Test 2

Question 1

diff btw a nonsense mutation in 3rd codon and missense mutation in 3rd codon

Answer 1

nonsense: translated to 2 AA
missense: create change in 1 AA

Question 2

what could account for silent mutation?

Answer 2

different 3rd codon encodes the same AA

Question 3

legs of a phage are disrupted; what stage would that impact?

Answer 3

attachment

Question 4

picture of plasmid and restriction enzyme; how many pieces are there after the cuts?

Answer 4

3

Question 5

Ames test

Answer 5

at least twice as much; increase

Question 6

phage therapy will affect person’s own cell?

Answer 6

no because it will only lyse the cell of the virus, not the person’s own cell

Question 7

positive sense +ssRNA wants to create more of its genome; what mechanism does it use?

Answer 7

use the host’s ribosome to translate its own RNA dependent RNA polymerase

Question 8

okazaki fragment: translation

T/F?

Answer 8

F

Question 9

how does virus get its capsule?

Answer 9

from the cell membrane as it leaves

Question 10

what does transposon need ?

Answer 10

transposase

Question 11

can transposon move from one plasmid to the next?

Answer 11

not unless there’s a sex pilus

Question 12

what is wrong about prion?

Answer 12

it is not a unique virus

Question 13

DnaG

Answer 13

no initiation due to DNA poly III not being able to attach

Question 14

IF2

Answer 14

no initiation of translation due to no binding site for initial tRNA on P site

Question 15

what doesn’t utilize homologous recombination?

Answer 15

F plasmid conjugation

Question 16

general transduction happens during what replication process?

Answer 16

assembly

Question 17

spontaneous mutation happens during what phase?

Answer 17

replication

Question 18

RNA polymerase adds nucleotide at the ___ while DNA poly adds nucleotides before the ___

Answer 18

promotor, origin

Question 19

how does inosine at the 3rd position save energy?

Answer 19

allows fewer tRNA to be made

Question 20

riboswitch

Answer 20

change the 2ndary structure of mRNA

Question 21

a trp operon has trp A, B, C, D, E…..will transcribe a:

Answer 21

polycistronic

Question 22

auxotroph for arginine can grow on medium that contain:

Answer 22

everything except the answer that says “except arginine”

Question 23

T4 phage has dsDNA; how does it replicate its genome?

Answer 23

bacterial DNA polymerase

Question 24

Avery, Macleod, and McCarty confirm DNA by:

Answer 24

testing enzymatic digestions on all 3 compounds

Question 25

prokaryotic replication

Answer 25

semiconservative and bidirectional

Question 26

if host cell couldn’t do endocytosis, which would be affected?

Answer 26

naked ssRNA virus

Question 27

what would affect ability to attach to host cell?

Answer 27

B and D
receptors on host cell altered
enzyme on host cell degrades the attachment on the virus

Question 28

where does influenza virus gets its classification of respiratory virus?

Answer 28

it specifically attaches to receptors in lung

Question 29

mosquito species contains a Class IV virus that infect people; suddenly another species of mosquitos starts to infect people with the same virus; what is the molecular mechanism that could explain the change of vector?

Answer 29

mutation of virus leads to new attachment site that enables the virus to attach to the new mosquito species

Question 30

virus has enveloped particle; explain how this helps them evade host defense mechanism?

Answer 30

the virus will make its protein an when it’s budding out it will take a portion of the host cell membrane with it, creating an envelope; this envelope is recognized as self so the virus will not get attacked

Question 31

difference between generalized and specialized transduction?

Answer 31

generalized: where a segment of host cell DNA is carried from one bacterial cell to another accidentally by a bacterial virus phage
specialized: where only a few specific genes (near sit of integration) from one bacterial cell are transferred to the 2nd bacterial host by a phage; virus takes part of host chromosome with it but leaves part of the virus prophage behind; so it’s a defective phage that delivers DNA to the new host

Question 32

F plasmid conjugation

Answer 32

F+ donor has a fertility plasmid
F+ donor produces a sex pilus that connects to F- recipient
F plasmid migrates into F- cell via sex pilus while replication is occurring and at the end of conjugation the recipient cell becomes F+

Question 33

Hfr conjugation

Answer 33

Hfr sends incomplete F plasmid and part of its DNA (can be all of DNA) to the recipient cell
the longer the cell to cell contact time, the greater the amount of DNA transferred
at the end the recipient cell remains F- but now has a new gene/trait

Question 34

F’ plasmid conjugation mechanism

Answer 34

F plasmid can de-integrate from the host chromosome and create a F’ plasmid, which has F+ and some other genes; this allows passage of genetic info from chromosome of one cell to another
the de-integration is inaccurate so host cell DNA is taken along with the F plasmid
rolling circle replication is employed
at the end both donor and recipient cell are F’ and capable of conjugation with F- cell

Question 35

transformation

Answer 35

a cell taking up extracellular DNA directly without cell to cell contact

Question 36

Class IV replication; how it uses host machinery to replicate and what kind of enzymes it brings with itself

Answer 36

+ssRNA virus

• mRNA (encoded on ssRNA) is translated immediately into the host cell RNA dependent RNA pol
• the pol synthesizes a -ssRNA template, which is used as the template for viral genome replication
• once genome is replicated, proteins are translated
• so once the capsid, packaging proteins, and genome are made, they are assembled in the cytoplasm of host cell
• it only brings its own mRNA and is easily translated into protein by the host mechanism

Question 37

if there’s a nonsense mutation in the first codon, what happens to the gene?

Answer 37

nonsense mutation in gene 1 will disrupt the entire sequence