

30%

Question 19

The transcribed, but not translated, sequence that is immediately upstream of the region that encodes the functional product is called the __________ region.

Answer 19

leader

Question 20

A __________ mutation is one that causes premature termination of the synthesis of the protein product.

Answer 20

nonsense

Question 21

Which of the following best represents the order of gene transfer in an Hfr × F- mating?

Answer 21

part of the plasmid followed by part of the chromosome

Question 22

In order to take up a naked DNA molecule, a cell must be __________, which may occur only at certain stages in the life cycle of the organism.

Answer 22

competent

Question 23

During replication the 2 strands of the DNA molecule are unwound from one another by enzymes called

Answer 23

helicases.

Question 24

In __________ ribosomes can attach to the mRNA and begin translation even though transcription has not been completed.

Answer 24

prokaryotes

Question 25

Plasmids that have genes that decrease bacterial susceptibility to antibiotics are called __________ factors.

Answer 25

resistance

Question 26

what is the central dogma of DNA replication

Answer 26

DNA--replication-->DNA--transcription--> RNA (can reverse transcription back to DNA) --translation-->protein

Question 27

compare/contrast DNA replication in bacteria and eukaryotes

Answer 27

-in bacteria single origin, bidirectional 2 replication forks going in opposite directions -in eukaryotes multiple origins, linear multiple replication forks

Question 28

describe how DNA replicates

Answer 28

- DNA B helicase is responsible for separating the two strands of parental DNA. - The strands are kept apart by single-stranded DNA binding proteins (SSB), allows for synthesis of an RNA primer by DNA primase. - DNA gyrase eases the strain. - The lagging strand is synthesized in short fragments called Okazaki fragments. - A new RNA primer is required for the synthesis of each Okazaki fragment.

Question 29

replication fork movement is in the _______ direction

Answer 29

3'-5

Question 30

RNA primer adds ____ bases

Answer 30

10

Question 31

new DNA is added at __ side

Answer 31

3'

Question 32

DNA polymerase adds new dna in opposite direction of

Answer 32

replication fork

Question 33

are okazaki fragments larger in bacteria or eukaryotes?

Answer 33

bacteria

Question 34

how are RNA primers removed

Answer 34

- DNA polymerase 1 removes RNA primer and fills gap with DNA on lagging strand, nick remains - DNA ligase links Okazaki fragments together by sealing nicks - complete chromosome produced

Question 35

-nucleic acid on lagging strand during replication made up of 10 RNA bases

Answer 35

Okazaki Fragments

Question 36

removes RNA primer and puts in DNA

Answer 36

DNA polymerase I

Question 37

nucleotide sequence that codes DNA

Answer 37

gene

Question 38

how many RNA polymerase do bacteria and eukaryotes have

Answer 38

bacteria-1 | eukaryotes-3

Question 39

describe transcription

Answer 39

- Transcription begins at the +1 position in DNA and proceeds to the right (3'-5' direction) - RNA polymerase recognition site is at -35 and RNA polymerase binding site (Pribnow box) is at -10 in the promotor region - template strand transcription starts synthesizing RNA - translation stop codon is right before the trailer - mRNA is produced

Question 40

all cellular organisms use ___ as start codon

Answer 40

AUG

Question 41

describe translation

Answer 41

- template produced from transcription serves as code - codons mRNA codons are formed with corresponding bases, U instead of T - start codon is at AUG with corresponding anticodons that make the tRNA with functional AA protein attached

Question 42

begins translation in bacteria

Answer 42

FMET

Question 43

if the mRNA strand is AUG AGC GAC, then the anticodons are

Answer 43

UAC UCG CUG

Question 44

if the template strand is TAC TCG CTG, then the mRNA codons are

Answer 44

AUG AGC GAC

Question 45

codons that don't have corresponding RNA are

Answer 45

stop codons | ex: UAA, UAG, UGA

Question 46

what happens in eukaryotic RNA processing

Answer 46

- entire gene both intron and exons, transcribed to RNA by RNA poly (eukaryotic DNA) - introns removed - exons spliced together without introns forming mRNA that will pass thru nuclear membrane into cytoplasm - become ribosomes for translation

Question 47

segments of DNA that are non-coding sequences

Answer 47

introns

Question 48

bacteria and archaea have transcription/ translation linked because

Answer 48

they don't have a nucleus or introns

Question 49

how was insulin revolutionized for diabetes

Answer 49

since eukaryotic genes cannot work in bacteria, human insulin took processed mRNA (exons) and made DS RNA