Separate mark scheme — do not issue with the student worksheet
Time guide: — · Questions: 32 · Total marks: 104
Written in Eduqas A-Level style. Answer in continuous prose where the marks require explanation.
Indicative marking points. Award marks for equivalent scientific or mathematical wording. Do not issue this sheet with the student worksheet.
1.
State what is meant by the genetic code.
[1 mark]
triplet, degenerate, non-overlapping, universal
2.
State what is meant by transcription.
[1 mark]
DNA → mRNA in the nucleus
3.
State what is meant by translation.
[1 mark]
mRNA + tRNA + ribosome → polypeptide
4.
State what is meant by a mutation.
[1 mark]
change in DNA base sequence
5.
State what is meant by meiosis.
[1 mark]
two divisions, haploid gametes, variation
6.
State what is meant by natural selection.
[1 mark]
differential survival and reproduction
7.
State what is meant by speciation.
[1 mark]
new species form when gene flow stops
8.
State what is meant by taxonomy.
[1 mark]
classification into domain to species
9.
State what is meant by biodiversity.
[1 mark]
variety of species, genetic and habitat
10.
State what is meant by an antibody in immunity.
[1 mark]
specific protein from plasma cells
11.
Jac is asked about the genetic code in a Eduqas Biology paper.
(a) [2 marks]
codons code for amino acids
(b) [3 marks]
start and stop
12.
Jac is asked about transcription in a Eduqas Biology paper.
(a) [2 marks]
RNA polymerase
(b) [3 marks]
template strand
13.
Jac is asked about translation in a Eduqas Biology paper.
(a) [2 marks]
anticodon pairing
(b) [3 marks]
peptide bonds
14.
Jac is asked about a mutation in a Eduqas Biology paper.
(a) [2 marks]
substitution, insertion, deletion
(b) [3 marks]
frameshift is usually worse
15.
Jac is asked about meiosis in a Eduqas Biology paper.
(a) [2 marks]
crossing over and independent assortment
(b) [3 marks]
fertilisation adds more variation
16.
Jac is asked about natural selection in a Eduqas Biology paper.
(a) [2 marks]
allele frequencies change
(b) [3 marks]
directional or stabilising
17.
A DNA sequence has 600 bases. Maximum amino acids
[3 marks]
Final answer: 200
18.
Chi-squared: 3:1 expected of 80 plants. Expected recessive
[3 marks]
Final answer: 20
19.
Index of diversity N(N−1)/Σn(n−1). If N=10 and Σ=12, D
[3 marks]
Final answer: 7.5
20.
Heterozygous cross Aa × Aa. Probability of aa
[3 marks]
Final answer: 0.25
21.
A gene pool has p=0.8. If HWE, frequency of heterozygotes
[3 marks]
Final answer: 0.32
22.
A 4-base sequence has 4⁴ possible combinations
[3 marks]
Final answer: 256
23.
Jac carries out a Eduqas-style required practical linked to genetic information and variation. This is a typical Eduqas required-practical style question.
(a) [2 marks]
Independent: the independent variable for this topic
Dependent: the measured outcome
(b) [2 marks]
keep all other variables constant
so the test is fair / only one variable is changed
(c) [2 marks]
repeat and calculate a mean / use a tighter method
24.
Jac carries out collecting valid data for genetic information and variation. This is a typical Eduqas required-practical style question.
(a) [2 marks]
Independent: a chosen factor
Dependent: a quantitative measurement
(b) [2 marks]
calibrated instrument
so the test is fair / only one variable is changed
(c) [2 marks]
systematic error from zero error
25.
Jac carries out drawing a graph for genetic information and variation. This is a typical Eduqas required-practical style question.
(a) [2 marks]
Independent: x-variable
Dependent: y-variable
(b) [2 marks]
same scale / same apparatus
so the test is fair / only one variable is changed
(c) [2 marks]
not drawing a line of best fit through the trend
26.
Jac carries out evaluating a method about genetic information and variation. This is a typical Eduqas required-practical style question.
(a) [2 marks]
Independent: method change
Dependent: precision / accuracy
(b) [2 marks]
same sample size
so the test is fair / only one variable is changed
(c) [2 marks]
too few repeats
27.
Compare the genetic code with transcription.
[4 marks]
triplet, degenerate, non-overlapping, universal
DNA → mRNA in the nucleus
give one linked difference
28.
Compare transcription with translation.
[4 marks]
DNA → mRNA in the nucleus
mRNA + tRNA + ribosome → polypeptide
give one linked difference
29.
Compare translation with a mutation.
[4 marks]
mRNA + tRNA + ribosome → polypeptide
change in DNA base sequence
give one linked difference
30.
Compare a mutation with meiosis.
[4 marks]
change in DNA base sequence
two divisions, haploid gametes, variation
give one linked difference
31.
Apply your knowledge of speciation to this situation: allopatric vs sympatric
[3 marks]
allopatric vs sympatric
32.
Apply your knowledge of taxonomy to this situation: binomial names