bio paper 1 2018

• A person with AIDS may take longer than a healthy person to recover from a Salmonella infection.

  Why?

  • immune system damaged
  • white blood cells cannot kill bacteria/salmonella as effectively
• Which cleaning liquid is the more effective? a or b?

  B- greater reduction in number of bacteria in both locations
• What measurement would the scientist need to take to calculate the area where no bacteria were growing?

  radius
• Give one change to the investigation that would allow the scientist to check if the results are repeatable?


  repeat the experiment again and see if results are similar
• Both cleaning liquids cost the same per dm3.

  Suggest one other factor the restaurant owner should consider when choosing which cleaning liquid to use.

  toxicity of product
• Describe two differences in the response of person R and person S to the exercise.


  • person r heart rate increased slower that person s
  • person r heart rate levelled off whereas person s continued to increase

  
• Urea is transported in the blood plasma.

  Name two other substances transported in the blood plasma.

  • carbon dioxide
  • glucose
• Explain why having more red blood cells per cm3 of blood is an advantage to an athlete.


  • more rbc means more haemoglobin present
  • more oxygen can be transported
  • to muscle cells so that they can respire which gives them more energy
• Which two blood vessels carry deoxygenated blood?


  • pulmonary artery
  • vena cava
• Compare the structure of an artery with the structure of a vein.


  • artery has thicker muscular walls whereas vein has thinner muscular wall
  • artery has narrower lumen than vein
  • veins have valves whereas arteries don't
• Where is the pacemaker located?


  a group of cells that act as a pacemaker are located in the right atrium
• What condition may be treated using an artificial pacemaker?


  an irregular heartbeat
• Explain why the masses of the eggs increased. (eggs were placed in acid for 24 hours)

  • mass increase bc water entered via osmosis
  • from dilute solution in beaker to conc solution in egg
  • through a partially permeable membrane
• Explain how the student could modify the investigation to determine the concentration of the solution inside each egg.

  • use 5 conc of sugar solution
  • plot percentage change on graph
  • look for where the curve crosses the zero percent change
• Explain how calcium ions are moved from the shell into the cytoplasm of the egg


  • ions move from low conc to high conc
  • via active transport against the conc gradient
  • which requires energy
• Give the reason why the mouthpiece of an aphid contains a high concentration of dissolved sugars after feeding


  has been feeding on phloem
• What is the function of the cell membrane?


  controls the movement of substances in and out of the cell
• if there was blockage from pancreas to small intestine why would a child grow slower?


  • pancreas releases digestive enzymes therefore fewer would enter small intestine and fewer would break down food
  • less absorption of nutrients
  • fewer amino acids entering bloodstream
  • less protein made
• if there was blockage from alveoli to lungs why would a child grow slower?


  • alveoli allow diffusion of oxygen into blood
  • therefore less oxygen entering and available for respiration
  • less energy available for growth (don't say produced)
• Describe how scientists may use stem cells to create healthy lungs that are not rejected by the CF patient.


  • take stem cells from patient
  • remove CF gene
  • create embryo using these stem cells
  • remove stem cells from embryo so they can differentiate into lung cells
• Two reasons why some people disagree with the use of stem cells to create new organs for transplants


  • ethical concern of embryo being potential human life
  • risk of cancer
• describe test for glucose


  • add benedicts solution
  • heat to 60 degrees Celsius
  • blue to brick red
• answer the question.

  lipase breaks down fat into fatty acids (and glycerol) (and) fatty acids lower the pH (and when) fatty acids cause the pH to be below 10 (the indicator becomes colourless)

  
• answer the questions.

  -observation of colour change is subjective / based on opinion

  -bile emulsifies fats creates a larger surface area (of fat) (so) lipase can break down fat (to produce fatty acids) more quickly / effectively