Protein synthesis

Question 1

cell organelles involved in protein synthesis

Answer 1

• Nucleus
• Ribosome
• Endoplasmic reticulum
• Golgi body

Question 2

what is a codon

Answer 2

group of three nucleotides (every three codes for a specific amino acid)

Question 3

gene

Answer 3

group of codons (300-500) - codes for a specific protein

Question 4

start codon

Answer 4

methionine

Question 5

how many codons are there

Answer 5

64

Question 6

how many codons code for amino acids

Answer 6

61

Question 7

how many stop codons are there

Answer 7

3

Question 8

what is the central dogma

Answer 8

the prosses of protein synthesis
- turning DNA to RNA and finally into a polypeptide

Question 9

transcription (elongation)

Answer 9

• builds an mRNA strand that is complementary to the transcribed DNA strand with the substitution of uracil in place of thymine

Question 10

transcription (initiation)

Answer 10

• RNA polymerase binds to the promoter segment of DNA

Question 11

promoter region

Answer 11

• high in adenine and thymine
• a recognition site for RNA polymerase (TATA box)

Question 12

template strand

Answer 12

strand of DNA the RNA polymerase is transcribing

Question 13

coding strand

Answer 13

strand of DNA that is left alone during transcription

Question 14

Transcription (termination)

Answer 14

• RNA polymerase releases once it hits the terminator sequence

Question 15

after transcription

Answer 15

the hydrogen bonds reform once again connecting the DNA strands

Question 16

post transcription modification

Answer 16

caping and tailing

Question 17

caping

Answer 17

5’ cap is added to the start of mRNA

Question 18

tailing

Answer 18

a string of 200 adenine ribonucleotides is added to the end 3’ with assistance from poly-A- polymerase giving it the name Poly- A- tail

Question 19

Introns and Extrons

Answer 19

• introns are “useless” DNA and exons are important for protein synthesis/ folding
• introns are removed from mRNA after transcription, but before it leaves the nucleus
• if the introns are left in they will alter the folding of the protein rendering it usless

Question 20

how are introns removed

Answer 20

• spliceosomes (remove introns and connect exons)

Question 21

what happens to introns once they are removed

Answer 21

their nucleotides are broken down and recycled

Question 22

ribosome structure

Answer 22

2 units, built independently and then joined together
- large subunit (60S)
- small subunit (40S)
binding sites A (acceptor cite) and P (peptide cite)
- each site can hold one codon at a time

Question 23

purpose of the ribosome

Answer 23

translate mRNA and build the polypeptide chain

Question 24

tRNA

Answer 24

• transfer RNA
• single-stranded nucleic acid (5’- 3’)
• cross-shaped
• delivers the indicated amino acids
• binds to ONE specific amino acid

Question 25

anticodon

Answer 25

located on one of tRNA’s arms
- complementary to mRNA codons being read by the ribososme

Question 26

aminoacyl-tRNA-synthetases

Answer 26

attaches the appropriate amino acid to tRNA

Question 27

Translation (initiation)

Answer 27

ribosome recognizes and binds to the mRNA 5’cap

Question 28

translation (elongation)

Answer 28

mRNA moves through the ribosome 5’-3’
- the starter codon conects at the p site and the following codon connects to the the a cite

Question 29

what is the start codon

Answer 29

AUG

Question 30

what bond connects the amino acids

Answer 30

peptide bond

Question 31

termination step one

Answer 31

ribosome reaches the stop codon and the release factor will let go of the polypeptide chain

Question 32

termination step 2

Answer 32

polypeptide enters the Golgi apparatus to be folded and stored or sent out right away in a vesicle