AQA A Level Biology

Topic Questions

2.1 Cell Structure

1a3 marks

Figure 1 below shows the structure of an animal cell.

Figure 1

screenshot-2023-05-23-073614

State the name and function of the organelles labelled A-C in Figure 1.

1b2 marks

Name two organelles that would be found in a plant cell but not in the cell in Figure 1. 

1c1 mark

Describe the role of the cell surface membrane.

1d2 marks

In addition to the cell surface membrane, eukaryotic cells have many internal membrane-bound structures, including structures called lysosomes. Describe the structure of lysosomes and their role within cells.

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2a1 mark

Give the meaning of the term specialised cell

2b2 marks

Figure 1 below shows a diagram of a series of muscle cells.

Figure 1screenshot-2023-05-23-074808

State how each of the two labelled features help the muscle cells to be specialised.

2c2 marks

Figure 2 below shows a representation of a xylem cell, another example of a specialised cell.screenshot-2023-05-23-075150

Identify and explain one feature visible in Figure 2 that could help with xylem cell  specialisation. 

2d3 marks

Name an example of a specialised cell other than muscle cells and xylem cells and explain how it is specialised. 

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3a1 mark

Give a definition for the term tissue in biology.

3b3 marks

Table 1 below provides information about several types of mammalian tissue and their levels of cellular organisation. 

Table 1

Cell type

Tissue

Organ

Organ system

Muscle cell

Muscle 

X

Circulatory

Neurone

Nerve

Brain

Y

Rod cell

Retina

Z

Visual

Name the organs and systems marked X, Y and Z.

3c2 marks

The lining of the small intestine contains epithelial cells, one of which is shown in Figure 1 below.

Figure 1 

screenshot-2023-05-23-080745

Identify two features of the epithelial cell in Figure 1 that adapt it for its function and explain how each feature helps.

3d3 marks

Describe the levels of cellular organisation that include the epithelial cell shown in part c).

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4a3 marks

Figure 1 below shows the general structure of a prokaryotic cell.

Figure 1screenshot-2023-05-23-081713

Identify the structures labelled A-C in Figure 1.

4b1 mark

State how structure A labelled in Figure 1 differs from the equivalent structure in a plant cell.

4c2 marks

Name two other structures that might be found in a prokaryotic cell that are not shown in Figure 1 and state their function.

4d2 marks

A prokaryotic cell measures 2 μm in diameter and a eukaryotic cell measures 0.1 mm. Calculate how many times larger the eukaryotic cell is than the prokaryotic cell.

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5a3 marks

Table 1 contains information about prokaryotic cells, eukaryotic cells, and viruses.

Table 1

 

Eukaryotic cells

Prokaryotic cells

Viruses

Cellular

Yes

Yes

No

Size

X

0.5-5 μm

2 nm

Genetic material

DNA

DNA

Y

Ribosomes

Z

Small / 70s

Absent

Use your knowledge of cell and virus structure to fill the gaps marked X, Y, and Z.

5b2 marks

Figure 1 below shows an example of a virus particle.

Figure 1

screenshot-2023-05-23-082954Name the structures labelled A and B in Figure 1

5c1 mark

Figure 2 below shows the process that takes place when a virus infects a host cell.

Figure 2

screenshot-2023-05-23-083243

Describe what is happening at point X in Figure 2 to produce copies of the original virus.

5d3 marks

Some virus particles have another layer of molecules surrounding them in addition to that labelled B in part b) above. Use information from Figure 2 to state where this additional layer comes from, and how its formation can damage host cells.

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1a1 mark

A biologist prepared a sample of organelles extracted from an animal cell. The following method was used:

Step 1: An ice-cold, buffered solution was added to the liver tissue (it has the same water potential as the liver tissue).

Step 2: The liver and solution were blended in a homogeniser.

Step 3: The mixture from the homogeniser was filtered.

Step 4: The filtered liquid was centrifuged at low speed. A pellet appeared in the bottom of the centrifuge tube.

Step 5: The liquid above the pellet was decanted into a second centrifuge tube and spun at a higher speed to obtain a sample of mitochondria.

Name the organelle that made up most of the first pellet after centrifuging at a low speed (step 4).

1b1 mark

The second centrifuge tube was spun at a higher speed to obtain a sample of mitochondria (step 5). Suggest why.

1c3 marks

Explain how the inner membrane of the mitochondria is adapted to its function.

1d3 marks

Name three structures in a eukaryotic cell that cannot be identified using an optical microscope.

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2a3 marks

Figure 1 shows the structure of the organism Chlamydomonas.

q2-2-1-cell-structure-hard-aqa-gcse-biology

Name three structures shown in Figure 1 that are present in eukaryotic cells but are not present in prokaryotic cells.

2b2 marks

Suggest what kind of organism Chlamydomonas is, based on the information shown in Figure 1. Give reasons for your suggestion. 

2c5 marks

Describe the function of a chloroplast and the structural features that enable it to carry out these functions.

2d2 marks

Figure 1 below shows a photograph of an organelle taken with an electron microscope.

q3-2-1-cell-structure-hard-aqa-gcse-biology

Name the parts of the organelle labelled A and B.

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3a4 marks

Structures V to Z are organelles within a plant cell.

  • V - Nucleus
  • W - Chloroplast
  • X - Golgi apparatus
  • Y - Mitochondrion
  • Z - Cell Wall

Complete Table 1 by identifying the correct letter next to each statement.

Table 1

Statement

Letter

Has membranes arranged in stacks and contains DNA

 

Is permeable to water and all solutes

 

Contains chromatin

 

Produces vesicles

 
3b2 marks

Mammals feed their young with milk that is synthesized and expressed by mammary gland cells. These gland cells have evolved to contain large numbers of mitochondria and Golgi apparatus. The milk contains a high concentration of protein to feed an infant’s growth.

Explain how these adaptations could aid the synthesis and expression of milk.

3c2 marks

State the contents and function of the mitochondrial matrix.

3d2 marks

Scientists investigated the effect of an exercise programme on the number and area of the inner mitochondrial membranes in skeletal muscle. They took samples of muscle from a large number of volunteers before and after the exercise programme. From each sample, they cut thin sections and used these to determine the mean number of mitochondria per μm2 and the mean area of inner mitochondrial membranes. The results are shown in Table 1 below.

Table 1

 

Before training

After training

 

Mean

Standard deviation

Mean

Standard deviation

Mean number of mitochondria per μm2

3.4

± 0.9

2.8

± 0.6

Mean area of inner mitochondrial membrane / μm2

1.2

± 0.45

3.0

± 0.6

Using the data from Table 1 suggest the effect of the exercise programme on the mitochondria.

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4a2 marks

Bacteriophages are viruses that kill bacteria. Researchers investigated the use of bacteriophages to alleviate the symptoms of bacterial lung infections. They inoculated the lungs of rats with a pathogenic bacterium. The rats were then divided into two groups, J and K:

  • The rats in group J were untreated.
  • The rats in group K were given bacteriophage treatment by means of an aerosol spray that they inhaled.

After 5 days, the researchers killed the rats and excised their lungs. The lungs were washed out with a set volume of fluid. The researchers used a technique to count the number of live bacteria in the fluid. Figure 1 below shows the researchers’ results. The mean and the range of data are shown for each group.

q4-2-1-cell-structure-hard-aqa-gcse-biology

Suggest the scientists’ null hypothesis and experimental hypothesis for this investigation.

4b1 mark

Which is the only correct statement about the structures of the bacteriophage and the bacterium?

  • A - Both have ribosomes.
  • B - Both have a cell-surface membrane.
  • C - The bacteriophage has a capsid and the bacterium has a cell-surface membrane.
  • D - The bacteriophage has a cell wall and the bacterium has a capsid.
4c2 marks

In some cases, the researchers needed to carry out a serial dilution of the sample before performing a count of the bacteria.

Use data from Figure 1 to account for the researchers’ choices to perform serial dilutions in some cases but not for others.  

4d3 marks

Using only the graph in Figure 1, analyse the effectiveness of the bacteriophage in treating the lung infection in rats. Do not consider statistical analyses in your answer.

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5a2 marks

Figure 1 below shows a diagram of a cholera bacterium.

q4-2-2-1-cell-structure-hard-aqa-gcse-biology

Name W and X and state their function.

5b4 marks

Name four structures that are present in an epithelial cell from the small intestine but not present in a cholera bacterium.

5c2 marks

Cholera bacteria can be viewed using a transmission electron microscope (TEM) or a scanning electron microscope (SEM). 

State one advantage of using a TEM and one advantage of using an SEM.

5d2 marks

An outbreak of cholera occurred in London in 1849. Figure 2 below shows the relationship between the number of deaths from cholera and the height at which people lived above sea level.

q5d-2-1-cell-structure-hard-aqa-gcse-biology

Describe the results shown in Figure 2.

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1a2 marks

Figure 1 shows part of a prokaryotic cell.

prokaryotic-cell-diagram

Name the structures labelled R and S in the diagram in Figure 1.

1b2 marks

Name the structures labelled P and Q in the diagram in Figure 1.

1c2 marks

Phospholipids and glycoproteins are two biological molecules, each are the main constituent of structures found in prokaryotic cells.

i)
Name the structure(s) (P, Q, R or S) in which phospholipids are the main
biological molecule found.
ii)
Name the structure(s) (P, Q, R or S) in which glycoproteins are the
main biological molecule found.
1d2 marks

In certain conditions, some prokaryotic cells can divide every 25 minutes.

Assuming that each cell divides every 25 minutes, calculate the number of cells that will be present after 3.75 hours if the starting population contains 2.45 × 103 cells. Assume no cells die during this time.

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2a2 marks

Figure 1 shows a diagram of an animal cell.

diagram-of-an-animal-cell

Name the organelles labelled F and H.

2b2 marks

Name two structures present in plant cells that are not present in animal cells.

2c2 marks

A scientist used the method below to prepare a sample of organelle F in Figure 1 from muscle cells: 

  • Step 1: Place muscle tissue in a solution that is ice-cold, buffered and has the same water potential as the muscle tissue.
  • Step 2: Place the muscle tissue and solution into a blender. Blend for 3 minutes.
  • Step 3: Filter the blended mixture.
  • Step 4: Centrifuge the filtrate at a low speed. A pellet should be seen at the bottom of the centrifuge tube.
  • Step 5: Pour off the liquid from the first centrifuge tube into a second centrifuge tube.
  • Step 6: Centrifuge this liquid at a high speed. A sample of organelle F is obtained.

In terms of obtaining a sample of organelle F, explain why the solution used in step 1 had to be ice-cold and had to have the same water potential as the muscle tissue. 

2d2 marks

Explain why the muscle tissue and solution first had to be blended, and why the resulting mixture then had to be filtered (steps 2 and 3).

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3a2 marks

Figure 1 shows a chloroplast as seen with an electron microscope.

q3-chloroplast

Name J and K.

3b2 marks

Describe the function of the organelle in Figure 1.

3c3 marks

Describe how a sample of the organelle in Figure 1 could be obtained from leaf tissue using cell fractionation techniques. 

You will not gain marks for including information about any solutions in your answer.

3d3 marks

Table 1 below shows features of a mitochondrion and a chloroplast.

Table 1

Feature

Mitochondrion

Chloroplast

Single outer membrane

 

 

Diffusion of carbon dioxide into the organelle

 

 

Starch grains

 

 

Complete the table with ticks (✔) where a feature is present.

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4a2 marks

Figure 1 shows a drawing of part of an animal cell as seen through an electron microscope.

q4-part-of-an-animal-through-electron-chloroplast

Name the organelles labelled L and M.

4b2 marks

Explain why the shapes of the two organelles labelled O in Figure 1 appear different.

4c1 mark

Give the function of organelle M in Figure 1.

4d3 marks

Large numbers of organelle O (in Figure 1) are found in the small intestine epithelial cells. Explain why these cells are adapted in this way. 

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5a2 marks

Figure 1 shows a diagram of an organism called Chlamydomonas that lives in freshwater.

q5-chlamydomonas

Name two features of the Chlamydomonas cell that are not found in animal cells. 

5b3 marks

Use Figure 1 to explain three adaptations of Chlamydomonas that enable this organism to maintain a high rate of photosynthesis.

5c2 marks

A scientist used an optical microscope to observe Chlamydomonas. Name two eukaryotic structures that cannot be identified using an optical microscope.

5d2 marks

Using your knowledge of osmosis, suggest why Chlamydomonas uses starch as a carbohydrate store.

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