Cambridge IGCSE™

* 8 4 6 1 0 0 3 2 8 7 *

BIOLOGY 0610/42
Paper 4 Theory (Extended) February/March 2023

1 hour 15 minutes

You must answer on the question paper.

No additional materials are needed.

INSTRUCTIONS
● Answer all questions.
● Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs.
● Write your name, centre number and candidate number in the boxes at the top of the page.
● Write your answer to each question in the space provided.
● Do not use an erasable pen or correction fluid.
● Do not write on any bar codes.
● You may use a calculator.
● You should show all your working and use appropriate units.

INFORMATION
● The total mark for this paper is 80.
● The number of marks for each question or part question is shown in brackets [ ].

This document has 20 pages. Any blank pages are indicated.

DC (EF/JG) 311941/4
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1 (a) Fig. 1.1 is a simplified diagram of the circulatory system in humans.

A
F

Y
E B

C
D

other organs

Fig. 1.1

(i) State the letter from Fig. 1.1 that represents the blood vessel that contains blood with the
highest concentration of oxygen.

..................................................................................................................................... [1]

(ii) State the letter from Fig. 1.1 that represents the hepatic portal vein.

..................................................................................................................................... [1]

(iii) State all the letters from Fig. 1.1 that represent arteries.

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(iv) Explain the importance of the part labelled Y in Fig. 1.1.

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(v) State the evidence from Fig. 1.1 that the diagram shows a double circulation system.

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(b) Fig. 1.2 shows the pressure of blood flowing through different blood vessels as it travels
around the body. (Venules are narrow vessels that connect capillaries to veins.)

18

16

14

12

blood 10
pressure
/ kPa 8

0
arteries X capillaries venules veins
type of blood vessel

Fig. 1.2

(i) Blood vessels X in Fig. 1.2 supply blood to skin-surface capillaries and have a role in
maintaining a constant internal temperature.

State the name of the blood vessels that are represented by the letter X in Fig. 1.2.

..................................................................................................................................... [1]

(ii) Explain reasons for the changes in pressure seen in the arteries in Fig. 1.2.

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(iii) Using the information in Fig. 1.2, explain the structural adaptations of arteries and veins.

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[Total: 14]

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2 A student investigated the digestion of starch.

Fig. 2.1 shows the apparatus she used.

distilled water distilled water

dialysis dialysis
tubing tubing

starch solution starch solution

+ amylase

test-tube A test-tube B

Fig. 2.1

Dialysis tubing is used to represent a cell membrane.

The dialysis tubing material allows small molecules to move across it, but not larger molecules.

Test-tubes A and B were set up as shown in Fig. 2.1 and placed in a water-bath at 37 °C for
30 minutes.

The liquid outside the dialysis tubing in test-tubes A and B was tested with Benedict’s solution at
0 minutes and after 30 minutes.

Table 2.1 shows the results.

Table 2.1

colour with Benedict’s solution colour with Benedict’s solution

test-tube
at 0 minutes at 30 minutes

A blue blue

B blue red

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(a) Using the information in Fig. 2.1 and Table 2.1, explain the reasons for the difference in the
results for test-tubes A and B in Table 2.1.

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(b) Complete Table 2.2 by writing in the names of the missing enzymes, substrates and products.

Table 2.2

enzyme substrate product or products

pepsin

fatty acids and glycerol

trypsin

glucose

[4]

(c) State the name of the structures that increase the surface area for absorption in the small
intestine.

............................................................................................................................................. [1]

[Total: 11]

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3 (a) Fig. 3.1 shows part of a classification diagram for plants.

(i) Complete Fig. 3.1.

plants

ferns ...........………………….............

monocotyledons ...........………………….............

Fig. 3.1
[2]

(ii) Describe two identifying features of monocotyledons.

1 ........................................................................................................................................

2 ........................................................................................................................................
[2]

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(b) Fig. 3.2 shows the life cycle of a fern. The life cycle of a fern has some similarities and some
differences compared with the life cycles of other plants.

The letters represent processes that occur during the life cycle.

The haploid stages of the life cycle are represented by (n).

The diploid stages of the life cycle are represented by (2n).

A B
spores (n)

adult sporophyte adult gametophyte (n)

(2n) C

D C

zygote gametes (n)

(2n)

not to scale

Fig. 3.2

(i) The adult sporophyte has 1200 chromosomes in its body cells.

State the number of chromosomes in the body cells of the gametophyte.

..................................................................................................................................... [1]

(ii) Identify and describe process A in Fig. 3.2.

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(iii) State the name of process D in Fig. 3.2.

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(c) Fig. 3.3 shows the parts of two flowers from two different plants of the same species.

Fig. 3.3

(i) Describe what is meant by the term species.

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(ii) Annotate Fig. 3.3 to show the mechanism of cross-pollination by:

• labelling the structures involved

• drawing an arrow to show the pathway of pollen.
[3]

(iii) Draw an X on Fig. 3.3 to show where fertilisation occurs. [1]

(iv) Explain the disadvantages of cross-pollination compared with self-pollination.

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[Total: 18]
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4 (a) Fig. 4.1 is a photograph of a tree that has been girdled.

Girdling involves removing a complete circle of bark and phloem from around the tree.

Fig. 4.1

(i) Explain why the area above the girdle in Fig. 4.1 will become swollen.

Use the terms source and sink in your answer.

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(ii) Explain why the leaves in girdled trees are still able to receive mineral ions from the
roots.

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(b) Explain why glucose made during photosynthesis is required for the absorption of mineral
ions by the roots.

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(c) State the balanced symbol equation for photosynthesis.

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[Total: 11]

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5 The eye is a sense organ that is part of the nervous system.

(a) Explain why the eye can be described as a sense organ.

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(b) State the two parts of the central nervous system.

1 ................................................................................................................................................

2 ................................................................................................................................................
[2]

(c) Fig. 5.1 is a diagram of a section through the human eye.

A
H

C
G D

Fig. 5.1

(i) Draw an X on Fig. 5.1 to identify the blind spot. [1]

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(ii) Table 5.1 shows some of the parts labelled in Fig. 5.1, their names and their functions.

Complete Table 5.1.

Table 5.1

name of the part letter in Fig. 5.1 function

transmits impulses to the central nervous system

cornea

[3]

(d) State the names of the two effectors that contract and relax during the pupil reflex.

................................................................... and ................................................................... [1]

(e) Explain why a person is unable to focus on distant objects if the suspensory ligaments
become permanently overstretched.

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[Total: 12]

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6 Golden rice is a type of rice that has been genetically modified to contain a nutrient called
beta-carotene.

Fig. 6.1 shows the genetic modification process used to produce golden rice.

bacterial cell plant DNA

rice plant cells

infected with the
genetically modified
bacteria

rice plants
with the ability
to produce
beta-carotene
are grown

tissue culture

not to scale

Fig. 6.1

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(a) Using the information in Fig. 6.1, complete the sentences to describe how rice is genetically
modified to contain beta-carotene.

The part labelled A in the bacterial cell is a ................................................... .

Part A is extracted and cut using a .................................................. enzyme forming

..................................................... ends.

The part labelled B is the .................................................. that codes for the production of

beta-carotene.

The enzyme used to cut part A is also used to cut part B from the plant DNA.

Part B is inserted into the part labelled A using the enzyme .......................................... .

This forms the part labelled C, which is called a ........................................................... .

Part C is put into a bacterium. The bacterium is taken up by rice plant cells, giving them the

ability to produce beta-carotene.

Tissue culture is a form of .............................................................. reproduction that is used to

produce many identical rice plants producing beta-carotene for commercial use.
[7]

(b) Apart from structural features, state two reasons why bacteria are useful for genetic
modification.

1 ................................................................................................................................................

2 ................................................................................................................................................
[2]

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(c) Discuss the disadvantages of genetically modifying rice plants to produce beta-carotene.

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(d) Beta-carotene is required to produce vitamin A, which is essential for eye function.

State the nutrient required to prevent:

scurvy .......................................................................................................................................

rickets. ......................................................................................................................................
[2]

[Total: 14]

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