CHS_2016_Bio_Prelim_ANS.pdf

2016 SECONDARY 4 BIOLOGY PRELIMINARY EXAMINATION 3 Mark Scheme 5158/01 (40 marks) 1 A 2 B 3 B 4 B 5 A 6 C 7 C 8 C 9 A 10 C 11 D 12 C 13 A 14 C 15 B 16 C 17 D 18 C 19 B 20 D 21 C 22 C 23 B 24 C 25 A 26 D 27 B 28 A 29 B 30 C 31 D 32 D 33 D 34 A 35 A 36 D 37 C 38 D 39 B 40 A 5158/02 Section A (50 marks) 1 (a) V – stomach [1] W– large intestine / colon / rectum [1] I: intestine unqualified 1 (b) mp 1 breaks up food into small(er) pieces [1] R: molecules mp 2without chemical change [1] A: without enzymes mp 3by teeth / muscles [1] A: mastication / chewing / churning mp 4to mix (with digestive juice) [1] mp 5increases surface area [1] mp 6for enzyme action [1] mp 7speeds up chemical digestion [1] mp 8easier to swallow [1] [max 3] 1 (c) for mp 1positive correlation / as (relative) body mass increases + timein digestive system increases [1] mp 2any two or more figures from the graph (units must be quoted at least once) [1] against mp 3two/one/few/some + are outliers/anomalies (e.g. either outlier quoted) [1] mp 4any figure(s) from the graph [1] mp 5(description of) some mammals do not fit the + pattern/trend [1] mp 6 any example from the graph [1] 118 trendylineinstns 33two/one/few/two/one/fewsomesome+ are outliers/anomalies + are outliers/anomalie((e.g. either oute.g. either out 4any figure(s) from the graph [1]ny figure(s) from the graph [1] 5(description of) some mammals d(description of) some mammals do not fit the + pattern/trenot fit the + pattern/tr 6any example fromthe graph [1]1]

mp 7 only information about 26 species of mammal / small sample size [1] mp 8idea about unknown validity [1] mp 3-8 [max 3] mp 1-2 + mp 3-8 [max 4] 2 (a) function letter on Figure 1.1 name structure that separates oxygenated and deoxygenated blood F septum [1] structure that prevents backflow of blood from ventricle to atrium D bicuspid/mitral/atrioventricular + valve A: “AV valve” R: right atrioventricular valve [1] blood vessel that carries deoxygenated blood B H pulmonary artery vena cava [1] chamber of the heart that contains deoxygenated blood J G right atrium right ventricle [1] . 2 (b) (i) mp 1 pulse rate increases and remains constant [1] mp 2immediate/sudden/steep/rapid/AW + increase in pulse rate [1] R: exponential mp 3increases from 44–48 bpm to 164–170 bpm / increases by 120–126 bpm/ by 3.5 to 4 timesor approx 4 [1] mp 4maximum / 164–170 bpm + at 4 min(utes) / 2 min(utes) after race starts [1] R: no units used [max 3] 2 (b) (ii) mp 1 adrenaline stimulates incr ease in + heart/pulse rate [1] mp 2increase in blood + carbon dioxide (concentration) / acidity + detected [1] A: decrease in pH mp 3nerves stimulate heart to beat faster [1] mp 4ref to muscle contraction / AW [1] mp 5muscles require more energy / muscles are doing more work [1] mp 6(rate of aerobic) respiration increases [1] R: ‘produce’ energy mp 7increase demand for + oxygen / glucose [1] mp 8ref to removal of + carbon diox