DNA structure

What’s a nucleotide

Monomer that joins together to make a polymer of DNA

Explain the structure of a mononucleotide

Phosphate has an ester bond with a pentose from its C4 on the left, the C1 creates a glycosidic bond with a nitrogenous base, 2 condensation reactions from the bonds

Explain the key factors of DNA

Deoxyribose nucleic acid, contains info on making polypeptide proteins, controls cell processes, double helix-anti parallel, 3 prime end joins to 5 prime end

What are the 5 bases and the key information

Adenine, thymine-DNA only, uracil-RNA only, guanine, cytosine

What’s the formula for each sugar

Deoxyribose-C5H10O4

Ribose-C5H10O5

What’s key about RNA

Contains ribose, single helix and shorter, C3-C5 are bonded

How does each base bond

Adenine to thymine or uracil, cytosine to guanine

What’s a phophodiester

2 sugars together

What else is key about bases and their bonding

Purines bond to pyramidines as purines are double ringed and the others are single ringed, double ringed are adenine and guanine

Explain the process of diphosphoesters forming

C3 aligns with phosphate groups to make a dinucleotude, condensation reaction occurs removing H2O creating a phosphodiester bond, across the chains the are flipped and its hydrogen bonds between chains

What is the structure of DNA

Double helix, anti parallel as 5 prime end bonds to 3 prime end, between strands between pyramidines and purines, cytosine-guanine has 3 hydrogen bonds, adenine-thymine has 2 hydrogen bonds

Explain change in DNA

DNA codes for a protein so when that changed the primary structure changes so the R group changes, so the active site alters so no longer complentary, no enzyme substrate complexes can form

What is ATP

Adenosine triphosphate, which is and adenine base bonded to a ribosome in a glycosidic, ribose to phosphate 1 is an ester bond and then phosphate to phosphate is phosphate bond

What can be done to ATP

Formed which stores energy via condensation reaction and use of ATP synthesise, breaking which releases energy via hydrolysis reaction and use of ATP hydrolyse

Inorganic phosphate is added in both reactions to ADP

What is the process of semi conservative DNA replication

1-DNA helices breaks hydrogen bonds between polynucleotide strands, both separate + act as templates

2-Free DNA nucleotides (free floating in cytoplasm) align by complementary base pairing (A-T)

3-DNA polymerase joins adjacent nucleotides-condensation reaction forms phosphodiester bond

4-2 identical copies each with half original+half newly synthesised-semi conservative

What is the process of DNA polymerase

-DNA polymerase is complementary to 3’

-During synthesis the leading strand is synthesised continuously

-The lagging strand is slower and synthesised in fragments (okazaki fragments)

-DNA licase joins fragments together

-Forms phosphodiester bond

How did Meselson and Stahl prove DNA replication was semi conservative

Bacteria was grown on Nitrogen 15, then it was removed and plated onto Nitrogen 14 so eventually half DNA will be Nitrogen 14 and 15