AQA GCSE Combined Science: Trilogy Biology Paper 1 (Foundation), 2022: Question 6

14 marks · Standard Demand difficulty · Extended Answer

Identify biological structures by size, describe the cell cycle and differentiation, and compare human growth data from a graph.

Practise this question

Question

A multi-part exam question about cell division. It includes a list of structures to order by size (cell, chromosome, gene, nucleus). Figure 9 shows a diagram of a fertilized egg cell dividing into an embryo and then differentiating into red blood cells, muscle cells, and nerve cells via Process A. Figure 10 is a pie chart representing the cell cycle with three stages: Stage 1, Stage 2 (mitosis), and Stage 3. Figure 11 is a line graph showing the mean height in cm of boys and girls from birth to age 18, with two intersecting lines representing the different growth patterns.
Question text

06 This question is about cell division.

06.1 Write the biological structures from the box in the correct order of size.

[1 mark]

cell chromosome gene nucleus

Smallest

Largest

Figure 9 shows how a fertilised egg cell can produce specialised cells.

Figure 9

06.2 Name Process A.

[1 mark]

06.3 How many cell divisions are needed to form a 16-cell embryo from the original

fertilised egg cell?

[1 mark]

Number of cell divisions =

06.4 In humans a fertilised egg cell contains 23 pairs of chromosomes.

How many chromosomes will there be in each of the embryo cells?

[1 mark]

06.5 Figure 10 represents a cell cycle for a human embryonic cell.

Figure 10

Describe one change in the cell that occurs during each of the stages of the

cell cycle.

[3 marks]

Stage 1

Stage 2

Stage 3

Cell division is important in the growth of multicellular organisms.

06.6 Figure 11 shows the mean height of boys and of girls from birth to age 18 years.

Figure 11

Compare the growth of boys with the growth of girls.

Use data from Figure 11 in your answer.

[6 marks]

06.7 Give one way that cell division by mitosis is important in fully grown animals.

[1 mark]

Mark scheme

Show the mark scheme The mark scheme for Question 6. It lists the correct order for 06.1 as gene, chromosome, nucleus, cell. Process A is identified as differentiation. The number of cell divisions for 06.3 is 4. The number of chromosomes for 06.4 is 46. For 06.5, it describes changes in each stage of the cell cycle like DNA replication in Stage 1 and cytoplasm division in Stage 3. For 06.6, it provides a level-based marking grid for comparing the growth of boys and girls, with indicative content comparing heights and growth rates at various ages. For 06.7, it states mitosis is for tissue repair or cell replacement.

Question 6

AO /

Question Answers Extra information Mark

Spec. Ref.

06.1 gene must be in this order 1 AO1

4.1.1.1

chromosome 4.1.1.2

4.1.2.1

nucleus

cell

AO /

Spec. Ref.

06.2 differentiation ignore specialisation 1 AO1

4.1.1.4

AO /

Spec. Ref.

06.3 4 allow 15 1 AO2

4.1.2.2

AO /

Spec. Ref.

06.4 46 allow 23 pairs (of chromosomes) 1 AO2

4.1.2.1

– OMBINED SCIENCE: TRILOGY – – 4.1.2.2

AO /

Spec. Ref.

06.5 Stage 1 any one from: 1 AO1

• (cell) growth 4.1.2.2

• increase in number of sub- allow increase in number of

cellular structures organelles / ribosomes /

mitochondria

• DNA replicates allow genetic material for DNA

allow DNA doubles / duplicates

• chromosomes double /

duplicate / replicate

Stage 2 any one from: ignore mitosis occurs 1

• (one set of) chromosomes allow chromosomes line up

pulled to each end of cell across the centre of the cell

allow chromosomes move to

opposite ends of the cell

• two nuclei form allow nucleus divides / splits

(into two)

Stage 3 any one from: 1

• cytoplasm / membrane allow cytokinesis

divides

• two identical cells formed– OMBINED SCIENCE: TRILOGY – –

AO /

Question Answers Mark

Spec. Ref.

06.6 Level 2: Scientifically relevant features are identified; the way(s) in 4–6 AO3

which they are similar / different is made clear and (where

appropriate) the magnitude of the similarity / difference is noted.

Level 1: Relevant features are identified and differences noted. 1–3 AO2

– OMBINED SCIENCE: TRILOGY – –

No relevant content 0

Indicative content 4.1.2.2

General comparisons:

• boys height at birth (slightly) greater than girls height

• boys are (slightly) taller than girls up to age 11

• correct height comparisons eg boys are approximately 4 / 5 cm

taller than girls up to age 11

• girls and boys are the same height at age 11

• girls are taller than boys between age 11 and age 14

• girls and boys are the same height at age 14

• boys are taller than girls above age 14

• correct height comparisons eg boys are 5 to 18 cm taller than

girls above age 14

• boys (eventually) grow taller than girls

• boys carry on growing for a longer time than girls

• girls stop growing age 13 / 14 / 15 and boys stop growing age 17

/ 18

Rate comparisons:

• rate of growth similar up to age 10 / 11

• girls grow faster than boys between 10 / 11 and 14

allow girls have a greater increase in height between 11 and 14

• growth spurt occurs at a younger age in girls

• growth spurt starts age 10 / 11 in girls and age 13 / 14 in boys

• increased rate of growth in girls aged 10 to 13 /14 and in boys

aged 13 to 17 / 18

Key points for Level 2 are correct reference to 0-11 year period, 11-

26 14 period and after age 14, with at least one correct reference to

rate of growth or use of–correct values of height andOMBINED SCIENCE: TRIage to illustrateLOGY– –

rate.

AO /

Spec. Ref.

ignore growth

06.7 AO1

repair of tissues allow repair of organs 1 4.1.1.4

ignore repair of cells 27

or

replacement of cells allow replacement of tissues

ignore replacement of organs

Total Question 6 14

How to answer it

Cell Division, Mitosis, and Human Growth

What this question tests

This question assesses your understanding of biological hierarchy (size order), the process of cell differentiation, the stages of the cell cycle (mitosis), and your ability to interpret and compare complex graphical data regarding human growth rates.

Part (a): Biological Hierarchy

Question 06.1

💡 Key Knowledge

  • Gene: A small section of DNA.
  • Chromosome: Coiled up DNA containing many genes.
  • Nucleus: The organelle that contains chromosomes.
  • Cell: The basic unit of life containing the nucleus.

✅ Correct Order (Smallest to Largest)

  1. Gene
  2. Chromosome
  3. Nucleus
  4. Cell
[1 mark]

Part (b): Differentiation & Cell Counting

Questions 06.2 & 06.3

✅ Answers

06.2: Differentiation

06.3: 4 divisions

📐 Calculation: Cell Divisions

Cells double every division (2n):

  1. 1 cell → 2 cells (1st division)
  2. 2 cells → 4 cells (2nd division)
  3. 4 cells → 8 cells (3rd division)
  4. 8 cells → 16 cells (4th division)

Note: The mark scheme also allows "15" if you interpreted it as how many individual division events occur in total, but "4" is the standard expected answer.

❌ Common Errors

In 06.2, do not say "specialisation". While the cells become specialised, the process itself is called differentiation.

Part (c): Chromosomes & The Cell Cycle

Questions 06.4 & 06.5

🧠 Exam Technique: Describing Stages

For 06.5, the examiner wants to know what happens inside the cell. Avoid just naming the stage (e.g., don't just write "mitosis" for Stage 2).

✅ Correct Answers

06.4: 46 (or 23 pairs)

06.5 Stage 1: DNA replicates OR sub-cellular structures (like mitochondria) increase in number.

06.5 Stage 2: One set of chromosomes is pulled to each end of the cell.

06.5 Stage 3: The cytoplasm and cell membrane divide to form two cells.

💡 Mitosis Facts

  • Embryo cells are diploid body cells. They must have the full set of 46 chromosomes.
  • Mitosis produces genetically identical daughter cells.

Part (d): Data Analysis (Growth Graph)

Question 06.6

6 Mark Extended Response

🧠 How to get 6 Marks (Level 2)

To reach the top marks, you must compare similarities and differences, mention rates of growth, and use specific data points (ages and heights) from the graph.

✅ Model Answer Points

  • Birth to Age 11: Boys are slightly taller than girls (e.g., 4-5 cm taller).
  • Age 11 to 14: Girls grow faster than boys and become taller than them.
  • Age 14 to 18: Boys have a growth spurt, overtake girls, and end up taller.
  • Final Height: Boys continue growing until 17/18, whereas girls' growth levels off around 14/15.

❌ Common Pitfalls

Students often forget to mention that at Age 11 and Age 14, the heights are actually the same (where the lines cross). Mentioning these "cross-over" points is key for high marks.

Part (e): Mitosis in Adults

Question 06.7

✅ Correct Answer

Repair of tissues OR replacement of cells.

[1 mark]

❌ The "Fully Grown" Trap

The question specifies fully grown animals. Therefore, you cannot say "for growth". If an animal is fully grown, it is no longer increasing in size; it is only maintaining its body.

Summary Diagram Description

If you were to draw the cell cycle (06.5), Stage 1 should be the largest part of the pie chart (Interphase). Stage 2 (Mitosis) shows the nucleus splitting, and Stage 3 (Cytokinesis) shows the cell pinching into two.

Topics

Biology · B1: Cell Biology

Question and mark scheme from the AQA GCSE Combined Science: Trilogy examination, Biology Paper 1 (Foundation), 2022. QuestionVault is an independent revision resource; questions remain the copyright of the awarding body.