IGCSE Biology Modular Exam SAMs | Pearson Edexcel 4BI1 Practice Paper | Digital Download

Biology Unit 2 (Modular)
Mark Scheme
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Question Answer Additional guidance Mark
Number
1(a) lymphocytes / eq Ignore white blood cells 1
Reject phagocytes




Question Answer Additional guidance Mark
Number
1(b)(i) An answer that makes reference to one of 1
the following:

• both alleles expressed (1) Accept both alleles work
together / both alleles
• both alleles affect the work together to form a
phenotype (1) third phenotype /
phenotype depends
• both alleles show their upon both alleles
characteristics / traits (1)
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Question Answer Mark
Number
1(b)(ii) The only correct answer is D (A, B, AB and O ) 1

A is incorrect as the cross could also produce AB and O

B is incorrect as the cross could produce also AB and O

C is incorrect as the cross could also produce A, and B




Question Answer Additional guidance Mark
Number
1(c) 4.7(4) x 107 (2) one mark for 47400000 or 2
47.4 million
or 47 million
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or other incorrect standard
forms using 47(4)

Correct answer gains all
marks




Pearson Edexcel International GCSE in Biology (Modular) (4XBI1) – Sample Assessment Materials 73
Issue 1 – March 2024 © Pearson Education Limited 2024

, Question Answer Additional guidance Mark
Number
1(d) An explanation that makes reference to three of 3
the following:

• artificial cells are not (bi)concave / red
blood cells are (bi)concave (1)

• artificial cells have smaller SA(:vol ratio)
/ red blood cells have larger SA (:vol
ratio) (1)

• artificial cells absorb / bind / release less
oxygen / red blood cells absorb bind more Accept artificial cells
oxygen / release more oxygen / eq (1) carry less oxygen / red
blood cells carry more
oxygen



Accept artificial cells
have slower diffusion
(of oxygen) / red
• artificial cells do not pass through blood cells have faster
capillaries easily / eq / red blood cells diffusion (of oxygen)
pass through capillaries more easily / eq
(1)



Question Answer Additional guidance Mark
Number
1(e) An explanation that makes reference to the 1
following:
Allow no fibrinogen
• no platelets (1)




74 Pearson Edexcel International GCSE in Biology (Modular) (4XBI1) – Sample Assessment Materials
Issue 1 – March 2024 © Pearson Education Limited 2024