Oxford Revise AQA GCSE Combined Science Foundation | Chapter B14 answers

B14: Reproduction

Question

Answers

Extra information

Mark

AO / Specification reference

01.1

B

as the chromosomes are identical/the same size / XX

1

1

AO2

4.6.1.8

01.2

nucleus

1

A01

4.6.1.8

01.3

XX

XX

XY

XY

1

1

AO1

4.6.1.8

01.4

50% / 1 in 2

allow ½ or 1:1

1

AO1

4.6.1.8

01.5

1/4

1

AO1

4.6.1.8

02.1

mitosis

1

AO1

4.6.1.1

02.2

C

A

E

B

D

award four marks for all statements in correct order

award three marks for 3 or 4 statements correct

award one or two marks for 1 or 2 correctly ordered statements respectively

4

AO1

4.6.1.1

02.3

any two from:

sexual reproduction:

requires two parents

produces four gametes

gametes produced are genetically different

gametes mix / fuse / mixing of genetic material

accept converse for any of the marks

2

AO1

4.6.1.1

4.6.1.2

03.1

ovaries

1

AO1

4.6.1.2

03.2

testes

1

AO1

4.6.1.2

03.3

Feature

Meiosis

Mitosis

Produces clones

Produces four gametes

Halves the number of chromosomes in a cell

Cell divides once

award one mark for each correct row

4

AO1

4.6.1.2

04.1

23

46

alleles

dominant

recessive

1

1

1

1

1

AO1

4.6.1.6

04.2

BB – homozygous dominant

Bb – heterozygous

bb – homozygous recessive

all three correct for 2 marks

One or two correct for 1 mark

2

AO1

4.6.1.6

04.3

BB – Brown eyes

Bb – Brown eyes

bb – Blue eyes

1

1

1

AO1

4.6.1.6

04.4

the baby may be born with brown eyes, or may be born with blue eyes

1

AO2

4.6.1.6

04.5

as the mother may be heterozygous for the eye colour gene

1

AO2

4.6.1.6

05.1

DNA is a polymer

DNA is twisted into a helix

1

1

AO1

4.6.1.4

05.2

gene – section of DNA coding for a characteristic

chromosome – long strand of DNA

genome – entire genetic material found in an organism

nucleus – part of a cell containing DNA

award three marks for 4 correctly matched definitions

award two marks for 2 or 3 correctly matched definitions

award one mark for 1 correctly matched definition

3

AO1

4.6.1.4

05.3

One from:

Identify cause of genetic disease

Identify possible treatment of inherited disorder

study human migration patterns

link genetic factors to a disease

accept any other appropriate suggestion

1

AO3

4.6.1.4

06.1

24

1

AO2

4.6.1.6

06.2

12

1

AO2

4.6.1.6

06.3

two parents are required

gametes fuse together

1

1

AO1

4.6.1.6

06.4

Any four from:

copies of the DNA / genetic information is made

cell divides twice

to form four gametes / pollen cells

each with a single set of chromosomes

each pollen cell is genetically different / non identical

4

A02

4.6.1.2

07.1

polydactyly

1

AO1

4.6.1.7

07.2

it is caused by a recessive allele

it affects cell membranes resulting in thick mucus being produced

1

1

AO1

4.6.1.7

07.3

ethical:

an unborn fetus has a ‘right to life’ social:

enables parents to evaluate potential impact on their lives economic:

allows a couple to consider whether they are able to financially support the child

cost of procedure small compared with cost of lifetime care

Award one mark for each statement matched correctly

4

AO3

4.6.1.7

08.1

(sperm contains) 23 (chromosomes)

(egg contains) 23 (chromosomes)

(during) fertilisation (the genetic material joins together)

(cell divides by) mitosis

(each nucleus in an embryo contains) 46 (chromosomes)

1

1

1

1

1

AO1

4.6.1.2

08.2

it involves two parents

genetically different offspring are produced

1

1

AO1

4.6.1.1

08.3

pollen

egg cell / ovule

1

1

AO1

4.6.1.1

09.1

polymer / chain of nucleotides

two strands

arranged as a double helix

1

1

1

A01

4.6.1.4

09.2

specific sequence of amino acids

create a specific protein (which carries out a particular function)

1

1

A01

4.6.1.4

09.3

the complete set of genes / genetic material present in a cell / organism

1

AO1

4.6.1.4

09.4

find genes linked to disease

understand / design treatments for inherited disorders

trace ancestry /human migration

1

1

1

A01

4.6.1.4

10.1

ethanol

carbon dioxide

1

1

AO1

4.4.2.1

10.2

independent variable – temperature

dependent variable – volume of gas produced

control variable – time over which gas is collected

award one mark for one correctly matched variable

2

AO2

4.4.2.1

10.3

all data points plotted correctly

appropriate line of best-fit drawn (smooth)

1 mark for at least two data points plotted correctly

2

1

AO2

AO3

4.4.2.1

MS 4C

10.4

any two from:

As temperature increases, rate of reaction / volume of gas produced increases

until 40 ℃

after 40 ℃ rate of reaction decreases

2

AO3

4.4.2.1

MS 4a

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