RS-T04-Q7 · Krebs 循环「四碳受体再生」

先自己写完再对答案；卡住的地方回看这段讲解（公开课时间码 18:40–21:20）

来源 9700_s16_qp_41.pdf → 9700_s16_ms_41.pdf　|　小问：全部小问

触发题型：看到 Outline Krebs cycle / 问为什么叫循环 / 问每轮产物

✅ Mark Scheme 得分点（原文）

逐条计分：n 分写 n 条；红字为考官明确不接受（Do not accept）

(a)

1. both have ribose (sugars) ; R ribulose
2. ATP has 1, ribose / pentose / sugar, NAD has 2 ; I ref. to additional hexose
3. both have, adenine / purine (base) ; I adenosine
4. NAD has, nicotinamide / pyrimidine (base) ;
5. ATP has 3 phosphates, NAD has 2 ;
6. [max 3]

(b)

1. accept synthesise / produce / convert to, for ‘make’ for all mp
2. make (named), protein / polypeptide / peptides ; A protein synthesis / translation
3. make (named), disaccharide / oligosaccharide / polysaccharide / glycogen ; R non-
4. mammalian examples such as starch or cellulose
5. make (named), triglycerides / lipids / phospholipids / steroids / cholesterol ;
6. A glycogenesis
7. make, nucleotide / polynucleotide / nucleic acid / DNA / RNA ;
8. A transcription / DNA replication
9. AVP ; e.g. named example of, polymerisation / condensation
10. A phosphorylation example
11. [max 2]

(c)

1. substrate-linked / substrate-level, phosphorylation ; I condensation reaction
2. [1]

(d)

1. hydrogen, carrier / acceptor ; A gets reduced or gains H / H+ and electrons
2. I donates R H2 / hydrogen molecules
3. (acts as a) coenzyme ; A enables dehydrogenases to work
4. ref. to glycolysis / respiration in anaerobic conditions ; A anaerobic respiration
5. I aerobic
6. [max 2]

(e)

1. ‘more’ needed once plus implied for second mp
2. more, C-H bonds / hydrogen(s) / reduced ; I C-C bonds
3. R more hydrogen bonds R hydrocarbons
4. accept produces / gives / results in for ‘makes’ in mp 2 and mp3
5. (makes) more reduced NAD ;
6. makes more ATP per, gram / molecule / mole / unit mass ;
7. A releases / results in / gives, more energy per, g / etc.
8. more, aerobic respiration / electron transport chain (ETC) / oxidative
9. phosphorylation / chemiosmosis ; A higher rate of for ‘more’
10. [max 2]