AQA A-level BIOLOGY (7402/1)
Paper 1 Mark scheme 2021
SPECIMEN V1
polymer - ---ASNWERS----long molecules formed from combinations of many monomers joined together
condensation reaction - ---ASNWERS----a chemical reaction in which two or more molecules join and
produces one water molecule
hydrolysis reaction - ---ASNWERS----A chemical reaction that breaks apart a larger molecule by adding a
molecule of water
isomers - ---ASNWERS----Compounds with the same chemical formulae but different structures.
carbohydrates - ---ASNWERS----compounds made from carbon, hydrogen and oxygen (monosaccharides,
disaccharides and polysaccharides), important energy store
disaccharide - ---ASNWERS----two monosaccharides joined together by a glycosidic bond
polysaccharide - ---ASNWERS----many sugar units joined by a glycosidic bond
maltose - ---ASNWERS----α glucose + α glucose
lactose - ---ASNWERS----glucose + galactose
sucrose - ---ASNWERS----glucose + fructose
where is lactose found? - ---ASNWERS----milk
where is maltose found? - ---ASNWERS----germinating seeds
where is sucrose found? - ---ASNWERS----table sugar
cellulose - ---ASNWERS----polymer of β glucose
starch - ---ASNWERS----polymer of α glucose (amylose + amylopectin)
what is the structure of cellulose? - ---ASNWERS----long, unbranched chains of β glucose, insoluble
where is cellulose found? - ---ASNWERS----plant cell walls
why is cellulose strong? - ---ASNWERS----chains linked by h bonds form microfibrils giving high tensile
strength to prevent osmotic lysis
,what is the structure of starch? - ---ASNWERS----long, highly-branched, compact helix and insluble
where is starch found? - ---ASNWERS----energy stores in plants
glycogen - ---ASNWERS----storage form of glucose in animals, compact, highly-branched structure
limits of the Benedict's test - ---ASNWERS----isn't specific or sensitive
what is the test for reducing sugars? - ---ASNWERS----Benedict's test
what colour will the solution be in the presence of reducing sugars? - ---ASNWERS----green → red
(nearer red, higher conc reducing sugar)
what is the test for starch? - ---ASNWERS----iodine test
if starch is present, what colour will the iodine be? - ---ASNWERS----orange → blue-black
covalent bond - ---ASNWERS----a chemical bond in which two atoms share a pair of electrons
ionic bond - ---ASNWERS----the bond between two oppositely charged ions
hydrogen bond - ---ASNWERS----the attraction between a partially positive hydrogen atom(δ+) and a
partially negative atom(δ-)
lipid - ---ASNWERS----compounds mostly made from carbon and hydrogen (triglycerides and
phospholipids), energy store, thermal insulator, for buoyancy and protection
triglyceride - ---ASNWERS----1 glycerol + 3 fatty acid tails joined by an ester bond
glycerol - ---ASNWERS----a three-carbon alcohol with a hydroxyl group(-OH) attached to each
, fatty acid - ---ASNWERS----a carboxylic acid made of a hydrocarbon chain + a terminal carboxyl group
saturated fatty acid - ---ASNWERS----no double bonds between carbon atoms, maximising the number of
hydrogen atoms that can attach to the carbon skeleton.
unsaturated fatty acid - ---ASNWERS----a fatty acid with one or more double bonds between the carbons
(mono or poly)
polar - ---ASNWERS----molecule with partial charges due to a difference in electronegativity
hydrophobic - ---ASNWERS----water repulsion
hydrophillic - ---ASNWERS----attracted to water
what is the test for lipids? - ---ASNWERS----emulsion test
describe the emulsion test - ---ASNWERS----mix with ethanol and add water, white cloudy emulsion =
lipid
amino acid - ---ASNWERS----monomer of proteins
amino acid structure - ---ASNWERS----central carbon atom, hydrogen atom, variable (R) group, carboxyl
group (COOH) and amine group (NH2)
amine group - ---ASNWERS-----NH2
carboxyl group - ---ASNWERS-----COOH
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