12 questions · 80 marks · ≈ 1 hour · spans 12 of 21 topics
Assembled from the topic question banks — not an official Edexcel paperThe image shows three different biological molecules.
Name the biological molecules represented by X, Y and Z.
Name one element found in all three of the biological molecules shown in part (a).
With reference to molecule Z from part (a):
(i) Describe the test used to identify the molecule in a sample of food.
(2 marks)
(ii) Explain the effect of very high temperature on the shape of this molecule.
(2 marks)
A student uses a light microscope to look at a human cheek cell.
The student makes this drawing of the cell.
Name the organelle shown in the drawing.
Mitochondria are organelles that are too small to be seen using a light microscope.
The drawing shows a mitochondrion that has been magnified.
The actual length of this mitochondrion is 6 μm.
[1 μm = 0.001 mm]
Calculate the magnification of this drawing.
The table gives information about mitochondria in different human cells.
| Cell | Mean number of mitochondria per cell | Mean volume of cell in µm3 | Mean number of mitochondria per µm3 |
|---|---|---|---|
| Heart muscle | 5 000 | 15 000 | |
| Sperm | 75 | 30 | 2.50 |
| Egg | 600 000 | 4 000 000 | 0.15 |
(i) What is the mean number of mitochondria per μm3 in a heart muscle cell?
(1 mark)
| ☐ | A | 0.33 |
|---|---|---|
| ☐ | B | 3 |
| ☐ | C | 10 000 |
| ☐ | D | 75 000 000 |
(ii) Comment on the differences in the data for the sperm and for the egg.
(3 marks)
Almost at the same time that the reflex response results in the person removing their hand from the hot tray in the oven, the hormone adrenaline is released.
(i) Define the term hormone.
(ii) Describe the effect of adrenaline on the body.
The diagram shows a nephron from a human kidney.
(i) Which row of the table is correct?
| Glomerulus | Where selective reabsorption takes place | Where most water is reabsorbed | |
|---|---|---|---|
| A | P | Q | R |
| B | Q | S | R |
| C | P | R | U |
| D | Q | R | U |
(ii) Blood entering structure P is under high pressure.
Describe what happens at structure P in the nephron.
The diagram shows apparatus a student uses to compare inhaled and exhaled air.
The student breathes into and out of the mouthpiece for one minute.
(i) Explain which flask exhaled air passes through.
(2 marks)
(ii) Explain the changes that will happen in the limewater in flask A and in flask B.
(2 marks)
(iii) The student uses limewater to compare the composition of exhaled and inhaled air.
Suggest an alternative substance that they could use.
(1 mark)
Describe the role of the diaphragm and the intercostal muscles in inhalation.
Which of the following correctly shows the levels of organisation in an organism in order of size from the smallest to the largest?
| ☐ | A | Organelle, cell, organ, tissue, organ system |
|---|---|---|
| ☐ | B | Organelle, cell, tissue, organ, organ system |
| ☐ | C | Cell, organelle, tissue, organ, organ system |
| ☐ | D | Cell, tissue, organelle, organ, organ system |
State the meaning of the term organ.
Name an example of an organ found in the following groups of organisms:
(i) Plants
(1 mark)
(ii) Animals
(1 mark)
Give two differences between organisms in the plant group and organisms in the animal group.
During a science lesson a student writes down the following statement about osmosis.
| The active movement of molecules through a membrane from a region of low concentration to a region of high concentration. |
|---|
Using your knowledge of osmosis, suggest what is wrong with this statement.
The diagram shows two human red blood cells. The cell labelled B had been placed in concentrated salt solution.
Describe the changes to the cell labelled B.
Explain why the cell labelled B has changed shape.
A student placed a sample of red blood cells into pure water for 30 minutes. When they checked the blood/water solution under a microscope they could not identify any intact cells.
Explain what is likely to have happened to the red blood cells after being in water.
Soda lime absorbs carbon dioxide.
A student uses this method to investigate the effect of carbon dioxide on photosynthesis.
(i) Describe how the student will test the leaves for starch.
(ii) Suggest one safety precaution the student should follow when testing a leaf for starch.
Explain the expected results for the leaf in the flask with soda lime when tested for starch.
Write the balanced symbol equation for respiration
Some scientists wanted to investigate respiration rates in different areas of a plant.
They measured carbon dioxide production in the roots and leaves of a plant at night time.
The table shows the rate of carbon dioxide production that they measured.
| Part of the plant | Mean rate of carbon dioxide production / cm3 m-2 s-1 |
|---|---|
| Leaves | 0.042 |
| Root | 0.056 |
Calculate the percentage difference in carbon dioxide production in the leaves compared to the roots.
The carbon dioxide readings shown in the table in part (b) were all taken during the night time.
Suggest a reason for this.
Suggest an explanation for the results shown in the table in part (b).
In order to collect the data about carbon dioxide produced by the roots of the plant, scientists took samples of the air from the soil around the plant roots and adjusted it to account for atmospheric carbon dioxide levels.
Suggest why the readings they took may still be higher than the actual rate of carbon dioxide production in the plant roots.
Casgevy is given as a single-dose treatment.
A scientist concludes that Casgevy is the best option for treating sickle cell anaemia.
Evaluate the scientist's conclusion.
The bacterium S. aureus is commonly found on the skin and in the nose of 30% of healthy people.
The diagram shows a cluster of this bacterium.
Some strains of S. aureus are resistant to the antibiotic methicillin. These strains are known as MRSA.
To reduce the spread of MRSA, a group of scientists investigate different handwashing techniques used by hospital staff.
They measure the mean percentage reduction in MRSA bacteria on hands.
The table shows the scientists' results.
| Method | Mean percentage (%) reduction in MRSA on hands |
|---|---|
| extended washing (90 seconds) | 20.2 |
| alcohol-based sanitiser | 23.4 |
| extended washing + alcohol-based sanitiser | 24.1 |
| standard hospital handwashing protocol | 18.6 |
Give two conclusions from these results.
The diagram shows the human female reproductive system.
(i) Which label shows where ovulation occurs?
(1 mark)
| ☐ | A |
|---|---|
| ☐ | B |
| ☐ | C |
| ☐ | D |
(ii) Which label shows where fertilisation usually occurs?
(1 mark)
| ☐ | A |
|---|---|
| ☐ | B |
| ☐ | C |
| ☐ | D |
The diagram shows the changes in thickness of the uterus lining and levels of two hormones produced by the ovary during a menstrual cycle.
(i) Hormones X and Y are produced by the ovaries.
Name X and Y.
(2 marks)
(ii) Explain the function of hormone X during the menstrual cycle.
(2 marks)
The diagram shows a human fetus developing in the uterus.
Explain how the structure of the placenta enables the efficient exchange of substances between the fetus and the mother.