PAPER 1

• What is the focus of the AQA GCSE Biology paper 1?


  Cells, organization, infection and response, and bioenergetics
• What is the difference between eukaryotic and prokaryotic cells?


  Eukaryotic cells have a nucleus, while prokaryotic cells do not
• What is the function of the cell membrane?


  It keeps everything inside the cell and is semi-permeable
• What is the role of mitochondria in a cell?


  Mitochondria are where respiration takes place, releasing energy
• What do ribosomes do in a cell?


  Ribosomes are where proteins are assembled
• What is the function of chloroplasts in plant cells?


  Chloroplasts contain chlorophyll and are where photosynthesis takes place
• What is the purpose of a permanent vacuole in plant cells?


  It stores sap
• How do bacteria multiply?


  Bacteria multiply by binary fission
• What is the procedure for culturing bacteria on agar using aseptic technique?


  • Lift the lid of the dish towards a flame to move microbes away
  • Use sterilized equipment to place bacteria culture
  • Tape the lid on loosely to allow air in
  • Incubate at 25°C
• How many pairs of chromosomes do humans have?


  Humans have 23 pairs of chromosomes
• How do you calculate the area of a circle in a bacterial culture experiment?


  Use the formula $A =$$\frac{\pi d^2}{4}$
• What is the difference between diploid and haploid cells?


  Diploid cells have 23 pairs of chromosomes, while haploid cells have 23 single chromosomes
• What is the process of mitosis?


  Mitosis is the process where genetic material is duplicated and two identical cells are formed
• Where are stem cells found in humans?

  Stem cells are found in human embryos and bone marrow
• What are the key differences between diffusion and osmosis?


  • Diffusion: Movement of molecules from high to low concentration, does not require energy
  • Osmosis: Diffusion of water across a semi-permeable membrane
• What factors can increase the rate of diffusion and osmosis?

  Increasing concentration difference, temperature, or surface area
• What is the role of stem cells in medicine?


  Stem cells can be used to combat conditions like diabetes and paralysis
• Describe the practical procedure for investigating osmosis using potato cylinders.


  1. Cut equal size potato cylinders and weigh them
  2. Place in test tubes with varying sugar concentrations
  3. After a day, weigh again and calculate percentage change in mass
  4. Plot results against sugar concentration
• What is the function of enzymes?

  Enzymes are biological catalysts that speed up chemical reactions
• What is active transport?


  Active transport is the movement of substances against a concentration gradient using energy
• What is the lock and key principle in enzyme activity?


  The substrate must fit the enzyme's active site to form a complex
• What happens to an enzyme at its optimum temperature?


  The rate of enzyme activity increases until the enzyme denatures
• How do you determine the optimum temperature or pH for an enzyme?


  1. Mix enzyme with substrate at different temperatures or pH levels
  2. Time how long it takes for the reaction to complete
  3. Plot results and identify the lowest point for optimum conditions
• What color does iodine turn in the presence of starch?


  Iodine turns from brown to black in the presence of starch
• What is the role of the respiratory system?


  The respiratory system provides oxygen for respiration and removes carbon dioxide
• What is the pathway of air during breathing?

  Air moves down the trachea into the bronchi, bronchioles, and alveoli
• How does oxygen enter the blood from the alveoli?


  Oxygen diffuses from the alveoli into the blood vessels
• What is the function of hemoglobin in red blood cells?

  Hemoglobin binds to oxygen for transport in the blood
• What is the structure of the heart?

  The heart has four chambers: right atrium, right ventricle, left atrium, and left ventricle
• What is the role of valves in the heart?


  Valves prevent backflow of blood
• What is the difference between arteries and veins?

  Arteries carry oxygenated blood away from the heart, while veins carry deoxygenated blood to the heart
• What is coronary heart disease (CHD)?


  CHD is caused by the buildup of fatty deposits in the coronary arteries
• What is the purpose of statins?


  Statins reduce cholesterol levels to prevent fatty deposits
• What is cardiovascular disease (CVD)?

  CVD is a non-communicable disease caused by internal factors
• What is the difference between communicable and non-communicable diseases?


  Communicable diseases are caused by pathogens, while non-communicable diseases arise from internal factors
• What are the main components of the circulatory system?


  • Heart
  • Blood vessels (arteries, veins, capillaries)
  • Blood (red blood cells, white blood cells, platelets)
• What is the condition caused by blocked coronary arteries?

  Coronary heart disease (CHD)
• What is the purpose of statins?


  Statins are drugs that reduce cholesterol levels.
• What do faulty heart valves result in?


  Backflow of blood.
• What components does blood carry besides red blood cells?

  White blood cells and platelets.