Practice Paper 2 (Cambridge International IGCSE Biology)

The equation below represents a chemical process that occurs in the cells of living organisms.

glucose + oxygen → carbon dioxide + water

Which characteristics of living organisms would this equation be associated with?

A student cut a section through a plant, finding a group of long, microscopic structures which lacked end walls or any cell contents.

Which row of the table below correctly identifies the structure described in the statement above?

Three statements about the role of water in mammals are given below:

1. Water forms a major part of the cytoplasm, allowing substances to dissolve and participate in metabolic reactions within the cell
2. Substances, such as urea and excess salts, are able to dissolve in water making them easier to remove from the body in urine
3. Allows substances to be transported around the body in the blood

Which of the statements above are true?

Extended only

The shape and structure of molecules allows them to carry out their specific functions.

Which row of the table below correctly describes a feature of each molecule that makes it specific?

Extended

The diagrams below show an amylase enzyme catalysing the breakdown of part of a starch molecule into smaller molecules of maltose.

Which diagram has three correct labels?

The diagram shows a cross-section of part of a leaf

What is the name of the cell labelled X?

How does physical digestion help chemical digestion?

Extended only

Which row of the table below shows substances transported through the phloem and xylem, and the direction of transport, correctly?

Extended

The diagram below shows a vertical section through a human heart.

Which row of the following table has the correct names for the structures labelled in the diagram?

Below are statements about methods of controlling the spread of disease.

1. Boiling drinking water reduces the risk of transmitting waterborne pathogens
2. Disinfecting surfaces reduces the risk of transmitting pathogens via direct contact
3. Collecting food waste in sealed bins reduces the likelihood of animals spreading pathogens
4. Treating sewage before releasing it into rivers prevents the direct transmission of pathogens between individuals

Which statements are correct?

Some amphibians, such as frogs, can use their skin as a gas exchange surface.

What are the most likely characteristics of the surface of the skin in these amphibians?

Glucose is broken down in the chemical processes of aerobic respiration.

Which row of the table below shows the correct products of this breakdown?

What is urea produced from?

The image below shows a cell from the nervous system. The cell forms part of a reflex arc.

An impulse moves along the neurone from Q to P.

What structures would be found at P and Q?

Which statement best describes the mode of action of antibiotic drugs?

Which structure in the male reproductive system makes the fluid for sperm to swim in?

What is the transmission of genetic information from generation to generation called?

New strains of the crop plant wheat can be produced by cross-breeding disease resistant plants with those that give high yields of grain.

What is this an example of?

The food web shows the feeding relationships in a woodland.

If all the chaffinches in the food web die, which effect would this have?

Which of these describe the effect of nuclear fall-out pollution?

Which cell structure makes bacteria useful for genetic modification?

A student wanted to investigate the sensitivity of the skin to temperature change.

Fig. 1 shows part of their experimental set up.

Fig. 1

The students followed the following method:

1. Fill three beakers with water of a different temperatures: one with cold water at 10-15°C, one with warm water at 25°C, and one with hot water at 40-50°C.
2. Place the index finger of the left hand into the cold water and the index finger of the right hand into the hot water. Leave submerged for 2 minutes.
3. After 2 minutes remove both fingers from the hot and cold water and place them repeatedly, but alternately, into and out of the warm for one second at a time. Do this for 1 minute.
4. Record your observations of the sensations felt.

(i)

Identify one variable that needs to be kept constant throughout the experiment.

(ii)

Suggest how the student could make the test more reliable.

Extract:

A student wanted to investigate the sensitivity of the skin to temperature change.

Fig. 1 shows part of their experimental set up.

The students followed the following method:

1. Fill three beakers with water of a different temperatures: one with cold water at 10-15°C, one with warm water at 25°C, and one with hot water at 40-50°C.
2. Place the index finger of the left hand into the cold water and the index finger of the right hand into the hot water. Leave submerged for 2 minutes.
3. After 2 minutes remove both fingers from the hot and cold water and place them repeatedly, but alternately, into and out of the warm for one second at a time. Do this for 1 minute.
4. Record your observations of the sensations felt.

A second student also investigated the sensitivity of the skin. They used a hairpin to determine whether one or two prongs of a hairpin could be felt on different areas of the hand and arm.

1. One student closed their eyes whilst another used the hairpin to gently but firmly touch the skin with either one or two prongs for 1 second.
2. The student with their eyes closed guessed how many prongs were being pressed onto their skin.
3. The test was repeated with increasing gaps of the hair pin prongs on different areas of the hand and arm.

The aim was to determine the most sensitive area of those tested.

Fig. 2 shows the forearm being tested.

Fig. 2

Their results are shown in Table 1.

Table 1

(i)

Identify the variable that is measured (the dependent variable).

(ii)

Describe a source of error associated with the student's experiment.

(iii)

Explain improvements that could be made to overcome the source of error.

Extract:

Table 1

distance of hairpin prongs / mm | area of arm or hand | number of occasions on which the prong number was detected correctly 5 | palm | 2 | forearm | 1 | elbow | 1 10 | palm | 2 | forearm | 2 | elbow | 1 15 | palm | 2 | forearm | 2 | elbow | 2

Draw a graph of the students results shown in Table 1.

A scientist discovered a new organism and observed some cells from the organism. Table 1 below shows some of the features observed during examination.

Table 1

Suggest which Kingdom the organism belongs to using the observations recorded by the scientist.

Extended only

The scientist used DNA sequencing to further study the cells.

Explain why the scientist used DNA sequencing.

Extract:

African leopard: A-T-T-C-C-G-G-G-A-T-C-G-G-T-T-A-T-C-A African lion: A-G-T-G-T-A-G-A-A-A-C-T-T-T-A-C-T-A-C Cheetah: A-T-T-A-C-G-G-G-A-G-C-C-G-T-T-A-T-G-A African wildcat: G-T-A-C-G-A-T-G-T-A-G-C-A-T-A-G-T-G-G

Extended only

Table 2 shows the DNA base sequence of four species of cat.

Table 2

Explain which two species are most closely related.

Extended

Cats are animals that share some similarities and differences with prokaryotes.

Compare the main features of animals and prokaryotes.

Fig. 1 shows a photograph of a woodlouse.

Image courtesy of Donald Hobern. Licensed under Creative Commons Attribution 2.0 Generic license. Reused and distributed under conditions found at: https://creativecommons.org/licenses/by/2.0/deed.en.

Fig. 1

(i)

Draw a large diagram of the woodlouse in Fig.1.

(ii)

The magnification of the woodlouse in Fig.1 is ×9.

The length of line PQ is 48 mm.

Calculate the actual width of the woodlouse using the formula and the measurement of line PQ.

$\mathrm{magnification}=\frac{\mathrm{length} \mathrm{of} \mathrm{line} \mathrm{PQ}}{\mathrm{actual} \mathrm{width} \mathrm{of} \mathrm{woodlouse}}$

Give your answer to three significant figures.

Arrange the structures in the list in increasing order of organisation, starting with the smallest structure.

The first one has been done for you.

The boxes on the left show different parts of a flowering plant.

The boxes on the right are terms that describe different levels of organisation.

Draw one straight line from each part of a flowering plant to the correct level of organisation.

The boxes on the left show different parts of an animal.

The boxes on the right are terms that describe different levels of organisation.

Draw one straight line from each part of the animal to the correct level of organisation.

Fig. 1 shows a red blood cell.

The cell contains no nucleus.

Fig.1

Explain why a red blood cell does not contain a nucleus.

A student investigated the effect of the concentration of sugar solutions on osmosis in potato cells.

Step 1 The student labelled four test-tubes A, B, C and D.

Step 2 The volumes of 1 mol per dm³ sugar solution and distilled water shown in Table 1.1 were used to make solutions containing different concentrations of sugar in each test-tube.

(i) Complete Table 1.1 by writing in the concentration of the sugar solution in test-tube C.

Table 1.1

Step 3 The student was given four potato cylinders which had all been cut from one potato. The diameters of the potato cylinders were all the same but the lengths of the potato cylinders varied.

Step 4 The student cut all four potato cylinders to exactly 40mm in length.

Step 5 One potato cylinder was put into each labelled test-tube. The potato cylinders were left in the sugar solutions for 20 minutes.

Step 6 After 20 minutes the potato cylinders were removed from the test tubes.

Fig. 1.1 is a diagram showing the actual size of the potato cylinders from test-tubes A, B, C and D at the end of step 6.

(ii) Prepare a table to record the results in the space provided.

Measure the length of each of the potato cylinders in Fig. 1.1 and record these measurements in your table.

(iii) Explain why it was important that the potato cylinders were all cut to the same length in step 4.

(iv) Identify the variable that the student changed in this investigation (independent variable).

(v) Suggest two improvements that you could make to the method used in this investigation.

(vi) Describe one safety precaution that should be taken while preparing the potato cylinders in step 4.

Plan an investigation to find out the effect of temperature on osmosis in plant tissue.

Potato cells contain starch grains.

(i) State the solution that would be used to test for the presence of starch and give the result of a positive test.

Fig. 1.2 is a photomicrograph of some plant cells that contain starch grains.

(ii) Draw a large diagram of cell X in Fig. 1.2.

Label one starch grain on your drawing.

(iii) Line AB represents the diameter of the starch grain. Measure the length of line AB on Fig. 1.2.

length of line AB ................................................ mm

Calculate the actual diameter of the starch grain using your measurement for line AB, the information in Fig. 1.2 and the formula:

Give your answer to two significant figures.