Exam questions

• DNA base pairs


  Bonded together in a DNA molecule
• Extracting DNA from peas


  1. Crush peas

  2. Add washing up liquid and water

  3. Add enzyme protease

  4. Heat and filter

  5. Pour filtrate into test tube and add ice cold ethanol
• Protease enzyme


  Added to break down proteins and release DNA
• Ice cold ethanol was poured into the filtrate to precipitate the DNA
• Chlamydia


  Sexually transmitted infection (STI) with the median number of people diagnosed
• Chlamydia


  Communicable disease that can be transmitted from person to person
• Preventing transmission of chlamydia

  Use protection during sexual activity
• Chlamydia can be treated with antibiotics
• HIV


  Can lead to the onset of AIDS by weakening the immune system
• How Klebsiella pneumoniae bacteria developed resistance to antibiotics

  1. Through natural selection, where bacteria with resistance genes survive and reproduce, passing on resistance

  2. Overuse of antibiotics kills susceptible bacteria and allows resistant strains to dominate
• Prokaryotic cell


  Does not have a nucleus
• Stages of antibiotic development after discovery


  1. Testing for safety and efficacy

  2. Clinical trials

  3. Regulatory approval
• Milk B rose to the surface because it had a lower density than water
• Adding lipase to milk B


  Caused a change in pH from 7 to 5
• No change in pH when lipase was added to milk A
• Boiled lipase added to milk B did not change the pH
• Preparing microscope slide to show mitosis in garlic root

  1. Cut root tip

  2. Fix and stain cells

  3. Mount on slide
• Mitosis


  Produces two genetically identical daughter cells
• Cancer increases cell division
• Pig embryo genetically engineered to not grow pig kidneys
• Using human stem cells


  To grow human kidneys in genetically modified pig embryos
• Comparing number of organ transplants needed vs donors available from 1991-2018
• Scientists genetically engineer animals to produce organs for transplants to address shortage of human donors
• Genetically engineering bacteria to produce human insulin


  1. Insert human insulin gene into bacteria

  2. Bacteria transcribe and translate the gene to produce human insulin protein

  3. Insulin protein is harvested and purified
• Centre Number
• Impulse passing from relay neurone to motor neurone


  1. Substrate binding

  2. Transition state facilitation

  3. Catalysis

  4. Release
• Reflex arc


  A rapid, automatic response to a stimulus
• The median result for the students is 210 milliseconds
• Comparing reaction times to red squares turning into yellow squares

  1. Conduct the same experiment but use red squares instead of blue squares

  2. Measure and compare the reaction times of the students

  3. Analyse if the colour change affects reaction time
• World Health Organization


  Defines health as a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity
• Differences between communicable and non-communicable diseases


  • Communicable diseases can be transmitted from one person to another
  • Non-communicable diseases cannot be transmitted from one person to another
• Reducing/preventing the spread of tuberculosis (TB)


  • Isolating infected individuals
  • Improving sanitation and hygiene
• The number of people with TB in the countries are: Germany 6100, Belgium 1000, Portugal 2400, UK 5400, France 5800
• People with AIDS


  More susceptible to TB
• Cell Q is in metaphase and cell R is in anaphase
• Processes in prophase


  • Chromosomes condense
  • Nuclear envelope breaks down
• The diameter of one cell in Figure 4 is 75 µm
• Adjusting a microscope to view a slide at 400x magnification


  1. Adjust the coarse focus to bring the specimen into view

  2. Adjust the fine focus to sharpen the image

  3. Adjust the objective lens to the 40x magnification
• Benefits and risks of using stem cell therapy to treat arthritis


  • Benefits: Stem cells can differentiate into new cartilage cells to replace damaged ones
  • Risks: Stem cell therapy is still experimental, there are ethical concerns, and the long-term effects are unknown
• Alcohol consumption


  Increases the risk of developing liver cancer