Stress, Smoking, Diet Etc Are Examples of Lifestyle

Feversham College

A-level Biology (7401/7402)
Section 8 Practical Skills / Name:
Class:

Author:
Date:
Time:
Marks:
Comments:

M1.(a) (i)1.Sex;

2.Lifestyle;

Stress, smoking, diet etc are examples of lifestyle.

3.Body mass;

3. Allow weight for mark point 3.

4.Health;

Reject: height.

5.Ethnicity;

6. Genetic factors / family history;

2 max

(ii)1.Large sample / number / 410 000;

Reject: random

2.Long time period / 8.5 / many years;

3.Different countries / more than one country;

2

(b) Correct answer of 209 / 209.1 = 2 marks;

Answer of 210 = one mark

Incorrect answer but multiplies by 8.5 = 1 mark;

2

(c) Age affects risk of cancer;

Must relate to cancer not just to illness

1

(d) 1.Correlation does not mean causal relationship;

1. Reject casual for point 1.

Reference to 'due to other factors' on its own is not enough for a mark

2.Tea / coffee contains other substances / different amounts of caffeine / estimated intake (of tea / coffee);

3.No control group;

4.Only one type of cancer studied / further studies required / only one investigation / study / group;

4

(e) (i)1.Treated the same;

2. Accept decaffeinated

2.No caffeine;

2. Reject placebo.

2

(ii)1.Absorb different amounts;

Reject: Different body masses

2.Broken down by enzymes / digested;

3.Different blood volumes;

4.Differences in metabolism;

5.Caffeine from a different source;

1 max

(iii)1.Less oxygen / glucose to (cancer) cells;

'Reduces cell division' on its own should not be credited.

2.Less carcinogens;

3.Reduces spread of cancer (cells);

1 max

[15]

M2. (a) Endonuclease / restriction enzyme;

1

(b) DNA made of base pairs;
Each base pair is same length / occupies same distance
along backbone;

2

(c) (i) Second blank box from left labelled 6;

1

(ii) Distance moved depends on length / number of base pairs /
second longest fragment / second shortest distance identified;

1

(d) 5;

1

[6]

M3. (a) mass of undifferentiated / unspecialised / totipotent cells;
uncontrolled cell division;

(not ‘repeated’)

metastasis / (cells break off and) form new tumours /
spread to other parts of body;

3

(b) cancer takes time to develop / exposure when young but cancer
triggered later; other organs destroyed before death occurs /
metastasis affects other organs;
immune system less effective in old people;
longer time of exposure to UV / accumulation of mutagenic effect;

1 max

(c) dark skin / melanin / pigment stops UV light / prevents burning;
so less cancer risk in dark skinned people / less likely to develop tumours;

(allow converse)

2

[6]

M4. (a) No cadmium;Other conditions same as cadmium-treated group;

2

(b) (i) As a measure of the effect due to cadmium /
to make a comparison;

1

(ii) Becoming more methylated;

Ignore later slight decrease/no change

1

(iii) Production of more methyltransferase enzyme /
increased activity of transferase;

Extra incorrect relevant information - cancel

1

(c) RNA-polymerase could not bind (to DNA / to promoter);mRNA of p16 could not be made / no transcription of p16 gene;

2

(d)Any four from:1. Cadmium causes expression of methyltransferase gene /
increased activity transferase (from 2 to 3 weeks in);2. Methyl groups on to promoter / p16 gene / suppressor (gene);3. (p16) normally suppresses tumour growth;4. p16 protein / p16 expression falls after 4 weeks / after methylation;5. Tumour formation occurs (after 10 weeks) after p16 falls /
after suppressor gene activity falls;

4 max

[11]

M5.(a) 1.Carriers are heterozygous / have one normal copy and one mutant copy of gene / have one recessive allele / don't have the condition;

2.Both have DNA that binds (about) half / 50% amount of probe (that non-carrier does);

3.Probe binds to dominant / healthy allele so only one copy of exon in their DNA / have one copy of gene without exon / base sequence for probe to bind to;

3. Accept normal and gene

3. Accept have a deletion mutation

3

(b) 1.Introns not translated / not in mRNA / (exons) code for amino acids / introns do not code for amino acids;

1. Accept not expressed

1. Accept polypeptide / protein for amino acids

2.Mutations of these (exons) affect amino acid sequences (that produce) faulty protein / change tertiary structure of protein;

2. Accept deletion leads to frameshift

2. In this context, accept affects protein made

3.So important to know if parents’ exons affected, rather than any other part of DNA / introns;

Accept converse arguments involving - eg introns do not code for amino acids / proteins

Reject references to making amino acids, once

3

(c) 1.Restriction mapping / described;

2.DNA / base sequencing (of fragments) / description / name of method;

2

[8]

M6. (a) Correct answer: 1.25;

Ignore working

OR(if wrong answer)

/ = 1 mark

125 but wrong order of magnitude = 1 mark

2

(ii)C has myosin / thick (and actin / thin) filaments;

OR

A has only actin / thin (/ no myosin / no thick) filaments;

1 max

(b) When contracted:

Thick & thin filaments/myosin & actin overlap more;

Interaction between myosin heads & actin / cross-links form;

Movement of myosin head;

Thin filaments / actin moved along thick filaments / myosin;

Movement of thin filaments / actin pulls Z-lines closer together;

Displacement of tropomyosin to allow interaction;

Role of Ca2+;

Role of ATP;

Allow ref. to ‘sliding filament mechanism’ /
described if no other marks awarded

4 max

(c) (i) 8 has DMD but 3 and 4 do not / 12 has DMD but 6 and 7
do not / neither parent has the condition but their child has;

Allow parents 3 and 4 give 8, parents 6 and 7 give 12

1

(ii) 4 AND 7;

1

(iii) Parental genotypes: 6 = XDY AND 7 = XDXd

AND

Gametes correct for candidate’s P genotypes ‒ e.g.

XDand Y + XDandXd;

Offspring genotypes correctly derived from gametes e.g.

XDXD+ XDXd+ XDY + XdY;

Male offspring with MD correctly identified: XdY;

Probability = 0.25 / correct for candidates offsprings genotypes;

Accept ¼ / 1 in 4 / 1:3 / 25%

NOT ‘3:1’ / ‘1:4’

4

(d) (i) No gene fragment G;

1

(ii) Only one copy of gene fragment F;

Male has only one X-chromosome / is XY
(c.f. female has two / is XX);

2

(iii) 10 has only one copy of gene fragment G;

10 has only one normal X-chromosome / has one abnormal /
has only one normal allele / has one Xd/ is XDXd/ is heterozygous;

11 has two normal X-chromosomes / has 2 normal alleles /
is XDXD/ has not got Xd/ has 2 copies of (F and) G;

3

(e) (i) To prevent rejection / prevent antibody production vs. injected cells /
injected cells have (foreign) antigen (on surface);

1

(ii) Shows effect of cells / not just effect of injection / not just effect of
salt solution;

1

(iii) Only one person tested so far ‒ need more to see if similar results /
need more to see if reliable;

Need to assess if new (dystrophin positive) muscle fibres are
functional / if muscle becomes functional;

Can’t tell how widespread effect is in the muscle / sample taken
near injection site;

Need to test for harmful side effects;

Need to test if successful for other mutations of dystrophin gene;

Need to assess permanence / longevity of result/insufficient time
allowed in investigation;

(In this patient) only small response / %;

Further sensible suggestion;

4 max

[25]

M7. (a) Cocaine (binding) changes shape of transporter/prevents dopamine binding;

Reject references to active site

Transporter cannot move (bound) dopamine (through membrane / protein /
into cell);
Dopamine remains / builds up in synapses (leading to feelings of pleasure);

3

(b) (i) Polymerase chain reaction / PCR;

1

(ii) Single-stranded DNA;

Reject reference to a single strand of DNA

Bases / sequence complementary to DNA / gene to be identified;

(Radioactively / fluorescent) labelled so that it can be detected;

2 max

(c) Mutation changes base sequence of gene / DNA;

Accept references to active site

(Thus) changing amino acid sequence;
Changes tertiary structure / shape of protein/transporter;
Cocaine binding site changes/cocaine cannot bind;
Dopamine can still bind (and be transported);

3 max

[9]

M8.(a) 1.No effect at 25°C

The question only refers to plants with GB

1. Reject same mass

2.Keeps growing at 30°C and 35°C / up to 35°C (more than without GB);

3.Above 35°C, falls but grows more than plant without GB;

3. Accept at all temperatures above 25°C more growth than without GB

2 max

(b) (i)Significantly different / SEs do not overlap ;

Accept converse without GB

1

(ii)(As temperature increases,)

1.Enzyme activity reduced / (some) enzymes denatured;

2.Less photosynthesis, so fewer sugars formed;

3.Less respiration / less energy / ATP for growth;

4.Less energy for named function associated with growth

4. Eg mitosis, uptake of mineral ions

4

(c) 1.(Rubisco activase attaches to thylakoid and) this changes shape / tertiary structure (of enzyme) / blocks active site / changes active site;

Note - question states enzyme stops working when it attaches to thylakoid, not before

1. Accept rubisco in this context

2.(This) prevents substrate / RuBP entering active site / binding;

2. Accept prevents ES complex forming

2. Accept no longer complementary to substrate / RuBP

2

(d) 1.GB prevents / reduces binding of rubiscoactivase to (thylakoid membrane);

1. Accept enzyme instead of rubiscoactivase. Accept rubisco

2.(Prevents it) up to 35°C;

3.(So) rubiscoactivase / enzyme remains active;

4.(So) photosynthesis / light-independent stage still happens;

4. Accept descriptions of light-independent stage

5.Above 35°C, some binding still occurs but less than without GB, so less reduction in growth;

4 max

(e) 1.Looked for information / journals, on crop plants that grow at high temperatures;

1. “other research” is minimum accepted

1. Accept previous experiments research with temperature resistant crops

Ignore simple references to looking at previous studies / other plants - need to relate to this context

2.(Crop plants cited in this research) contain / make GB;

3.So assumed making plants produce GB makes them resistant to high temperatures;

2 max

[15]

M9.(a) 1.To allow comparison;

2.Because different number of cells in samples / different times for incubation / numbers become easier to manipulate;

2

(b) 203.7(%);;

Allow 1 mark for 21.8 / 10.7

Allow 1 mark for correct answer (203.74) but not correctly to 1 dp

204 = 1 mark

2

(c) (i)1.(At every concentration) uptake is faster at 37°C / at higher temperature;

2.Due to faster respiration / ATP production;

2

(ii)1.Uptake at 37°C only small increase / levelling off / almost constant as carrier proteins full;

Accept ‘no (significant) change’

Ignore use of numbers

2.Concentration of imatinib is not the limiting factor;

2

[8]

M10.(a) 1.Rank all STs in ascending order;

2.Find value with same number (of people) above and below.

Accept find middle value

2

(b) Not ethical to fail to treat cancer.

1

(c) Yes since with ipilimumab:

1.Median ST increased by 2.1 months;

2.Percentage of patients showing reduction in tumours increased from 10.3% to 15.2%;

No because:

3.No standard errors shown / no (Student) t- test / no statistical test carried out;

4.(So) not able to tell if differences are (statistically) significant / due to chance (alone);

5.Improvement might only be evident in some patients / no improvement in some patients;

6.Quality of (extra) time alive not reported;

If answers relate only to ‘Yes’ or ߢNo’, award 2 marks max

4 max

(d) 1.Faulty protein recognised as an antigen / as a ‘foreign’ protein;

2.T cells will bind to faulty protein / to (this) ‘foreign’ protein;

3.(Sensitised) T cells will stimulate clonal selection of B cells;

4.(Resulting in) release of antibodies against faulty protein.

3 max

[10]

M11.(a) 1.Methylation prevents transcription of gene;

2.Protein not produced that prevents cell division / causes cell death / apoptosis;

3.No control of mitosis.

3

(b) 1.Scatter graph;

2.Fat on x axis and death rate on y axis;

3.(Because) looking at relationship between two discrete / independent variables.

3

(c) 1.(Trend) shows positive correlation / shows the more fat in diet, the higher death rate from breast cancer;

2.But number of points off line / anomalies.

2

[8]

M12.(a) 1. Removes (main / largest) source of oestrogen / (different) mice produce different amounts of oestrogen;

Accept: so oestrogen from ovaries not a confounding variable − idea of.

2. (Allows) oestrogen to be controlled / oestrogen to be made by aromatase only / only oestrogen made in lungs to be involved.

Reject: references to injection of aromatase.

2

(b) 1. (Anastrozole) prevents / reduces oestrogen production;

2. (Fulvestrant) stops remaining oestrogen binding / less oestrogen binds to receptors.

Note: brackets around drug names.

2

(c) (Yes for Group T)

1. Least tumours per animal (from fig. 1);

Accept: ‘mean values’ for tumour area.

2. Lowest (mean) tumour area / size (from fig. 2);

3. Lowest top of range;

(But)

4. Means (tumour area) are similar;

Where candidates confuse range and standard deviation, do not give credit.

5. Ranges overlap / share values so differences may not be real / treatments may be just effective in reducing tumour;

Ignore significance

6. Range affected by outliers / SD’s would be better;

7. Done on mice / not done on women / humans;

8. Only 10 mice used per group / small sample size so may not be representative / reliable;

9. Might be side effects;

10.Only did for 15 weeks so maximum effect of drugs may not have been seen.

5 max

(d) 1. Tumours may be different depths / area does not take depth into account / tumours are 3-D / are not 2-D;

Neutral: different sizes

Accept: height / thickness for depth

2. (Measure) tumour volume / mass / weight.

2

(e) 1. Allows tumours to grow / develop / form;

Neutral: gives drug more time to work.

2. (So) can investigate treatment rather than prevention (of tumours) / when tumour / cancer is more advanced.

Accept: to see whether it can destroy / treat / stop growth of a tumour (that already exists) / to allow / assess treatment of a tumour

2

(f) 1. Unethical (not to treat patients) / may increase probability of patients dying / getting more ill;

Reject: references to giving people tumours

2. Use normal cancer drugs / treatment.

Accept: named type of cancer treatment, e.g. chemotherapy

2

[15]

M13.(a) 1. Cut (DNA) at same (base) sequence / (recognition) sequence;

Accept: cut DNA at same place

2. (So) get (fragments with gene) R / required gene.

Accept: ‘allele’ for ‘gene’ / same gene

2

(b) 1. Each has / they have a specific base sequence;

2. That is complementary (to allele r or R).

Accept description of ‘complementary’

2

(c) 1. Fragments L from parent rr, because all longer fragments / 195
base pair fragments;

Ignore: references to fragments that move further / less, require identification of longer / shorter or 195 / 135

Accept: (homozygous) recessive

2. Fragments N from parent RR, because all shorter fragments / 135 base pair fragments;

1 and 2 Accept: A3 for 195 and A4 for 135

2. Accept: (homozygous) dominant

3. (M from) offspring heterozygous / Rr / have both 195 and 135 base pair fragments.

Accept: have both bands / strips

Reject: primer longer / shorter

3

(d) 1. (Cells in mitosis) chromosomes visible;

2. (So) can see which chromosome DNA probe attached to.

2

(e) (i)1. For comparison with resistant flies / other (two) experiments
/ groups;

Ignore: compare results / data / no other factors

2. To see death rate (in non-resistant) / to see effect of insecticide in non-resistant / normal flies.

Accept: ‘pesticide’ as ‘insecticide’

Accept to see that insecticide worked / to see effect of enzyme

2

(ii)(PM must be involved because)

1. Few resistant flies die (without inhibitor);

2. More inhibited flies die than resistant flies;

3. (PM) inhibited flies die faster (than resistant flies);

(Other factors must be involved because)

4. Some resistant flies die;

5. But (with inhibitor) still have greater resistance / die slower than non-resistant flies.

Accept: (with inhibitor) die slower than non-resistant flies

4 max

[15]

Page 1