OCR a level biology module 2 key terms

2.1/2.2

Prokaryotic / eukaryotic cells

cell without membrane bound organelle ribosomes 70s / cell with membrane bound organelles ribosomes 80s

nucleus

contains DNA and controls gene expression

Mitochondria

site of aerobic respiration and ATP production, often referred to as the powerhouse of the cell. inner membrane is folded into cristae for a large surface area for ATP synthesis

Ribosome

site of protein synthesis translate mRNA into polypeptide chains

RER

Rough endoplasmic reticulum —> synthesis, transports and modifies proteins

SER

smooth endoplasmic reticulum —> synthesised lipids and steriods, detoxification

Golgi apparatus

Modifies, sorts and packages proteins into vesicles for transport or secretion

lysosome

a vesicle that Contains hydrolytic enzymes for intracellular digestion

Nuclear envelope

A double membrane surrounding the nucleolus with nuclear pores for transport

Nucleolus

region within the nucleus where ribosomes are assembled

Cristae

Folds within mitochondrial inner membrane that increases surface area for respiration/ ATP synthesis

Chloroplast

Organelle where photosynthesis occurs in plant cells contains: thylakoid, granum,

Thylakoid

flattened membrane sacs in chloroplasts where light dependent reaction (LDR) occurs.

Chloroplast LDR

using light energy to split water (photolysis) into electrons protons and oxygen generating ATP and reduced NADP ( photo-phosphorylation via chemiosmosis)

Granum

A stack of thylakoids within a chloroplast which increase SA for light dependent reaction to occur

Cell wall

Rigid structure in plant cells providing support, made of cellulose, fungus cells = made of chitin, bacteria cells = peptidoglycan

Vacuole

large organelle in plant cells maintaining turgor pressure

2.2 Monomer

A small molecular unit that can join to form polymers with a covalent bond

2.2 Polymer

a large molecule made up of many monomers

2.2 Condensation reaction

a reaction forming a bond between molecules due to the removal of water

2.2 Hydrolosis reaction

a reaction breaking a bond by the addition of H2O

2.2 Carbohydrate

Molecule contain C, H, O

2.2 Monosachiride

a single sugar unit that can not be hydrolysed e.g (Glucose, fructose, Galactose)

2.2 Disachride

2 monosachrides together eg glucose+glucose = Maltose

2.2 Polysacchride

long chains of Monosacchrides e.g Starch, glycogen and cellulose

2.2 Glycosidic Bond

bond formed between sugar molecules formed by condensation reaction

2.2 Lipid

Non-polar molecules including fats and oils used for energy stores. insoluble to water

2.2 Triglyceride

Primary form for energy storage, made up of glycerol and 3 fatty acids

2.2 Ester bonds

Bond formed between glycerol and 3 fatty acids

2.2 Protein

Polymers of amino acids with structural and functional roles.

2.2 Amino Acids

The monomer of proteins containing an amine group, carboxyl group, and R group.

2.2 Peptide bond

bond fromed between amino acids

2.2 Primary structure

sequence of amino acids in a protein

2.2 Secondary Structure

folding of protein chains into alpha or beta sheets connected by hydrogen bonds

2.2 Tertiary Structure

further folding forming a specfic 3D shape

2.2 Quatenary structure

association of multiple polypetide chains

2.2 Enzyme

A biological catalyst that speeds up reactions

2.2 Active site

region of an enzyme where the substrate binds on the enzyme substrate complex

2.2 Lock and Key model vs induced fit model

The Lock-and-Key model sees enzymes and substrates as rigid, perfectly matching shapes (like a key in a lock), while the widely accepted Induced Fit model shows the enzyme's active site as flexible, changing shape (like a glove moulding to a hand) to perfectly embrace the substrate for catalysis,