Biology 0610/42 February/March 2021: question paper and mark scheme
Cambridge IGCSE Biology (0610), Paper 4 Theory (Extended), February/March 2021. Read both free below, or download them. Done the paper? Get it marked by AI against this mark scheme.
(a) Fig. 1.1 is a diagram showing the position of some organs in the human body.
A
B
C
E
D
Fig. 1.1
Some of the organs shown in Fig. 1.1 are endocrine glands.
Table 1.1 shows the names of some of the endocrine glands, their identifying letters and the hormones that they produce.
Complete Table 1.1.
Table 1.1
name of endocrine gland letter in Fig. 1.1 hormone produced
C
insulin
testes
[3]
(b) Fig. 1.2 shows two graphs representing:
• the relative blood concentrations of two hormones, A and B, released by the ovaries during the menstrual cycle
• the thickness of the lining of the uterus.
relative blood concentration A B of the hormones
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 days
thickness of the lining of the uterus
0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 days
Fig. 1.2
(i) Describe the roles in the menstrual cycle of hormone A.
…… [3]
(ii) State the day in Fig. 1.2 when ovulation is most likely to occur.
…… [1]
(iii) State the days in Fig. 1.2 when the lining of the uterus is lost from the body.
…… [1]
(c) The female contraceptive pill is a chemical method of birth control, which is available in many countries.
(i) Describe the social implications of the increased availability of the female contraceptive pill.
…… [2]
(ii) The hormones in the female contraceptive pill can enter rivers.
Describe the negative impacts of female contraceptive hormones entering rivers and contaminating drinking water.
…… [3]
(iii) State two barrier methods of contraception.
1 ……
2 ……
[2]
[Total: 15]
Mark scheme
1(a) 3 one mark for each correct row
name of gland letter in Fig. 1.1 hormone produced
adrenal C adrenaline
pancreas E insulin
testis D testosterone
;;;
1(b)(i) hormone A is oestrogen ; 3
stimulates repair / thickening, of uterus lining ;
inhibits FSH secretion ;
stimulates secretion of LH ;
1(b)(ii) 12 / 13 / 14 / 15 / 16 ; 1 A 12–16
1(b)(iii) days 0–6 ; 1
1(c)(i) 1 lowers / controls, birth rate ; 2
2 more choice over when to start a family ;
3 fewer abortions / unwanted pregnancies / fewer adoptions ;
4 more women in the workforce ;
5 increased women in education ;
6 increase in (named) STIs ;
7 ref. to religious views ;
8 AVP ;
1(c)(ii) (named example of) feminisation of aquatic organisms ; 3
reduction in fertility in humans / reduced sperm count in men ;
reduction, in fertility / sperm count, in fish / aquatic organisms ;
reduction in population in, fish / aquatic organisms ;
AVP ;
1(c)(iii) condom ; 2
femidom ;
diaphragm ;
AVP ;
(a) Fig. 2.1 is a diagram of a prokaryotic cell.
not to scale
Fig. 2.1
(i) State one visible feature in Fig. 2.1 that identifies this cell as a prokaryotic cell.
…… [1]
(ii) State one cell structure that is present in the cells of all organisms.
…… [1]
(b) Prokaryotes, Animals and Plants are three of the five kingdoms of organisms.
State the names of the two other kingdoms.
1 ……
2 ……
[2]
(c) Fig. 2.2 shows part of the nitrogen cycle.
nitrogen in atmosphere
proteins in proteins in animals plants animal waste B C
dead organisms
A nitrate ions in soil
Fig. 2.2
(i) Describe processes A, B and C in Fig. 2.2.
…… [6]
(ii) State the name of the process that plants use to absorb nitrate ions.
…… [1]
[Total: 11]
Mark scheme
2(a)(i) (bacterial) plasmid / loop of DNA / circular chromosome ; 1
2(a)(ii) ribosomes / (cell) membrane / cytoplasm ; 1
2(b) fungus ; 2
protoctist ;
2(c)(i) 1 idea of involvement of (named) bacteria ; 6
2 idea that A is decomposition / decay / deamination ;
3 releasing ammonium (ions) (to the soil) ;
4 idea that A is (also) nitrification / ref to nitrifying ;
5 convert ammonium (ions) to, nitrite / nitrate, (ions) ;
6 B is nitrogen fixation / ref to nitrogen fixing ;
7 by lightning ;
8 in, root nodules / leguminous plants ;
9 idea that C is denitrification / ref to denitrifying ;
10 in anaerobic conditions (described) ;
2(c)(ii) active transport ; 1 A diffusion
(a) The activity of the heart can be monitored using different methods.
Fig. 3.1 shows two ECG traces. One trace was recorded when the person was at rest and the second trace was recorded during exercise.
The length of time taken for one heart beat is indicated in Fig. 3.1 on the ECG trace recorded at rest.
one heart beat
at rest
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 time / s
during exercise
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2 2.4 2.6 2.8 time / s
Fig. 3.1
(i) Estimate the resting heart rate of the person from their ECG trace in Fig. 3.1.
Space for working.
…… beats per minute
[2]
(ii) Explain why the ECG trace recorded during exercise differs from the ECG trace recorded at rest.
…… [4]
(iii) Suggest one other way of monitoring the activity of the heart.
…… [1]
(b) If exercise is very intense an oxygen debt is formed.
(i) Complete the sentence.
An oxygen debt results in a build-up of …… in the
…… during vigorous exercise.
[2]
(ii) Outline how the body removes an oxygen debt.
…… [4]
[Total: 13]
Mark scheme
3(a)(i) (17 × 0.04(s)) = 0.68 (s) OR (2.8 ÷ 4) = 0.7 OR (4 ÷ 2.8) = 1.43 (beats 2 A unrounded answers
per s) ;
(60 ÷ 0.68) = 88 (bpm) OR (60 ÷ 0.7) = 86 (bpm) OR (1.43 × 60) = 86
(bpm) ;
3(a)(ii) ECG during exercise: 4
1 increased, frequency of heart beats / pulse rate ;
2 exercising muscles require more energy ;
3 for muscle contraction ;
4 increase in respiration ;
5 faster blood flow (to muscles) ;
6 to supply more, oxygen / glucose ;
7 to remove more carbon dioxide ;
3(a)(iii) listening to the valves of the heart shutting / count pulse rate / AW ; 1
3(b)(i) lactic acid ; 2
muscles / blood ;
3(b)(ii) 1 breathing rate, is / remains, high ; 4
2 heart rate, is / remains, high ;
3 to provide oxygen ;
4 to breakdown / to remove, lactic acid ;
5 lactic acid removed by aerobic respiration ;
6 to carbon dioxide (and water) ;
7 lactic acid is broken down in the liver ;
(a) A leaf can be described as an organ.
Define the term organ.
…… [1]
(b) Fig. 4.1 is a photomicrograph of a cross section of part of a leaf.
A
B
C
Fig. 4.1
(i) Identify the tissue labelled A in Fig. 4.1.
…… [1]
(ii) Identify the structure labelled C in Fig. 4.1.
…… [1]
(iii) Describe how the tissue labelled B is adapted to maximise photosynthesis.
…… [3]
(c) (i) State two substances that are transported only in the phloem.
…… [1]
(ii) Explain why some parts of a plant can act as both a source and a sink.
…… [2]
(d) The effect of carbon dioxide concentration on the rate of oxygen production in an aquatic plant was measured.
• A lamp was used to keep the light intensity constant.
• The oxygen gas released by the plant was collected in a gas syringe.
• The plant was placed in water that was kept constant at 20 °C.
Fig. 4.2 shows the results.
(i) The rate of oxygen production was assumed to be the same as the rate of photosynthesis.
Suggest why the rate of oxygen production was not the same as the rate of photosynthesis.
…… [2]
0.30
0.25
rate of oxygen 0.20 production
/ cm3 per m2 per s
0.15
0.10
0.05
0.00
0 200 400 600 800 1000 1200 1400 1600 concentration of carbon dioxide / μmol per dm3
Fig. 4.2
(ii) Explain the results shown in Fig. 4.2.
…… [3]
(e) The investigation was repeated with the same type of aquatic plant at 10 °C.
Draw a line on Fig. 4.2 to predict the results at 10 °C. [2]
[Total: 16]
Mark scheme
4(a) structure made up of a group of tissues, working together to perform a 1
specific function(s) ;
4(b)(i) A – (upper) epidermis ; 1 R lower epidermis
4(b)(ii) C – vascular bundle ; 1 A xylem and phloem / vein
4(b)(iii) B is the palisade, mesophyll / tissue / layer / cells ; 3
cells are tightly packed / AW ;
ref. to many chloroplasts / lots of chlorophyll ;
(cells) positioned at the top of the leaf ;
(large vacuole) ensures chloroplasts are at the edge of cells ;
AVP ;
4(c)(i) sucrose and amino acids ; 1
4(c)(ii) (acts as a ) source when it is (moving sucrose from) a region of 2
production / photosynthesising ;
(acts as a ) sink when it is, growing / storing / respiring / a region of
utilisation ;
4(d)(i) not all the oxygen is, released / collected / measured (from the plant) ; 2
some is used in respiration ;
some is dissolved in the water ;
(therefore) the rate of photosynthesis may appear lower than it
actually is ;
4(d)(ii) 1 carbon dioxide is required for photosynthesis ; 3
2 initially carbon dioxide concentration is limiting the rate of
photosynthesis ;
3 (after 500 μmol per dm3) carbon dioxide concentration is not
limiting the rate of photosynthesis / other factors are limiting the
rate of photosynthesis ;
4 ref. to named limiting factor ;
4(e) initial gradient is less steep ; 2
plateau below original line ;
(a) Measles is a transmissible disease.
The percentage of the population that were vaccinated against measles in a country was determined.
The number of confirmed cases of measles in the country was also recorded.
Fig. 5.1 shows the data that were collected between 1975 and 2010.
160 000
100 140 000
90 120 000
80 100 000 number of percentage cases of of the measles population 70 80 000 vaccinated against measles
60 60 000
50 40 000
40 20 000
30 0
1975 1980 1985 1990 1995 2000 2005 2010 year
Key: percentage of population vaccinated number of cases of measles
Fig 5.1
(i) Calculate the percentage change in the number of cases of measles between 1980 and
1990.
Space for working.
……%
[2]
(ii) Describe the data shown in Fig. 5.1.
…… [4]
(iii) Explain how vaccination protects people against a transmissible disease such as measles.
…… [5]
(b) The human body has several defences against pathogens.
(i) State two of the body’s chemical barriers to pathogens.
1 ……
2 ……
[2]
(ii) Describe the process of blood clotting.
…… [3]
[Total: 16]
Mark scheme
5(a)(i) (140 000 – 14 000) / 140 000 × 100 ; 2
90 (%) ;
5(a)(ii) 1 decrease in number of cases of measles as the percentage of the 4
population vaccinated against measles increases ;
2 percentage of the population vaccinated increases (until 1995)
and then fluctuates ;
3 measles cases decrease, then remain constant ;
4 ref. to rapid change before 1995 in percentage vaccinated and
number of cases ;
5 number of cases remains the same from, 2000 / 2005, while
percentage vaccinated fluctuates / decreases ;
6 correct data quote ;
5(a)(iii) 1 harmless / dead / attenuated, pathogen is given ; 5
2 antigens are present on pathogens ;
3 (antigens) trigger an immune response ;
4 lymphocytes / memory cells produce antibodies ;
5 ref. to specificity ;
6 memory cells are produced ;
7 antibodies destroy pathogen ;
8 providing long term immunity / recognise pathogen if it
returns / ref. to active immunity / AW ;
5(b)(i) mucus ; 2
hydrochloric / stomach, acid ;
AVP ;;
5(b)(ii) ref. to involvement of platelets ; 3
fibrinogen converted to fibrin ;
forms a mesh (trapping red blood cells) / forms scab ;
AVP ;
(a) Fig. 6.1 shows a food web.
hawks
snakes
rabbits grasshoppers mice
grass corn
Fig. 6.1
(i) State the number of trophic levels in the food web in Fig. 6.1.
…… [1]
(ii) State the name of one organism that feeds at both the third and fourth trophic levels from Fig. 6.1.
…… [1]
(iii) State the name of the type of energy that is transferred between trophic levels.
…… [1]
(b) The total biomass of the snakes is much less than the total biomass of the mice in the food web shown in Fig. 6.1.
Explain why the total biomass of the snakes is less than the total biomass of the mice.
Use the term energy in your answer.
…… [3]
(c) Food shortages that result in famine can be caused by many factors.
Describe how drought can contribute to famine.
…… [3]
[Total: 9]
Mark scheme
6(a)(i) 4; 1
6(a)(ii) hawks ; 1
6(a)(iii) chemical ; 1
6(b) 1 snakes occupy a higher trophic level than mice ; 3
2 (most of the) energy is lost between the trophic levels ;
3,4 examples of energy loss ;;
5 not enough energy to sustain larger biomass (of snakes) at higher
trophic levels / AW ;
6(c) 1 drought is a lack of, water / rainfall ; 3
2 destruction of, crops ;
3 seeds / plants, can’t germinate ;
4 soil erosion / desertification ;
5 plants need water for photosynthesis ;
6 plants wilt ;
7 less, food / water, for livestock ;
8 AVP ;
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Biology 0610/42 for February/March 2021 is out of 80 marks, with 1 hour 15 minutes to answer it, across 6 questions.
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