transcription & translation - exam 1

Question 1

gene

Answer 1

a segment of DNA that contains instructions for making an RNA

Question 2

features of a gene

Answer 2

start site - transcription unit - terminator

promoter

RNA transcript = compl. to template strand of DNA

Question 3

promoter

Answer 3

where RNA polymerase binds

enzyme that transcribes RNA from DNA

Question 4

RNA polymerase

Answer 4

catalyzes formation of RNA using DNA template

Question 5

initiation

Answer 5

RNA pol binds promoter

RNA pol finds promoter & unwinds DNA

adds nts complementary to template

builds RNA in 5’-3’ direction

Question 6

elongation

Answer 6

RNA pol moves “downstream” elongating RNA transcript

Question 7

termination

Answer 7

RNA pol recognizes terminator & falls off

Question 8

where does transcription occur

Answer 8

nucleus

Question 9

replication product

Answer 9

2 double stranded dna molecules

Question 10

direction of synthesis in replication

Answer 10

5’-3’

Question 11

enzymes in replication

Answer 11

dna pol, helicase, primase, ligase

Question 12

where does replication occur

Answer 12

nuclues

Question 13

when does replication occur

Answer 13

before cell division

Question 14

of template strands in replication

Answer 14

2

Question 15

transcription product

Answer 15

single stranded rna molecule

Question 16

direction of synthesis in transcription

Answer 16

5’-3’

Question 17

enzymes in transcription

Answer 17

rna pol

Question 18

when does transcription occur

Answer 18

always

Question 19

of template strands in transcription

Answer 19

1

Question 20

mRNA

Answer 20

messenger

info carrier

used by ribosomes to make proteins

Question 21

tRNA

Answer 21

transfer
connection between mRNA & protein

single stranded & folded into “t” shape

doesn’t contain info found in protein coding gene

Question 22

rRNA

Answer 22

ribosomal

Question 23

snRNA

Answer 23

small nuclear

Question 24

how do eukaryottes modify mRNA after transcription

Answer 24

addition of cap & a tail

intron removal

Question 25

5' cap

Answer 25

stability of RNA molecule so single strand doesn't get cut off position of mRNA on ribosome

Question 26

poly-A tail

Answer 26

stability of RNA molecule so nuclease doesn't chop it away - longer tail = longer life - doesn't matter if repeated As get chopped exit form nucleus - polyA binding proteins w/ a nuclear export signal

Question 27

intron

Answer 27

intervening sequence must be removed

Question 28

exon

Answer 28

expressed sequence stays in

Question 29

RNA splicing

Answer 29

introns removed & exons spliced together pre mRNA w/ introns: "B!0)0g% is my f@^0r!t3" mature mRNA w/out introns: "Biology is my favorite."

Question 30

how can eukaryotes produce many more proteins than they have genes

Answer 30

alternative RNA splicing one gene can encode more than 1 polypeptide

Question 31

where are ribosomal subunits made

Answer 31

nucleolus - made separately leave the nucleolus thorough nuclear pores into cytosol

Question 32

where does translation occur

Answer 32

in cytosol

Question 33

4 binding sites on a ribosomal unit

Answer 33

E - exit P - tRNA w/ polypeptide A - tRNA w/ amino acid on small subunit - mRNA binding

Question 34

translation initiation

Answer 34

mRNA binds to small subunit - 5' cap helps w/ positioning - start codon in P site 1sr tRNA comes in & binds to start codon large subunit binds

Question 35

translation elongation

Answer 35

anticodon of next charged tRNA binds to codon in A site tRNA-met bond brokem - met forms peptide bond w/ next amino acid ribosome moves down mRNA - A site is vacant =tanslocation uncharged tRNA in E site exits

Question 36

translation termination

Answer 36

stop codon enters A site release factor binds in A site complex falls apart

Question 37

missense mutation

Answer 37

different amino acid put into protein consequence: it depends, hydrophobic & philic, where in protein mutation is (active site)

Question 38

nonsense mutation

Answer 38

stop codon replaces amino acid encoding codon consequence: shortened protein -- BAD

Question 39

silent mutation

Answer 39

no change in amino acid & no protein folding issues consequence: often none

Question 40

frameshift mutaion

Answer 40

nucleotide pair insertion/deletion everything after insertion/deletion is wrong, all shifted down one consequence: wrong protein is made -- BAD

Question 41

mutation in germ cell

Answer 41

mutation can be passed to offspring

Question 42

mutation in somatic cell

Answer 42

mutation not present in offspring