DNA replication and protein synthesis

Question 1

What does DNA Helicase do ?

Answer 1

Splits the dna strand into two single strands .

Question 2

What happens after the dna strand is split in two ?

Answer 2

Free floating nucleotides go towards their complementary bases and attach onto them.

Question 3

What does DNA polymerase do ?

Answer 3

Catalyzes the reactions between the sugar phosphate backbones of the nucleotides .

Question 4

What is the leading strand ?

Answer 4

It runs three prime to five prime so the dna polymerase can run allong it straight after the dna helicase therefore it can catalyze the reactions quickly.

Question 5

What is the lagging strand ?

Answer 5

It runs five prime to three rime therefore the dna polymerase cant run from the end of the strand straight away so has to wait till it has unzipped slightly then put it into fragments , meaning it takes more time to add nucleotides on this strand .

Question 6

What is an okazaki fragment?

Answer 6

fragments of the strand needs to split off so that the dna polymerase can catalyze the reaction of joining the sugar phosphate backbones .

Question 7

what does dna ligase do ?

Answer 7

It is the enzyme that puts the okazaki fragments back together to form the complete dna strand.

Question 8

What is meant by semi-conservative ?

Answer 8

Each dna strand has half of the origional one

Question 9

What id the promoter base ?

Answer 9

It is the base that is on a split up dna strand that tells the ribose nucleotides where to start attaching on for that gene .

Question 10

What is the antisense strand ?

Answer 10

the strand of dna that the rna nucleotides attach onto using complementary base pairing .

Question 11

What is the sense strand ?

Answer 11

The strand that is copied, as the new pre mrna strand has used complementary base pairing to match up with the other strand .

Question 12

Whta does rna polymerase do ?

Answer 12

It catalyzes the reactions between the the nucleotides and forms strong covalent phosphodiester bonds.

Question 13

After how many base pairs does the mrna molecule peel off from the dna strand ?

Answer 13

8

Question 14

What are introns ?

Answer 14

the non coding bases in a sequence that are removed through splicing before becoming mrna.

Question 15

What are exons ?

Answer 15

the coding bases in a sequence that are the bases needed for that gene therefore they stay .

Question 16

What is an initiation codon ?

Answer 16

the base that a ribosome attaches onto of mrna so that it can start translation .

Question 17

What in the ribosome catalyses the formation of a peptide bond ?

Answer 17

ribosomal rna

Question 18

What is an anticodon ?

Answer 18

it is complementary to the start codon on a strand of mrna and is found on a trna molecule and attaches itself to the mrna by complementary base pairing .

Question 19

What happens once the trna has attached onto the right codon?

Answer 19

the amino acid attached onto it bonds witht he next amino acid atatched ontot he trna next to it then the first trna can leave, leaving the amino acid behind.

Question 20

What is a stop codon ?

Answer 20

the last codon of a gene that tell the ribosome to stop creating the polypeptide chain.

Question 21

What is created in protein synthesis ?

Answer 21

A polypeptide chain made up of amino acids.