Polynucelotides and DNA

Question 1

how do nucleotides join up together

Answer 1

join up between the phosphate group on on e nucleotide and the sugar of another via a CONDENSATION reaction

Question 2

what is a phosphodiester bond

Answer 2

one phosphate group bonded to two ester bonds

a chain of these forms a sugar phosphate backbone

Question 3

how many hydrogen bonds form between A=T

Answer 3

2

Question 4

how many H bonds between C=G

Answer 4

3

Question 5

how would you describe the DNA helix

Answer 5

two polynucleotide strands
running antiparallel to eachother
that twist to form a DNA double helix

Question 6

what is the 1st step of DNA replication

Answer 6

Dna helicase breaks the hydrogen bonds between the polynucleotide strands, causing the helix to unzip

Question 7

2nd DNA replication

Answer 7

each original strand acts as a template for a new strand

free dna nucleotdes attach to exposed bases on each template strand by complemntary base pairing

Question 8

3rd DNA replication

Answer 8

Dna polymerase joins the nucleotides of the new strand together, forming a sugar phosphate backbone

hydrogen bonds form between bases on the original and new strand. they twist to form a double helix

Question 9

4th dna replication

Answer 9

each new DNA molecule has one strand from the original DNA and one new strand.

this is know as SEMI CONSERVATIVE REPLICATION

Question 10

why does DNA replication have to be accurate?

Answer 10

to make sure genetic information is conserved

Question 11

what is mututation

Answer 11

a mutation is any change to the DNA base sequence

Question 12

why could a mutation be bad

Answer 12

could alter the amino acid sequence of a protein

which could even lead to the production of abnormal protein

however this may not be a bad thing because the abnormal might function better/worse/not at all