Biology 0610/43 May/June 2023: question paper and mark scheme
Cambridge IGCSE Biology (0610), Paper 4 Theory (Extended), May/June 2023. Read both free below, or download them. Done the paper? Get it marked by AI against this mark scheme.
(a) The movement of molecules within an organism can occur by diffusion and active transport.
Complete Table 1.1 by placing ticks (3) to show the correct features of each process.
Table 1.1
active feature diffusion transport
movement of particles always occurs across a cell membrane
movement of molecules during gas exchange
rate of movement of particles is higher when the concentration gradient is larger
requires energy from respiration
[4]
(b) Explain why active transport is important in root hair cells.
…… [3]
[Total: 7]
Mark scheme
1(a) 4 one mark per correct row
active
feature diffusion R each additional tick
transport
movement of particles always occurs
;
across a cell membrane
molecules moving during gas exchange ;
rate of movement of particles is higher
;
when the concentration gradient is larger
requires energy from respiration ;
1(b) any three from: 3
for ion, uptake / absorption ;
ion concentration lower in the soil than in the root (cell) / AW ;
movement against the concentration gradient / AW ;
creates a water potential gradient / AW ;
named example of ion e.g. nitrate / magnesium ;
Transpiration is the loss of water vapour from the leaves of a plant.
(a) Complete the sentence describing transpiration.
Water evaporates from the surfaces of the …… cells into the air
spaces and then …… out of the leaves, through the stomata, as
water vapour.
[2]
(b) Explain how water moves upwards in the xylem.
…… [3]
(c) A student investigated the effect of wind speed on the rate of transpiration in a small
Pachira aquatica tree.
They measured the rate of transpiration when the plant was placed in different wind speeds in both the light and the dark. The tree was given an adequate supply of water.
The results of this investigation are shown in Fig. 2.1.
7
6
5
rate of 4 transpiration
/ g per hr 3
2
1
0
0 2 4 6 8 10 12
wind speed / m per s
light dark
Fig. 2.1
(i) Describe and explain the results shown in Fig. 2.1.
…… [4]
(ii) The investigation was repeated in the light with the same species of tree in an environment where the humidity was higher.
Draw a line on Fig. 2.1 to predict the results in the light with increased humidity. [1]
(iii) The investigation described in 2(c) was repeated (different wind speeds in both the light and the dark).
However, the tree was not given an adequate supply of water during the investigation.
Predict the result and explain your prediction.
…… [4]
[Total: 14]
Mark scheme
2(a) mesophyll ; 2
diffuses ;
2(b) any three from: 3
transpiration pull ;
(draws up) a column of water ;
held together by forces of attraction between water molecules ;
(xylem forms) a continuous (empty) tube ;
loss of water from leaf reduces, water potential / hydrostatic pressure ;
AVP ; e.g. adhesion between water molecules and, wall
of xylem / AW
2(c)(i) describe (max three from): 4
as wind speed increases the rate of transpiration increases (in both
light and dark) / ora ;
(the rate of) transpiration is higher in the light (than the dark) / ora ;
the rate of increase in transpiration rate is higher in the light than the
dark / ora ;
ref change of gradient at wind speeds above 4 m per s (to 10 m per s) ;
comparative correct data quote including units ;
explain:
(transpiration rate) increases because the water vapour is removed
from outside the leaf faster / AW / ora ;
maintaining the concentration gradient for diffusion ;
(in the light) (more) stomata are open / stomata are open wider / ora ;
to allow, gas exchange / carbon dioxide to diffuse in / oxygen to diffuse
out, for photosynthesis ;
energy from light increases the, kinetic energy of the water
molecules / rate of evaporation of water ;
2(c)(ii) line drawn increasing with wind speed but below the light line ; 1 must start below 2 g per hr
A below the dark line
2(c)(iii) any four from: 4
prediction:
lower rate of / less, transpiration (in the light) ;
at all wind speeds ;
little change in the dark ;
explanation - max three from:
less water absorbed by the roots ;
water moves from the cells ;
by osmosis ;
(guard) cells, lose their turgidity / become flaccid ;
(in the light) stomata close ;
plant / leaves / tree, wilts ;
(little change in dark because) stomata already closed ;
Fig. 3.1 is a diagram of a section through a human heart.
A
B
C
Fig. 3.1
(a) Draw an X on the septum in Fig. 3.1. [1]
(b) Explain the reason for the difference between the thickness of the walls at B and at C in
Fig. 3.1.
…… [2]
(c) A red blood cell enters the vena cava at A in Fig. 3.1.
Explain how the red blood cell is moved from the vena cava to the aorta.
…… [6]
(d) An athlete measured her heart rate during a running race. She recorded it before the race, during the race and during her recovery.
Her results are shown in Fig. 3.2.
200
180
160
140 heart rate
/ beats per 120 minute
100
80
60
40
0 5 10 15 20 time / minutes start end of race of race
Fig. 3.2
(i) Suggest how the athlete could monitor the activity of her heart.
…… [1]
(ii) Calculate the percentage change in heart rate from the maximum heart rate reached during the race until the heart rate recorded at 18 minutes.
Give your answer to three significant figures.
Space for working.
…… %
[3]
(iii) Explain why heart rate must increase during exercise.
…… [3]
[Total: 16]
Mark scheme
3(a) X drawn on septum ; 1
3(b) any two from: 2 A ora for each point
left ventricle / thicker wall / B, contains more muscular tissue ;
left ventricle / thicker wall / B, can contract with more force ;
left ventricle / thicker wall / B , pumps blood at high(er) pressure ;
left ventricle / thicker wall / B, pumps blood a long(er) distance ; A left ventricle / thicker wall / B, pumps to whole
body while, right ventricle / thinner wall / C, pumps
to lungs only
3(c) (the red blood cell moves) 6
carried in the (flowing) blood ;
from the vena cava / A, into the right atrium ;
from the right atrium to the right ventricle as the right atrium,
contracts / pumps ;
out of the right ventricle into the pulmonary artery as the right ventricle
contracts ;
through the lungs / pulmonary circulation / into the pulmonary veins ;
from pulmonary vein to the left atrium ;
from the left atrium to the left ventricle as the left atrium contracts ;
out of the left ventricle into the aorta as the left ventricle contracts ;
(correct atria to correct ventricle) through the atrioventricular
valve / atrioventricular valves close to prevent backflow ;
(correct ventricle to (correct) artery) through the semilunar
valve / semilunar valves close to prevent backflow ;
3(d)(i) ECG / (measuring) pulse rate / listening to valves closing ; 1 A fitbit / fitness tracker / smartwatch
A description of taking pulse
3(d)(ii) –48.9(%) ;;; 3 MP1 correct readings from graph of 180 and 92
MP2 correct answer calculated as a negative
value to any number of significant figures (92 –
180)/180
MP3 correct rounding to three significant figures
ecf from previous step
3(d)(iii) any three from: 3
to increase blood flow to muscles ;
to provide more oxygen for (aerobic) respiration ;
to provide more glucose for respiration ;
to provide / release, more energy for contraction ; R produce energy
to remove (excess) CO2 produced ;
to transport / remove, lactic acid (to liver / from muscle) ;
to remove heat from muscles / ref to maintain constant internal body
temperature ;
(a) Urea is a waste product.
(i) Describe how urea is formed.
…… [3]
(ii) State the component of blood that transports urea.
…… [1]
(iii) State why urea must be excreted.
…… [1]
(iv) State the name of the blood vessel that carries blood away from the kidney.
…… [1]
(b) Fig. 4.1 shows a drawing of a nephron in the human kidney and associated blood vessels.
K
L
N
M
Fig. 4.1
Describe how the structures labelled in Fig. 4.1 produce urine.
…… [4]
(c) Urea can be used as a fertiliser as it is a source of nitrogen.
Explain the importance of nitrate ions to plants.
…… [1]
(d) A farmer applied fertiliser to a field next to a lake.
Suggest two precautions the farmer should take when applying fertiliser to reduce the risk of eutrophication occurring in the lake.
1 ……
2 ……
[2]
[Total: 13]
Mark scheme
4(a)(i) deamination ; 3
in the liver ;
the removal of the nitrogen-containing part ;
of excess amino acids ;
4(a)(ii) plasma ; 1
4(a)(iii) urea is, toxic / harmful / poison(ous) / a toxin ; 1
4(a)(iv) renal vein ; 1
4(b) any four from: 4
the glomerulus / K, is where the blood is filtered ;
water / glucose / urea / ions, move into, nephron / L ;
the nephron / L, reabsorbs all glucose ;
the nephron / L, reabsorbs some of the, water / ions ;
into, the blood / M / capillary ;
urine flows through N ;
urine contains urea and excess water and excess ions ;
AVP ; e.g. correct ref to, active
transport / diffusion / selective reabsorption
4(c) formation of, amino acids / proteins, for growth ; 1
4(d) any two from: 2
apply, less / suitable, amount ;
do not apply before rain / AW ;
do not apply too frequently ;
do not apply right next to the lake ;
do not apply onto bare soil ; (i.e. before crops are planted)
apply only when crops are actively growing ;
AVP ;
(a) Describe the role of progesterone in pregnancy.
…… [3]
(b) Fig. 5.1 shows a drawing of a section of a human placenta. The arrows show the direction of blood flow.
maternal artery from mother to mother maternal vein
space filled with maternal fetal capillary blood
umbilical arteries
from fetus to fetus from fetus umbilical vein not to scale
Fig. 5.1
Substances move across the placenta by diffusion.
(i) State the names of two useful substances that move from the blood of the mother to the blood of the fetus.
1 ……
2 ……
[2]
(ii) Using the information in Fig. 5.1, suggest how the placenta is adapted for efficient diffusion.
…… [3]
(c) The Rhesus (Rh) factor is a protein that is found on the surface of red blood cells in some people. If the protein is present then the individual is Rh positive.
The allele for the presence of the Rh factor is dominant and is represented by the letter D.
The recessive allele is represented by the letter d.
If a mother is Rh negative and the fetus is Rh positive there can be problems during pregnancy.
A Rh negative mother and a heterozygous Rh positive father have a child.
Complete the Punnett square and determine the probability of the child being Rh positive.
father’s gametes
mother’s gametes
probability ……
[3]
[Total: 11]
Mark scheme
5(a) any three from: 3
maintains pregnancy ;
prevents the menstrual cycle continuing during pregnancy / prevents
menstruation ;
maintains the (thickness of) lining of the uterus ;
inhibits contraction of the muscular wall of the uterus ;
prevents secretion of, FSH / LH ;
prevents, more follicles developing / ovulation ;
AVP ;
5(b)(i) any two from: 2
oxygen / glucose / amino acids / named nutrient
molecule / ions / water / (named) hormone / antibodies ;;
5b(ii) large surface area ; 3
short diffusion distance ;
concentration gradient is maintained / good blood supply ;
5(c) gametes: mother’s gametes d d and father’s gametes D d ; 3 ecf from previous step
offspring genotypes: Dd, Dd, dd and dd ;
probability: 0.5 / 50% / ½ / 1 in 2 ;
D d
d Dd dd
d Dd dd
(a) Fig. 6.1 shows the percentage of land covered by forest in a country from 1660 until 2000.
30
28
26
24
22 percentage of land covered 20 by forest
18
16
14
12
10
1650 1750 1850 1950 2050 year
Fig. 6.1
(i) Using the information in Fig. 6.1, state which 10-year period had the highest increase in the percentage of land covered by forest.
…… [1]
(ii) Outline how human activities could cause the change in the percentage of land covered by forest from 1660 to 1800 shown in Fig. 6.1.
…… [3]
(b) It is estimated that 40% of plant species are at risk of extinction.
Seed banks can store seeds from many species for a long time.
Table 6.1 shows some information about one plant species that is stored in a seed bank.
Table 6.1
mass of one seed / g percentage oil content percentage protein content
1.96 71 11
(i) Using the data shown in Table 6.1, calculate the mass of protein in one seed.
…… g [1]
(ii) Suggest why many plants can easily be conserved using seed banks.
…… [2]
(iii) Describe why conservation projects such as seed banks are important.
…… [5]
[Total: 12]
Mark scheme
6(a)(i) 1950s ; 1 A 1950 to,1959 / 1960
6(a)(ii) any three from: 3
pollution ;
climate change ;
land for housing / crop plantation / livestock / agriculture ;;
logging for, firewood / paper / timber / charcoal / fuel ;
for mining / extracting raw materials ;
AVP ; e.g. forest fires
6(b)(i) 0.2156 (g) ; 1 A 0.21 / 0.22 / 0.216
6(b)(ii) any two from: 2
seeds are, small / AW ;
seeds are easy to collect / AW ;
some plants produce many seeds ;
seeds can, be dormant / have low metabolism / AW ;
seeds do not need (much) maintenance / AW ;
6(b)(iii) any five from: 5
maintaining / increasing biodiversity ;
reduce (plant) extinction ;
preventing loss of animal species that depend on plant species ;
(moral) responsibility to save other species ;
protect / maintain, (vulnerable / AW) ecosystems ;
by supporting recycling of nutrients ;
by supporting flow of energy in, food chains / food webs ;
possible fuels ;
possible genes ;
possible drug sources ;
possible crop plants / selective breeding ;
allows for future research ;
AVP ;; e.g. prevent flooding / protect
livelihood / ecotourism / named conservation
project and advantage
(a) State the name of a chemical element that is found in all proteins but not in carbohydrates or fats.
…… [1]
(b) Table 7.1 shows the names of some biological molecules, enzymes and the organs that produce the enzymes.
Complete Table 7.1.
Table 7.1
enzyme that products of the catalyses the large biological breakdown of the organ that produces breakdown of the molecule large biological the enzyme large biological molecule molecule
oil pancreas
glycogen glycogen liver phosphorylase
maltose amylase
protein stomach
[4]
(c) State two hormones that can affect the concentration of glycogen in the liver.
1 ……
2 ……
[2]
[Total: 7]
Mark scheme
7(a) nitrogen ; 1
7(b) 4 one mark per correct row
enzyme that
products of the
large catalyses the organ that
breakdown of the
biological breakdown of the produces the
large biological
molecule large biological enzyme
molecule
molecule
fatty acids and
oil lipase pancreas
glycerol
glycogen
glycogen glucose liver
phosphorylase
salivary gland /
starch maltose amylase
pancreas
protein amino acid pepsin / protease stomach
;;;;
7(c) any two from: 2
insulin ;
glucagon ;
adrenaline ;
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Biology 0610/43 for May/June 2023 is out of 80 marks, with 1 hour 15 minutes to answer it, across 7 questions.
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