2024

• Suggest 2 reasons why the drinks company uses fructose in the drink rather than using glucose.

  • Fructose is more soluble than glucose, making it easier to dissolve in drinks.
  • fructose is metabolised more slowly than glucose, providing a longer-lasting energy source
• how can the student test the drink for sugar

  test: add Benedict's solution- heat it in a water bath-around 80 C for a few minutes

  colour of positive result: Brick red(indicating the presence of sugar)
• how can the student test the drink for protein?

  test: add the Biuret solution &mix

  colour of positive result:a purple/lilac
• Describe how protein and fat are digested.

  • Protein
  • protease
  • ○ (protein) broken down into amino acids
  • ○ (protease) produced in the stomach
  • ○ (protease) produced in the pancreas
  • ○ (protease) produced in the small intestine
  • ○ (hydrochloric) acid provides the correct pH for protease (in the stomach)

  Fat

  • lipase
  • ○ (fat) broken down into fatty acids
  • ○ (fat) broken down into glycerol
  • ○ (lipase) produced by the pancreas
  • ○ (lipase) produced by the small intestine
  • ○ bile
  • ○ (bile) produced by the liver
  • ○ (bile) released from the gall bladder
  • ○ emulsification of fats
  • ○ larger surface area for lipase
  • ○ neutralises acid to provide the correct pH for enzymes
• what was the independent variable for the investigation?

  concentration of salt solution

  
• why is it important to dry the tubes.

  to remove excess water
• what type of microorganism causes measles?

  A virus
• suggest 2 ways the spread of measles can be reduced

  1.isoate infected individuals to prevent contact with others

  2. maintain food hygiene practices, such as frequent handwashing & disinfecting surfaces.
• Describe how the measles vaccine helps a person to become immune to the measles pathogen.

  • The vaccines contain a weakened or inactive form of the measles virus.
  • When introduced into the body, it stimulates the immune system to produce specific antibodies in response to an antigen.
  • Memory cells are also produced, which remain in the bloodstream.
  • if the person is exposed to the measles virus in the future, the memory cells rapidly produce antibodies, preventing infection.
• norovirus is a type of virus.

  Explain how viruses cause illness.

  • virus invade host cells & replicate inside them
  • This damages or destroys the host cells, leading to illness
• Give 3 reasons why clinical trials are needed.

  • to ensure the drug is safe for humans
  • to check if the drug is effective for its intended purpose
  • to identify the correct dosage & possible side effects.
• Symbol equation for photosynthesis

  6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂
• explain why no gas was produced by the plant at 45 °c

  Enzymes required for photosynthesis become denatured at high temperatures, stopping the reaction.
• suggest 2 reasons against using a heater set at 25 °c in the greenhouse.(A person is growing tomatoes)

  • Higher temperature increases water loss through transpiration, stressing the plants
  • it may lead to faster growth of weeds and pests in the greenhouse.
• which tissues in the cut stem will differentiate into new root cells?

  meristem
• what type of microscope was used to view the bacteria?(to view specific tiny details)

  type of microscope: electron microscope

  Reason: it provides high magnification & resolution needed to view the small structures like bacteria.
• Give 3 ways that a prokaryotic cell is different from an eukaryotic cell

  • Prokaryotes lack a nucleus; Eukaryotic cells have a nucleus
  • Prokaryotic cells have no membrane-bound organelles; Eukaryotic cells do
  • Prokaryotes have smaller ribosomes compared to eukaryotes cells.
• Describe the process of the cell cycle.

  Interphase: the cell grows & DNA replicates

  mitosis: chromosomes are separated, the nucleus divides

  cytokinesis: cytoplasm divides, forming 2 identical daughter cells.
• Lung cancer is malignant.

  Explain what is meant by a malignant tumour.

  • A malignant tumour consists of cancerous cells
  • the cells divide controllably &invade surrounding tissues
  • They can spread to other parts of the body via the bloodstream or lymphatic system.
• Person A and Person B both exercise. Figure 6 shows their alveoli – Person A doesn't smoke, Person B does. Explain why Person B breathes faster during exercise.:

  • Person's B alveoli are damaged, reducing the surface area for gas exchange.• Less oxygen enters the bloodstream, leading to lower oxygen availability for muscles.• The body compensates by increasing breathing rate to meet oxygen demand.• More CO₂ needs to be expelled.
• Explain: (🟡) the causes and symptoms of angina and (🟢) how GTN reduces the symptoms of angina.

  Answer :

  🟡:• Angina occurs due to the narrowing of coronary arteries caused by a buildup of fatty deposits, which reduces blood flow to the heart muscle.• This results in insufficient oxygen reaching the heart, especially during physical exertion or stress.• Symptoms include chest pain, a feeling of tightness or pressure, fatigue & sometimes shortness of breath.

  🟢:• GTN is a vasodilator, meaning it relaxes & widens the coronary arteries.• This increases blood flow to the heart muscle, ensuring an adequate oxygen supply.• By improving oxygen delivery, GTN alleviates chest pain & reduces other symptoms of angina.