Bio al 2002
2002 AL Biology marking scheme
Paper 1 Section A
Terms with *, mark deduction for wrong spelling.
Alternatives and correct answers not listed in this document should be accepted.)
Marks
1 .1/2 mark for each correct answer
Column 1
E
earthworm
B
jellyfish
F
starfish
D
clam
2.
(2)
Concepts for mark allocation
•
worn-out organelles are enclosed by membrane forming vacuoles (1) worn-out organelles are enclosed by lysosomes (3)
•
lysosome releases hydrolytic enzymes into the vacuoles to digest the organelles (1)
•
digested materials are recycled for resynthesis (1)
Page total 5
3. (a)
corals obtain nutrients (1/2) and O 2 (1/2) from zooxanthellae for growth /respiration
(1)
colour conferred to corals attracts prey (1) zooxanthellae obtains protection / shelter from the corals (1) coral provides a stable living environment for zooxanthellae (1) zooxanthellae obtains CO2 (1/2) and NH 4+ (1/2) / nutrients from the corals for photosynthesis (1) / growth
(Bonus (I): NH4+ is toxic to coral, zooxanthellae can help to remove this substance from the coral.)
(b)
max. 2
max. 2
+bonus = 1
(max.=4)
(poss. max. = 5)
zooxanthellae stop contributing to the corals as they stop photosynthesis in darkness (1), compete with corals for 02 when they respire (1) / acquire nutrients from corals
(2)
Or produce metabolic wastes e.g. C02 that lowers pH which is harmful to corals produce toxic substances (1)
(accept other reasonable negative impact on corals)
(6)
Page total = 6
Poss. Page total = 7
4.
A
C
D
0
Name of fish
Key sequence
Squalus mitsukurii ('/2) lb, 3a
(1)
Lethrinus haematopterus (V2) lb, 3b, 4b (1)
Cleisthenes herzensteini (1/2) la, 2b
(1)
'/2 mark for underlining the scientific names of all fish
41/2
U = 1/2
(5)
Page total = 5
1
Marks
5.
specimen 1 (1/2)
(N.B. If matching of specimen is wrong, no mark even if reason is correct.)
Reasons : (accept other correct observable
Paper 1 Section A
Terms with *, mark deduction for wrong spelling.
Alternatives and correct answers not listed in this document should be accepted.)
Marks
1 .1/2 mark for each correct answer
Column 1
E
earthworm
B
jellyfish
F
starfish
D
clam
2.
(2)
Concepts for mark allocation
•
worn-out organelles are enclosed by membrane forming vacuoles (1) worn-out organelles are enclosed by lysosomes (3)
•
lysosome releases hydrolytic enzymes into the vacuoles to digest the organelles (1)
•
digested materials are recycled for resynthesis (1)
Page total 5
3. (a)
corals obtain nutrients (1/2) and O 2 (1/2) from zooxanthellae for growth /respiration
(1)
colour conferred to corals attracts prey (1) zooxanthellae obtains protection / shelter from the corals (1) coral provides a stable living environment for zooxanthellae (1) zooxanthellae obtains CO2 (1/2) and NH 4+ (1/2) / nutrients from the corals for photosynthesis (1) / growth
(Bonus (I): NH4+ is toxic to coral, zooxanthellae can help to remove this substance from the coral.)
(b)
max. 2
max. 2
+bonus = 1
(max.=4)
(poss. max. = 5)
zooxanthellae stop contributing to the corals as they stop photosynthesis in darkness (1), compete with corals for 02 when they respire (1) / acquire nutrients from corals
(2)
Or produce metabolic wastes e.g. C02 that lowers pH which is harmful to corals produce toxic substances (1)
(accept other reasonable negative impact on corals)
(6)
Page total = 6
Poss. Page total = 7
4.
A
C
D
0
Name of fish
Key sequence
Squalus mitsukurii ('/2) lb, 3a
(1)
Lethrinus haematopterus (V2) lb, 3b, 4b (1)
Cleisthenes herzensteini (1/2) la, 2b
(1)
'/2 mark for underlining the scientific names of all fish
41/2
U = 1/2
(5)
Page total = 5
1
Marks
5.
specimen 1 (1/2)
(N.B. If matching of specimen is wrong, no mark even if reason is correct.)
Reasons : (accept other correct observable