exam 4

Question 1

what is transcription?

Answer 1

synthesis of RNA using info in DNA

Question 2

what is translation?

Answer 2

synthesis of polypeptide using info in mRNA

Question 3

where does translation take place

Answer 3

ribosomes

Question 4

what does genetic info flow from

Answer 4

dna to rna to protein

Question 5

in which cell type do translation and transcription happen simultaneously?

Answer 5

prokaryotes

Question 6

how are the words of a gene transcribed in a codon?

Answer 6

three nucleotide words of mRNA

Question 7

what is the initiation codon?

Answer 7

AUG

Question 8

what are the stop codons

Answer 8

UAA, UGA, UAG

Question 9

true/false: more than one codon can specify a particular amino acid

Answer 9

true

Question 10

the genetic code is nearly _____

Answer 10

universal

Question 11

how is mRNA read?

Answer 11

5’ to 3’ end

Question 12

how is the template strand read?

Answer 12

3’ to 5’

Question 13

what signals the transcription start point?

Answer 13

promoters

Question 14

what do transcription factors bind to

Answer 14

TATA box promoter

Question 15

what is added during RNA processing?

Answer 15

5’ cap and 3’ tail

Question 16

what is spliced during RNA processing

Answer 16

introns

Question 17

what does translation require

Answer 17

mRNA, tRNA, ribosomes, and translation factors

Question 18

tRNA anticodons base-pairs are complementary to

Answer 18

codons on mRNA

Question 19

which site holds incoming tRNA and the next amino acid for the chain?

Answer 19

A site

Question 20

which site holds tRNA carrying growing polypeptide chain

Answer 20

P site

Question 21

which site is the exit site?

Answer 21

E site

Question 22

which direction does translation proceed along the mRNA?

Answer 22

5’ to 3’

Question 23

to which site does elongation continue to?

Answer 23

A site

Question 24

to serve as genetic material, a molecule must be able to what

Answer 24

replicate faithfully, contain complex info, encode phenotype, and have capacity to vary

Question 25

what is the inducible operon?

Answer 25

lac operon

Question 26

what is the repressible operon

Answer 26

trp operon

Question 27

the repressible operon ensures that transcription is

Answer 27

normally on but needs to be off

Question 28

the inducible operon ensures that transcription is

Answer 28

normally off needs to be on

Question 29

what bacteria does natural selection favor?

Answer 29

bacteria expressing only genes needed by cell

Question 30

what happens in feedback inhibition?

Answer 30

the end product of metabolic product shuts down further synthesis by inhibiting enzyme activity

Question 31

how do cells adjust production level of certain enzymes

Answer 31

gene expression regulation

Question 32

what is an operon

Answer 32

entire stretch of DNA including operator, promoter, and genes controlled

Question 33

where do genes in bacteria tend to be organized

Answer 33

clusters on bacterial chromosome, with transcription usually under control of single regulatory region

Question 34

when is a trp operon repressor in active state

Answer 34

in the presence of corepressor tryptophan

Question 35

what does a trp operon bind to

Answer 35

tryptophan

Question 36

if tryptophan levels are high, what happens to the trp operon?

Answer 36

gets turned off

Question 37

where do repressible enzymes usually function in, and what is the synthesis usually repressed by?

Answer 37

anabolic pathways; high levels of end product

Question 38

where do inducible enzymes usually function in, and what is synthesis usually repressed by?

Answer 38

catabolic; chemical signal

Question 39

what does the dense packing of heterochromatin do to the cell?

Answer 39

make it difficult to express encoded genetic info

Question 40

what does the addition of methyl groups do?

Answer 40

condense chromatin and reduce transcription

Question 41

what are non-adaptive evolutionary mechanisms?

Answer 41

mutations, gene flow, and genetic drift

Question 42

what is an adaptive evolutionary mechanism?

Answer 42

natural selection

Question 43

what is fitness defined by?

Answer 43

individual's contribution to future gens

Question 44

what is a common ancestor

Answer 44

species/individual no longer alive that gave rise to multiple current species

Question 45

can natural selection give rise to new traits?

Answer 45

no; can only increase or decrease heritable traits that are variable already in population

Question 46

natural selection acts on what?

Answer 46

individuals

Question 47

can individuals evolve?

Answer 47

no; only populations

Question 48

what is a phenotype

Answer 48

the observable physical and physiological traits of organism determined by genetics