Practical skills — AS & A Level Biology (9700) questions by topic
Serial dilutions, confidence-interval calculations and risk assessment anchor this practical topic: identifying the independent variable in an enzyme investigation, calculating a 95% confidence interval from a standard error, and justifying a suitable method for applying a plant hormone to roots only. Suggest, calculate and describe lead the command words, and calculate wants every step of a confidence-interval or dilution working shown, not just a final number.
This set gathers 61 real questions from 2023 to 2025 papers, and marks sit unusually high throughout, from 6 to 23, reflecting the multi-step nature of practical write-ups. Submitting full calculations and method descriptions for instant marking is especially valuable here, since a confidence-interval step skipped, or a variable already standardised being repeated, is flagged immediately.
What examiners look for
- Reports note that restating a variable already standardised in the question, such as time of sampling, is not separately credited.
- Risk descriptions linked to environmental hazards, such as trip hazards, are only credited when tied explicitly to injury risk for the scientists.
- A frequent statistical error describes a difference as 'insignificant' rather than using the precise phrase 'no significant difference'.
- Independent-variable answers are marked down when a broad category, such as different animal species, is given without the specific reference required, such as the type of substrate.
- Strong answers calculate a 95% confidence interval correctly from the standard error, use non-overlapping error bars to justify significance, and describe practical methods such as applying hormone solution directly to roots via soil or spray.
May–June 2025, Paper 31
A student is investigating the rate of diffusion of hydrochloric acid (HCl) into blue agar. Blue agar contains the indicator bromothymol blue. Blue agar turns yellow when it…
Answer this question and get it marked →A student is provided with a prepared slide of a transverse section (TS) of a leaf (labelled J1) and a diagram of a TS of a different leaf (Fig. 2.2). Observe the slide J1 and…
Answer this question and get it marked →May–June 2025, Paper 32
Invertase is an enzyme that catalyses the breakdown of sucrose into glucose and fructose. Invertase can be extracted from yeast cells. You will investigate the effect of an…
Answer this question and get it marked →K1 is a slide of a stained transverse section through a plant stem. Draw a large plan diagram of the region of the stem on K1 indicated by the shaded area in Fig. 2.1 (a quarter…
Answer this question and get it marked →May–June 2025, Paper 33
When plant tissue is placed into a solution of sodium chloride, water moves between the sodium chloride solution and the cells in the plant tissue. You will investigate the effect…
Answer this question and get it marked →L1 is a slide of a stained transverse section through a plant organ. Draw a large plan diagram of a region of the organ on L1 to include the epidermis and two vascular bundles.…
Answer this question and get it marked →May–June 2025, Paper 34
Catalase is an enzyme found in yeast cells. It catalyses the breakdown of hydrogen peroxide to produce water and oxygen. You will investigate the effect of copper sulfate on this…
Answer this question and get it marked →M1 is a slide of a stained transverse section through a leaf. Draw a large plan diagram of the region of the leaf on M1 indicated by the shaded area in Fig. 2.1 (a midrib region…
Answer this question and get it marked →May–June 2025, Paper 35
Complete Table 1.2 to show the volumes of E (100.0% catalase solution) and W (distilled water) needed to prepare at least three more concentrations of catalase, making a total…
Answer this question and get it marked →May–June 2025, Paper 37
Measure the diameter of one cylinder of plant tissue and calculate the radius, r. diameter = ................ mm r = ................ mm
Answer this question and get it marked →May–June 2025, Paper 38
You will carry out a serial dilution of the 1.0% copper sulfate solution, C, to reduce the concentration by half between each successive dilution. You need to prepare four…
Answer this question and get it marked →May–June 2025, Paper 51
Pepsin is an enzyme that is present in gastric juice. Gastric juice is secreted into the stomach of humans and many other animals. Pepsin catalyses the hydrolysis of proteins into…
Answer this question and get it marked →Golden orb weaver spiders, Nephila pilipes, are found in East Asia, South-east Asia and Australia. All female golden orb weaver spiders are black with yellow spots on their legs…
Answer this question and get it marked →May–June 2025, Paper 52
Phosphatases are enzymes that catalyse the removal of phosphate from other molecules, releasing inorganic phosphate (Pᵢ). A phosphatase can be extracted from mung bean seedlings,…
Answer this question and get it marked →Sponges are immobile, aquatic animals that live on rocks and sediment at the bottom of salt water environments. Scientists sampled the marine habitats along a length of coastline…
Answer this question and get it marked →May–June 2025, Paper 53
The short-beaked echidna, Tachyglossus aculeatus, is a mammal that eats ants and termites. Echidnas produce a protein called EchAMP in their saliva. Scientists think EchAMP kills…
Answer this question and get it marked →May–June 2025, Paper 54
A student investigated the effect of gibberellin (GA) and abscisic acid (ABA) on the germination of wheat grains. The student found out the following information: The molecular…
Answer this question and get it marked →A student investigated the oxygen consumption of isolated mitochondria under different conditions. Mitochondria were isolated by crushing liver cells in ice cold buffer and…
Answer this question and get it marked →May–June 2024, Paper 33
Test-tube R in Fig. 1.1 shows how a test-tube will be set up at the start of the investigation. Test-tube R contains a yeast cell suspension. Decide what you expect the contents…
Answer this question and get it marked →L1 is a slide of a stained transverse section through a plant stem. Draw a large plan diagram of the whole section on L1. Use a sharp pencil. Use one ruled label line and label to…
Answer this question and get it marked →May–June 2024, Paper 34
Table 1.2 shows how to prepare two of the concentrations of salicylic acid. You will prepare 10 cm3 of each concentration, using A and W. Decide which other concentrations of…
Answer this question and get it marked →Observe the region of the section on M1 indicated by the shaded area in Fig. 2.1. Draw a large plan diagram of this region. Use a sharp pencil. Include four vascular bundles in…
Answer this question and get it marked →May–June 2024, Paper 35
You will investigate the effect of different concentrations of ethanol on the release of red pigment from beetroot tissue. You will need to make different concentrations of…
Answer this question and get it marked →N1 is a slide of a stained transverse section through a plant leaf. Draw a large plan diagram of part of the leaf section on N1 to show the different tissues. The section that you…
Answer this question and get it marked →May–June 2024, Paper 51
Identify the independent variable in this investigation.
Answer this question and get it marked →State three environmental conditions in the glasshouse that should be standardised in the 10-week period of acclimatisation, other than the temperature of the glasshouse.
Answer this question and get it marked →Some scientists investigated the effectiveness of different mosquito repellents using a human volunteer. The scientists carried out the investigation on this person in a…
Answer this question and get it marked →May–June 2024, Paper 52
Identify the independent variable in this investigation.
Answer this question and get it marked →Fig. 2.1 shows a photomicrograph of stained tumour cells viewed using a light microscope at image magnification x400. An eyepiece graticule was placed across the nucleus of one of…
Answer this question and get it marked →May–June 2024, Paper 53
Identify the independent variable and the dependent variable in this investigation.
Answer this question and get it marked →Describe a method the student could use to make a solution of GA3 with a concentration of 1.90 x 10^-6 mol dm-3 and state the dilution factor used.
Answer this question and get it marked →October–November 2024, Paper 31
You will need to carry out a serial dilution of the 1.0% starch-milk solution, SM, to reduce the concentration by one fifth between each successive dilution. You will need to…
Answer this question and get it marked →Draw a large plan diagram of the region of the leaf on J1 indicated by the shaded area in Fig. 2.1. Use a sharp pencil. Use one ruled label line and label to identify the lower…
Answer this question and get it marked →October–November 2024, Paper 33
Carry out step 1 to step 7. Step 1: Put the five potato cylinders onto a white tile or cutting surface and cut each cylinder to a length of 4 cm. Step 2: Label a beaker 0 and put…
Answer this question and get it marked →Draw a large plan diagram of the region of the stem on K1 indicated by the shaded area in Fig. 2.1. Use a sharp pencil. Use one ruled label line and label to identify the…
Answer this question and get it marked →October–November 2024, Paper 34
Table 1.2 shows two of the concentrations of sugar solution you will use and how to prepare them. Decide which three other concentrations of sugar solution you will use. Complete…
Answer this question and get it marked →Draw a large plan diagram of the whole section on L1. Use a sharp pencil. Use one ruled label line and label to identify the endodermis.
Answer this question and get it marked →October–November 2024, Paper 35
The enzyme amylase catalyses the hydrolysis (breakdown) of starch to reducing sugars. A student investigated the effect of temperature on the hydrolysis of starch by the enzyme…
Answer this question and get it marked →M1 is a slide of a stained transverse section through a leaf. Draw a large plan diagram of the whole section on M1. Use a sharp pencil. Use one ruled label line and label to…
Answer this question and get it marked →October–November 2024, Paper 36
Blood plasma contains soluble proteins such as albumin. Albumin can be separated from blood plasma and used in medical treatments. When the pH changes, soluble proteins become…
Answer this question and get it marked →Starch grains are present in plant cells. The starch grains have different sizes and shapes depending on the type of plant. As the starch grains get larger, patterns form on the…
Answer this question and get it marked →October–November 2024, Paper 51
Algae are a diverse group of photosynthetic eukaryotes in the kingdom Protoctista. Rhodomonas salina and Skeletonema costatum are two species of alga that live in seawater. Fig.…
Answer this question and get it marked →A group of ecologists investigated the biodiversity of two peat bog ecosystems, A and B. Peat bogs are wetland ecosystems that often contain rare species. Fig. 2.1 shows an…
Answer this question and get it marked →October–November 2024, Paper 52
In the light-dependent stage of photosynthesis, electrons and hydrogen ions are accepted by the coenzyme NADP, which becomes reduced. DCPIP is a dye that can act as an electron…
Answer this question and get it marked →The two-spot ladybird, Adalia bipunctata, is a species of small, flying beetle that is found in northern Europe and other parts of the world. The wings of these beetles are…
Answer this question and get it marked →February–March 2023, Paper 52
Fig. 1.2 shows one type of colorimeter, with a hole to hold the colorimeter tube, a digital readout of absorbance and a colorimeter tube containing a 3 cm3 sample (blue filtrate).…
Answer this question and get it marked →The scientists planted GM rice and weedy rice in a field, as shown in Fig. 2.1. Fig. 2.1 shows GM rice plants at the centre, surrounded by concentric rings of weedy rice plants at…
Answer this question and get it marked →May–June 2023, Paper 51
State one variable that should be standardised in the procedure to obtain the liquid carrot extract, other than the carrot tissue, fine sand and apparatus used.
Answer this question and get it marked →Some scientists found out from a published source that 13 or more attached salmon lice usually cause the death of a sea trout kept in laboratory conditions. The scientists decided…
Answer this question and get it marked →May–June 2023, Paper 52
Describe how the student made a 1:10 dilution of the enzyme extract.
Answer this question and get it marked →State two variables that the scientists should standardise in this investigation.
Answer this question and get it marked →May–June 2023, Paper 53
A student noticed that a colour change occurred, from red to magenta, when the alginate beads with immobilised C. vulgaris were left in a container of hydrogencarbonate indicator…
Answer this question and get it marked →Suggest two variables that the scientists should have standardised in this investigation.
Answer this question and get it marked →October–November 2023, Paper 31
You will investigate the effect of temperature on the production of carbon dioxide gas by yeast cells. Yeast cells contain enzymes that break down glucose to release carbon…
Answer this question and get it marked →J1 is a slide of a stained transverse section through a plant stem. Draw a large plan diagram of the region of the stem on J1 indicated by the shaded area in Fig. 2.1. Use a sharp…
Answer this question and get it marked →October–November 2023, Paper 51
The student removed an apple that was 5 cm in diameter from a tree. The student measured the sugar content of the apple, which was low. This indicated that the apple was at the…
Answer this question and get it marked →Identify the independent variable and the dependent variable in this experiment.
Answer this question and get it marked →October–November 2023, Paper 52
State two variables that have been standardised in the investigation.
Answer this question and get it marked →Seedlings do not always grow straight. Suggest how the measurements of shoot length of the rice seedlings can be made as accurately as possible.
Answer this question and get it marked →October–November 2023, Paper 53
The student removed an apple that was 5 cm in diameter from a tree. The student measured the sugar content of the apple, which was low. This indicated that the apple was at the…
Answer this question and get it marked →Identify the independent variable and the dependent variable in this experiment.
Answer this question and get it marked →Other AS & A Level Biology topics
- Biological molecules (115)
- Cell structure (98)
- Transport in plants (91)
- Transport in mammals (77)
- Cell membranes and transport (67)
- Nucleic acids and protein synthesis (63)
- Enzymes (59)
- The mitotic cell cycle (58)
- Gas exchange (53)
- Infectious disease (49)
- Immunity (42)
- Inheritance (25)