organisation

• What is the difference between eukaryotic and prokaryotic cells?

  Eukaryotic cells have a nucleus, while prokaryotic cells do not
• What structures can be seen with a light microscope?

  Cells and possibly the nucleus
• What advantage does an electron microscope have over a light microscope?

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

  By dividing the image size by the magnification
• What is the function of the cell membrane?

  It keeps everything inside the cell and is semi-permeable
• What is the composition of the cell wall in plant cells?

  Cellulose
• 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?

  Storing sap
• How do bacteria multiply?

  By binary fission
• What is the purpose of using aseptic technique in culturing bacteria?

  To prevent contamination of the culture
• What is the formula to calculate the area of a circle?

  Area = $\frac{\pi d^2}{4}$
• What is the genetic material in eukaryotic cell nuclei?

  DNA stored in chromosomes
• How many pairs of chromosomes do humans have?

  23 pairs
• What are gametes and how many chromosomes do they have?

  Gametes have 23 chromosomes, not in pairs
• What is mitosis used for?

  For growth and repair by duplicating cells
• What happens to the genetic material during mitosis?

  It is duplicated and divided into two identical cells
• What are stem cells?

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

  In embryos and bone marrow
• 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 can the rate of diffusion be increased?

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

  We weigh, place in sugar solutions, and measure percentage change in mass
• What is active transport?

  Movement of substances against a concentration gradient using energy
• What is a tissue?

  A group of similar cells working together
• What is an organ?

  A structure made of different tissues working together
• What is an organ system?

  A group of organs working together for a specific function
• What is the role of bile in digestion?

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

  Biological catalysts that speed up chemical reactions
• What does amylase do?

  Breaks down starch into glucose
• What is the lock and key principle in enzyme activity?

  Substrates must fit the enzyme's active site to form a complex
• What happens to an enzyme at high temperatures?

  It can denature and lose its function
• What is the optimum temperature for enzyme activity?

  The temperature at which the enzyme works best
• What is the practical procedure for testing enzyme activity with amylase?

  Mix amylase with starch, time the reaction, and test with iodine
• What color does iodine turn in the presence of starch?

  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