RNA and protein synthesis (complete)

Question 1

What are the Three main differences between DNA and RNA

Answer 1

1. Bases (T in DNA, U in RNA)
2. The 2nd carbon of the sugar (oxidated in RNA, Deoxidated in DNA)
3. RNA is usually single stranded DNA is double stranded

Question 2

What are the three types of RNA

Answer 2

1. tRNA
2. rRNA
3. mRNA

Question 3

How do you differentiate between template and non template strands

Answer 3

the template strand is the DNA strand that Actually has the new DNA/RNA strand base pairing to it for a moment.

Question 4

How does the non-template strand of DNA compare to the DNA/RNA that is transcribed from it

Answer 4

it will be identical to the new daughter DNA strand (nearly identical to the new daughter RNA strand just with U and T switched)

Question 5

What are the other names for the non-template strand

Answer 5

the gene
coding strand
sense strand

Question 6

What are the other names of the template strand

Answer 6

non-coding strand

antisense strand

Question 7

What is mRNA and what does it do

Answer 7

it is messenger RNA and it codes for specific amino acid sequences to be put together into proteins

Question 8

What is a codon

Answer 8

a three base pair region on mRNA that codes for a specific amino acid

Question 9

is prokaryotic mRNA poly or monocistronic

Answer 9

polycistronic (mRNA contains information for more than one polypeptide)

Question 10

is eukaryotic mRNA poly or monocistronic

Answer 10

monocistronic (each mRNA strand only codes for one polypeptide)

Question 11

What is tRNA and what does it do

Answer 11

Transfer RNA

it binds specific Amino acids, and recognizes proper mRNA codons to deliver the appropriate amino acid

Question 12

What are the parts of tRNA

Answer 12

1. Acceptor stem

2. anticodon looop

Question 13

What does the acceptor stem of tRNA do

Answer 13

binds a specific amino acid

Question 14

what does the anticodon loop of tRNA do

Answer 14

reads the codon of the mRNA, binds to it, delivering the appropriate amino acid in the sequence

Question 15

What is rRNA and what does it do

Answer 15

ribosomal RNA

it makes up 65% of the ribosome, it is the catalytic region of the ribosome

Question 16

Which types of RNA are read and used to create proteins

Answer 16

only mRNA

Question 17

What is RNA transcription

Answer 17

Using a segment of DNA to create RNA

Question 18

in which direction is RNA and DNA synthesized

Answer 18

the 5’ to 3’ direction

Question 19

in which direction do the polymerases read the template strand

Answer 19

the 3’ to 5’ direction

Question 20

do prokaryotic RNA polymerases require a primer

Answer 20

nope

Question 21

do prokaryotic RNA polymerases have exonuclease activity (proofreading)

Answer 21

nope

Question 22

how does RNA transcription in prokaryotes happen

Answer 22

1. Sigma binds to the promotor region (-10, -35)
2. sigma recruits RNA polymerase 3 (this is the holoenzyme sigma+RNA polymerase 3)
3. sigma opens the DNA helix
4. RNA polymerase 3 begins to add RNA bases
5. Sigma releases
6. mRNA synthesis continues until the RNA polymerase 3 reaches the transcription termination region of DNA

Question 23

What does sigma do in prokaryotic RNA transcription

Answer 23

it binds to the promoter region of DNA

10 and 35 base units upstream of the start codon

Question 24

is sigma used in eukaryotic RNA transcription

Answer 24

no

Question 25

What makes up the holoenzyme in prokaryotic RNA transcription

Answer 25

Sigma and RNA polymerase 3

Question 26

What opens the DNA double helix in prokaryotic RNA transcription

Answer 26

sigma

Question 27

what happens to sigma after RNA polymerase 3 begins adding bases and synthesizing mRNA

Answer 27

it leaves

Question 28

What are the three main RNA polymerases in eukaryotic, and what is their function

Answer 28

RNA polymerase 1 - rRNA RNA polymerase 2- mRNA RNA polymerase 3 - tRNA

Question 29

is prokaryotic RNA processed

Answer 29

no

Question 30

is eukaryotic RNA processed

Answer 30

highly

Question 31

what is involved in eukaryotic rRNA processing

Answer 31

preribosomal rRNAs are cleaved by ribonucleases into the three ribosomal RNAs

Question 32

What is involved in eukaryotic tRNA processing

Answer 32

1. 5' end is cleaved off 2. certain bases are modified 3. a portion of the anticodon loop is removed

Question 33

What is involved in eukaryotic mRNA processing

Answer 33

1. 5' capping 2. 3' polyadenylation 3. intron splicing

Question 34

What is 5' capping

Answer 34

addition of guanosine to the 5' end

Question 35

what is the purpose of 5' capping

Answer 35

1. make the mRNA more stable 2. assist in the mRNA leaving the nucleus 3. assists in mRNA translation to protein

Question 36

What is 3' polyadenylation

Answer 36

the addition of many AAA's to the 3' end of mRNA

Question 37

What is the purpose of 3' poly AAAA tail

Answer 37

1. transcription termination 2. helps in translation 3. mRNA stability 4. assists in mRNA leaving the nucleus

Question 38

What is intron splicing

Answer 38

the removal of introns (non-coding parts of mRNA)

Question 39

which are kept in the mRNA, introns or exons

Answer 39

exons

Question 40

What enzyme does intron splicing

Answer 40

splicosome

Question 41

what are the two things the splicosome does in removing introns

Answer 41

1. exonuclease activity (cuts) | 2. ligase activity (binds two mRNA ends together)

Question 42

What is alternative intron splicing

Answer 42

two or more proteins can be made from one mRNA because some exons can also be removed during intron splicing if the exon is between two introns it can be removed with them

Question 43

can viral RNA be used to make DNA

Answer 43

yep

Question 44

What is a codon

Answer 44

a triplet of nucleotides that codes for a specific amino acid

Question 45

What does it mean that the genetic code is degenerate

Answer 45

one codon can only generate one specific amino acid, but one amino acid can be generated from different codons

Question 46

What is the start codon

Answer 46

AUG (ATG in the coding strand of DNA)

Question 47

What are the stop codons

Answer 47

UAA UAG UGA

Question 48

how many potential reading frames are there for RNA

Answer 48

3

Question 49

how many potential reading frames are there for DNA

Answer 49

6 (3 for each single strand)

Question 50

What determines which reading frame will be used

Answer 50

the location of the start codon

Question 51

how many possible codons are there

Answer 51

64 (4 nucleotides in groups of 3)

Question 52

What are the different types of DNA mutations

Answer 52

1. silent mutations 2. missense mutations 3. nonsense mutations 4. splice site mutations 5. frameshift mutations

Question 53

What is a silent mutation

Answer 53

a change in a codon that doesn't result in a different amino acid

Question 54

what is a missense mutation

Answer 54

a change in a codon that does result in a different amino acid

Question 55

what is a nonsense mutation

Answer 55

a change in a codon that results in an early stop codon

Question 56

what is a splicesite mutation

Answer 56

it alters the way introns are removed

Question 57

what is a framshift mutation

Answer 57

one or two nucletide addition or deletion that causes the reading frame to shift. from the point of the mutation on, every amino acid will be affected.

Question 58

what is the wobble effect of tRNA anticodon binding to mRNA codon

Answer 58

the first two bases in the tRNA bind tightly to the first two bases in the mRNA, but the last one doesn't have to be a perfect match

Question 59

what does the wobble effect allow

Answer 59

it allows one anticodon (tRNA) to be able to bind to multiple mRNA codons

Question 60

what are the parts of the ribosome

Answer 60

large and small subunit

Question 61

what does the ribosome do

Answer 61

brings mRNA and tRNA together and puts the amino acid chain together

Question 62

What are the 4 steps of protein synthesis

Answer 62

1. activation of amino acids 2. initiation 3. elongation 4. termination

Question 63

what is activation of amino acids

Answer 63

when aminoacyl-tRNA synthetases put an amino acid on the appropriate tRNA

Question 64

what is the enzyme that adds amino acids to the appropriate tRNA

Answer 64

aminoacyl-tRNA synthetase

Question 65

how does the initiation step of protein synthesis go

Answer 65

1. IF 3 and IF 1 are bound to the small ribosomal subunit 2. small subunit binds to the shine delgarno sequence of mRNA 3. Fmet-tRNA hooks onto the codon (with help of IF 2) 4. all three initiation factors leave 5. large subunit binds to the small subunit and mRNA

Question 66

what is the shine delgarno sequence of mRNA

Answer 66

a purine rich sequence upstream of the start codon to which the small subunit binds

Question 67

what is the function of IF1 (initiation factor 1)

Answer 67

prevent premature binding of a tRNA to the A site of the ribosome

Question 68

what is the function of the IF 3 (initiation factor 3)

Answer 68

prevents premature assembly of the small and large subunit

Question 69

what is the function of IF 2 (initiation factor 2)

Answer 69

helps tRNA fMET get to the p site

Question 70

What are the three sites of the ribosome

Answer 70

A site P site E site

Question 71

What happens at the A site of ribosomes

Answer 71

new tRNAs enter

Question 72

What happens at the P site of ribosomes

Answer 72

Peptide bonds are formed between amino acids that are in the A and P sites

Question 73

what happens at the E site of ribosomes

Answer 73

the used up tRNA's leave

Question 74

What are polysomes

Answer 74

when several ribosomes are translating the same mRNA strand

Question 75

what is coupled transcription/translation

Answer 75

when an mRNA is being transcribed from DNA, and at the same time a ribosome is translating it into a protein

Question 76

Does coupled transcription/translation happen in eukaryotes

Answer 76

nope, only in prokaryotes

Question 77

What causes termination of protein synthesis

Answer 77

1. stop codon reaches the A site | 2. release factors enter

Question 78

what do release factors do

Answer 78

1. cause polypeptide to be released | 2. cause the ribosome to dissociate