Edexcel GCSE Biology 2027 Predicted Practice Paper — Paper 1 Higher

Answer ALL questions. Write your answers in the spaces provided. You must write down all the stages in your working.

Section A

Answer all questions. This paper is written in a Pearson Edexcel Paper 1 practice style.

• 1

  Question A1 (10 marks)

  A student investigates osmosis using cylinders cut from a raw potato. Five cylinders of equal mass (2.50 g each) are placed in different sucrose solutions for 60 minutes, then reweighed. Concentration (mol/dm^3): 0.0, 0.2, 0.4, 0.6, 0.8 Final mass (g): 2.72, 2.60, 2.50, 2.36, 2.20 (a) Define osmosis. (2 marks) (b) Calculate the percentage change in mass for the cylinder in the 0.0 mol/dm^3 solution. Show your working. (2 marks) (c) State, with a reason, the concentration at which the sucrose solution was closest to the concentration of the potato cell cytoplasm. (2 marks) (d) Explain, in terms of water potential, why the cylinder in the 0.8 mol/dm^3 solution lost mass. (2 marks) (e) Suggest two variables the student should control to make the investigation valid. (2 marks)

  (Total for Question A1 is 10 marks)
• 2

  Question A2 (10 marks)

  Enzymes are biological catalysts. A student investigates the effect of pH on the rate at which the enzyme amylase breaks down starch. Iodine solution is used to detect starch: it turns blue-black when starch is present and stays orange-brown when starch is absent. The time taken for the starch to disappear is recorded at each pH. pH: 4, 5, 6, 7, 8 Time for starch to disappear (s): 180, 90, 45, 60, 150 (a) Name the products formed when amylase breaks down starch. (1 mark) (b) Calculate the rate of reaction at pH 6 in units of 1/s (reciprocal seconds). Show your working. (2 marks) (c) State the optimum pH for this amylase and justify your answer using the data. (2 marks) (d) Explain, in terms of enzyme structure, why the reaction was very slow at pH 4. (3 marks) (e) Describe how the student could use a water bath to control temperature during this investigation. (2 marks)

  (Total for Question A2 is 10 marks)
• 3

  Question A3 (10 marks)

  Figure shows a cross-section idea of a leaf and the process of photosynthesis. Photosynthesis can be summarised by the word equation: carbon dioxide + water -> glucose + oxygen (a) State what provides the energy for photosynthesis and name the substance that absorbs it. (2 marks) (b) Write the balanced symbol equation for photosynthesis. (2 marks) (c) A grower increases the carbon dioxide concentration in a greenhouse but the rate of photosynthesis does not increase. State what is meant by a 'limiting factor' and give one factor, other than carbon dioxide, that could be limiting the rate. (2 marks) (d) Describe how the glucose made in photosynthesis is used by the plant. Give two different uses. (2 marks) (e) Explain one way the structure of a palisade mesophyll cell is adapted for photosynthesis. (2 marks)

  (Total for Question A3 is 10 marks)
• 4

  Question A4 (10 marks)

  The human circulatory system transports substances around the body. Blood is pumped by the heart through arteries, capillaries and veins. (a) Name the blood vessel that carries oxygenated blood away from the heart to the body. (1 mark) (b) Describe two structural differences between an artery and a vein, and relate each to its function. (4 marks) (c) The heart is described as having a 'double circulation'. Explain what this means. (2 marks) (d) A person's resting heart rate is 72 beats per minute and their stroke volume (blood pumped per beat) is 70 cm^3. Calculate their cardiac output in cm^3 per minute. Show your working. (2 marks) (e) State one lifestyle factor that can increase the risk of coronary heart disease. (1 mark)

  (Total for Question A4 is 10 marks)
• 5

  Question A5 (10 marks)

  A student uses a light microscope to examine cheek cells and onion cells. (a) State two structures that are present in the onion (plant) cell but absent from the cheek (animal) cell. (2 marks) (b) The student views a cell that measures 30 mm across the eyepiece image. The magnification used was x400. Calculate the real (actual) diameter of the cell in micrometres (um). Show your working. (1 mm = 1000 um.) (3 marks) (c) State one advantage of using an electron microscope rather than a light microscope. (1 mark) (d) Describe the function of the following organelles: mitochondria and ribosomes. (2 marks) (e) The onion cells are treated with a stain before viewing. Explain why a stain is used. (2 marks)

  (Total for Question A5 is 10 marks)

Section B

Answer all questions. Quantitative answers must show working.

• 1

  Question B1 (10 marks)

  Cystic fibrosis is a genetic disorder caused by a recessive allele (f). The dominant allele (F) codes for a normal protein. A man and a woman, neither of whom has cystic fibrosis, have a child who does have the disorder. (a) State what is meant by the term 'recessive allele'. (2 marks) (b) Give the genotypes of the man and the woman. Explain your answer. (2 marks) (c) Draw a genetic (Punnett) cross to show the possible genotypes of their children. Use it to state the probability that their next child will have cystic fibrosis. (3 marks) (d) State the probability, as a ratio, of a child being a carrier (heterozygous). (1 mark) (e) Explain the difference between the terms 'genotype' and 'phenotype'. (2 marks)

  (Total for Question B1 is 10 marks)
• 2

  Question B2 (10 marks)

  The human body keeps blood glucose concentration within narrow limits by homeostasis. The pancreas monitors and controls blood glucose using hormones. (a) Name the hormone released by the pancreas when blood glucose concentration rises too high, and state which organ it acts on. (2 marks) (b) Describe what happens to the excess glucose after this hormone is released. (2 marks) (c) Explain how the body responds when blood glucose concentration falls too low. Refer to the hormone involved. (3 marks) (d) Type 1 diabetes is a condition in which the pancreas does not produce enough insulin. State how Type 1 diabetes is usually treated. (1 mark) (e) Blood glucose control is an example of negative feedback. Explain what is meant by negative feedback. (2 marks)

  (Total for Question B2 is 10 marks)
• 3

  Question B3 (10 marks)

  A scientist investigates the effect of exercise on breathing rate. A volunteer's breathing rate is measured at rest and again immediately after 3 minutes of running. Breathing rate at rest: 15 breaths per minute Breathing rate after exercise: 33 breaths per minute (a) Calculate the percentage increase in breathing rate caused by the exercise. Show your working. (2 marks) (b) Explain why breathing rate increases during exercise. Refer to respiration in your answer. (3 marks) (c) During very intense exercise, muscle cells may respire anaerobically. Write the word equation for anaerobic respiration in human muscle cells. (2 marks) (d) Explain what is meant by the term 'oxygen debt' and how it is repaid. (3 marks)

  (Total for Question B3 is 10 marks)
• 4

  Question B4 (10 marks)

  Communicable diseases are caused by pathogens. Different types of pathogen cause different diseases and can be spread in different ways. (a) Name the type of pathogen that causes each of the following diseases: measles and malaria. (2 marks) (b) Describe how the spread of malaria can be reduced. Give two methods. (2 marks) (c) White blood cells defend the body against pathogens. Describe two ways in which white blood cells do this. (2 marks) (d) Explain how vaccination provides protection against a disease. (3 marks) (e) Explain why antibiotics are not used to treat diseases caused by viruses. (1 mark)

  (Total for Question B4 is 10 marks)
• 5

  Question B5 (10 marks)

  Ecologists study how organisms interact in ecosystems and how energy and materials are transferred. The diagram below represents a food chain in a grassland: grass -> grasshopper -> frog -> snake (a) State what the arrows in a food chain represent. (1 mark) (b) Name the trophic level occupied by the frog. (1 mark) (c) The grass in one square metre transfers 24 000 kJ of energy. The grasshoppers store 2400 kJ. Calculate the percentage of energy transferred from the grass to the grasshoppers. Show your working. (2 marks) (d) Explain why energy is lost between trophic levels, and why this limits the length of a food chain. (3 marks) (e) Describe the role of decomposers in the carbon cycle. (3 marks)

  (Total for Question B5 is 10 marks)