Essay about Science: Blood and Correct Formulae Ignore

Submitted By arianagrande73
Words: 5557
Pages: 23

Biology 1 Answers HIGHER

1. (a) (i) 38 (1)
1
(ii) 19 (1)
1

(b) (i) different versions / types of the (same) gene (1) allow specific examples e.g. D and d are alleles of gene allow one is recessive and one is dominant
1
(ii) a correct diagram (1) black panther cub / black fur named or identified as dd (1) no need to identify parents for correct diagram mark

middle stage not essential in diagram if 1st and 3rd stages correct ignore matching lines in above diagram just look for correct letters

allow dd circled but not labelled for second mark
2
[5]

2. (a) (i) (becomes) thin(ner) / flat(tens) (1) allow a before and after diagram ignore references to ciliary muscles or suspensory ligaments ignore smaller or bends/ longer focus or focal length / contracts / longer allow less curvature / less curved
1
(ii) relaxes (1) ignore gets longer / expands / stretches
1
(iii) (become) tight(er) / taut (1) ignore contract / stretches / squeezed / pulled / get longer
1

(b) any three from need more / extra oxygen / enough oxygen (1) (repay ) oxygen debt (1) lactic acid built up / made or produced during run (1) (because of) anaerobic respiration (1) (oxygen needed) to break down / remove lactic acid
/ oxidise lactic acid (1) ignore to recover ignore reference to aerobic respiration ignore just oxygen
3

(c) (i) line from amino acids to protein (1) lines from fatty acids and glycerol to fat (1)

both needed if more than 3 lines drawn deduct one mark for each extra line to a minimum of zero
2

(ii) (food) can be absorbed /
(food) can pass into the blood (stream) /
(food) can be transported in the blood /
(food) can pass through the wall of the intestine / so diffusion possible (1) ignore references to body not through cell wall not just into the wall of the intestine ignore gut
1
[9] 3. (a) glucose (1) allow sugar / correct formula not food
1

(b) (i) insufficient supply of oxygen / lack of oxygen (1) not no oxygen / insufficient blood / not enough time to get oxygen ignore in oxygen debt
1
(ii) any two from: lactic acid (accumulates) (1) (which is) painful / cramp / (causes) fatigue / aches (1) oxygen debt occurs (1) ignore toxic / poisonous / harmful / damage
2

(c) any two from: more heat is generated / lose extra heat / increase heat loss (1) to maintain body temperature / homeostasis / prevent heat stroke (1) vasodilation / blood vessels widen (1) controlled by brain / hypothalamus (1) ignore gets hotter ignore just lose heat ignore cool down allow cool down faster not blood vessels move closer to surface
2

(d) stay hydrated / rehydrate / avoid dehydration / maintain internal environment / balance inputs and outputs / homeostasis (1) allow because he has lost water / replace lost water
1
[7]
4. (a) parents = Ff (1) gametes = F and f from each parent (1) offspring = FF, Ff, Ff, ff (1) probability = 1 in 4 / 0.25 / 25% / 1/4 / 1:3 (1) must state parent genotypes separately to gametes not 1 in 3 or 1:4 or 1/3
4

(b) (i) A, T, C, G (any order) (1)
1
(ii) different sequence / order / pattern (1) allow some are missing not different bases / different combinations / linked differently
1
(c) to prevent resistant strains spreading / being selected for / AW (1) not reference to the person becoming resistant / the disease becoming resistant allow bacteria can develop resistance not to stop bacteria mutating
1
[7]

5. (a) (i) dehydration (1) if answer line is blank, allow dehydration circled, underlined or ticked in list above
1
(ii) homeostasis (1) allow negative feedback
1

(b) (i) any one from take malaria tablets (1) use insect repellent or insecticide (1) description of way to prevent being bitten (1) allow named anti-malarial drugs e.g. larium, quinine ignore reference to injections / vaccination / immunisation
/inoculation
e.g. cover up / use mosquito net / avoid areas or…