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$: missestruch.com€¦ · Web viewCreated by the \'abHTML to RTF .Net\'bb 5.8.2.9 Topic 6 GCSE Past Paper questions, Mark=124 Time allowed=130 Q1. Figure 1 shows a type of camel called$
Topic 6 GCSE Past Paper questions,

Mark=124 Time allowed=130

Q1.Figure 1 shows a type of camel called a dromedary (Camelus dromedarius).

The dromedary lives in hot, dry deserts.

(a) One adaptation of the dromedary is ‘temperature tolerance’.

This means that the animal’s body temperature can rise by up to 6 °C before it starts to sweat.

Explain how temperature tolerance can help the dromedary to survive in the desert.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(2)

(b) Three more adaptations of the dromedary are given in Figure 1.

Give a reason why each adaptation helps the animal survive in the desert.

Fat store ___________________________________________________________

___________________________________________________________________

MissEstruch.com Page 1 of 40

Produces little urine and very dry faeces __________________________________

___________________________________________________________________

Hard mouth _________________________________________________________

___________________________________________________________________(3)

There are several species of the camel family alive today.

Scientists think these species evolved from a common ancestor that lived in North America about 45 million years ago (Mya).

Figure 2 shows:

• where four modern species of the camel family live today

• how the ancestors of these camels migrated from North America.

(c) Which two of the four modern species of camel do scientists believe to be most closely related to each other?

Give the reason for your answer.

_____________________________ and _____________________________

Reason ____________________________________________________________

___________________________________________________________________(1)


(d) Describe the type of evidence used for developing the theory of camel migration shown in Figure 2.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(2)

(e) Explain how several different species of camel could have evolved from a common ancestor over 45 million years.

(6)(Total 14 marks)

Q2.In humans, chromosome X and chromosome Y are the sex chromosomes.

(a) Most cells in the human body contain two sex chromosomes.

Which type of cell does not have two sex chromosomes?

Tick one box.

Liver cell

Muscle cell

Nerve cell

Red blood cell

(1)

(b) Apart from the sex chromosomes, how many other chromosomes are there in most human body cells?

Tick one box.

21 23 44 46

(1)

Stickler syndrome is an inherited disorder that causes damage to the eye.

One of the symptoms of Stickler syndrome is that black spaces can appear in the visual image.

(c) Which part of the eye is affected by Stickler syndrome?


Tick one box.

Ciliary muscles

Iris

Retina

Suspensory ligaments

(1)

Stickler syndrome is caused by the inheritance of a dominant allele.

The diagram shows the inheritance of Stickler syndrome in two families.

Use the following symbols in your answers to (d) and (e):A = the dominant allele for Stickler syndromea = the recessive allele for unaffected vision.

(d) Explain why none of the children of persons 7 and 8 have Stickler syndrome.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(2)

(e) Person 12 marries person 18.

Use a Punnett square diagram to find the probability that their first child will be a female with Stickler syndrome.


Probability of a female child with Stickler syndrome = ________________________(4)

(Total 9 marks)

Q3.Our understanding of genetics and inheritance has improved due to the work of many scientists.

(a) Draw one line from each scientist to the description of their significant work.

Scientist Description of significant work

Carried out breeding experiments on pea plants.

Charles Darwin

Wrote 'On the origin of species'.

Alfred Russel Wallance

Worked on plant defence systems.

Gregor Mendel

Worked on warning colouration in animals.

(3)

(b) In the mid-20th century the structure of DNA was discovered.

What is a section of DNA which codes for one specific protein called?

___________________________________________________________________(1)

(c) Figure 1 shows one strand of DNA.

The strand has a sequence of bases (A, C, G and T).

Figure 1

How many amino acids does the strand of DNA in Figure 1 code for?

Tick one box.

2


3

4

6

(1)

(d) Mutations of DNA cause some inherited disorders.

One inherited disorder is cystic fibrosis (CF).

A recessive allele causes CF.

Complete the genetic diagram in Figure 2.

• Identify any children with CF.

• Give the probability of any children having CF.

Each parent does not have CF.

The following symbols have been used:

D = dominant allele for not having CF

d = recessive allele for having CF

Figure 2

Probability of a child with CF = _____________________(3)

(e) What is the genotype of the mother shown in Figure 2?

Tick one box.

Heterozygous

Homozygous dominant


Homozygous recessive

(1)(Total 9 marks)

Q4.This question is about the cell cycle.

(a) Chromosomes are copied during the cell cycle.

Where are chromosomes found?

Tick one box.

Cytoplasm

Nucleus

Ribosomes

Vacuole

(1)

(b) What is the name of a section of a chromosome that controls a characteristic?

___________________________________________________________________(1)

Figure 1 shows information about the cell cycle.


(c) Which stage of the cell cycle in Figure 1 takes the most time?

Tick one box.

Cell growth

Copying of chromosomes

Mitosis

(1)

(d) During mitosis cells need extra energy.Which cell structures provide most of this energy?

Tick one box.

Chromosomes

Cytoplasm

Mitochondria

Ribosomes

(1)

(e) The cell cycle in Figure 1 takes two hours in total.The cell growth stage takes 45 minutes.

Calculate the time taken for mitosis.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

Time = ____________________ minutes(2)

Figure 2 shows some cells in different stages of the cell cycle.



(f) Which cell is not dividing by mitosis

Tick one box.

(1)

(g) Cell E in Figure 2 contains 8 chromosomes.Cell E divides by mitosis.

How many chromosomes will each new cell contain?

Tick one box.

2

4

8

16

(1)

(h) Why is mitosis important in living organisms?

Tick one box.

To produce gametes


To produce variation

To release energy

To repair tissues

(1)(Total 9 marks)

Q5.The diagram shows how scientists can use genetic engineering to produce human growth hormone.

(a) Human growth hormone is made by the pituitary gland.


The human DNA containing the gene for growth hormone can be taken from a white blood cell.

Give the reason why the gene does not have to be taken from cells in the pituitary gland.

___________________________________________________________________

___________________________________________________________________(1)

The figure above shows that the plasmid contains two genes for antibiotic resistance:• a gene for resistance to the antibiotic ampicillin• a gene for resistance to the antibiotic tetracycline.

(b) Explain how the structure of Enzyme 1 allows it to cut the gene for tetracycline resistance, but not the gene for ampicillin resistance.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(3)

(c) In the final step of the diagram above, very few bacteria take up a plasmid containing the gene for growth hormone.

Some bacteria take up an unmodified plasmid.

Most bacteria do not take up a plasmid.

Complete the table below.• Put a tick in the box if the bacterium can multiply in the presence of the

given antibiotic.• Put a cross in the box if the bacterium cannot multiply in the presence of the

given antibiotic.

Bacterium can multiply in the presence of

Ampicillin Tetracycline

Bacterium + plasmid with growth hormone gene

Bacterium without a plasmid

Bacterium with an unmodified plasmid

(d) The figure above shows that the bacterium containing the gene for human growth


hormone multiplies by cell division.

This produces a clone of bacteria.

Explain why all the bacteria in this clone are able to produce growth hormone.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(3)

(Total 10 marks)

Q6.Fossils give evidence about organisms that lived a long time ago.

(a) Scientists have found very few fossils of the earliest life forms.

Give one reason why.

___________________________________________________________________

___________________________________________________________________(1)

Below is a photograph of a fossilised fish.

(b) Suggest how the fossil in the photograph above was formed.

___________________________________________________________________

___________________________________________________________________


___________________________________________________________________

___________________________________________________________________(2)

(c) The species of fish shown in the photograph above is now extinct.

Give two possible causes of extinction.

1. _________________________________________________________________

___________________________________________________________________

2. _________________________________________________________________

___________________________________________________________________(2)

Modern fish species have evolved from fish that lived a long time ago.

Evolution is caused by mutation and natural selection.

(d) What is a mutation?

Tick one box.

A change in a gene

Accidental damage to an organism

An organism with a new characteristic

The loss of a species

(1)

(e) Describe the process of natural selection.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(3)

(Total 9 marks)


Q7.Blood is filtered in the kidneys.

Some substances are then reabsorbed.

The amount of each substance reabsorbed varies.

Each day, a person:• filters 180 dm3 of water out of the blood• produces 2 dm3 of urine.

The diagram shows the process of filtration in the kidney.

(a) Explain why protein is not found in the urine of a healthy person.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(2)

(b) Explain why glucose is not found in the urine of a healthy person.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(2)

(c) Explain:• why urea and sodium ions are found in urine• why their concentration is higher on a hot day than on a cold day.


___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(3)

(d) The information below gives some features of two types of treatment for kidney disease.

Dialysis treatment

• A dialysis session lasts about 8 hours.

• A person needs 3 dialysis sessions every week for the rest of their life.

• The person must have a diet low in protein and salt.

• Dialysis costs £30 000 per year.

Kidney transplant

• A kidney transplant requires surgery using general anaesthetic.

• A suitable kidney donor is needed.

• Drugs are used to suppress the immune system.

• A transplant, and the first year’s medical care, costs £51 000.

• After the first year, the cost of drugs is £5 000 per year.

Evaluate the use of a kidney transplant instead of dialysis treatment for kidney disease.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(6)


(Total 13 marks)

Q8.Living organisms are classified into the following groups:• Kingdom• Phylum• Class• Order• Family• Genus• Species

(a) Which scientist first suggested this type of classification system?

Tick one box.

Alfred Russel Wallace

Carl Linnaeus

Charles Darwin

Gregor Mendel

(1)

The stone plant, Lithops bromfieldi, is adapted to live in very dry deserts.

Figure 1 shows several stone plants.


(b) Give the genus to which the stone plant belongs.

____________________________(1)

(c) The stone plant has many adaptations that help it to survive in the desert.

Draw one line from each adaptation to how the adaptation helps the stone plant to survive.

(4)

The jerboa is a small desert animal.

Figure 2 shows a jerboa.


The jerboa is adapted for survival in the desert.The jerboa spends the daytime in its underground burrow.The jerboa only leaves its burrow to look for food during the night.

(d) Describe how these adaptations help the jerboa to survive in the desert.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(2)

(e) What type of adaptations are described in Question (d)?

Tick one box.

Behavioural

Functional

Structural

(1)(Total 9 marks)

Q9.Fossils provide evidence about organisms that lived a long time ago.

(a) Give one way a fossil may be formed.

___________________________________________________________________

___________________________________________________________________(1)

Figure 1 shows the fossils of two species of ammonite.



(b) Use a ruler to measure the diameter of P and the diameter of Q in millimetres.

Diameter of P = ____________________ mm

Diameter of Q = ____________________ mm(1)

(c) Calculate the diameter of the real fossil of ammonite Q.

Use your answer to part (b) and the scale factor given in Figure 1.

___________________________________________________________________

___________________________________________________________________

Diameter of the real fossil of ammonite Q = ____________________ mm(1)

(d) How many times larger is ammonite Q compared to ammonite P?

Tick one box.

0.4 0.8 1.25 2.5

(1)

(e) Describe two ways the fossil of ammonite Q is different from the fossil of ammonite P.

Do not give answers referring to size.

1. _________________________________________________________________


___________________________________________________________________

2. _________________________________________________________________

___________________________________________________________________(2)

(f) Figure 2 shows:• four layers of rock, A, B, C and D• where the fossils of ammonites P and Q were found.

Which statement is evidence that ammonite Q may have evolved from ammonite P?

Tick one box.

P and Q are both found in limestone.

Q was found in newer rocks than P.

P is a darker colour than Q.

Q has a smaller mass than P.

(1)

(g) Suggest how long ago ammonites P and Q were alive.

Tick one box.

100 years

1000 years


100 million years

100 billion years

(1)

(h) Ammonites are now extinct.

Suggest three possible causes of extinction.

1. _________________________________________________________________

___________________________________________________________________

2. _________________________________________________________________

___________________________________________________________________

3. _________________________________________________________________

___________________________________________________________________(3)

(i) Give one reason why scientists cannot be sure about what caused the ammonites to become extinct.

___________________________________________________________________

___________________________________________________________________(1)

(Total 12 marks)

Q10.In the mid-19th century, a scientist studied inheritance in pea plants.

The scientist’s work was the beginning of our modern understanding of genetics.

(a) What is the name of this scientist?

Tick one box.

Alfred Russel Wallace

Charles Darwin

Gregor Mendel

Jean-Baptiste Lamarck


(1)

(b) In the mid-20th century, other scientists identified the chemical substance that makes up genetic material.

What is the name of the chemical substance that makes up genetic material?

Tick one box.

Carbohydrate

DNA

Lipid

Protein

(1)

(c) A gene often has two alleles.

One allele is dominant and the other allele is recessive.

When is a recessive allele expressed as a characteristic?

Tick one box.

When the dominant allele is not present

When the recessive allele is inherited from the female parent

When the recessive allele is inherited from the male parent

When the recessive allele is present on only one of the chromosomes

(1)

A scientist investigated the inheritance of height in pea plants.

The scientist crossed tall pea plants with short pea plants.

Figure 1 shows the scientist’s results.

Figure 1



All tall offspring

In questions (d) and (e), use the following symbols to represent alleles:

T = the dominant allele for tall.t = the recessive allele for short.

(d) In Figure 1, the genotype of plant 1 is TT.

Give the genotype of plant 2.

__________________________(1)

(e) The scientist crossed plant 3 with plant 4.

Complete Figure 2 to show the offspring produced from this cross.

Figure 2


(2)

(f) Draw a circle around one of the homozygous offspring in Figure 2.(1)

(g) What is the ratio of tall plants : short plants in the offspring in Figure 2?

Ratio of tall plants : short plants = _______________ : _______________(1)

(Total 8 marks)

Q11.Chromosomes carry genetic information.Chromosomes are found in nearly all human cells.

(a) How many chromosomes are there in most human body cells?

Tick one box.

23

24

46

48

(1)

(b) How many chromosomes are there in a human gamete cell?

____________________________(1)

(c) Complete the sentences.

Choose the answers from the box.

The female gamete is called the ____________________________.

The male gamete is called the ____________________________.

The female gamete is produced in the ____________________________.


Gametes are produced by a type of cell division

called ____________________________ .

Male and female gametes join together in a process

called ____________________________ .(5)

In humans, the sex chromosomes are called X and Y.

The diagram shows the inheritance of sex chromosomes.

(d) Complete the diagram above to show the sex chromosomes inherited by the offspring.

(2)

(e) What is the chance that a child produced by these parents will be female?

Tick one box.

1 in 2

1 in 3

1 in 4

3 in 4

(1)

(f) The parents shown in the diagram above have five children.

Give two reasons why these children all look different from each other.

1. _________________________________________________________________


___________________________________________________________________

2. _________________________________________________________________

___________________________________________________________________(2)

(Total 12 marks)

Q12.Earthworms are small animals that live in soil. Earthworms have no specialised gas exchange system and absorb oxygen through their skin.

(a) What is the name of the process in which oxygen enters the skin cells?

Tick one box.

Active transport

Diffusion

Osmosis

Respiration

(1)

The table below shows information about four skin cells of an earthworm.

CellPercentage of oxygen

Outside cell Inside cell

A 9 8

B 12 8

C 12 10

D 8 12

(b) Which cell has the smallest difference in percentage of oxygen between the outside and the inside of the cell?

Tick one box.

(1)

(c) Which cell will oxygen move into the fastest?


Tick one box.

(1)

(d) Earthworms have a large surface area to volume ratio.

Suggest why a large surface area to volume ratio is an advantage to an earthworm.

___________________________________________________________________

___________________________________________________________________(1)

(e) The earthworm uses enzymes to digest dead plants.

Many plants contain fats or oils.

Which type of enzyme would digest fats?

___________________________________________________________________

___________________________________________________________________(1)

(f) Earthworms move through the soil.

This movement brings air into the soil.

Dead plants decay faster in soil containing earthworms compared with soil containing no earthworms.

Explain why.

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________

___________________________________________________________________(3)

(g) When earthworms reproduce, a sperm cell from one earthworm fuses with an egg cell from a different earthworm.

Name the process when an egg cell and a sperm cell fuse.

___________________________________________________________________(1)


(h) Some types of worm reproduce by a process called fragmentation.

In fragmentation, the worm separates into two or more parts. Each part grows into a new worm.

What type of reproduction is fragmentation?

___________________________________________________________________(1)

(Total 10 marks)


Mark schemes

Q1.(a) less sweating so less water loss

1

(as) no / little water available in desert1

(b) (fat store) can be metabolised / respired to water1

(little urine…) conserve water1

(hard mouth) not damaged by spines on plants / on foodornot damaged by hard / dry food

1

(c) dromedary / C.dromedariusand bactrian / C. bactrianus

no mark for the names, but must be identifiedbecausesame genus

ignore ‘both are Camelus’1

(d) any two from:

• the fossil record• oldest fossils in N. America

or• newer fossils in S. America / in Asia / in Africa

allow numbers for ages (45 Mya and 3 Mya / 6 Mya)

• chemical / DNA analysis of living speciesallow radioactive dating of fossils

2

(e) isolation of separate camel populations by seaorby mountains

1

habitat variation / described between populationsallow examples – biotic (e.g. food / predators) or abiotic

1

genetic variation / mutation in each population1

45 million years is sufficient time to accumulate enough mutations1

natural selectionor


better adapted survive to reproduce1

pass on favourable allele(s)allow gene(s)

1[14]

Q2.(a) red blood cell

1

(b) 441

(c) retina1

(d) 7 and 8 / the parentsdo not have A (allele)or only have a (allele) or are aa

allow converse – if parents had an A (allele) they would have Stickler syndrome

1

so children cannot inherit Aor can only inherit a

or

the parents show the recessive characteristic

so must be homozygous(recessive)or must be aaor parents cannot have A

1

(e) parental genotypes:12 = Aa and 18 = aa

or parental gametes:12 = A + a and 18 = a + a

1

derivation of offspring genotypesallow ecf

1

identification of Aa offspring as Stickler1

probability = 0.25 / / 1 in 4 / 25% / 1:3allow ecf – e.g. 0.5 if 12 = AAdo not accept 3:1do not accept 1:4

1


[9]

Q3.(a)

3

(b) a geneallow allele

1

(c) 41

(d) correct derivation of children’s genotypes1

identification of children with cystic fibrosis (dd)1

0.25allow ecfallow ¼ / 25% / 1 in 4 / 1:3

1

do not accept 1:4

(e) heterozygous1

[9]

Q4.(a) nucleus

1

(b) gene(s)allow allele(s)

1

(c) copying of chromosomes1

(d) mitochondria


1

(e) 60 − 45or120 − 105

1

15 (minutes)1

an answer of 15 (minutes) scores 2 marks

(f) C1

(g) 81

(h) to repair tissues1

[9]

Q5.(a) white blood cells have the same DNA / genes / chromosomes

orhave the gene for GH

allow have all the genesallow all body cells (except RBCs) have all of the genes

1

(b) enzyme has specifically-shaped active site1

the 2 antibiotic resistance genes have different (sequence of) bases1

only Tetracycline-resistance gene fits (active site of) enzymeoronly Tetracycline-resistance gene is complementary to (active site of) enzyme

1

(c)

Ampicillin Tetracycline

✔

✔ ✔

1 mark for each correct rowif no other mark, allow 1 mark for one correct column

111

(d) clone produced by asexual reproductionallow by ‘mitosis’

1


all DNA / all genes are copiedallow GH gene copiedallow plasmid copied

1every cell receives a copyorreceives every geneorreceives GH geneorreceives plasmidorgenetically-identical cells

1[10]

Q6.(a) (organism) soft-bodied

allow lack hard parts / skeleton / shellallow (organism) eaten / decayed

or

(fossil) destroyedallow buried (very) deepallow they are (very) small

1

(b) any two from:• the fish (dies) buried in sediment / sand / mud

allow other examples of sedimentsdo not accept rock(s)

• (only) the soft parts decayed / eaten or the hard parts / bones did not decay or were not eaten

• mineralisation occurredallow description of mineralisation e.g. bones turned to stoneallow imprinted (in the sediment)

2

(c) any two from:ignore pollution

• drought• ice age / global warming• volcanic activity

allow earthquakes / tsunami

• asteroid / meteor collision• (new) predators

allow hunters / poachersallow eaten


• (new) disease / named pathogen• competition for food

allow lack of food

• competition for matesallow isolation or lack of mates

• lack of habitat or habitat changeif no other marks awarded allow natural disaster / climate change / weather change / catastrophic event / environmental change for 1 mark

2

(d) a change in a gene1

(e) there is variation (between members of a species)allow mutation

1

better adapted surviveallow ‘survival of the fittest’

1

(reproduce and) pass on (favourable) allele(s) / gene(s) / mutation(s) / DNA / genetic material

ignore pass on characteristic(s)1

allow in terms of an example[9]

Q7.(a) (molecules are) (too) large

1cannot pass through (filtration) membrane / (holes in) filterallow ‘is not filtered out of the blood’

1

(b) glucose is reabsorbedignore ‘is absorbed’ unless qualified by ‘into blood’

1all of it

1

(c) (molecules / ions) small so pass through filterornot all is reabsorbed

allow the body needs to maintain the right balance of ions and urea in the bloodignore ‘are filtered’ unqualified

1

more water reabsorbed on a hot day1

due to more water lost in sweat


‘more’ needed at least once to gain both marks1

(d) Level 3 (5-6 marks):A judgement, strongly linked and logically supported by a sufficient range of correct reasons, is given.

Level 2 (3-4 marks):A judgement, supported by some relevant reasons is given.

Level 1 (1-2 marks):Relevant points are made. If there is a judgement, this is asserted, but not logically linked to the points made.

No relevant content (0 marks)

Indicative content

pro transplant:• (dialysis requires repeated treatments to prevent) build-up of toxins

orto prevent raised blood pressure between sessions

• inconvenience of dialysis, e.g. long sessions of immobility or repeated hospital visits

• (dialysis requires restricted diet) to prevent build-up of urea / ions• there is a greater risk of infection with dialysis e.g. repeated puncturing of skin

or use of non-sterile equipment allows entry of microorganisms• there is a risk of blood clots with dialysis• dialysis more expensive in the long term / 2+ years

orexamples given e.g. 2 yrs dialysis = £60 000 compared with 2 yrs after

transplant= (£51 000 + £5 000) = £56 000

• transplant is a long term treatment or may remain healthy for many years

con transplant:• shortage of kidney donors leading to long waiting time• requires death of another person or live donation leaving a person with just

one kidney• exploitation of poor people for donor kidneys (paying for organs)• need to match tissue type• rejection – role of wbcs / lymphocytes• need immunosuppressant drugs – susceptibility to infection• dangers of surgery – physical damage / infection / brain damage from

anaesthetic• high initial cost – limited funding (either personal or NHS / CCG)

[13]

Q8.(a) Carl Linnaeus

1

(b) Lithopsextras cancelignore capitalisation / non-capitalisation

1


(c) 1 mark per lineextra line from adaptation negates the mark for that adaptation

1111

(d) any two from:• cooler underground / at night

orthe jerboa can keep cool

• loses less waterorsweats less

• less likely to be seen (by predators / prey)2

(e) behavioural1

[9]

Q9.(a) any one from:

• animal / plant (dies and) body covered in sediment / mud• bones / shells / hard parts do not decay• minerals enter bones / parts are replaced by other materials / mineralisation• preserved traces / footprints / burrows / rootlet traces / impressions / casts

allow covered in tar / ice1

(b) (diameter P =) 60and(diameter Q =) 75

allow ± 1 mm1

(c) 150allow ecf from (b)

1

(d) 2.51

(e) any two from:• Q has fewer spirals


• Q has more (radial) ridgesallow stripes / etc

• Q’s ridges are more pronounced

• Q has more elongated shapeaccept Q is less circular / roundallow other correct descriptions

2

(f) Q was found in newer rocks than P1

(g) 100 million years1

(h) any three from:

• flooding• drought• ice age

ignore pollutionif none of these points given allow climate change / global warming / weather change / environmental change for 1 mark

• volcanic activity• asteroid collision

ignore pollutionif none of these points given allow natural disaster / catastrophic event for 1 mark

• (new) predators (allow hunters / poachers)• (new) disease / named pathogen• competition for food• competition for mates• isolation

lack of habitatorhabitat change

3

(i) lack of evidenceorcannot perform experiment to find out

do not accept no evidenceallow no proofallow no one was there to observe

1[12]

Q10.(a) Gregor Mendel

1


(b) DNA1

(c) when the dominant allele is not present1

(d) ttallow homozygous recessive

1

(e)

all 3 correct = 2 marks2 correct = 1 mark0 or 1 correct = 0 marksallow tT for Tt

2

(f) circle drawn around either TT or tt on Figure 2allow circles drawn round both

1

(g) correct ratio from part (e) e.g. 3 : 1allow multiples of stated ratioallow 3 : 1 if no answer to part (e)

1[8]

Q11.(a) 46

1

(b) 23allow ecf from 2.1 – ie half of answer given in 2.1

1

(c) egg1

sperm1

ovary1

meiosis1

fertilisation


1

correct order onlycorrect spelling only

(d) all 4 correct = 2 marks2 or 3 correct = 1 mark0 or 1 correct = 0 marksignore correct / incorrect identification of male and female offspring

2

(e) 1 in 21

(f) any two from:

• multiple genes determine appearanceallow several / many genes determine appearance

• different combinations of allelesallow description of combinations of alleles’ allow genes for alleles

• different environmental effectsallow example e.g. eat different diets

• from different egg / sperm2

[12]

Q12.(a) diffusion

1

(b) A1

(c) B1

(d) (earthworm) can absorb more oxygen (in a given time)or


increases / more gas exchangeallow get / obtain / take in more oxygenignore easier absorption of oxygenignore references to food

1

(e) lipase1

(f) more oxygen (in soil with earthworms)allow earthworms bring oxygen to soil

1

(for) more (aerobic) respirationdo not accept anaerobic respiration

1

(of) bacteria / fungi / microorganisms / microbes / decomposers1

reference to more is only needed once for the first two marking points

(g) fertilisationignore sexual reproduction

1

(h) asexual (reproduction)allow cloning

1[10]


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