B1.2 What happens in cells

Define active site

the part of the enzyme which is specific to the substrate and has a complementary shape to it

Define denaturing

the permanent change in the shape of an enzymes active site that stops the enzyme from functioning normally

Define DNA (deoxyribonucleic acid)

A polymer made up of four nucleotides, each consisting of a phosphate group and a common sugar which has one four different bases attached

Define nucleotides

The monomers of DNA that consist of a common sugar, a phosphate group and a base attached to the sugar

What are the four nucleotides

A G T C

adenine

Guanine

Thymine

Cytosine

What is the enzyme specificity

Enzymes will only act on specific substrates that have a complementary shape to the active site of the enzyme

What is the lock and key hypothesis

A theory that describes how substrates must be the correct shape to the active of an enzyme

Whats a monomer

A small molecule which can be bonded to other identical monomers to form a large polymer.

Whats a polymer

Many small molecules (monomers) chemically joined together to make 1 large molecule

What’s amylase

Ab enzyme that breaks down carbohydrates not simple sugars, produced in the pancreas and salivary glands

What’s lipase

An enzyme that breaks down lipids into fatty acids and glycerol

What’s a protein

A large molecule synthesised from amino acid monomers

What’s protein synthesis

The formation of proteins from amino acids which takes place in the ribosomes

What’s transcription

The unzipping of the DNA molecule around the gene, copying it to mRNA in the nucleus

What’s translation

Translating the mRNA sequence to an amino acid sequence during protein synthesis

Where does protein synthesis occur

the ribosomes

Draw a DNA nucleotide

Whats the 3 components of a DNA nucleotide

nitrogenous base

a sugar (deoxyribose)

a phosphate

Which two nucleotides form double bonds and which two form triple bonds

double - A and T

triple - C and G

What are the C - G and T - A base pairs described as

complementary

how many bases are needed to make a single amino acid, what is the code name for this

3

triplet code

copied DNA = messenger RNA

this has no T

transcription process

Define a catalyst

a substance that speeds up a chemical reaction without being used up itself