rna replication

Question 1

codon

Answer 1

base triplet of mRNA . mRNA transport genetic info o protein synthesis.

Question 2

anti-codon

Answer 2

tRNA transport amino acid to ribosomes for protein synthesis

Question 3

protein synthesis

Answer 3

translation. coded amino acids are built in the protein chain

Question 4

DNA replication

Answer 4

Forwarding genetic info into a new cell during cell division.

Question 5

replication

Answer 5

it is semiconservative , this is ,the produced new double helix is composed of 1 parental and 1 newly synthesised strand.

Question 6

3 phases of DNA replication

Answer 6

initiation, elongation, termination

Question 7

initiation in prokaryotes

Answer 7

start point = replication origo , that is composed of consensus sequences

Question 8

dna A (initiation in prokaryotes )

Answer 8

proteins recognise replication origo and bind to dnaA binding sites

Question 9

dnaB and dnaC (initiation in prokaryotes)

Answer 9

• bind to DNA A protein
• they have helices activity
• H-bonds between complementary base pairs get split
• double helix opens at replication oligo and replication bubble is formed.

Question 10

Single Strand Binding Proteins (SSB- proteins) (initiation in prokaryotes)

Answer 10

complementary base pairs are not allowed to match again so as to keep two strands separate from each other.

Question 11

synthesis of new strand (initiation in prokaryotes)

Answer 11

free 3’-OH-group is needed.

primers bind to parental dna single strands

Question 12

primer

Answer 12

a short RNA sequence with free 3’-OH-group

Question 13

synthesis of primers

Answer 13

happens by primosomes

Primosome is a protein complex, where the most important component is primase enzyme, synthesising primer

Question 14

elongation of replication in prokaryotes

Answer 14

the second step of replication

Question 15

Leading strand(elongation in prokaryotes)

Answer 15

continuous synthesis happens • Only one primer is needed

Question 16

Lagging strand (elongation in prokaryotes)

Answer 16

discontinuous synthesis happens , several short fragments are formed.

Question 17

Okazaki fragment

Answer 17

primer+ Dna

Question 18

DMA polymerase III (elongation in prokaryotes)

Answer 18

is responsible for the synthesis of the new DNA stranddirection of synthesis is 5’3’
(DNA dependent DNA polymerase III)

Question 19

building nucleotides in the new strands

Answer 19

Deoxyribonucleoside triphosphate (dNTP) –> Deoxyribonucleoside monophosphate (dNMP) are built in + inorganic pyrophosphate is released

Question 20

termination of replication in prokaryotes

Answer 20

third phase of replication where -DNA polymerase III dissociates.
- DNA polymerase I hydrolyses and remove primers

Question 21

DNA polymerase I (termination in prokaryotes)

Answer 21

• hydrolyse and cut out primers (with 5’-3’ exonuclease activity)
• with 5’-3’ polymerase activity , fills space between separate DNA fragments by building appropriate nucleotides in the chain

Question 22

DNA ligase

Answer 22

ligation of newly synthesised DNA fragments at sugar-phosphate backbone (uses ATP for the formation of phosphodiester bonds)

Question 23

function of DNA ligase

Answer 23

1. DNA ligase hydrolyses one ATP to AMP and PPin so, the activated AMP molecule binds to enzyme
2. The 5’-end of DNA fragment forms phosphodiester bond with the 3’-end of the neighboring DNA fragment
3. AMP dissociates from the enzyme

Question 24

topoisomerase

Answer 24

remove tenseness during replication