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edexcel biology ial unit 4, Exams of Biology

This comprehensive review session focuses on dissecting past biology exam papers to enhance understanding and boost exam performance. During the session, each question is analyzed in detail, covering the key concepts and methodologies required to answer effectively. We will:Break Down Complex Questions: Simplify and clarify intricate questions, making them more approachable.Provide Thorough Explanations: Offer in-depth explanations for each answer, highlighting important biological principles and processes.Discuss Common Pitfalls: Identify common mistakes and misconceptions, and provide strategies to avoid them..Encourage Active Participation: Involve participants in discussions to reinforce learning and address specific queries.Ideal for students aiming to solidify their knowledge, this review session ensures a thorough understanding of past papers, fostering confidence and readiness for future exams.

Typology: Exams

2023/2024

Available from 06/24/2024

senushi-dinara
senushi-dinara 🇱🇰

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P6545BA

(:,?021 (^) Pedrrar iid!(atio) (^) Ltd. 1i1i1/li1i1t

Please check the examination details below before entering your candidate jnformation Candidate surname Other names

Pearson Edexcel^

Centre Number Candidate Number

Level 3 GCE

You must have:

Calculator, HB pencil, ruler

Biology A (Salters^ Nuffield)

Advanced PAPER 1 : The Natural Environment and Species Survival

lnstructions

o Use black inkcr ball-point pen.

r (^) Fill in the boxes at the top of this page (^) with your (^) name, centre number^ and candidate number.

a Answer all questions.

o Show your working in any calculation questions and include units in your answer

where (^) appropriate.

o Answer the questions in the spaces provided

  • there^ may^ be^ more^ space^ than^ you^ need"

lnformation o (^) The total mark for this paper is 100. a (^) The marks for each question (^) are shown in brackets

  • use this^ as^ a^ guide^ as^ to^ how much time^ to^ spend on each question.

o You may use a scientific calculator.

o ln questions rnarked with an asterisk (*), marks will be awarded for your ability to

structure your answer logically, showing how the points that you make are related or follow on from each other where appropriate.

Advice

a Read each question carefully before you start to answer it.

a (^) Try to answer every question. I (^) Check your (^) ans,rers if you (^) have tlme (^) at the end.

a Good luck with your examination.

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Some questions must be answered^ with^ a^ cross^ in^ a^ box^ X. lf^ you change^ your mind about^ an answer, put a line through the box& and then markyour new answer with a <ross X.

Climate change has been linked to the release^ of carbon dioxide from^ some power^ stations.

(a) The main reason that carbon dioxide acts as a greenhouse gas is because it

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n D reflects ultraviolet radiation absorbed^ by^ the^ Earth's^ atmosphere

{b) Name^ the^ plant organelle that =^ fixes^ carbon dioxide from^ the^ atmosphere.

<l,loro (^) 1"pla5\ '-'

(c) Net primary productivity (NPP) is a measlrre of the increase in biomass of a plant.

Explain why respiration affects the production^ of biomass.

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(d) Some power stations burn wo*d chips inrtead of forsilfuels to produce *lectrieity.

The photcgraph^ shows wcod chips at a power station.

o Mr. Amarin Jitnathum/Shutterstock

It is thcught that burning wood chips is more beneficial to the environment

because in the long term it does not add carbon dioxide to the atmosphere.

Explain why burning wood chips does not increase carbon dioxide to the

atmosphere in the lcng term.

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Skulls can be used as evidence for human *volution.

The only type^ of human^ present^ today^ is^ the^ modern^ human.^ ln^ the^ past,^ another

type of human, called Neanderthal, occupied the same geographical^ area.

The photograph^ shows^ the^ skulls^ of both^ types^ of human.

Modern human skull Neanderthal skull O hairymuseummatt/DrMikeBaxter

Genetic studies now show that these two types of human have interbred.

(a) Only small quantities of DNA can be extracted fror"n the remains af Neanderthal hurfrans.

The quantity^ of extracted DNA^ is amplified using |. (^) : n A DNA profiling

A B polymerase chain reaction ,

n C RNA profiling

n (^) D translation chain reaction

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these two types 0f human.

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interbreeding between the two types of human.

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3 During the civilwar^ in^ Mozambique,^ from^1977 to^ 1992,9}a/o^ of the^ African^ elephants

were killed for the ivory^ in^ their^ tusks.

Since 1992,^ the elephant population in Mozambique^ has^ increased.

The photograph shows a^ group of elephants in^ Mozambique.

Elephant

without tusks

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A study of an elephant population in Mozambique^ was carried^ out^ in^ 2017.

The elephants studied^ were all^ born before^ 1992'

The table shows^ the^ number of^ elephants^ with^ ind^ without^ tusks.

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with tusks

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i,,-, Elephants^ {'. Numuerof^ elephants '

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(a) The presence of tusks^ is^ controlled^ by^ a^ singte^ gene.^ The^ allele^ for^ tusks^ is^ known

to be dominant.

The frequency of alleles^ in^ a^ population^ can be^ determined^ using^ the

Hardy-Weinberg equation.

Calculate the frequency of the dominant^ and^ recessive^ alleles^ in this population.

Give your^ answer^ to^2 decimal^ places'

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Frequency of the recessive^ allele^ ........-..-?^ t^?^!^.

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(b) In most African elephant populations ,2o/o to 4olo of elephants do not grow tusks.

(i) (^) Explain why the percentage of elephants without tusks in Mozambique will probably increase in the future.

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(ii) (^) Describe how the Hardy-Weinberg equation can be used to provide evidence for changes in the elephant population in Mozambique.

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4 Fertilisation in humans^ involves^ the fusion^ of^ a^ sperm cell^ with^ an^ egg^ cell.

(a) (i) After the sperm cell nucleus fuses with the egg cell nucleus,^ the^ single fertilised cell is^ described as^ a

n A diploid gamete

haploid gamete

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(b) Cell division of the fertilised cell produces a ball of totipctent cells.

(i) (^) Give the meaning of the term totipotent cell. {:)

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{iii This ball^ of^ cells^ continues^ to^ divide to form^ th*^ embryo.^ The cells^ of^ the

*mbryo become specialised to form^ t:ssues and organs.

Describe how^ cells^ become specialised.

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(c) Factors such as the diet of the rnother during pregnancy can {ause epigenetic

changes in the embryc"

Explaln how^ epigen*tic changes affect^ the development^ of tissues^ In^ the^ enrbryo.

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{Tatal for^ Question 4 = 10 marks}

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$ tffildlife {onservation can involve keeping animals in zoos as well as protecting^ habitats.

(a) Describe the roles that zoos play in animal conservation.

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(b) Habitats can be destroyed by road building.

A link road is planned to connect two major roads.

The diagram shows the two possible^ sites for the link road and two woodland habitats.

II I (^) -,f II

major road

lrom digeaseE

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(i) (^) State what is meant by the term habitat.

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(ii) To decide which of the two link roads should be buitt, studies of the

biodiversity of woodlands P and Q need to be carried out.

Discuss what information needs to be colletted from the two woodlands to

make a decision about the site of the link road.

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Hereditary spherocytosis is a^ condition^ that^ affects red^ blood^ cells.

This inherited condition is raused by a gene mutation that affects the shape of the

cellsurface membrane.

{a} Describe^ the structure^ of^ the^ cell surface membrane.

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l.-,1\x', ib]^ The red^ blosd^ cells^ of indivlduals^ with^ spher{ytssis ar^ spherical^ ir:rstead^ of having a biconcave disc sh*pe.

Explain the effect^ *f^ spherocytosis^ on the^ uptakeof^ oxygen^ hy red^ bload^ cells. ,".|

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{c) Most^ cases^ sf^ hereditary^ spherocytosis^ are^ cau,c€d^ by a^ dominant^ albie,

Use a'genetic diagram to determine the probability^ of a child inheriting this conditi*n

if one parent^ is heteroeygous and the other parent^ does^ not^ have^ the condition.

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$,tr, The stems *f plants contain tissues

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(i) (^) Which labelled structure in the photograph contains lignin? {r} n Ar

N BF

rel N DH

{ii) The^ diagram^ shows^ a^ transvers€ section^ through^ a^ plant^ stqp,

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Which of the^ labelled^ structures in^ the^ photograph^ is^ located in the^ area

labelled J in the diagram?

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e plant stem.

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(h) The photograph shows a cross section of part of the stem of a plant.

Fibres can be extracted from stems similar to this one and used instead of fibres

produced from oil-based plastics.

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(i) (^) The part (^) of the stem labelled L contains

tr A phloem that transports organic (^) rotut"i M

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ffi A^ phloem that transports^ organie^ solutes^ ;

tr B sclerenchyma fibres thattransportwater.9> 5 cleve (^) n chl^ - a

n (^) C sieve tubes that synthesise organic solutes ) (^) tra (^) n :y r'j-' ' ' n D xylem vessels that transport water and mineral ians N

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{iii) The^ structure labelled^ N^ is^ a

El A part of the phloem that transports water

ffi B sclerenchyma fibre that provides (^) support

E C sieve tube that transports organic solutes

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(M The line labelled X on the photograph represents the width of the vascular bundle.

The actual width of the vascular bundle is 320pm.

Calculate the magnification (^) of the image. j.i

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Explain why the production^ of fibres from nettles is more sustainable than fibres

produced from crude oil. {3}

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E Penicillin is^ an antibi*tic.^ lt^ was^ discovered^ in^ 1928"^ Since^ then^ many^ antibiotics^ have been identified and are widely used in the treatment of hacterial infections.

{a} State^ what^ is^ meant^ by^ the term bacteriostatic^ antibi*tic.

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(bi (^) Scientists have recently disc*rrered a Rew class of antibiotics that bind to ribssomes.

(i),Explainwhytheseantibioticscouldaffecttheproductionofproteinsinbacteria.*,

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(ii) These new antibiotics attach to a site on the ribosome not affected by any

known antibiotics.

Deduce why these new antibiotics might be used to treat bacteria that are

resistant to other antibiotics.

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*(iii) (^) Scientists have isolated these new antibiotics and tested (^) their effectiveness

against bacteria that are resistant to other types of antibiotic.

Devise a laboratory procedure to compare the effectiveness of penicillin with

one of the new antibiotics.

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(Total for Question I = 12 marksl

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The human immunocleficiency virus^ (HlV),^ shown^ in^ the image, causes

acquired immunodeficiency syndrome (^) {AIDS).

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(a) HIV particles contain

n A DNA and DNA polymerase

tl B DNA and reverse transcriptase

I C RNA and DNA polymerase

q (^) D RNA and reverse transcriptase

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{b) HIV^ enters^ and^ destroys^ T^ helper^ cells.^ This can^ cause^ AIDS.

(i) (^) Describe haw HIV particles (^) are able to enterT helper cells.

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{ii} Exptain^ why^ the d€structifi^ of T^ helper (ells^ eailss^ th^ symptms^ of^ Al*5"

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{c) A^ snralt^ number of people^ have^ been identified who^ are^ resistant^ to^ HlV.

They have a mutation in^ a gene cadinE^ for^ a protein^ in^ the cell membrane.

(i) (^) Dedute why this mutation makes these people (^) resistant to HIV infection. {}}

can* (^) bin/ wi+h Hfv Yeceptor 5o vira\ RNA^ cann'o-f

(iii (^) Stem cell therapy can be used to treat patients infected with HlV.

The (^) bone marrow of these patients can be destroyed using radiotherapy.

The patients^ can then be given stem cells from the bone marrow of a donor

who has this mutation.

Explain why these stem cells may prevent^ HIV causing AIDS. (,4]

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(Total (^) for (^) Question 9 * (^14) markel

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I0 Anthropogenic climate change is^ linked to an increase^ in carbon dioxide in the atmospher*.

(a) (^) The World Meteorologiral Association recorded carban dioxide levels af 405 ppm

in2A17.

This is an increase a€ 46a/o since '1817.

Calculate the level of carhon dioxide in 1817. {ft}

x ++6 = Loe

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