A Level Biology - Chapter 1

monomer

small sub unit that makes up a polymer

polymer

large complex molecule made up of small sub units

condensation reaction

monomers bond and release a molecule of water

hydrolysis

water used to break a chemical bond

monosaccharide

monomer that makes up a carbohydrate

carbohydrate bond

glycosidic

test for reducing sugars

benedict’s reagent, heat - brick red

test for non-reducing sugars

benedict’s reagent - blue, dilute HCl, heat, neutralise with NaHCO3 - brick red

starch

polysaccharide, alpha glucose, amylose - coiled, amylopectin - branched, 1-4 glycosidic bonds, insoluble, small, good storage molecule, plants

glycogen

polysaccharide, alpha glucose, highly branched, compact, glucose released quickly good for energy release, animals

cellulose

polysaccharide, beta glucose rotated 180, long, unbranched, straight, 1-6 glycosidic bonds, hydrogen bonds between chains, microfibrils - fibres, structural support, plants

test for starch

iodine - blue/black

lipid bond

ester

triglyceride

1 glycerol, 3 fatty acid tails, hydrophobic, insoluble, saturated/unsaturated, storage, release energy, don’t affect water potential

phospholipid

1 glycerol, 2 fatty acid tails. 1 phosphate group, hydrophilic head hydrophobic tails, cell membrane

test for lipids

emulsion test - ethanol, shake, water - white milky emulsion

protein

polypeptide chain of amino acids

polypeptide bond

peptide

amino acid

H2NCHRCOOH

primary structure

sequence of amino acids

secondary structure

hydrogen bonds - alpha helix, beta pleated sheet

tertiary structure

hydrogen bonds, ionic bonds, disulfide bridges, dependent on R groups and their positions

quaternary structure

more than one polypeptide chain

test for proteins

biuret test - NaOH, copper(II) sulfate - purple

enzyme

biological catalyst, increases rate of reaction by lowering activation energy

active site

part of the enzyme where the substrate molecules bind to, specific

ESC

enzyme substrate complex formed when substrate fits into enzyme’s active site, lowers Ea by holding molecules close (joining) or putting strain on bonds in substrate (splitting)

lock and key

substrate fits into enzyme perfectly

induced fit

substrate binds, active site changes shape slightly to make it more complimentary

temperature

higher temperature more kinetic energy substrate more likely to collide with active site, optimum temperature, too low not enough energy, too high denatured active site no longer specific

pH

optimum pH specific to enzyme, too low or too high denatures active site

substrate concentration

higher concentration more ESCs higher rate of reaction, however active sites saturated at a certain point so rate plateaus

enzyme concentration

higher concentration more ESCs higher rate of reaction, rate plateaus if substrate limited

competitive inhibitors

similar shape to substrate, bind to active site, prevent ESC

non-competitive inhibitor

bind to surface of enzyme, change tertiary structure and shape of active site, prevents ESC

DNA

deoxyribonucleic acid, double helix, ATCG, long

RNA

ribonucleic acid, single strand, AUCG, short

nucleotide

DNA & RNA monomer, phosphate, ribose and base, complimentary base pairing

DNA/RNA bond

phosphodiester

DNA replication

semi-conservative - DNA helicase breaks hydrogen bonds between strands, each strand act as a template for complimentary base pairing, DNA polymerase join nucleotides phosphodiester bond, one old one new strand

ATP

adenosine triphosphate - adenine, ribose and 3 phosphate groups, hydrolysed into ADP and inorganic phosphate releasing a lot of energy

phosphorylation

inorganic phosphate makes compound more reactive

water

metabolite, solvent, hydrogen bonding, cohesive, high latent heat of vaporisation, high specific heat capacity

inorganic ions

specific roles - FE2+ haemoglobin, H+ pH, Na+ cotransport and action potentials, PO43- DNA/RNA/ATP phosphorylation and cell membranes