summary

• What can we see with a normal light microscope?

  Cells and possibly the nucleus
• What does an electron microscope allow us to see?

  Finer details of subcellular structures
• What is the resolving power of electron microscopes compared to light microscopes?

  Higher resolving power
• How can we calculate the actual size of a cell?

  By knowing the magnification
• What is the formula for magnification?

  Magnification = image size / object size
• How do you find the actual cell size using magnification?

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

  Eukaryotic and prokaryotic cells
• What characterizes eukaryotic cells?

  They have a nucleus containing DNA
• What type of cells are plant and animal cells?

  Eukaryotic cells
• What do prokaryotic cells lack?

  A nucleus
• Where is DNA found in prokaryotic cells?

  In a ring called a plasmid
• What do both eukaryotic and prokaryotic cells contain?

  Similar organelles or subcellular structures
• What is the function of the cell membrane?

  Keeps everything inside the cell
• What does semi-permeable mean in relation to the cell membrane?

  Allows certain substances to pass through
• What do plant cells and most bacteria have that provides structure?

  An extra cell wall made of cellulose
• What is cytoplasm?

  The liquid where most chemical reactions occur
• Where does respiration take place in a cell?

  In the mitochondria
• What is the role of ribosomes?

  Assemble or synthesize proteins
• What do chloroplasts contain and where are they found?

  Chlorophyll for photosynthesis in plant cells
• What is a permanent vacuole in plant cells used for?

  Storing sap
• How do bacteria multiply?

  By binary fission
• What is the practical method for culturing bacteria?

  • Use agar in a Petri dish
  • Employ aseptic technique to avoid contamination
  • Lift the lid towards a flame
  • Use sterilized equipment
  • Incubate at 25°C
• How do you calculate the area of a circle in a bacterial culture?

  Using $\frac{\pi d^2}{4}$
• What do eukaryotic cell nuclei contain?

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

  23 pairs
• What type of cells are gametes?

  Haploid cells
• What is the process by which new cells are made for growth and repair?

  Mitosis
• What happens during the mitosis process?

  Genetic material is duplicated and divided
• What is the result of mitosis?

  Two identical cells
• Where are stem cells found in humans and animals?

  In embryos and bone marrow
• What can stem cells specialize into in bone marrow?

  Blood cells
• How can stem cells be used in medicine?

  To combat conditions like diabetes and paralysis
• What is cloning used for in plants?

  To prevent species extinction or produce crops
• What is diffusion?

  Movement from high to low concentration
• What is passive transport?

  Movement that does not require energy
• What is osmosis specifically related to?

  Diffusion of water across a membrane
• What happens when there is a higher concentration of glucose outside a cell?

  Water moves out of the cell
• What factors can increase the rate of diffusion and osmosis?

  Concentration difference, temperature, surface area
• What is the practical method for investigating osmosis using potatoes?

  • Cut equal size cylinders from potatoes
  • Weigh them and place in sugar solutions
  • After a day, reweigh and calculate percentage change
  • Plot percentages against sugar concentration
  • Determine concentration with no change in mass
• What is active transport?

  Movement against a concentration gradient using energy