Gene 2 Protein

Question 1

Genes meaning

Answer 1

specific sequences of nucleotides -> specify the amino acid sequence of proteins via transcription and translation

Question 2

How is a triplet genetic code made?

Answer 2

3 nucleotides specify each amino acid to make them

Question 3

Transcription meaning

Answer 3

the DNA-directed synthesis of mRNA

Question 4

When do eukaryotic cells modify RNA?

Answer 4

after transcription and before translation

Question 5

translation meaning

Answer 5

RNA-directed synthesis of a polypeptide (protein)

Question 6

where does translation occur and what does it involve?

Answer 6

on ribosomes and involves tRNA

Question 7

Where does post-transitional processing of proteins occur?

Answer 7

in ER

Question 8

How do mutations affect nucleotides?

Answer 8

they can affect protein structure and function

Question 9

mRNA function

Answer 9

carries information from DNA in the nucleus to the site of protein synthesis in the cytoplasm

Question 10

central dogma meaning

Answer 10

genes code for proteins

Question 11

what does RNA contain?

Answer 11

ribose sugar and uracil

Question 12

codons meaning

Answer 12

genetic instructions for proteins (AA chain) is written as series of non-overlapping, three nucleotide “words”

Question 13

start codon

Answer 13

AUG

Question 14

stop codon

Answer 14

UAA,UAG,UGA

Question 15

RNA transcript

Answer 15

mRNA is a polymer of RNA nucleotides which is complimentary to the sequence of DNA nucleotides

Question 16

what is the RNA polymer made of?

Answer 16

RNA polymerase

Question 17

Initiation of transcription

Answer 17

RNA polymerase binds to a promoter, DNA strand unwinds; RNA polymerase initiates RNA synthesis at start point on template strand

Question 18

Elongation of Transcription

Answer 18

RNA polymerase moves downstream, unwinding DNA, and elongating RNA transcript at 3’ end. DNA strands reform as double helix

Question 19

Termination of transcription

Answer 19

RNA polymerase reaches terminator sequence, mRNA is released and polymerase deattaches from DNA

Question 20

RNA polymerase other regulatory proteins

Answer 20

sigma protein (bacteria)
transcription factors (eukaryotes)

Question 21

what do sigma/transcription factors do?

Answer 21

they recognized and bind tightly to the promotor regions of the DNA where transcription begins. Also guide RNA polymerase to correct part of DNA

Question 22

Promoters are?

Answer 22

sequence of DNA nucleotides including start point but extending 20-30 nucleotides upstream, with TATA sequence

Question 23

Promoters specific short sequences are

Answer 23

TATAAT in bacteria (-10 box, 10 base pairs upstream)
TATA box in eukaryotes ( 30 base pairs upstream)

Question 24

Several transcription factors recognize?

Answer 24

the TATA box and bind to DNA before RNA polymerase can bind correctly

Question 25

what do additional transcription factors do?

Answer 25

bind to DNA along with polymerase, forming transcription initiation complex which unwinds DNA and starts RNA synthesis

Question 26

RNA polymerase unwinds the double helix...

Answer 26

exposing 10-20 DNA nucleotides at a time for complimentary base-pairing with RNA nucleotides

Question 27

What end does newly synthesized mRNA transcript emerge?

Answer 27

5' end

Question 28

When does termination occur

Answer 28

when RNA polymerase reaches a DNA sequence that functions as a stop signal

Question 29

processing of primary mRNA in the nucleus before export and translation

Answer 29

1) RNA splicing 2) enzyme-catalyzed addition of 5' cap 3) enzyme-catalyzed addition of 3' polyA tail

Question 30

what does RNA splicing do?

Answer 30

removes introns and splices or joins exons

Question 31

what does RNA splicing involve?

Answer 31

snRNPS (snurps) in a mulit-part complex called the spliceosome

Question 32

what do caps and tails do?

Answer 32

protect mRNA from enzyme breakdown and enhance efficiency of translation

Question 33

Alternative splicing

Answer 33

during splicing selected exons can be removed from primary RNA transcript along with introns. Cutting the RNA transcript in different ways result in different proteins

Question 34

Translation involves?

Answer 34

ribosomes and transfer RNA

Question 35

(poly) ribosomes are?

Answer 35

the site of protein synthesis

Question 36

what forms a polypeptide? (protein)

Answer 36

sequence of nucleotide bases in mRNA is translated into a sequence of amino acids

Question 37

how does an mRNA codon get translated into a specific amino acid

Answer 37

involves another form of RNA: tRNA

Question 38

Ribosomal RNA + proteins small sub-unit

Answer 38

has mRNA binding site (section of rRNA nucleotides)

Question 39

ribosomal RNA + proteins large subunit

Answer 39

has 3 tRNA binding sites (A, P, E)

Question 40

Elongation of polypeptides during translation

Answer 40

1) tRNA with its amino acid diffuses into the A site and its anticodon binds to a codon on the mRNA 2) A peptide bond forms between the amino acid held by the tRNA in the A site and the growing polypeptide held by the tRNA in the P site 3) ribosome moves ahead down the mRNA template and all 3 tRNAs move one position down and the tRNA in the E site exits

Question 41

A site means

Answer 41

acceptor site

Question 42

P site means

Answer 42

peptide site

Question 43

E site means

Answer 43

exit site

Question 44

Post-translational modification of proteins

Answer 44

polypeptide or amino acid chain is folded into 3D shape

Question 45

Chemical modifications of proteins

Answer 45

addition of carbohydrates via glycosylation is an example

Question 46

where are proteins packaged

Answer 46

membrane-bound vesicles for storage in the cell or export via exocytosis