Oxford Revise AQA GCSE Combined Science Foundation | Chapter B3 answers

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Question Answers Extra information Mark AO / Specification reference
01.1 process by which cells divide to produce two identical cells   1

AO1

4.1.2.2
01.2

C

B

A

D

1 mark for one correct

2 marks for two correct

3 marks for all correct

 3

AO2

4.1.2.2
01.3

Any two from:

  • Cell membrane divides
  • Cytoplasm divides
  • Cell divides to form two cells
   2

AO2

4.1.2.2
02.1

undifferentiated

differentiation

  

1

1

AO1

4.1.2.3
02.2 They could replace faulty cells / (differentiate into cells that could) produce insulin.   1

AO3

4.1.2.3
02.3

Adult stem cells:

  • found in bone marrow
  • can produce a few cell types in the body

Embryonic stem cells:

  • can produce all cell types in the body
  • found in embryos
  

1

1

1

1

AO1

4.1.2.3
02.4 No risk / less risk of rejection / some people may not agree with using transplanted material   1

AO3

4.1.2.3
02.5 Risk of infection / ethical or religious objection / no track record of success as a treatment Accept other reasonable suggestions 1

AO3

4.1.2.3
03.1

Gene – A section of DNA which codes for a characteristic

DNA – The chemical that makes up genetic material

Chromosome – A long strand of DNA

1 mark for one correct

2 marks for all correct

 2

AO1

4.1.2.1
03.2

gene

chromosome

nucleus

cell

1 mark for one structure in the correct order

2 mark for two structures in the correct order

3 marks for all structures in the correct order

 3

AO1

4.1.2.1
03.3 chromosomes   1

AO1

4.1.2.1
04.1 Stage 2   1

AO1

4.1.2.2
04.2 Stage 1   1

AO1

4.1.2.2
04.3

ribosomes

mitochondria

  

1

1

AO1

4.1.2.2
05.1

A – nucleus

B – chromosome

C – gene

  

1

1

1

AO2

4.1.2.1
05.2

nucleus

DNA

chromosomes

genes

characteristic

  

1

1

1

1

1

AO1

4.1.2.1
05.3 two   1

AO1

4.1.2.1
06.1 growth / repair   1

AO1

4.1.2.2
06.2

(1 – DNA replicates)

2 – Chromosomes line up in the middle of the cell

3 – One set of chromosomes is pulled to each end of the cell

4 – Two nuclei are formed

5 – Cell membrane divides

6 – Two identical cells are formed

1 mark for one sentence in the correct order

2 marks for two sentences in the correct order

3 marks for three sentences in the correct order

4 marks for all in the correct order

 4

AO1

4.1.2.2
06.3 Mitosis   1

AO1

4.1.2.2
07.1 Stage   1

AO1

4.1.1.5
07.2 40 mm   1

AO2

4.1.1.5

MS 3d
07.3

Light:

  • lower magnification
  • can observe living organisms

Electron:

  • greater magnification
  • can only observe dead organisms
  

1

1

1

1

AO1

4.1.1.5
07.4 Daphnia would be damaged / killed by using electron microscope   1

AO2

4.1.1.5
08.1

DNA

Chromosome

genes

  

1

1

1

AO1

4.1.2.1
08.2 Specialised cells make different parts of the body.   1

AO1

4.1.2.2

4.1.1.4
08.3

DNA replicates / two copies of the chromosomes form

one set of chromosomes is pulled to each end of the cell

the nucleus divides

cytoplasm and/or cell membrane divide

 Full marks can be awarded from a series of labelled diagrams

1

1

1

1

AO1

4.1.2.2
09.1 Meristem   1

AO1

4.1.2.3
09.2 C   1

AO2

4.1.2.3
09.3 DNA replication → mitosis → elongation → differentiation   1

AO1

4.1.2.3

4.1.1.4
09.4

Animal stem cells

  • Differentiation occurs at a very early stage
  • Differentiations produced are permanent

Plant stem cells

  • Differentiation occurs throughout life
  • Differentiation can be reversed or changed

1 mark for two answers correct

2 marks for all correct

 2

AO1

1.2.3

1.1.4
10.1 Meristems contain undifferentiated cells   1

AO1

1.2.3
10.2 It produces genetically identical offspring / genetic material in the offspring derives from the parent plant only   1

AO1

1.2.3
10.3

Any two from:

  • Quicker
  • Cheaper
  • Plants can be transported over a large area / reproduced in a different area
  • Advantageous characteristics can be maintained
   2

AO2

1.2.3
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