Year 10 Paper 3: Cells, Digestion and Respiration
Covers cell structure and transport, cell division and stem cells, digestion and the circulatory system, the body's defence systems and how disease is treated, and respiration and exercise.
Year 10 here means a typical teaching order, not a syllabus rule. No exam board defines what belongs to Year 10, and schools sequence the course differently. Check it against your own scheme of work before using it to decide what a class has covered.
Questions
Question 1 [2 marks]
Cell Structure and Transport
A student is studying an animal cell under a microscope.
State the function of the mitochondria and state the function of the ribosomes in the cell.
Question 2 [2 marks]
Human Defence Systems and Treating Disease
State what an antibiotic is, and state what type of pathogen antibiotics are effective against.
Question 3 [3 marks]
Digestion and the Circulatory System
Humans have a double circulatory system.
Describe what is meant by a double circulatory system, and state why this is an advantage.
Question 4 [3 marks]
Cell Division and Stem Cells
Stem cells can be found in embryos and in some adult tissues.
Describe one difference between embryonic stem cells and adult stem cells.
Question 5 [3 marks]
Respiration and Exercise
After vigorous exercise, lactic acid that has built up in the muscles needs to be removed.
State where in the body lactic acid is transported to be broken down, and state what happens to it there.
Question 6 [3 marks]
Human Defence Systems and Treating Disease
Describe what happens at the site of a cut in the skin to help prevent pathogens entering the body and to begin the healing process.
Question 7 [3 marks]
Cell Division and Stem Cells
Cancer can result when cells divide by mitosis in an uncontrolled way.
State what is meant by a tumour, and state the difference between a benign tumour and a malignant tumour.
Question 8 [3 marks]
Respiration and Exercise
State three ways an organism uses the energy released by respiration.
Question 9 [5 marks]
Cell Division and Stem Cells
Describe the three main stages of the cell cycle that a cell goes through before and during division.
Question 10 [5 marks]
Respiration and Exercise
A student's breathing rate was recorded before and after exercise. At rest, the student took 15 breaths per minute, each with a volume of 0.5 litres. Immediately after exercise, they took 30 breaths per minute, each with a volume of 2 litres.
Calculate the student's total volume of air breathed per minute (minute ventilation) at rest and immediately after exercise, using minute ventilation = breathing rate x breath volume, and calculate how many times greater the minute ventilation is after exercise compared with at rest.
Question 11 [4 marks]
Human Defence Systems and Treating Disease
A new drug is trialled at several doses. Out of 50 patients given a 40 mg dose, 35 showed an improvement. Out of 50 patients given an 80 mg dose, 38 showed an improvement.
Calculate the percentage of patients who improved at each of these two doses, and state which dose shows the greater percentage improvement.
Question 12 [5 marks]
Respiration and Exercise
Describe how the human body stores extra glucose after a meal, and describe how this stored glucose can be used to provide energy for muscles during exercise.
Question 13 [4 marks]
Human Defence Systems and Treating Disease
A new painkiller was tested in a double-blind trial. Of 200 patients given the drug, 150 reported reduced pain. Of 200 patients given a placebo, 60 reported reduced pain.
Calculate the percentage of each group that reported reduced pain, and use your answer to comment on the effectiveness of the drug.
Question 14 [5 marks]
Cell Structure and Transport
A student sets the eyepiece lens of a microscope to a magnification of x10 and the objective lens to a magnification of x40.
Calculate the total magnification produced by the microscope. The student then measures a cell using this microscope and finds its magnified image is 8000 micrometres wide. Calculate the actual width of the cell in micrometres.
Question 15 [5 marks]
Human Defence Systems and Treating Disease
In a trial, 3% of 2000 vaccinated people caught a disease, compared with 15% of 2000 unvaccinated people.
Calculate the number of people who caught the disease in each group, and calculate the vaccine's efficacy using efficacy (%) = (1 - (rate in vaccinated group / rate in unvaccinated group)) x 100.
Question 16 [5 marks]
Cell Structure and Transport
A red blood cell placed in a beaker of pure water will swell and may burst. A red blood cell placed in a concentrated salt solution will shrink.
Explain, in terms of osmosis, why the red blood cell behaves differently in each solution.
Model solutions
| Question 1[2 marks] | |
|---|---|
| Answer or working | Marks |
| mitochondria: site of (aerobic) respiration, releasing energy | B1 |
| ribosomes: site of protein synthesis | B1 |
| Final answer: Mitochondria: aerobic respiration (releases energy); ribosomes: protein synthesis | |
| Question 2[2 marks] | |
|---|---|
| Answer or working | Marks |
| an antibiotic is a medicine/drug that kills bacteria (or prevents their growth) inside the body | B1 |
| antibiotics are effective against bacterial pathogens (not viruses) | B1 |
| Final answer: An antibiotic kills bacteria (or stops them growing) inside the body; antibiotics are effective against bacteria, not viruses | |
| Question 3[3 marks] | |
|---|---|
| Answer or working | Marks |
| blood passes through the heart twice on one complete circuit of the body, once to the lungs and once to the rest of the body | B1 |
| one circuit carries deoxygenated blood to the lungs to be oxygenated, and the other carries oxygenated blood to the body | B1 |
| this allows blood to be repressurised (pumped again) after the lungs, so oxygen is delivered to the body more quickly and efficiently | B1 |
| Final answer: Blood passes through the heart twice per circuit, once to the lungs and once to the body, allowing it to be repressurised so oxygen reaches tissues faster | |
| Question 4[3 marks] | |
|---|---|
| Answer or working | Marks |
| embryonic stem cells can differentiate into any type of cell (they are pluripotent) | B1 |
| adult stem cells can only differentiate into a limited range of cell types | B1 |
| a named source, such as adult stem cells being found in bone marrow while embryonic stem cells are found in early embryos | B1 |
| Final answer: Embryonic stem cells can become any cell type; adult stem cells (e.g. in bone marrow) can only become a limited range of cell types | |
| Question 5[3 marks] | |
|---|---|
| Answer or working | Marks |
| lactic acid is carried in the blood to the liver | B1 |
| in the liver, lactic acid is converted back into glucose | B1 |
| this conversion requiring oxygen (this is part of the oxygen debt repaid during recovery) | B1 |
| Final answer: Lactic acid is transported in the blood to the liver, where it is converted back into glucose, using oxygen as part of the oxygen debt | |
| Question 6[3 marks] | |
|---|---|
| Answer or working | Marks |
| blood clots (clotting factors cause platelets and fibrin to form a clot), sealing the wound | B1 |
| the clot dries to form a scab, which acts as a barrier preventing pathogens entering | B1 |
| skin cells below the scab grow/divide to repair the tissue | B1 |
| Final answer: Blood clots and forms a scab that seals the wound and prevents pathogens entering, while new skin cells grow underneath to repair the tissue | |
| Question 7[3 marks] | |
|---|---|
| Answer or working | Marks |
| a tumour is a mass of abnormal cells caused by uncontrolled cell division | B1 |
| a benign tumour grows but does not spread to other parts of the body | B1 |
| a malignant tumour (cancer) can spread to other parts of the body, invading and damaging surrounding tissue | B1 |
| Final answer: A tumour is a mass formed by uncontrolled cell division; a benign tumour does not spread to other body parts, but a malignant tumour can spread and invade other tissues | |
| Question 8[3 marks] | |
|---|---|
| Answer or working | Marks |
| movement/muscle contraction | B1 |
| keeping warm (maintaining a constant body temperature in mammals and birds) | B1 |
| building larger molecules from smaller ones, such as building proteins from amino acids (or for growth/active transport) | B1 |
| Final answer: Energy from respiration is used for movement, keeping warm, and building larger molecules (e.g. proteins) from smaller ones | |
| Question 9[5 marks] | |
|---|---|
| Answer or working | Marks |
| a growth stage (interphase), where the cell grows and increases the number of sub-cellular structures such as mitochondria and ribosomes | B1 |
| DNA replication, where the genetic material is duplicated to form two copies of each chromosome | B1 |
| mitosis, where the chromosomes are separated and the nucleus divides to form two genetically identical nuclei | B1 |
| division of the cytoplasm and cell membranes, forming two identical daughter cells | B1 |
| the daughter cells produced being genetically identical to the parent cell and to each other | B1 |
| Final answer: The cell grows and replicates its DNA and organelles, chromosomes are separated during mitosis into two genetically identical nuclei, then the cytoplasm divides to form two identical daughter cells | |
| Question 10[5 marks] | |
|---|---|
| Answer or working | Marks |
| resting minute ventilation = 15 x 0.5 | M1 |
| 7.5 litres per minute | A1 |
| post-exercise minute ventilation = 30 x 2 = 60 litres per minute | M1 |
| using ratio = post-exercise value / resting value | M1 |
| 60 / 7.5 = 8 times greater | A1 |
| Final answer: Resting minute ventilation = 7.5 litres per minute; after exercise = 60 litres per minute, which is 8 times greater | |
| Question 11[4 marks] | |
|---|---|
| Answer or working | Marks |
| 40 mg percentage = (35 / 50) x 100 | M1 |
| 70% | A1 |
| 80 mg percentage = (38 / 50) x 100 | M1 |
| 76%, with the 80 mg dose showing the greater improvement | A1 |
| Final answer: 70% improved at 40 mg and 76% improved at 80 mg; the 80 mg dose shows the greater percentage improvement | |
| Question 12[5 marks] | |
|---|---|
| Answer or working | Marks |
| after a meal, excess glucose is converted into glycogen (a storage carbohydrate) in the liver and in muscle cells | B1 |
| glycogen being a more compact way of storing this energy than glucose | B1 |
| during exercise, glycogen stored in the muscles can be broken down (converted) back into glucose directly inside the muscle cells | B1 |
| glycogen stored in the liver can also be broken down into glucose, which is released into the blood | B1 |
| this glucose being used as a substrate for respiration in the muscle cells, releasing energy for contraction | B1 |
| Final answer: Excess glucose is stored as glycogen in the liver and muscles; during exercise this glycogen is converted back into glucose, either directly in the muscle cells or released into the blood from the liver, providing the glucose muscle cells respire to release energy | |
| Question 13[4 marks] | |
|---|---|
| Answer or working | Marks |
| drug group percentage = (150/200) x 100 = 75% | M1 |
| placebo group percentage = (60/200) x 100 = 30% | M1 |
| comparing the two percentages | M1 |
| the drug is effective because a much greater percentage of patients on the drug reported reduced pain than on the placebo (75% compared with 30%) | A1 |
| Final answer: 75% (drug) versus 30% (placebo); the drug appears effective since a far higher proportion improved than with the placebo | |
| Question 14[5 marks] | |
|---|---|
| Answer or working | Marks |
| total magnification = eyepiece magnification x objective magnification | M1 |
| total magnification = 10 x 40 = x400 | A1 |
| using actual size = image size / magnification | M1 |
| substituting 8000 / 400 | M1 |
| actual width = 20 micrometres | A1 |
| Final answer: Total magnification = x400; actual width of the cell = 20 micrometres | |
| Question 15[5 marks] | |
|---|---|
| Answer or working | Marks |
| vaccinated cases = 3% of 2000 = 60 | M1 |
| unvaccinated cases = 15% of 2000 = 300 | M1 |
| using efficacy = (1 - (3 / 15)) x 100 | M1 |
| substituting to get (1 - 0.2) x 100 | A1 |
| 80% efficacy | A1 |
| Final answer: 60 people caught the disease in the vaccinated group and 300 in the unvaccinated group; the vaccine's efficacy is 80% | |
| Question 16[5 marks] | |
|---|---|
| Answer or working | Marks |
| osmosis is the movement of water molecules from a dilute solution to a concentrated solution through a partially permeable membrane | B1 |
| pure water is more dilute (has a higher water concentration) than the cytoplasm inside the cell | B1 |
| water moves into the cell by osmosis down this concentration gradient, causing the cell to swell and potentially burst | B1 |
| the concentrated salt solution has a lower water concentration than the cytoplasm | B1 |
| water moves out of the cell by osmosis, causing it to shrink | B1 |
| Final answer: In pure water, water moves into the cell by osmosis (higher water concentration outside), causing it to swell/burst; in concentrated salt solution, water moves out of the cell by osmosis (lower water concentration outside), causing it to shrink | |