Edexcel GCSE Biology

Topic Questions

2.2 Growth in Organisms

1a
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1 mark

Which of the following gives an accurate description of growth in animals and plants?

  A A permanent change in shape or size
  B Cell differentiation and cell division
  C A permanent increase in size or mass
  D Cell division and cell elongation

1b1 mark

Growth charts can be used to monitor the growth of babies.

Explain why this may be important.

1c
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2 marks
(i)

 A baby is measured to be on the 75th percentile for mass.

Explain what this means.

(1)

(ii)

The median birth weight of a baby boy in the UK is 7.8 lbs (3.5 kg).

If a baby boy is born weighing 7.8 lbs (3.5 kg), what percentile would he be on?

(1)

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2a
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1 mark

State the name of the process by which cells become specialised.

2b
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2 marks

An unspecialised bone marrow stem cell develops into a red blood cell.

Describe the changes which occur in an unspecialised cell in order for the cell to become a specialised cell such as a red blood cell.

2c
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1 mark

State the importance of cell specialisation for an organism.

2d
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2 marks

Cell specialisation is different in cells of plants compared to animals.

(i)

Which of the following correctly describes cell specialisation in plants?

(1)

  A Only some plant cells can become specialised
  B Plant cells become specialised during the embryonic stage
  C Most types of plant cell have the ability to become specialised into different cell types
  D All plant cells are examples of stem cells

(ii)

Which of the following incorrectly describes cell specialisation in animals?

(1)

  A Cell elongation occurs during the specialisation process of animal cells
  B Most animal cells become specialised early 
  C Adult stem cells retain the ability to become specialised into different cell types
  D When animal cells become specialised, they perform different functions

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3a
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4 marks

Fig. 1 shows a growth chart for baby boys showing how their mass changes between birth and 24 months.


growth-chart-sq

Fig. 1

(i)

Give the mass of a child which was born in the 90th percentile.

(1)
(ii)

At 6 months, the child had a mass of 8kg.

Identify which percentile the child was on at 6 months.

(1)

(iii)

The midwife monitoring the child was not concerned about the change in percentile readings for this child.

Suggest why.

(2)
3b
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2 marks

For the child in part (a) (ii), calculate the child's average gain in mass per month.

3c
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2 marks

Babies that are born before 37 weeks of pregnancy are termed premature. There are growth charts specifically for monitoring the growth of premature infants until they reach the predicted due date for birth. At this point, the standard birth chart can be used.

Suggest why premature infants must be monitored in this way.

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4a
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3 marks

Plant growth occurs through three different cellular processes;

  • division
  • differentiation
  • elongation

Describe these processes in the context of plant growth.

4b
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1 mark

Name the key hormone responsible for cell elongation in plant cells.

4c
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3 marks

A stimulus is a change which triggers a response.

(i)

Identify the stimulus which activates the hormone discussed in part (b)

(1)

(ii)

Suggest why it is important that plant cells respond to the stimulus described in part (i)

(2)

4d
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2 marks

Fig.1 shows a root hair cell which is a specialised cell found in plant roots.  

root-hair-cell-igcse-and-gcse-biology-revision-notes

Identify one feature of this cell which has developed through the differentiation of an unspecialised cell and explain how that feature allows the cell to carry out its function.

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5a
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1 mark

The diagram in Fig.1 shows how unspecialised stem cells can develop into a variety of different cell types in the human body.

bone-marrow-stem-cells-sq

Fig.1

Name the process which occurs at X

5b
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3 marks

Fig.2 shows a section of muscle tissue. The cells seen in the tissue from Fig. 2 have already been through process X identified in part (a). During this process, the cells synthesized many mitochondria.

Muscle cells, IGCSE & GCSE Biology revision notes

Fig.2

(i)
Name the process which takes place in the mitochondria.

(1)

(ii)
Explain why it is important for the muscle cells to contain many mitochondria.
(2)
5c
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1 mark

Plant growth occurs through cell division at the growing roots and shoots. In these regions, meristem tissue is found which contains the stem cells of the plant.

Cells from this region of the plant can be used to grow entire new plants which are genetically identical to the parent plant.

State why bone marrow stem cells seen in part (a) cannot be used to develop all the different tissues of the human body in the same way.

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1a
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4 marks

Figure 1 shows the number of red blood cells.

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Figure 1

Explain how the red blood cell is differentiated to perform its functions. 

1b
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1 mark

When a mammal consumes more food than it needs to supply its energy requirements, one consequence is that the animal lays down subcutaneous (beneath the skin) fat. 

Describe the type of cell in which subcutaneous fat gets stored.

1c
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2 marks

In 2002, a farmer planted a row of trees at the edge of his farmland to screen neighbouring houses from view. At the time of planting, the mean height of the trees was 4.56 metres.

Twenty years later, in 2022, the mean height of the trees had reached 11.5 metres.

Calculate the percentage increase in the mean height of the trees over the twenty year period. Use an appropriate number of significant figures in your answer. 

1d
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2 marks

Plants such as fruit trees can often develop a tumour-like growth of undifferentiated cells called a crown gall. These have been likened to a plant form of cancer. 

An example of a crown gall growing on a tree trunk is shown in Figure 2.

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Figure 2

Suggest why a tree is much less likely to die as a result of a crown gall than a person is to die of cancer.

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2a6 marks

Compare and contrast the structures of eukaryotic and prokaryotic cells.

Include reference to the relative sizes of cellular structures in your answer.

2b1 mark

Figure 1 shows a cell found in the glands responsible for producing saliva in the mouth.

saliva-1

Figure 1

Identify the protein, produced by these cells, that is required for the digestion of carbohydrates.

2c4 marks

Suggest how the cell in Figure 1 is adapted for its function.

2d2 marks

Describe how cell specialisation results in a zygote developing into a baby.

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3a
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3 marks

Higher Tier Only

Complete Table 1 to show the correct size conversions. Record your answers as ordinary numbers.

Table 1

Measurement Unit Conversion Unit
15.3 cm   µm
0.002 mm   µm
3 x 10-6 m   µm

3b
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2 marks

Higher Tier Only

The mass of bacterial cells was measured in femtograms (fg).

1 femtogram = 1 x 10-15g

bacterial-growth-2

Figure 1

Calculate the mass of bacteria, in grams, immediately after binary fission when the cell growth rate was 0.1 fg s-1.

Give your answer in standard form.

3c
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3 marks

The electron micrograph shows some cellular structure in a leaf. A student uses their ruler to measure the scale bar, which they find to be 1.5 cm.

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Figure 2

Calculate the magnification of the image.

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4a
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2 marks

Cell A (Figure 1) shows a differentiated cell. 

Describe one of the adaptations of Cell A and explain how this helps the cell do its job.2-2-growth-in-organisms-hardFigure 1

4b
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4 marks
(i)
The actual length of the cell in Figure 1 is 85.2µm.

The length of the image is 108mm. 

Calculate the magnification of the image. Give your answer to one decimal place.

(2)

(ii)

A different cell has an image size of 72mm.

Calculate the actual size of this cell when it has been magnified 600 times. Give your answer in µm.

(2)

4c
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6 marks

The growth of plants can be affected by environmental conditions. . 

Design an experiment to investigate the effect of salt on the growth of plants.

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5a
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5 marks

Figure 1 below gives some information on the height of girls from ages 0-18 months in the UK. Data from the 3rd, 10th, 25th, 50th, 75th, 90th and 97th percentile are shown.2-2-

Figure 1

(i)
What is the length/height of a 3 month-old baby in the 97th percentile?

(1)

(ii)
What is the percentage increase in height/length of a 7 month baby in the 10th percentile to a 14 month-old baby in the 75th percentile?

Give your answer to 3 significant figures.

(2)

(iii)
Explain what is meant by 90th percentile on this graph.

(2)

5b
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4 marks

Human growth hormone (HGH) can be given to children who are growing at a  significantly slower rate than their peers. HGH increases the absorption of amino acids into cells and also stimulates glucose uptake.

Suggest how HGH increases growth in humans. 

5c
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5 marks

Cells in a developing embryo undergo a period of rapid cell division.

(i)
Describe what is produced when a single cell divides by mitosis. 

(3) 

(ii)
Explain why cells in a developing embryo need to differentiate.

(2)

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1a
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2 marks

Figure 1 below gives some information about the growth of girls aged 0 - 3 years in the USA. Data for the 25th, 50th and 75th percentiles are shown.

1

Figure 1

Use the data from Figure 1 to deduce the mass that 75% of infant girls in the USA will be below on the day of their first birthday. 

1b
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2 marks

Describe the usefulness of monitoring data such as the mass of children, like the data shown in Figure 1.

1c
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3 marks

Using the chart in part 1(a), calculate the rate of growth of an average girl in the USA between the ages of 1 and 3 years old.

State your answer in g month-1 and to three significant figures.

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2a
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3 marks

Explain what is meant by the term 'cell differentiation'.

2b
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2 marks

From the list of plant and animal cells given in Figure 1, choose the two cell types that are relatively undifferentiated. 

root hair cell zygote cheek cell palisade mesophyll cell onion skin cell
meristem cell egg cell heart muscle cell stomatal guard cell pollen cell

Figure 1

2c
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2 marks

During the human lifetime from fertilisation to death, the average growth rate of cells in an individual fluctuates with the time of life. There are two distinct periods of life in which there is a very high growth rate.

Suggest what these two stages are; you may give approximate age ranges. 

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3a
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4 marks

Describe the main events that lead to the development of cancer.

3b
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3 marks

One process that accompanies tumour formation is called angiogenesis, which is the formation of new blood vessels from existing blood vessels in the vicinity of the tumour.

Some cancer research is targeted at preventing angiogenesis. 

Suggest why preventing angiogenesis could have benefits in the treatment of cancer. 

3c
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3 marks

Compare and contrast the characteristics of benign and malignant tumours.

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4a
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4 marks

Figure 1 shows the lower part of a growing root from an onion plant. The location of the xylem tissue is shown. 

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Figure 1

(i)
Identify the types of cell at positions A and B.

A _______________________

B _______________________

(2)

(ii)
Explain the significance of the cells labelled B to the growing root structure.
(2)
4b
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1 mark

Describe the role of cells in the region labelled C in Figure 1.

4c
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1 mark

State the technique used by gardeners/plant growers that utilises a plant's ability to grow new tissues from undifferentiated cells. 

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