Nucleotides

What are the two types of nitrogenous bases and describe their structure

Purines - 2 carbon ring structures (adenine and guanine)

Pyrimidines - 1 carbon ring structures ( cytosine, thymine and uracil )

Why is complementary base pairing important?

To help maintain the order of the genetic code when DNA replicates

What reaction and bond form between nucleotides?

Condensation

Phosphodiester bond

What is the polymer of nucleotides called?

Polynucleotide

What is a phosphodiester bond?

A strong covalent bond that forms between pentose sugar and phosphate between different nucleotides

What is does ATP stand for, what does it contain and why do we need it?

Adenosine triphosphate

Adenine, ribose, 3 inorganic phosphate groups

Essential for metabolism

Immediate source of energy for biological processes

How is ATP made, broken down and what happens when it does?

Made during respiration via a condensation reaction using enzyme ATP synthase

Hydrolysed using enzyme ATP hydrolase

Breaking bonds between phosphate groups releases a little energy

Inorganic phosphate can bind to other compounds to make them more reactive

What does DNA stand for and do?

Deoxyribonucleic acid

Codes for the sequence of amino acids in the primary structure of a protein

Determines final 3D structure and function

What is the structure of DNA?

Double helix

Two anti-parallel strands joined by H bonds between bases

How does DNA structure relate to its function?

Stable structure - sugar phosphate backbone (covalent bonds) and double helix

Weak H bonds- easy to break during respiration

Large molecule that carries a lot of information

Complementary base pairing allows identical copies to be made

Explain the steps of DNA precipitation

1. Homogenise the cell with detergent- breaks open cell membranes to release contents

2. Filter to remove large debris

3. Add salt to break H bonds between the DNA and water molecules

4. Add protease to digest the proteins associated with the DNA

5. Add ice-cold ethanol to precipitate DNA from the solution. DNA appears as white strands