Unit 4 ATP and Respiration - Chemstuff | Mr Banks's ... 4 ATP and Respiration - Chemstuff | Mr...
50
Unit 4 Populations & Environment ATP & Respiration Practice Exam Questions
Transcript of Unit 4 ATP and Respiration - Chemstuff | Mr Banks's ... 4 ATP and Respiration - Chemstuff | Mr...
Unit 4
Populations & Environment
ATP & Respiration
Practice Exam Questions
1. Fig. 1 shows the link reaction and the Krebs cycle.
Fig. 1
(a) (i) State the precise location of the reactions shown in Fig. 1.
………………………………………………………………………………………………………… [1]
(ii) State the metabolic pathway that has pyruvate as an end product.
………………………………………………………………………………………………………… [1]
(b) Label on Fig. 1, the stages where,(i) decarboxylation reactions occur; label these with the letter C. [2]
(ii) dehydrogenation reactions occur; label these with the letter H. [3]
(c) Describe the role of NAD in respiration.
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
…………………………………………………………………………………………………………
………………………………………………………………………………………………………… [3]
(d) Compare the fate of pyruvate in anaerobic respiration in yeast and mammalian cells.
………………………………………………………………………………………………………..
………………………………………………………………………………………………………..
………………………………………………………………………………………………………..
………………………………………………………………………………………………………..
………………………………………………………………………………………………………..
………………………………………………………………………………………………………..
………………………………………………………………………………………………………..
……………………………………………………………………………………………………….. [4]
(e) Explain why, in the absence of oxygen, the electron transfer chain in the mitochondria does not operate.
………………………………………………………………………………………………………..
………………………………………………………………………………………………………..
………………………………………………………………………………………………………..
………………………………………………………………………………………………………..
………………………………………………………………………………………………………..
……………………………………………………………………………………………………….. [3]
[Total: 17]
2
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
Answers and markscheme
1 (a) (i) matrix of the mitochondrion; 1
(ii) glycolysis; 1
(b) (i) C between6C and 5C;5C and 4C;between pyruvate and acetyl CoA; 2 max
(ii) H at:NAD NADH in link reaction;3 places where NAD NADH in Krebs cycle;FAD FADH in Krebs cycle; 3
(c) reduced in, glycolysis / link reaction / Krebs;transports electrons / hydrogen ions;to inner membrane of mitochondrion;oxidised;releases electrons and hydrogen ions;used in ETC to form gradient of hydrogen ions;used to drive synthesis of ATP; 3
(d) mammalspyruvate is, reduced / converted, to lactate;NAD red is oxidised;one step reaction / catalysed by lactate dehydrogenase;
yeastpyruvate is decarboxylated;CO2 is produced;ethanal;reduced / converted, to ethanol; 4 max
(e) oxygen is needed for the final step;final, hydrogen / electron, acceptor;without it NAD red is not oxidised; 3
[Total: 17]
2
3
4
5
6.
8
7
9
10
11
12.
13.
14
15
16
17
18
(ii) 30 [however derived] = 2 marks [Note; question concerns ATP made in mitochondria only]
If incorrect figure given then only 1 max possible – check working for any two correct intermediate figures in correct context, e.g.:
2.5 x 10 [from NADH] AND 1.5 x 2 [from FADH] = 1 markOR
2 x 2.5 (from glycolysis NADH) AND 2ATP (from Krebs cycle) = 1 mark 2
