Cambridge International AS A Level - PMT

This document has 20 pages. Blank pages are indicated.

© UCLES 2019 [Turn over

Cambridge International AS & A Level

BIOLOGY 9700/04Paper 4 A Level Structured Questions For examination from 2022MARK SCHEME

Maximum Mark: 100

Specimen

9700/04 Cambridge International AS & A Level – Mark Scheme For examination SPECIMEN from 2022

of 20© UCLES 2019

Gen

eric

Mar

king

Prin

cipl

es

Thes

e ge

nera

l mar

king

prin

cipl

es m

ust b

e ap

plie

d by

all

exam

iner

s w

hen

mar

king

can

dida

te a

nsw

ers.

The

y sh

ould

be

appl

ied

alon

gsid

e th

e sp

ecifi

c co

nten

t of t

he m

ark

sche

me

or g

ener

ic le

vel d

escr

ipto

rs fo

r a q

uest

ion.

Eac

h qu

estio

n pa

per a

nd m

ark

sche

me

will

als

o co

mpl

y w

ith th

ese

mar

king

pr

inci

ples

.

GE

NE

RIC

MA

RK

ING

PR

INC

IPLE

1:

Mar

ks m

ust b

e aw

arde

d in

line

with

:

•th

e sp

ecifi

c co

nten

t of t

he m

ark

sche

me

or th

e ge

neric

leve

l des

crip

tors

for t

he q

uest

ion

•th

e sp

ecifi

c sk

ills

defin

ed in

the

mar

k sc

hem

e or

in th

e ge

neric

leve

l des

crip

tors

for t

he q

uest

ion

•th

e st

anda

rd o

f res

pons

e re

quire

d by

a c

andi

date

as

exem

plifi

ed b

y th

e st

anda

rdis

atio

n sc

ripts

.

GE

NE

RIC

MA

RK

ING

PR

INC

IPLE

2:

Mar

ks a

war

ded

are

alw

ays

who

le m

arks

(not

hal

f mar

ks, o

r oth

er fr

actio

ns).

GE

NE

RIC

MA

RK

ING

PR

INC

IPLE

3:

Mar

ks m

ust b

e aw

arde

d po

sitiv

ely:

•m

arks

are

aw

arde

d fo

r cor

rect

/val

id a

nsw

ers,

as

defin

ed in

the

mar

k sc

hem

e. H

owev

er, c

redi

t is

give

n fo

r val

id a

nsw

ers

whi

ch g

o be

yond

the

scop

e of

the

sylla

bus

and

mar

k sc

hem

e, re

ferr

ing

to y

our T

eam

Lea

der a

s ap

prop

riate

•m

arks

are

aw

arde

d w

hen

cand

idat

es c

lear

ly d

emon

stra

te w

hat t

hey

know

and

can

do

•m

arks

are

not

ded

ucte

d fo

r err

ors

•m

arks

are

not

ded

ucte

d fo

r om

issi

ons

•an

swer

s sh

ould

onl

y be

judg

ed o

n th

e qu

ality

of s

pelli

ng, p

unct

uatio

n an

d gr

amm

ar w

hen

thes

e fe

atur

es a

re s

peci

fical

ly a

sses

sed

by th

e qu

estio

n as

indi

cate

d by

the

mar

k sc

hem

e. T

he m

eani

ng, h

owev

er, s

houl

d be

una

mbi

guou

s.

GE

NE

RIC

MA

RK

ING

PR

INC

IPLE

4:

Rul

es m

ust b

e ap

plie

d co

nsis

tent

ly e

.g. i

n si

tuat

ions

whe

re c

andi

date

s ha

ve n

ot fo

llow

ed in

stru

ctio

ns o

r in

the

appl

icat

ion

of g

ener

ic le

vel

desc

ripto

rs.

GE

NE

RIC

MA

RK

ING

PR

INC

IPLE

5:

Mar

ks s

houl

d be

aw

arde

d us

ing

the

full

rang

e of

mar

ks d

efin

ed in

the

mar

k sc

hem

e fo

r the

que

stio

n (h

owev

er; t

he u

se o

f the

full

mar

k ra

nge

may

be

lim

ited

acco

rdin

g to

the

qual

ity o

f the

can

dida

te re

spon

ses

seen

).


of 20© UCLES 2019

GE

NE

RIC

MA

RK

ING

PR

INC

IPLE

6:

Mar

ks a

war

ded

are

base

d so

lely

on

the

requ

irem

ents

as

defin

ed in

the

mar

k sc

hem

e. M

arks

sho

uld

not b

e aw

arde

d w

ith g

rade

thre

shol

ds o

r gra

de

desc

ripto

rs in

min

d.

Scie

nce-

Spec

ific

Mar

king

Prin

cipl

es

1 E

xam

iner

s sh

ould

con

side

r the

con

text

and

sci

entif

ic u

se o

f any

key

wor

ds w

hen

awar

ding

mar

ks. A

lthou

gh k

eyw

ords

may

be

pres

ent,

mar

ks

shou

ld n

ot b

e aw

arde

d if

the

keyw

ords

are

use

d in

corr

ectly

.

2 Th

e ex

amin

er s

houl

d no

t cho

ose

betw

een

cont

radi

ctor

y st

atem

ents

giv

en in

the

sam

e qu

estio

n pa

rt, a

nd c

redi

t sho

uld

not b

e aw

arde

d fo

r any

co

rrec

t sta

tem

ent t

hat i

s co

ntra

dict

ed w

ithin

the

sam

e qu

estio

n pa

rt. W

rong

sci

ence

that

is ir

rele

vant

to th

e qu

estio

n sh

ould

be

igno

red.

3 A

lthou

gh s

pelli

ngs

do n

ot h

ave

to b

e co

rrec

t, sp

ellin

gs o

f syl

labu

s te

rms

mus

t allo

w fo

r cle

ar a

nd u

nam

bigu

ous

sepa

ratio

n fro

m o

ther

syl

labu

s te

rms

with

whi

ch th

ey m

ay b

e co

nfus

ed (e

.g. e

than

e / e

then

e, g

luca

gon

/ gly

coge

n, re

fract

ion

/ ref

lect

ion)

.

4 Th

e er

ror c

arrie

d fo

rwar

d (e

cf) p

rinci

ple

shou

ld b

e ap

plie

d, w

here

app

ropr

iate

. If a

n in

corr

ect a

nsw

er is

sub

sequ

ently

use

d in

a s

cien

tific

ally

co

rrec

t way

, the

can

dida

te s

houl

d be

aw

arde

d th

ese

subs

eque

nt m

arki

ng p

oint

s. F

urth

er g

uida

nce

will

be

incl

uded

in th

e m

ark

sche

me

whe

re

nece

ssar

y an

d an

y ex

cept

ions

to th

is g

ener

al p

rinci

ple

will

be

note

d.

5 ‘L

ist r

ule’

gui

danc

e (s

ee e

xam

ples

bel

ow)

Fo

r que

stio

ns th

at re

quire

n re

spon

ses

(e.g

. Sta

te tw

o re

ason

s …

):

•Th

e re

spon

se s

houl

d be

read

as

cont

inuo

us p

rose

, eve

n w

hen

num

bere

d an

swer

spa

ces

are

prov

ided

•A

ny re

spon

se m

arke

d ig

nore

in th

e m

ark

sche

me

shou

ld n

ot c

ount

tow

ards

n •

Inco

rrec

t res

pons

es s

houl

d no

t be

awar

ded

cred

it bu

t will

stil

l cou

nt to

war

ds n

•R

ead

the

entir

e re

spon

se to

che

ck fo

r any

resp

onse

s th

at c

ontra

dict

thos

e th

at w

ould

oth

erw

ise

be c

redi

ted.

Cre

dit s

houl

d no

t be

awar

ded

for a

ny re

spon

ses

that

are

con

tradi

cted

with

in th

e re

st o

f the

resp

onse

. Whe

re tw

o re

spon

ses

cont

radi

ct o

ne a

noth

er, t

his

shou

ld

be tr

eate

d as

a s

ingl

e in

corr

ect r

espo

nse

•N

on-c

ontra

dict

ory

resp

onse

s af

ter t

he fi

rst n

resp

onse

s m

ay b

e ig

nore

d ev

en if

they

incl

ude

inco

rrec

t sci

ence

.


of 20© UCLES 2019

6 C

alcu

latio

n sp

ecifi

c gu

idan

ce

C

orre

ct a

nsw

ers

to c

alcu

latio

ns s

houl

d be

giv

en fu

ll cr

edit

even

if th

ere

is n

o w

orki

ng o

r inc

orre

ct w

orki

ng, u

nles

s th

e qu

estio

n st

ates

‘sho

w

your

wor

king

’.

Fo

r que

stio

ns in

whi

ch th

e nu

mbe

r of s

igni

fican

t fig

ures

requ

ired

is n

ot s

tate

d, c

redi

t sho

uld

be a

war

ded

for c

orre

ct a

nsw

ers

whe

n ro

unde

d by

th

e ex

amin

er to

the

num

ber o

f sig

nific

ant f

igur

es g

iven

in th

e m

ark

sche

me.

Thi

s m

ay n

ot a

pply

to m

easu

red

valu

es.

Fo

r ans

wer

s gi

ven

in s

tand

ard

form

, (e.

g. a

× 1

0n ) in

whi

ch th

e co

nven

tion

of re

stric

ting

the

valu

e of

the

coef

ficie

nt (a

) to

a va

lue

betw

een

1 an

d 10

is n

ot fo

llow

ed, c

redi

t may

stil

l be

awar

ded

if th

e an

swer

can

be

conv

erte

d to

the

answ

er g

iven

in th

e m

ark

sche

me.

U

nles

s a

sepa

rate

mar

k is

giv

en fo

r a u

nit,

a m

issi

ng o

r inc

orre

ct u

nit w

ill n

orm

ally

mea

n th

at th

e fin

al c

alcu

latio

n m

ark

is n

ot a

war

ded.

E

xcep

tions

to th

is g

ener

al p

rinci

ple

will

be

note

d in

the

mar

k sc

hem

e.

7 G

uida

nce

for c

hem

ical

equ

atio

ns

M

ultip

les

/ fra

ctio

ns o

f coe

ffici

ents

use

d in

che

mic

al e

quat

ions

are

acc

epta

ble

unle

ss s

tate

d ot

herw

ise

in th

e m

ark

sche

me.

S

tate

sym

bols

giv

en in

an

equa

tion

shou

ld b

e ig

nore

d un

less

ask

ed fo

r in

the

ques

tion

or s

tate

d ot

herw

ise

in th

e m

ark

sche

me.

Mar

k sc

hem

e ab

brev

iatio

ns:

;

sepa

rate

s m

arki

ng p

oint

s/

se

para

tes

alte

rnat

ives

with

in a

mar

king

poi

ntR

reje

ctI

ig

nore

mar

k as

if th

is m

ater

ial w

as n

ot p

rese

ntA

acce

pt (a

less

than

idea

l ans

wer

whi

ch s

houl

d be

mar

ked)

CO

ND

indi

cate

s m

ark

is c

ondi

tiona

l on

prev

ious

mar

king

poi

ntO

WTT

E

or w

ords

to th

at e

ffect

(acc

ept o

ther

way

s of

exp

ress

ing

the

sam

e id

ea)

AW

al

tern

ativ

e w

ordi

ng (w

here

resp

onse

s va

ry m

ore

than

usu

al)

UN

DER

LIN

E ac

tual

wor

d gi

ven

mus

t be

used

by

cand

idat

e (g

ram

mat

ical

var

iant

s ac

cept

ed)

max

indi

cate

s th

e m

axim

um n

umbe

r of m

arks

that

can

be

awar

ded

ECF

cr

edit

a co

rrec

t sta

tem

ent t

hat f

ollo

ws

a pr

evio

us w

rong

ans

wer

MP

m

arki

ng p

oint

(with

rele

vant

num

ber)

( )

th

e w

ord

/ phr

ase

in b

rack

ets

is n

ot re

quire

d, b

ut s

ets

the

cont

ext

OR

A

or

reve

rse

argu

men

t


of 20© UCLES 2019

Exam

ples

of h

ow to

app

ly th

e lis

t rul

e

Sta

te th

ree

reas

ons

... [3

]

A 1. C

orre

ct

22.

Cor

rect

3. W

rong

B (4

resp

onse

s)1.

Cor

rect

, Cor

rect

,

32.

Cor

rect

3. W

rong

igno

re

C (4

resp

onse

s)1.

Cor

rect

22.

Cor

rect

, Wro

ng

,

3. C

orre

ctig

nore

D (4

resp

onse

s)1.

Cor

rect

22.

Cor

rect

, CO

N (o

f 2.)

, (

disc

ount

2)

3. C

orre

ct

E (4

resp

onse

s)1.

Cor

rect

32.

Cor

rect

3. C

orre

ct, W

rong

F (4

resp

onse

s)1.

Cor

rect

22.

Cor

rect

3. C

orre

ct

CO

N (o

f 3.)

(d

isco

unt 3

)

G (5

resp

onse

s)1.

Cor

rect

32.

Cor

rect

3. C

orre

ct

Cor

rect

CO

N (o

f 4.)

igno

reig

nore

H (4

resp

onse

s)1.

Cor

rect

22.

Cor

rect

3. C

ON

(of 2

.)

Cor

rect

(dis

coun

t 2)

I (4

resp

onse

s)1.

Cor

rect

22.

Cor

rect

3. C

orre

ct

CO

N (o

f 2.)

(d

isco

unt 2

)


of 20© UCLES 2019

Que

stio

nA

nsw

erM

arks

1(a)

(i)E

ukar

ya ;

1

1(a)

(ii)

any

one

from

: 1

habi

tat d

estru

ctio

n / h

abita

t fra

gmen

tatio

n / d

efor

esta

tion

/ log

ging

;

2 di

seas

e ;

3 hu

ntin

g ;

4 AV

P ;

e

.g. l

ow g

enet

ic d

iver

sity

/ la

rge

rang

e an

d lo

w p

opul

atio

n de

nsity

1

1(a)

(iii)

any

thre

e fro

m:

1 ca

ptiv

e br

eedi

ng /

AW ;

2 re

leas

e in

to th

e w

ild ;

3 co

nser

vatio

n pr

ojec

ts (i

n M

adag

asca

r) /

esta

blis

h re

serv

es ;

4 ed

ucat

ion

/ rai

se a

war

enes

s ;

5 re

sear

ch ;

6 ve

terin

ary

care

;

7 AV

P ;

e

.g. f

urth

er q

ualif

icat

ion

of m

arki

ng p

oint

ra

ise

fund

s

3


of 20© UCLES 2019

Que

stio

nA

nsw

erM

arks

1(b)

(i)an

y fiv

e fro

m:

1 ge

ogra

phic

al, i

sola

tion

/ bar

rier ;

2 (d

ue to

) nam

ed b

arrie

r ; e

.g. r

iver

s / m

ount

ains

3 (w

est a

nd e

ast p

opul

atio

ns) u

nabl

e to

inte

rbre

ed /

no

gene

flow

/ AW

;

4 di

ffere

nt, s

elec

tion

pres

sure

s / e

nviro

nmen

tal c

ondi

tions

, (ac

ting

on w

est a

nd e

ast p

opul

atio

ns) ;

5 di

ffere

nt m

utat

ions

(in

wes

t and

eas

t pop

ulat

ions

) / A

W ;

6 so

diff

eren

t alle

les

sele

cted

for (

in w

est a

nd e

ast p

opul

atio

ns) ;

7 re

f. to

gen

etic

drif

t ;

8 (w

est a

nd e

ast p

opul

atio

ns) s

epar

ated

for a

long

tim

e ;

9 re

f. to

cha

nge

in g

ene

pool

;

10

AVP

;

5

1(b)

(ii)

allo

patri

c ;

1

Que

stio

nA

nsw

erM

arks

2(a)

A –

nod

e of

Ran

vier

;

B –

axo

n ;

C –

cel

l bod

y ; a

ccep

t som

a

3

2(b)

trans

mit,

impu

lses

/ ac

tion

pote

ntia

ls, f

rom

, CN

S /

sens

ory

neur

ones

/ re

lay

neur

ones

/ in

term

edia

te n

euro

nes

;

to, e

ffect

ors

/ mus

cle

/ gla

nds

;

2


of 20© UCLES 2019

Que

stio

nA

nsw

erM

arks

2(c)

any

four

from

:

1 S

chw

ann

cells

wra

p ar

ound

, the

axo

n / B

;

2 (to

form

) mye

lin s

heat

h ; a

ccep

t axo

n m

yelin

ated

3 in

sula

te th

e ax

on /

ref.

to la

ck o

f mov

emen

t of i

ons

;

4 de

pola

risat

ion

/ act

ion

pote

ntia

ls, c

an o

nly

occu

r at,

node

s (o

f Ran

vier

) / A

;

5 re

f. to

loca

l circ

uits

;

6 ac

tion

pote

ntia

ls ju

mp

from

nod

e to

nod

e / s

alta

tory

con

duct

ion

;

7 AV

P ;

4


of 20© UCLES 2019

Que

stio

nA

nsw

erM

arks

3(a)

eith

eran

y th

ree

from

:

1 ca

rbon

dio

xide

con

cent

ratio

n, h

ighe

r / in

crea

sed

;

2 (c

arbo

n di

oxid

e co

ncen

tratio

n) n

o lo

nger

lim

iting

fact

or ;

3 (c

arbo

n di

oxid

e fro

m) c

oral

/ po

lyp,

resp

iratio

n ;

4 (in

crea

sed

CO

2) fo

r, C

alvi

n cy

cle

/ lig

ht in

depe

nden

t rea

ctio

ns, i

n al

gae

;

5 fu

rther

det

ail o

f effe

ct o

f CO

2 co

ncen

tratio

n on

bin

ding

of C

O2

to ru

bisc

o ;

or any

thre

e fro

m:

6 te

mpe

ratu

re, h

ighe

r / in

crea

sed

;

7 (te

mpe

ratu

re) n

o lo

nger

lim

iting

fact

or ;

8 (in

crea

sed

tem

pera

ture

due

to) c

oral

/ po

lyp,

resp

iratio

n ;

9 (in

crea

sed

tem

pera

ture

) for

, Cal

vin

cycl

e / l

ight

inde

pend

ent r

eact

ions

, in

alga

e ;

10

furth

er d

etai

l of e

ffect

of t

empe

ratu

re o

n en

zym

e-ca

taly

sed

reac

tions

;

3


of 20© UCLES 2019

Que

stio

nA

nsw

erM

arks

3(b)

any

thre

e fro

m:

1 pi

gmen

ts a

bsor

b, v

iole

t-blu

e / 4

00–4

90 n

m /

lam

p co

lour

s, w

ell /

bes

t / m

ost /

at 8

(out

of 1

0) p

eaks

; 2

rate

of p

hoto

synt

hesi

s of

alg

ae in

crea

ses

with

mor

e lig

ht a

bsor

bed

;

3 re

f. to

tran

sfer

of,

orga

nic

nutri

ents

/ ox

ygen

, to

poly

ps fr

om a

lgae

;

4 co

ral g

row

th (i

ncre

ases

) with

mor

e (a

lgal

) pho

tosy

nthe

sis

; R

pro

duct

s re

spire

d to

giv

e gr

owth

5 AV

P ;

e

.g. v

iole

t / b

lue

/ 400

–490

nm

, lig

ht is

the

sam

e as

whe

re c

oral

s liv

e

3

3(c)

any

four

from

:

1 on

ly in

volv

es p

hoto

syst

em I

;

2 lig

ht e

nerg

y ab

sorb

ed (b

y ac

cess

ory

pigm

ents

) ;

3 pa

ssed

on

to, c

hlor

ophy

ll a

/ prim

ary

pigm

ent /

reac

tion

cent

re ;

4 el

ectro

n, e

xcite

d to

hig

her e

nerg

y le

vel /

em

itted

from

chl

orop

hyll

;

5 co

llect

ed b

y el

ectro

n ac

cept

or ;

6 pa

ssed

alo

ng e

lect

ron

trans

port

chai

n ;

7 AT

P pr

oduc

ed b

y ch

emio

smos

is ;

8 el

ectro

n re

turn

s to

chl

orop

hyll

;

4


of 20© UCLES 2019

Que

stio

nA

nsw

erM

arks

4(a)

(i)an

y tw

o fro

m:

1 to

, sep

arat

e th

e tw

o st

rand

s / d

enat

ure

DN

A ;

A m

ake

ssD

NA

2 by

bre

akin

g hy

drog

en b

onds

(bet

wee

n ba

ses)

;

3 so

that

bas

es a

re e

xpos

ed ;

4 to

pro

duce

tem

plat

e st

rand

s fo

r (co

mpl

emen

tary

) cop

ying

;

2

4(a)

(ii)

any

two

from

:

1 (p

rimer

) bin

ds /

anne

als,

to D

NA

by c

ompl

emen

tary

bas

e pa

iring

;

2 id

ea o

f atta

chin

g cl

ose

to th

e sp

ecifi

c se

ctio

n of

DN

A ;

3 (D

NA

) pol

ymer

ase

atta

ches

to, d

sDN

A /

prim

er ;

4 AV

P ;

e

.g. r

ef. t

o fo

rwar

d an

d re

vers

e pr

imer

s / A

W

2

4(a)

(iii)

any

two

from

:

1 (T

aq p

olym

eras

e), i

s he

at s

tabl

e / w

orks

at h

igh

tem

pera

ture

;

or

othe

r pol

ymer

ases

are

not

hea

t sta

ble

;

2 (s

o) d

oes

not n

eed

to b

e ad

ded

agai

n fo

r eac

h cy

cle

/ nee

ds re

plac

ing

only

afte

r a n

umbe

r of c

ycle

s

or

othe

r pol

ymer

ases

nee

d re

plac

ing

regu

larly

;

3 pr

oces

s is

, mor

e ef

ficie

nt /

fast

er (t

han

norm

al D

NA

poly

mer

ase)

;

2

4(b)

(i)al

l the

, DN

A /

gene

tic m

ater

ial (

in a

per

son’

s ce

ll)

or com

bine

d nu

clea

r and

mito

chon

dria

l DN

A ;

1

4(b)

(ii)

type

of c

ell:

(nam

ed) w

hite

blo

od c

ell /

leuc

ocyt

ean

dre

ason

: it c

onta

ins,

a n

ucle

us /

DN

A ;

1


of 20© UCLES 2019

Que

stio

nA

nsw

erM

arks

4(b)

(iii)

any

four

from

:

1 re

f. to

, pro

bes

/ rep

orte

rs, a

re (s

hort)

leng

ths

of s

sDN

A ;

2 co

mpl

emen

tary

to th

e fa

ulty

, alle

les

/ DN

A, b

eing

test

ed fo

r ;

3 m

any

copi

es o

f one

type

of p

robe

pla

ced

in e

ach

cell

(of t

he m

icro

arra

y) ;

4 sa

mpl

e D

NA

mad

e si

ngle

stra

nded

; 5

sam

ple

DN

A la

belle

d (w

ith fl

uore

scen

t ‘ta

gs’)

;

6 fa

ulty

DN

A, h

ybrid

ises

/ bi

nds,

with

, pro

bes

/ ssD

NA

;

7 un

boun

d sa

mpl

e D

NA

was

hed

off

or

bo

und

sam

ple

DN

A w

ill n

ot b

e w

ashe

d of

f ;

8 la

ser /

UV

ligh

t, us

ed to

det

ect p

rese

nce

of, f

luor

esce

nce

/ hyb

ridis

ed p

robe

s / a

llele

s /

DN

A ;

4

4(b)

(iv)

any

four

from

:

1 in

form

ed c

hoic

e ab

out m

akin

g lif

esty

le c

hang

e ;

2 in

form

ed c

hoic

e ab

out w

heth

er p

reve

ntat

ive

treat

men

t nee

ded

;

3 if

not p

rese

nt re

mov

es w

orry

;

4 al

low

s pr

even

tativ

e tre

atm

ent t

hat m

ay b

e ch

eape

r tha

n tre

atin

g di

seas

e its

elf ;

5 al

low

s in

form

ed c

hoic

e ab

out h

avin

g ch

ildre

n ;

6 po

sitiv

e im

plic

atio

ns fo

r life

insu

ranc

e ;

4


of 20© UCLES 2019

Que

stio

nA

nsw

erM

arks

5(a)

(i)sa

rcom

ere

shor

tens

/ Z

lines

mov

e cl

oser

toge

ther

or ref.

row

ing

mot

ion

of th

e he

ad /

pow

er s

troke

;

1

5(a)

(ii)

any

thre

e fro

m:

1 (A

TP) b

inds

to m

yosi

n he

ad ;

2 hy

drol

yse

by, A

TPas

e / m

yosi

n he

ad ;

3 he

ad d

etac

hes

from

act

in ;

4 he

ad ti

lts b

ack

to o

rigin

al p

ositi

on ;

3

5(b)

(i)af

fere

nt a

rterio

le is

wid

er th

an e

ffere

nt a

rterio

le /

OR

A ;

1

5(b)

(ii)

base

men

t mem

bran

e ;

1

5(c)

(i)1

the

high

er th

e cr

eatin

ine

conc

entra

tion

the

low

er th

e G

FR ;

OR

A

2 fu

rther

qua

lific

atio

n of

rela

tions

hip

;

e

.g. e

xpon

entia

l cur

ve

inve

rsel

y pr

opor

tiona

l da

ta q

uote

for t

wo

poin

ts

Not

e:cr

eatin

ine

conc

entra

tion

is in

vers

ely

prop

ortio

nal t

o th

e G

FR =

2 m

arks

2

5(c)

(ii)

0.01

3 ;

g dm

–3 ;

2


of 20© UCLES 2019

Que

stio

nA

nsw

erM

arks

5(c)

(iii)

any

two

from

:

1 ki

dney

, dis

ease

/ da

mag

e ;

2 ca

ncer

;

3 de

hydr

atio

n ;

4 lo

w b

lood

pre

ssur

e ; A

loss

of b

lood

2

Que

stio

nA

nsw

erM

arks

6(a)

any

thre

e fro

m:

1 th

e gr

eate

r the

con

cent

ratio

n of

ext

ract

the

low

er th

e ac

tivity

of t

yros

inas

e ;

A in

vers

ely

prop

ortio

nal

2 ex

tract

act

s as

an

inhi

bito

r / e

nzym

e in

hibi

ted

;

3 bi

nds

to, a

ctiv

e si

te /

allo

ster

ic s

ite, (

of ty

rosi

nase

) ;

4 re

f. to

alte

rs p

H ;

5 re

f. to

ext

ract

cha

nges

act

ive

site

; A

ref.

to d

enat

ures

3

6(b)

(i)re

cess

ive

only

exp

ress

ed, w

hen

a do

min

ant a

llele

not

pre

sent

/ in

a h

omoz

ygot

e

or not e

xpre

ssed

in a

het

eroz

ygot

e ;

alle

ledi

ffere

nt, f

orm

/ va

riety

, of a

gen

e ;

2


of 20© UCLES 2019

Que

stio

nA

nsw

erM

arks

6(b)

(ii)

sym

bols

exp

lain

ede.

g. A

= a

llele

for,

mel

anin

pro

duct

ion

/ nor

mal

pig

men

t a

= al

lele

for,

no m

elan

in p

rodu

ctio

n / a

lbin

ism

;

pare

ntal

gen

otyp

es a

nd g

amet

es ;

e.g.

Aa

(and

Aa)

an

d A

a (a

nd A

a)

offs

prin

g ge

noty

pes

iden

tifyi

ng c

hild

with

alb

inis

m a

s aa

e.g.

(AA

A

a A

a)

aa ;

3

Que

stio

nA

nsw

erM

arks

7(a)

any

thre

e fro

m:

1 pr

edat

ion

;

2 co

mpe

titio

n fo

r foo

d / d

ecre

ase

in fo

od a

vaila

ble

/ lim

ited

amou

nt o

f foo

d ;

3 di

seas

e ;

4 lo

ss o

f, ha

bita

t / b

reed

ing

site

s ; A

siz

e of

hab

itat l

imite

d

5 pe

stic

ides

/ he

rbic

ides

;

6 re

f. to

cha

nge

in c

limat

e ;

3

7(b)

(i)sa

me

shap

e bu

t to

the

right

;1

7(b)

(ii)

dire

ctio

nal (

sele

ctio

n) ;

1

7(c)

(i)sa

me

posi

tion

but t

wo

peak

s ;

1

7(c)

(ii)

disr

uptiv

e (s

elec

tion)

;1


of 20© UCLES 2019

Que

stio

nA

nsw

erM

arks

8(a)

7 ;

4 ;

9 / 4

;

2 ;

10 ;

3 ;

6

8(b)

any

five

from

:

1 on

ly, g

lyco

lysi

s / c

onve

rsio

n of

glu

cose

into

pyr

uvat

e, o

ccur

s ;

2 (o

nly)

pro

duce

s 2

mol

ecul

es o

f ATP

(net

per

mol

ecul

e of

glu

cose

) ;

3 (o

nly)

sub

stra

te-li

nked

pho

spho

ryla

tion

(occ

urs)

;

4 py

ruva

te c

onve

rted

to la

ctat

e ;

5 la

ctat

e is

ene

rgy-

rich

/ AW

;

6 ox

ygen

not

ava

ilabl

e as

fina

l ele

ctro

n ac

cept

or ;

7 el

ectro

n tra

nspo

rt ch

ain

/ che

mio

smos

is /

oxid

ativ

e ph

osph

oryl

atio

n, d

oes

not o

ccur

;

8 m

ost A

TP is

pro

duce

d (in

aer

obic

con

ditio

ns) i

n, e

lect

ron

trans

port

chai

n / c

hem

iosm

osis

/ ox

idat

ive

phos

phor

ylat

ion

;

9 no

add

ition

al s

ubst

rate

-link

ed p

hosp

hory

latio

n fro

m K

rebs

cyc

le ;

5


of 20© UCLES 2019

Que

stio

nA

nsw

erM

arks

9(a)

(i)du

ng b

eetle

sp

ecie

snu

mbe

r on

gras

slan

d no

t gr

azed

Nn

Nn2

dn

A66

410.

873

0.76

2

B 7

740.

102

0.01

0

C 1

080.

014

0.00

0

D

85

0.01

10.

000

tota

l76

080.

772

Nn fi

gure

s co

rrec

t ;

Nn2

dn

calc

ulat

ed a

nd a

dded

up

;

D =

0.2

28 /

0.22

7 ; E

CF

tota

l fig

ure

subt

ract

ed fr

om 1

appl

y E

CF

for m

p2 a

nd m

p3

3

9(a)

(ii)

grea

ter s

peci

es e

venn

ess

on g

raze

d gr

assl

and

; OR

A

acce

pt m

ostly

, one

spe

cies

/ A

, on

not g

raze

d

graz

ing

incr

ease

s (d

ung

beet

le s

peci

es) (

bio)

dive

rsity

; O

RA

2


of 20© UCLES 2019

Que

stio

nA

nsw

erM

arks

9(b)

1 m

ark-

rele

ase-

reca

ptur

e / A

W ;

desc

riptio

n (m

ax 3

)2

deta

il of

trap

ping

; e.

g. p

itfal

l tra

p

3 de

tail

of m

arki

ng ;

e.g.

felt

tip p

en /

not t

o ha

ve a

dver

se e

ffect

s

4 re

leas

e of

mar

ked

beet

les

;

5 tim

e of

sec

ond

trapp

ing

deta

il ; e

.g. n

ot to

o so

on o

r mix

ing

won

’t oc

cur /

not

too

long

afte

r as

mig

ratio

n m

ay o

ccur

6 co

rrec

t for

mul

a fo

r Lin

coln

inde

x ;

4


of 20© UCLES 2019

Que

stio

nA

nsw

erM

arks

10an

y se

ven

from

:

1 re

f. to

regu

lato

ry g

ene

;

2 co

des

for r

epre

ssor

pro

tein

;

3 (r

epre

ssor

pro

tein

) bin

ds to

ope

rato

r ;

in p

rese

nce

of (a

llo)la

ctos

e:

4 (a

llo)la

ctos

e bi

nds

to re

pres

sor p

rote

in ;

5 w

hich

cha

nges

sha

pe ;

6 m

oves

aw

ay fr

om o

pera

tor /

AW

;

in a

bsen

ce o

f (al

lo)la

ctos

e:

in p

rese

nce

of (a

llo)la

ctos

e:

7 co

vers

par

t of p

rom

oter

or

pr

omot

er re

gion

now

unb

lock

ed ;

8 R

NA

poly

mer

ase

cann

ot b

ind

to p

rom

oter

or

R

NA

poly

mer

ase

can

now

bin

d to

pol

ymer

ase

;

9 st

ruct

ural

gen

es c

anno

t be

trans

crib

ed /

mR

NA

not

or

stru

ctur

al g

enes

now

, tra

nscr

ibed

/ ‘s

witc

hed

on’ /

mR

NA

sy

nthe

sise

d

synt

hesi

sed

;

10

enzy

mes

/ na

med

enz

yme,

can

not b

e sy

nthe

sise

d or

en

zym

es /

nam

ed e

nzym

e, c

an n

ow b

e sy

nthe

sise

d ;

7

Cambridge International AS A Level - PMT

Documents

Transcript of Cambridge International AS A Level - PMT