past paper questions

D

B

name Q and S

Q - phloem

S - xylem

observations that show that a cell is in prophase

explain how the organisation of homologous chromosomes during metaphase 1 increases genetic variation

suggest and explain why the cytoplasm of cell C and D reacted differently to the stain

intraspecific variation

describe and explain the precautions that must be taken for setting up and using a potometer

compare the properties and functions of fibrous and globular proteins in the human body

GLOBULAR PROTEINS Properties: • soluble • spherical / ball-shaped • have, 3D / tertiary / 3o, shape / structure • specific / complementary (to another molecule) • ref. conjugated / contain prosthetic group • temperature / pH, sensitive • hydrophilic on outside IGNORE size refs, compact, round, bond types Functions: Look for the general functional category name or description, or a named protein or glycoprotein example with some supporting detail. • enzymes / metabolic role / to catalyse reaction(s) / to lower activation energy • named enzyme + its specific role described • hormones / receptors / for cell signalling • named hormone / insulin + role described • antibody / for immunity / defence against infection • opsonin / antitoxin / agglutinin + role described • fibrinogen in blood clotting • to transport substances across cell membranes • carrier / channel / pump + role described • to transport substances in blood • haemoglobin + role described e.g. carry oxygen • to, package / organise DNA

FIBROUS PROTEINS Properties: • insoluble • elongated / long / rods / filaments / ropes / strands • strong / tough • flexible IGNORE size refs / compact / coiled / bond types / hard Functions: Look for the general category or for a named protein or glycoprotein example with supporting detail. Related categories and examples are paired or grouped together: • for structure • collagen in, bone / cartilage / connective tissue / tendons / ligaments / skin / blood vessels • fibrin + role described • for protection • keratin in, skin / hair / nails • to give, elasticity / elastic properties • elastin in, (named) blood vessels / alveoli / cartilage • for, contraction / mechanical movement • actin / myosin, in muscle • microtubules in, cilia / flagella / spindle / cytoskeleton

C

B

D

m - bronchiole

n - smooth musce

state 2 features of organisms that belong to the kingdom protoctista

describe how a pitfall trap can be set up