2.3

Question 1

Nucleotide

Answer 1

Consists of a pentose sugar, phosphate group and nitrogenous base

Monomers of nucleic acids

Regulate metabolic pathways

May be components of coenzymes

Question 2

DNA

Answer 2

Polynucleotide
Anti parallel
Covalent bond between sugar residue and phosphate group
Carry encoded info

Question 3

Hydrogen bonding

Answer 3

Adenine and thymine double bond 
Guanine and cytosine triple bond
- complimentary base pairing
Double helix gives more stability 
Allow molecule to unzip for transcription and replication

Question 4

How is DNA organised in cells

Answer 4

Nucleus

Looped DNA

Question 5

DNA replicating

Answer 5

Self replicating
Takes place during interphase before the cell actually divides
Semi-conservative
- double helix unwinds catalysed by gyrase enzyme
-unzips as hydrogen bonds break catalysed by DNA helicase
-free nucleotides are bonded to exposed bases
-polymerase catalyses the addition of the new nucleotide bases

Mutations can occur

Question 6

Transcription

Answer 6

The process of making mRNA from a DNA template

Gene unwinds and unzips
Hydrogen bonds break
RNA polymerase catalyses the formation of hydrogen bonds between RNA and DNA
Complementary
Out of NE to ribosome (Mg ions help)

Question 7

Translation

Answer 7

Formation of a protein at ribosomes by assembling amino acids into a particular sequence

Question 8

RNA

Answer 8

Ribose
Uracil
Single stranded
Shorter 
Three forms

Question 9

Genes

Answer 9

Length of DNA codes for polypeptide or length of RNA that is involved in regulating gene expression

Must be complimentary

Genetic code is near universal
Degenerate
Non-overlapping