required practicals

• What are the three types of variables in practical investigations?

  Independent, dependent, and controlled variables
• Why is it important to state the equipment used for measurements?

  It ensures clarity and accuracy in results
• What safety equipment should be used when working with chemicals?

  Goggles and gloves
• How can you reduce parallax error when measuring?

  Align your eye with the measurement mark
• What is a method to improve measurement accuracy?

  Take multiple or repeat measurements
• Why is it recommended to write answers in bullet points?

  It helps track different points made
• What should you do if you abbreviate points in your answers?

  Write them in full with proper English
• What is the procedure for preparing a microscope slide with onion skin?

  • Use a scalpel and tweezers to obtain a thin layer
  • Place it on a microscope slide
  • Add a drop of iodine to stain
  • Cover with a cover slip
• What is the first step when using a microscope?

  Start with the shortest objective lens
• How do you focus a specimen under a microscope?

  Use the coarse and fine focus knobs
• What is the standard form for micro measurements?

  Micro is times $10^{-6}$
• What is the aim of the osmosis practical with potato cells?

  To find the concentration of sugar in cells
• What should you do after placing potato cylinders in sugar solutions?

  Reweigh them after a set time
• What does a straight line on a graph of mass change against sugar concentration indicate?

  It shows the concentration where no osmosis occurs
• What is the independent variable in the enzyme practical?

  Temperature or pH
• How do you determine the end point in the enzyme practical?

  When iodine shows no color change
• What is the test for starch in food?

  Add iodine solution and check for color change
• How do you test for glucose in food?

  Add benedict's solution and heat it
• What indicates the presence of protein in food?

  Buret reagent turns from blue to purple
• What is the procedure to test for fats in food?

  Add cold ethanol, then water; check for cloudiness
• What is the aim of the photosynthesis practical?

  To determine light intensity's effect on photosynthesis
• How do you measure the rate of photosynthesis?

  Count bubbles or measure gas volume produced
• What is the relationship between light intensity and distance?

  Light intensity follows an inverse square relationship
• How do you calculate reaction time in the reaction time practical?

  Using $t =$$\sqrt{2s/a}$
• What is the independent variable in the reaction time experiment?

  Distractions like texting or sugary drinks
• What is the purpose of using a quadrat in ecology?

  To estimate the population of organisms
• How do you calculate the total population using quadrats?

  Mean number per square multiplied by total area
• What is the aim of the microbiology practical?

  To observe bacterial growth and antibiotic effects
• What technique ensures sterility in microbiology experiments?

  Using a bunsen flame to sterilize equipment
• What indicates a positive test for antibiotics on bacteria?

  Clear areas around antibiotic discs
• What is geotropism in plants?

  Roots grow downwards due to gravity
• What is phototropism in plants?

  Shoots grow towards light sources
• How do you measure the decay of milk in the decay practical?

  Time taken for the solution to decolorize
• What is the independent variable in the decay practical?

  Temperature of the solution
• What happens to enzyme activity at high temperatures?

  Enzymes denature and activity decreases
• What are the key steps in the decay practical?

  • Measure milk and add sodium carbonate
  • Add phenolphthalein indicator
  • Add lipase enzyme and time decolorization
  • Plot time against temperature