CIE iGCSE Co-Ordinated Science B2.1 Cell structure Exam Style Questions Paper 3
Question
(a) Fig. 10.1 shows the activity of some bacterial enzymes at different temperatures.
Complete the sentences to describe the results in Fig. 10.1.
The only two enzymes active at 60°C are enzymes ………………….. and ……………………
The greatest activity for enzyme E is at ………………….. °C.
The enzyme active over the greatest range of temperatures is enzyme ……………………
(b) State one factor, other than temperature, that affects enzyme activity.
………………………………………………………………………………………………………………………..
(c) Enzymes are proteins.
Circle the elements that all proteins are made from.
carbon calcium hydrogen
oxygen nitrogen
(d) State the name of the solution used to test for the presence of protein.
……………………………………………………………………………………………………………………………
(e) The boxes on the left show some biological molecules.
The boxes on the right show the smaller molecules they are made from.
Draw lines to link each biological molecule to all the smaller molecules they are made from.
▶️Answer/Explanation
Ans : 10(a) C ;
D ;
95 (°C) ;
C ;
10(b) pH / avp ;
10(c) carbon, hydrogen, oxygen and nitrogen all circled ;
10(d) biuret ;
10(e)
;;;
Question
(a) Fig. 1.1 is a diagram of a plant cell.
(i) State the letter in Fig. 1.1 that identifies the part:
that strengthens the cell …………………..
where photosynthesis occurs …………………..
where genetic material is stored. …………………..
(ii) State two letters that identify cell structures in Fig. 1.1 that are present in both animal and plant cells.
(b) Fig. 1.2 is a photomicrograph of a plant cell.
(i) State the two values you need to be able to calculate the actual size of the plant cell.
(ii) Complete the sentences to describe the effect of immersion in pure water on the plant cell in Fig. 1.2.
Use words or phrases from the list.
Each word or phrase may be used once, more than once or not at all.
amino acids assimilation glucose
osmosis partially permeable respiration
vacuole water
There is an increase in the size of the plant cell ……………………………………………………… .
This is because ……………………………………………………… enters the plant cell through the …………………………………………………….. membrane.
This process is called …………………………………………………….. .
▶Answer/Explanation
Ans:
1(a)(i) D ;
B ;
E ;
1(a)(ii) any two from:
A ;
E ;
F ;
1(b)(i) image size ;
magnification ;
1(b)(ii) vacuole ;
water ;
partially permeable (membrane) ;
osmosis ;
Question
(a) A person touches a hot pan and instantly removes their hand.
This is a reflex action.
The reflex arc is shown in Fig. 10.1.
(i) State the names of the stimulus and the effector in this reflex arc.
stimulus …………………………………………………………………………
effector …………………………………………………………………………
(ii) State the name of the neurone labelled X in Fig. 10.1.
(iii) The spinal cord is one part of the central nervous system.
State the name of the other part of the central nervous system.
(b) Neurones are the longest cells in the body.
One neurone measures 1.5 m in length.
One plant cell measures 0.1 mm in length.
Calculate how many times longer the neurone is than the plant cell.
(c) Hormones and nerve impulses both carry information around the body.
Identify if each statement is about hormones or nerve impulses.
They are carried in the blood. …………………………………………………………………………………….
They are produced by glands. …………………………………………………………………………………….
They are electrical signals. ………………………………………………………………………………………….
(d) Adrenaline is a hormone released in ‘fight or flight’ situations.
Describe two effects of adrenaline on the body.
1 …………………………………………………………………………
2 …………………………………………………………………………
▶️Answer/Explanation
Ans : 10(a)(i) stimulus – (change in) temperature ;
effector – muscle (in arm) ;
10(a)(ii) X – motor neurone ;
10(a)(iii) brain ;
10(b) evidence of conversion ;
(1500 / 0.1 or 1.5 / 0.0001) = 15000 / 1.5 × 104 ;
10(c) hormone
hormone
nerve impulse ;;
10(d) any two from:
increased depth of breathing / breathing rate ;
increased pulse rate / heart rate ;
widened pupils ;
AVP ;;
Question
(a) Fig. 1.1 is a diagram of a plant cell.
(i) Identify the letter from Fig. 1.1 that represents the part of the plant cell:
where photosynthesis occurs ………………………………………………………………………………..
where the genetic material is found ……………………………………………………………………….
that controls what substances enter the cell ……………………………………………………………
(ii) State the name of the part labelled B in Fig. 1.1.
…………………………………………………………………………………………………………………….
(iii) State the name of two structures in plant cells that are not found in animal cells.
1 ……………………………………………………………………………………………………………………….
2 ……………………………………………………………………………………………………………………….
(b) A student immerses pieces of potato in different concentrations of sucrose solution for 5 minutes.
The student measures the length of the potato before and after immersion.
Table 1.1 is a summary of the results.
(i) Use Table 1.1 to calculate the change in length of the potato when it is placed in the 0.4mol/dm$^{3}$ sucrose solution.
……………………………………………………………………………………………………………… mm
(ii) Complete the sentences to describe and explain the results in Table 1.1.
The potato with the smallest change in length has been immersed in a sucrose solution
with a concentration of ………………………………….. mol/dm$^{3}$.
The potato immersed in 0.8mol/dm$^{3}$ sucrose solution changed by ……………………….. mm in length.
The potato immersed in 0.2mol/dm$^{3}$ sucrose solution increases in length because water
is absorbed by the potato cells by the process of ………………………………….. .
▶️Answer/Explanation
Ans: 1(a)(i) A ;
E ;
D ;
1(a)(ii) cytoplasm ;
1(a)(iii) any two from:
chloroplast ;
vacuole ;
cell wall ;
1(b)(i) (+) 1.1 (mm) ;
1(b)(ii) 0.6 ;
(–) 1.1 ;
osmosis ;
Question
(a) Scientists investigate diffusion by measuring the distance travelled by two different dyes X and Y. They place the dyes on agar plates and measure the distance travelled every 15 seconds. Fig. 4.1 shows the results plotted on a graph. (Sub-topic – B3.1)
(i) Describe the general trend shown by both dyes in Fig. 4.1.
▶️Answer/Explanation
The general trend shown by both dyes is that the distance travelled increases with time. This indicates that diffusion is occurring, and the dyes are spreading out from their original position over time.
(ii) The dyes move through the agar by diffusion. The scientists calculate the average rate of diffusion for dye X after 30 seconds as:
\[ \frac{\text{distance travelled}}{\text{time taken}} = \frac{11}{30} = 0.37 \, \text{mm/s} \]
Calculate the average rate of diffusion for dye Y after 30 seconds.
▶️Answer/Explanation
From the graph, the distance travelled by dye Y after 30 seconds is 6 mm. Therefore, the average rate of diffusion for dye Y is:
\[ \frac{6 \, \text{mm}}{30 \, \text{s}} = 0.2 \, \text{mm/s} \]
(b) Describe the direction of motion of particles during diffusion. (Sub-topic – B3.1)
▶️Answer/Explanation
During diffusion, particles move from a region of higher concentration to a region of lower concentration. This movement occurs due to the random motion of particles, and it continues until the concentration of particles is uniform throughout the medium.
(c) Substances move into and out of cells by diffusion. (Sub-topic – B3.1)
(i) State the part of the cell that controls the movement of substances in and out of the cell.
▶️Answer/Explanation
The cell membrane controls the movement of substances in and out of the cell.
(ii) Circle two substances that diffuse into cells for respiration.
carbon dioxide fatty acids glucose oxygen starch water
▶️Answer/Explanation
The two substances that diffuse into cells for respiration are glucose and oxygen.
(d) Table 4.1 shows some components of plant cells and their function. Complete Table 4.1.
| Component of Plant Cell | Function |
|---|---|
| Vacuole | Contains cell sap to support the plant cell |
| Cytoplasm | Where chemical reactions occur / contains the cell structures / contains enzymes |
| Chloroplast | Where photosynthesis occurs |
▶️Answer/Explanation
The completed table is as follows:
| Component of Plant Cell | Function |
|---|---|
| Vacuole | Contains cell sap to support the plant cell |
| Cytoplasm | Where chemical reactions occur / contains the cell structures / contains enzymes |
| Chloroplast | Where photosynthesis occurs |
Question
(a) A researcher collects some information about organisms that live in a desert environment.
Fig. 10.1 is a summary of the information.
(i) Construct a food chain from the information given in Fig. 10.1.
…………………………………………………………………………………………………………………….
(ii) Table 10.1 contains the names of the organisms from Fig. 10.1 and some of the terms that can be used to describe them.
Complete Table 10.1 by placing ticks (√) in the boxes to show all the terms that describe each organism. Use only the information given in Fig. 10.1.
One row has been done for you.
(b) State the name of the type of organisms that get their energy from dead and waste organic matter.
……………………………………………………………………………………………………………………………
(c) State the name of the principal source of energy for all food chains.
……………………………………………………………………………………………………………………………
(d) Nutrition is one of the characteristics of living things.
State the name of three other characteristics.
1 ………………………………………………………………………………………………………………………………
2 ………………………………………………………………………………………………………………………………
3 ………………………………………………………………………………………………………………………………
(e) State the name of the basic building blocks of which all living organisms are made.
…………………………………………………………………………………………………………………………………
▶️Answer/Explanation
Ans: 10(a)(i) cactus → desert rats → snake → desert fox ;;
10(a)(ii)
1 mark for each correct row ;;;
10(b) decomposer ;
10(c) Sun ;
10(d) any three from:
movement ;
respiration ;
sensitivity ;
growth ;
reproduction ;
excretion ;
10(e) cells ;
Question
10. (a) (iv) State one function of root hair cells.
▶️Answer/Explanation
Answer: 
absorption (of water / mineral ions)
Sub-topic Code: B2.1 (Cell Structure)
Detailed Solution: Root hair cells are specialized for absorbing water and mineral ions from the soil.
10. (b) Calculate how many times longer this plant cell is compared to this animal cell.
▶️Answer/Explanation
Answer: 2.5
Sub-topic Code: B2.1 (Cell Structure)
Detailed Solution: The plant cell is 0.05 mm long, and the animal cell is 0.02 mm long. The plant cell is \( \frac{0.05}{0.02} = 2.5 \) times longer than the animal cell.
10. (c) State which type of animal cell transports oxygen.
▶️Answer/Explanation
Answer: red blood cell
Sub-topic Code: B8.1 (Circulatory System)
Detailed Solution: Red blood cells are specialized for transporting oxygen from the lungs to the rest of the body.
Question(a)
Fig. 1.1 is a diagram of a single-celled organism called a euglena.
(i) Table 1.1 shows some of the cell components of animal, euglena and plant cells. Complete Table 1.1 by placing ticks (✓) to show the correct cell components of each type of cell.
Use the information in Fig. 1.1 and your knowledge to answer the question.
| Type of cell | Cell wall | Chloroplast | Nucleus | Vacuole |
|---|---|---|---|---|
| Animal | ✓ | |||
| Euglena | ✓ | ✓ | ||
| Plant | ✓ | ✓ | ✓ | ✓ |
(ii) State evidence from Fig. 1.1 for and against euglena being a plant cell.
Evidence for: Euglena has chloroplasts, which are typically found in plant cells.
Evidence against: Euglena does not have a cell wall or a large central vacuole, which are characteristic of plant cells.
▶️Answer/Explanation
Answer:
(i) The completed table is shown above.
(ii) Evidence for: Euglena has chloroplasts, which are typically found in plant cells.
Evidence against: Euglena does not have a cell wall or a large central vacuole, which are characteristic of plant cells.
Question(b)
State the function of the nucleus.
The nucleus controls the cell’s activities and contains genetic material (DNA).
▶️Answer/Explanation
Answer: The nucleus controls the cell’s activities and contains genetic material (DNA).
Question(c)
The length of a palisade cell is 0.08 mm. The length of a red blood cell is 0.007 mm. Calculate how many times bigger a palisade cell is than a red blood cell. Give your answer to the nearest whole number.
To calculate how many times bigger the palisade cell is compared to the red blood cell, divide the length of the palisade cell by the length of the red blood cell:
\[ \text{Number of times bigger} = \frac{0.08 \, \text{mm}}{0.007 \, \text{mm}} \approx 11.428 \]
Rounding to the nearest whole number, the palisade cell is approximately 11 times bigger than the red blood cell.
▶️Answer/Explanation
Answer: 0.08÷ 0.007 or 11.428 ;
11 ;
Question(d)
Fig. 1.2 shows a type of nerve cell (neurone)
(i) Name the type of neurone shown in Fig. 1.2.
The type of neurone shown is a sensory neurone.
(ii) The type of neurone shown in Fig. 1.2 can be 1.5 m in length. Suggest why these cells need to be very long.
These cells need to be very long to transmit impulses over large distances, such as from the extremities of the body to the central nervous system.
▶️Answer/Explanation
Answer:
(i) The type of neurone shown is a sensory neurone.
(ii) These cells need to be very long to transmit impulses over large distances, such as from the extremities of the body to the central nervous system.