2023 Cambridge IGCSE Biology (0610) 模拟试题及答案详解

Plant tissue is placed into a concentrated sucrose solution that has a lower water potential than the cell cytoplasm.

Which row correctly identifies the net direction of water movement and the resulting state of the plant cells?

Which row correctly compares the products of anaerobic respiration in yeast cells with the products of anaerobic respiration in human muscle cells?

What changes occur in the diaphragm and external intercostal muscles during inspiration in humans?

A mixture of starch solution and salivary amylase is incubated at \(37\text{ }^\circ\text{C}\) at pH 7.0.

Samples are tested at the beginning of the experiment and after 30 minutes using iodine solution and Benedict's solution.

Which row shows the expected observations?

Which statement correctly describes a step in protein synthesis?

Which row correctly compares aerobic respiration with anaerobic respiration in human muscle cells?

Four identical cylinders of potato tissue, each with an initial mass of \(5.0\text{ g}\), were placed into test-tubes containing sucrose solutions of different concentrations: \(0.0\text{ mol/dm}^3\), \(0.2\text{ mol/dm}^3\), \(0.4\text{ mol/dm}^3\), and \(0.8\text{ mol/dm}^3\). The water potential of the potato tissue is equivalent to a \(0.3\text{ mol/dm}^3\) sucrose solution. Which row shows the expected final masses of the cylinders after \(2\text{ hours}\)?

Which changes occur to the diaphragm and the volume of the thorax during inspiration in humans?

An investigation was carried out to measure the rate of photosynthesis of an aquatic plant at various light intensities. The temperature was maintained at \(20\text{ }^\circ\text{C}\) and the carbon dioxide concentration was \(0.04\%\). Above \(50\text{ arbitrary units}\) of light intensity, the rate of photosynthesis reached a plateau. When the carbon dioxide concentration was increased to \(0.10\%\) at \(60\text{ arbitrary units}\), the rate of photosynthesis increased significantly. What was the limiting factor for photosynthesis at \(60\text{ arbitrary units}\) of light intensity and \(0.04\%\) carbon dioxide?

Which row correctly identifies a digestive enzyme, the organ that secretes it into the alimentary canal, and the main products of its chemical reaction?

The table compares features of aerobic respiration with anaerobic respiration in human muscle cells. Which row correctly identifies features of aerobic respiration? [Row A: Oxygen used: Yes | Lactic acid produced: No | Relative energy released per glucose molecule: High] [Row B: Oxygen used: Yes | Lactic acid produced: Yes | Relative energy released per glucose molecule: Low] [Row C: Oxygen used: No | Lactic acid produced: No | Relative energy released per glucose molecule: High] [Row D: Oxygen used: No | Lactic acid produced: Yes | Relative energy released per glucose molecule: Low]

Cylinders of potato tissue of equal initial mass were placed in sucrose solutions of different concentrations for 2 hours. In a 0.6 mol dm\(^{-3}\) sucrose solution, the mass of the potato cylinder decreased by 5.5%. Which statement explains this change in mass?

Which set of actions occurs during inspiration (breathing in) in a human?

An experiment investigated the rate of photosynthesis in an aquatic plant. Carbon dioxide was supplied in excess. At a low light intensity of 400 lux, increasing the temperature from 15 °C to 25 °C produced no change in the rate of photosynthesis. What was the limiting factor for photosynthesis at 400 lux?

Which row correctly matches a digestive enzyme, its site of secretion, its substrate, and its main product?

During vigorous exercise, human muscle cells respire anaerobically.

Which row shows the product formed in the muscle cells and explains why an oxygen debt occurs?

Four identical potato cylinders were placed into test-tubes containing sucrose solutions of different concentrations. After two hours, the change in mass of each cylinder was recorded.

Which cylinder showed the greatest net movement of water out of its cells by osmosis?

Which row correctly describes the actions of the diaphragm and external intercostal muscles, and the resulting air pressure inside the lungs, during inspiration in a human?

A student investigated the effect of light intensity on the rate of photosynthesis in an aquatic plant. As light intensity increased above a certain level, the rate of photosynthesis remained constant.

Which statement explains why the rate remained constant?

Which row correctly identifies where bile is produced, where it is stored, and its main role in the digestive system?

Which row correctly identifies the products of aerobic respiration in human muscle cells and anaerobic respiration in yeast cells?

Cylinders of potato tissue of identical initial mass were placed in four sucrose solutions of different concentrations, P, Q, R, and S. After 60 minutes, the percentage change in mass was measured:

• Solution P: \(+8.5\%\)
• Solution Q: \(-4.2\%\)
• Solution R: \(0.0\%\)
• Solution S: \(-12.1\%\)

Which sequence places the solutions in order from the lowest water potential to the highest water potential?

What happens to the diaphragm and the external intercostal muscles during expiration at rest?

A sample of double-stranded DNA contains \(1200\) base pairs. Analysis shows that \(28\%\) of all the nitrogenous bases are cytosine (C).

How many adenine (A) bases are present in this sample of DNA?

A photomicrograph shows an organelle with an image length of \(18\text{ mm}\). The magnification of the image is \(\times 3000\).

What is the actual length of the organelle in micrometres (\(\mu\text{m}\))?

Which statement describes what happens to lactic acid produced in human muscle cells during vigorous exercise?

Four fresh potato cylinders, each measuring \(50\text{ mm}\) in length, were placed into four test-tubes containing sucrose solutions of different concentrations: P, Q, R, and S.

After 3 hours, their lengths were measured:
- Solution P: \(54\text{ mm}\)
- Solution Q: \(50\text{ mm}\)
- Solution R: \(47\text{ mm}\)
- Solution S: \(43\text{ mm}\)

Which statement is correct?

Which row correctly shows the actions of the muscles and the change in volume of the thorax during inspiration in a human?

An investigation was carried out to determine the effect of temperature on the rate of an enzyme-catalysed reaction.

Which statement explains why the rate of reaction decreases rapidly at temperatures significantly above the optimum temperature?

A student measured the rate of photosynthesis in an aquatic plant at different light intensities while keeping the temperature constant at \(20^\circ\text{C}\) and carbon dioxide concentration constant at \(0.03\%\).

At high light intensities, further increases in light intensity did not increase the rate of photosynthesis.

Which factor is limiting the rate of photosynthesis at these high light intensities?

Which row correctly compares anaerobic respiration in yeast cells with anaerobic respiration in human muscle cells?

Four identical potato cylinders, each with an initial mass of 2.00 g, were placed into four different concentrations of sucrose solution (P, Q, R, and S) for 60 minutes. The final masses were recorded:
• Solution P: 2.45 g
• Solution Q: 2.00 g
• Solution R: 1.65 g
• Solution S: 1.85 g

Which solution had the highest water potential?

Which set of changes occurs in the human thorax during inspiration at rest?

An investigation was carried out to measure the rate of photosynthesis in an aquatic plant. Light intensity and dissolved carbon dioxide concentration were maintained at very high levels, but the temperature was maintained at \(10\ ^\circ\text{C}\). Further increases in light intensity did not increase the rate of photosynthesis.

What was the limiting factor under these conditions?

Which row correctly identifies the organ of secretion, the substrate, and the optimum pH for the enzyme pepsin?

During vigorous exercise, anaerobic respiration takes place in human muscle cells. What happens to the lactic acid produced by this process during the recovery period?

Cylinders of potato tissue with an internal water potential of \(-600\text{ kPa}\) were placed into four different sucrose solutions. In which sucrose solution will the plant cells become plasmolysed and show the greatest decrease in mass?

Which row correctly identifies the state of the muscles and the volume change in the thorax during normal expiration at rest?

An investigation was conducted into the rate of photosynthesis of an aquatic plant at different light intensities and temperatures. Carbon dioxide concentration was kept high and constant throughout.

At \(10^\circ\text{C}\), the rate of photosynthesis reached a maximum at a light intensity of \(40\text{ arbitrary units}\) and did not increase further when light intensity was increased to \(60\text{ arbitrary units}\).

At \(25^\circ\text{C}\), the rate of photosynthesis continued to increase up to \(80\text{ arbitrary units}\).

What was the factor limiting the rate of photosynthesis at a light intensity of \(60\text{ arbitrary units}\) at \(10^\circ\text{C}\)?

Which statement correctly describes the sequence of events during protein synthesis in a cell?

1 Respiration is a fundamental metabolic process occurring in all living cells.

(a) Define the term aerobic respiration. [2]

(b) An investigation was carried out to determine the effect of temperature on anaerobic respiration in yeast (Saccharomyces cerevisiae). Suspensions of yeast in 5% glucose solution were incubated in water baths at five different temperatures. The volume of carbon dioxide gas evolved in 10 minutes was recorded.

Table 1.1 shows the results.

Table 1.1

| Temperature / °C | Volume of carbon dioxide collected in 10 min / cm³ |
| :--- | :--- |
| 20 | 12 |
| 30 | 28 |
| 40 | 42 |
| 50 | 22 |
| 60 | 0 |

(i) State the balanced chemical equation for anaerobic respiration in yeast. [2]

(ii) Using the data in Table 1.1, calculate the percentage increase in the volume of carbon dioxide collected when the temperature increased from 20 °C to 40 °C.

Space for working.

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

(iii) Explain why the volume of carbon dioxide evolved decreased when the temperature was increased from 40 °C to 60 °C. [3]

(c) During strenuous sprint exercise, human muscle cells respire anaerobically, producing lactic acid.

Describe what happens to lactic acid in the body after exercise has ceased to remove the oxygen debt. [4]

[Total: 13]

2 Plant tissues interact dynamically with their surrounding aqueous environment via osmosis.

(a) Define the term osmosis. [3]

(b) Cylinders of fresh potato tissue were cut to exactly 50 mm in length and weighed. Each cylinder had an initial mass of 5.00 g. Cylinders were immersed in sucrose solutions of concentrations 0.0, 0.2, 0.4, 0.6, and 0.8 mol/dm³ for 60 minutes.

(i) Explain why the potato cylinder placed in the 0.0 mol/dm³ (pure water) solution gained mass. [3]

(ii) The cylinder placed in 0.8 mol/dm³ sucrose solution had a final mass of 4.15 g.

Calculate the percentage change in mass of this potato cylinder.

Space for working.

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

(iii) State the condition of the cells in the potato cylinder after 60 minutes in 0.8 mol/dm³ sucrose solution, and describe their microscopic appearance. [2]

(c) Explain how water moves continuously from the root hair cells through the root cortex into the xylem vessels. [3]

[Total: 13]

3 The human gas exchange system is adapted to allow efficient diffusion of oxygen and carbon dioxide.

(a) Describe the mechanism of inspiration (breathing in) in a healthy human. [4]

(b) State three structural features of alveoli and explain how each feature adapts them for efficient gas exchange. [3]

(c) Cigarette smoke contains many harmful components, including carbon monoxide and tar.

(i) Describe the physiological effect of inhaling carbon monoxide on oxygen transport in the human body. [2]

(ii) Explain how tar damages the lining of the respiratory tract and leads to chronic bronchitis. [4]

[Total: 13]

4 Photosynthesis is the process by which plants manufacture carbohydrates from raw materials using light energy.

(a) State the balanced chemical equation for photosynthesis. [2]

(b) A student investigated the effect of light intensity on the rate of photosynthesis in the water plant Cabomba caroliniana.

The plant was placed in a beaker containing dilute sodium hydrogencarbonate solution. An LED lamp was placed at various distances from the beaker, and the number of oxygen bubbles released per minute was counted.

(i) State the independent variable and the dependent variable in this investigation. [2]

(ii) State two variables that must be controlled in this experiment and describe how each is kept constant. [4]

(c) In another experiment, the rate of photosynthesis of leaf discs was measured under varying light intensities at two different carbon dioxide concentrations (0.04% and 0.12%) at a constant temperature of 25 °C.

Describe and explain the effect of increasing light intensity on the rate of photosynthesis at both carbon dioxide concentrations. [5]

[Total: 13]

5 The human alimentary canal processes ingested food through mechanical and chemical digestion prior to absorption.

(a) State the precise site of production and the site of action for each of the following substances:

(i) Salivary amylase [2]

(ii) Hydrochloric acid [2]

(b) Explain the functions of bile in the digestion and processing of dietary lipids in the duodenum. [3]

(c) The ileum is the main site of nutrient absorption.

(i) State the names of two internal structures found inside an individual villus that transport absorbed nutrients away from the small intestine. [2]

(ii) Describe four adaptations of the small intestine that ensure rapid and efficient absorption of digested food molecules. [4]

[Total: 13]

1 (a) State two features of the gas exchange surface in humans. [2]

(b) A student investigated the ventilation of an athlete at rest and during vigorous exercise.

Table 1.1 shows the data collected.

Table 1.1

| Parameter | At rest | During vigorous exercise |
| :--- | :--- | :--- |
| breathing rate / breaths per minute | 12 | 32 |
| tidal volume / dm\(^3\) | 0.50 | 2.25 |
| minute ventilation / dm\(^3\) per minute | 6.00 | X |

(i) Calculate the percentage increase in tidal volume during vigorous exercise compared with at rest.

Space for working.

\(\text{percentage increase} =\) ........................................................... % [2]

(ii) Calculate the minute ventilation, X, during vigorous exercise.

Space for working.

\(\text{minute ventilation} =\) ........................................................... dm\(^3\) per minute [1]

(c) Describe the mechanism that causes inspiration (inhalation) in humans. [4]

(d) Explain why an athlete's breathing rate and breathing depth remain higher than resting values for several minutes after vigorous exercise has stopped. [4]

[Total: 13]

1 A student investigated the effect of glucose concentration on the rate of anaerobic respiration in yeast (Saccharomyces cerevisiae).

The student used the following method:
• Step 1: Prepared five test-tubes, each containing \(10\text{ cm}^3\) of yeast suspension.
• Step 2: Added \(10\text{ cm}^3\) of glucose solution of known concentration (\(0.0\), \(2.0\), \(4.0\), \(6.0\), and \(8.0\%\)) to each test-tube.
• Step 3: Placed a layer of liquid paraffin oil on top of each mixture.
• Step 4: Fitted a bung with a delivery tube connected to an inverted measuring cylinder filled with water.
• Step 5: Kept all test-tubes in a water-bath at \(35^\circ\text{C}\) for \(15\text{ minutes}\).
• Step 6: Recorded the volume of gas collected in the measuring cylinder after \(15\text{ minutes}\).

The results are shown in Table 1.1.

Table 1.1


glucose concentration / %
volume of gas collected in \(15\text{ minutes}\) / \(\text{cm}^3\)
mean volume of gas collected / \(\text{cm}^3\)
rate of gas production / \(\text{cm}^3\text{ per minute}\)


trial 1
trial 2
trial 3


0.0
0.3
0.2
0.4
0.3
0.02


2.0
3.1
3.4
3.1
3.2
0.21


4.0
5.9
6.2
6.5
6.2
0.41


6.0
8.4
8.7
8.4
8.5
[A]


8.0
9.2
8.9
9.2
9.1
0.61



(a) (i) Calculate the rate of gas production for the \(6.0\%\) glucose concentration at [A] in Table 1.1. Give your answer to two decimal places. [1]

(ii) Plot a line graph on the grid of glucose concentration on the x-axis against the rate of gas production on the y-axis. [4]

(iii) Describe the relationship between glucose concentration and the rate of gas production shown in Table 1.1. [2]

(iv) State the purpose of the layer of liquid paraffin oil added in Step 3. [1]

(v) State two variables that were kept constant in this investigation. [2]

(vi) Identify one source of experimental error in Step 6 and suggest an improvement to minimise this error. [2]

(vii) State the chemical reagent used to test for the gas produced by yeast respiration and describe the positive observation. [2]

(b) Plan an investigation to determine the effect of pH on the rate of respiration in yeast. [6]

2 Plant tissues can be investigated to determine cell structure, nutrient content, and water relations.

(a) Fig. 2.1 is a photomicrograph of a cross-section through a plant stem showing vascular bundles and cortical tissue.


[ PHOTOMICROGRAPH: Fig. 2.1 ]
Outer epidermis ---
Cortex ------------
Vascular bundle ---
Pith (central) ----
Line AB = 48 mm


(i) Make a large, clear biological line drawing of the sector of the stem showing the arrangement of tissues from the outer epidermis to the central pith. Do not draw individual cells. [4]

(ii) The line AB on Fig. 2.1 represents the actual diameter across one vascular bundle.
The measured length of line AB is \(48\text{ mm}\).
The actual width of the vascular bundle is \(0.60\text{ mm}\).

Calculate the magnification of Fig. 2.1.

Use the formula:
\[\text{magnification} = \frac{\text{length of line } \mathbf{AB}}{\text{actual width}}\]

Give your answer to two significant figures. [2]

(b) A student tested a sample of the plant stem tissue for two biological molecules: reducing sugars and starch.

Complete Table 2.1 to state the test reagent used, the procedure, and the positive observation for each biological molecule.

Table 2.1


biological molecule
reagent / test solution
method / procedure
positive result


reducing sugar
................................................
................................................
................................................


starch
................................................
add drops to sample at room temperature
................................................


[4]

(c) Another student investigated osmosis in plant tissue by placing cylinders of potato tissue of equal initial length (\(50\text{ mm}\)) into different concentrations of sucrose solution for \(60\text{ minutes}\).

The results are shown in Table 2.2.

Table 2.2


concentration of sucrose solution / \(\text{mol/dm}^3\)
initial mass / \(\text{g}\)
final mass / \(\text{g}\)
change in mass / \(\text{g}\)
percentage change in mass / \(\%\)


0.0
3.20
3.68
+0.48
+15.0


0.2
3.15
3.40
+0.25
+7.9


0.4
3.25
3.25
0.00
[X]


0.6
3.30
3.04
-0.26
-7.9


0.8
3.10
2.67
-0.43
[Y]



(i) Calculate the percentage change in mass for:
• \(0.4\text{ mol/dm}^3\) sucrose solution at [X]
• \(0.8\text{ mol/dm}^3\) sucrose solution at [Y]. Give your answer to one decimal place.

Space for working.

[X] .................................... %
[Y] .................................... %
[2]

(ii) Using the data in Table 2.2, state the estimated concentration of sucrose inside the potato cells. Explain your answer. [2]

(iii) Explain why the student calculated the percentage change in mass rather than using only the change in mass. [1]

(iv) State two variables that were kept constant in this osmosis investigation. [2]

(v) Suggest why the student blotted the potato cylinders with a paper towel before weighing them, and explain how failing to do so would affect the calculated percentage change in mass. [3]