Biology - Paper 1

• What is the main advantage of light microscopes?

  They are cheap to make.
• What can electron microscopes examine?

  Fine details like sub-cellular structures.
• How many chromosomes do human cells have?

  46 chromosomes.
• What type of cells are gametes?

  Haploid cells.
• What is the purpose of mitosis?

  To create new diploid cells for growth and repair.
• What are the stages of mitosis?

  1. Nucleus dissolves/divides
  2. Chromosomes move to opposite sides
  3. Cell divides into two new diploid cells
• What are stem cells capable of?

  Specializing to perform specific functions.
• What is diffusion?

  Movement of particles from high to low concentration.
• Why is diffusion considered passive?

  It doesn't require any energy.
• What factors can increase the rate of diffusion?

  Increasing temperature, surface area, or concentration difference.
• What is osmosis?

  Diffusion of water across a semi-permeable membrane.
• What is active transport?

  Movement of particles through a membrane requiring energy.
• What is the organization of biological structures from smallest to largest?

  • Cell
  • Tissue
  • Organ
  • Organ system
• What is the function of the mouth in digestion?

  To break down food mechanically.
• What enzyme is found in saliva?

  Amylase.
• What does the liver produce?

  Bile, which emulsifies lipids.
• What is the role of hydrochloric acid in the stomach?

  To chemically break down food.
• What does the pancreas secrete?

  Amylase, which breaks down starch.
• Where are nutrients absorbed in the digestive system?

  In the small intestine via villi.
• What is the function of the large intestine?

  To absorb water.
• What are enzymes?

  Special proteins that act as biological catalysts.
• How do enzymes work?

  They break down substances that fit their active sites.
• What is the optimum condition for enzymes?

  Conditions for maximum activity.
• What are the types of enzymes and their functions?

  • Carbohydrase: breaks down carbs into sugars
  • Amylase: breaks down starch into sugars
  • Protease: breaks down protein into amino acids
  • Lipase: breaks down lipids into glycerol and fatty acids
• What are the tests for starch, sugars, proteins, and lipids?

  • Starch: iodine (orange to black)
  • Sugars: Benedict's (blue to orange)
  • Proteins: Biuret (blue to purple)
  • Lipids: ethanol + water (cloudy)
• What are alveoli and their function?

  Small structures for gas exchange in lungs.
• What happens to oxygen in the bloodstream?

  It binds to hemoglobin in red blood cells.
• What is the pathway of air in the respiratory system?

  Trachea -> Bronchi -> Bronchioles -> Alveoli.
• What are communicable diseases caused by?

  Pathogens.
• What is cancer caused by?

  Uncontrollable cell division from genetic mutation.
• What are carcinogens?

  Substances that increase cancer risk.
• What is the difference between benign and malignant tumors?

  Benign tumors do not spread; malignant tumors do.
• What are the functions of different plant structures?

  • Flower: reproductive organs
  • Leaf: photosynthesis and gas exchange
  • Meristem: stem cell production
  • Phloem: carries sugars and nutrients
  • Xylem: carries water and minerals
  • Roots: water and mineral uptake
• What is a pathogen?

  A microorganism that causes disease.
• How do bacteria cause disease?

  By releasing toxins into our bodies.
• What is the role of lymphocytes in the immune response?

  They produce antibodies and antitoxins.
• What do phagocytes do?

  They ingest pathogens.
• What is a vaccine?

  A preparation of dead/weak viruses for immunity.
• Who discovered penicillin?

  Alexander Fleming.
• What is the purpose of antibiotics?

  To kill bacteria.