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• What types of cells can be observed with a normal light microscope?

  Cells and possibly the nucleus
• What is the advantage of using an electron microscope?

  It allows us to see finer details of organelles
• How can we calculate the actual size of a cell using a microscope?

  By dividing the image size by the magnification
• What are the two main groups of cells?

  Eukaryotic and prokaryotic cells
• What distinguishes eukaryotic cells from 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?

  It is where respiration takes place, releasing energy
• What do ribosomes do in a cell?

  They assemble or synthesize proteins
• What is the function of chloroplasts in plant cells?

  They contain chlorophyll and are where photosynthesis occurs
• What is a permanent vacuole in plant cells used for?

  It stores sap
• How do 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 on agar
  • Tape the lid partially to allow air in
  • Incubate at 25°C
• How do you calculate the area of a circle in a bacterial culture?

  Using the formula $A =$$\frac{\pi d^2}{4}$
• What is the chromosome number in human diploid cells?

  46 chromosomes (23 pairs)
• What is the process of mitosis?

  It is the duplication of genetic material and division into two identical cells
• What are gametes and how many chromosomes do they have?

  Gametes have 23 chromosomes, which is half of the diploid number
• What are stem cells?

  Cells that have not yet specialized
• Where are stem cells found in humans and plants?

  In human and animal embryos and the meristem of plants
• How can stem cells be used in medicine?

  To combat conditions like diabetes and paralysis
• What is diffusion?

  The movement of molecules from high to low concentration
• What is osmosis?

  The diffusion of water across a semi-permeable membrane
• How does the concentration of glucose outside a cell affect osmosis?

  If glucose concentration is higher outside, water moves out of the cell
• What factors can increase the rate of diffusion and osmosis?

  Increasing concentration difference, temperature, or surface area
• What is the practical procedure for investigating osmosis using potato cylinders?

  • Cut equal size potato cylinders and weigh them
  • Place in test tubes with varying sugar concentrations
  • After a day, weigh again and calculate percentage change in mass
  • Plot results against sugar concentration
• What is active transport?

  The movement of substances against a concentration gradient using energy
• What is the function of bile in digestion?

  To neutralize stomach acid and emulsify fats
• What are enzymes?

  Biological catalysts that speed up chemical reactions
• What is the relationship between cells, tissues, organs, and organ systems?

  Cells form tissues, tissues form organs, and organs form organ systems
• What is the function of amylase?

  To break down starch into glucose
• How do enzymes work according to the lock and key principle?

  The substrate fits into the enzyme's active site to form a complex
• What happens to an enzyme when it denatures?

  The active site changes shape, preventing substrate binding
• What is the optimum temperature for enzyme activity?

  The temperature at which the enzyme works best
• What is the effect of pH on enzyme activity?

  Extreme pH levels can denature enzymes
• What is the practical procedure for testing enzyme activity with amylase and starch?

  • Mix amylase with starch at different temperatures or pH levels
  • Remove drops every 10 seconds and test with iodine
  • Record the time taken for starch to be broken down
  • Plot results to find optimum conditions
• What color does iodine turn in the presence of starch?

  From brown to black
• What color does Benedict's solution turn in the presence of sugars?

  From blue to orange
• What color does Biuret's reagent turn in the presence of proteins?

  From blue to purple
• What happens to cold ethanol in the presence of lipids?

  It turns cloudy
• What is the difference between breathing and respiration?

  Breathing provides oxygen for respiration, which occurs in cells
• What is the pathway of air during breathing?

  Trachea, bronchi, bronchioles, alveoli