Quiz 4 study deck

Question 1

Where is the amino acid attachment site on tRNA

Answer 1

3’ end

Question 2

What part of the amino acid attaches to the tRNA

Answer 2

the carboxyl

Question 3

What does aminoacyl-tRNA synthetase do

Answer 3

recognizes specific AA

Question 4

How much energy does translation use

Answer 4

a lot- major consumer of Energy (need to cleave 4 high-energy bonds)

Question 5

Describe the antiparallel nature of codon recognition and binding

Answer 5

mRNA codon is read 5’-3’ by an anticodon that pairs 3’-5’

Question 6

Where does translation take place

Answer 6

on the ribosomes

Question 7

What are the 4 stages of protein synthesis

Answer 7

tRNA charging, initiation, elongation, termination

Question 8

What are the 3 steps of initiation

Answer 8

mRNA binds to subunit of ribosome, initiator tRNA binds to mRNA, large ribosome joins complex

Question 9

What does elongation require

Answer 9

70s complex, charged tRNAs, elongation factors, GTP

Question 10

What 3 sites do ribosomes have

Answer 10

APE

Question 11

Steps in elongation

Answer 11

charged tRNA binds to A site, forms peptide bond between A-P site, translocation

Question 12

When does termination occu

Answer 12

when a ribosome translocates to a termination codon

Question 13

What level does most gene regulation occur at

Answer 13

at a transcriptoinal level usually

Question 14

Contranslational modifications vs posttranslational modifications

Answer 14

contranslational: changes to proteins while still attached to ribosome
posttranslational: changes to protein after synthesis is done

Question 15

Are translated sequences removed the same way or different ways?

Answer 15

Translated sequences are trimmed by many different enzymes and by with many different chemical groups

Question 16

What is a common way that proteins are degraded

Answer 16

ubiquitination- label proteins for cellular destruction and rapid degredation

Question 17

What is the primary site of regulation in both prokaryotes and eukaryotes

Answer 17

transcription

Question 18

What are the regulatory elements

Answer 18

• Regulatory genes
  -Regulatory elements (DNA sequences that aren’t transcribed)
  -Constitutive genes

Question 19

What is an operon

Answer 19

group of bacterial genes that are transcribed together (often into a single mRNA)

Question 20

Negative vs positive control of an operon

Answer 20

Negative: regulatory protein is a repressor
Positive: Regulatory protein is an activator

Question 21

Describe lactose transport in bacteria

Answer 21

Glucose is preferred by bacteria over lactose, but repressor will bind to operator when need to use lactose for fuel

Question 22

Is lactose in the lac operon an inducer or repressor

Answer 22

Lactose is the inducer and releases the repressor

Question 23

What type of operon is Trp

Answer 23

Negative repressible (encode a reperssor that cannot bind to DNA without activator)
When Trp levels are high, trp binds to repressor and activates, halts transcription

Question 24

What is the stringent response

Answer 24

due to lack of amino acids, leads to inhibition of rRNA synthesis

Question 25

What do R proteins have a high affinity for

Answer 25

higher affinity for rRNA than mRNA (if rRNA concentration falls then r Protein binds to mRNA (inhibits translation)

Question 26

Are eukaryotic genes organized into operons?

Answer 26

nope, only prokaryotes have operons

Question 27

What is the nucleosome position influenced by

Answer 27

ATP dependent chromatin remodeling

Question 28

What is chromatin remodeling

Answer 28

chromatin remodeling complexes cause conformational change in DNA, nucleosome, or both

Question 29

What is histone modification

Answer 29

acetylation, methylation, phosphate group addition, decreases positive charge of proteins which decrease binding strength on DNA

Question 30

What is the change caused by maternal behavior in mice

Answer 30

Offspring of moms with high licking and grooming are less fearful as adults and have a different pattern of dna methylation (affects acetylation of histones and alter expression of glucocorticoid receptor genes)

Question 31

Describe the genetics of monozygotic twins over time

Answer 31

early in life, DNA methylation and acetylation are similar, but as older, have differences in content and distribution of DNA

Question 32

What are methylation patterns influenced by

Answer 32

the environment- twins have same methylation patterns to start and they change over time

Question 33

Describe one process that involves permanent rearrangements of DNA

Answer 33

Immunoglobulins are produced by B lymphocytes and recombined to generate specific antibodies