Cell structure and transport

• What is the maximum magnification of light microscopes?

  About ×2000
• What is the resolving power of light microscopes?

  About 200 nm
• What is the maximum magnification of electron microscopes?

  About ×2,000,000
• What is the resolving power of electron microscopes?

  Around 0.2 nm
• How is magnification calculated?

  Magnification = size of image / size of real object
• What is the keyword associated with the ability to distinguish two close objects?

  Resolving power
• What are the unit conversions for length measurements?

  • 1 km = 1000 m
  • 1 m = 100 cm
  • 1 cm = 10 mm
  • 1 mm = 1000 µm
  • 1 µm = 1000 nm
• What do light microscopes use to form an image?

  Beams of light
• What do electron microscopes use to form an image?

  Beams of electrons
• Why can't electron microscopes be used to view living objects?

  They require special conditions
• What is the difference in cost and usability between light and electron microscopes?

  Light microscopes are cheaper and easier
• What type of image does a transmission electron microscope produce?

  A 2D image
• What type of image does a scanning electron microscope produce?

  A 3D image
• What does resolving power allow you to see?

  Two dots separately
• What is the resolving power of a light microscope in micrometers?

  0.2 µm
• How does the resolving power of electron microscopes compare to light microscopes?

  Electron microscopes have better resolving power
• If the magnification is ×570, what is the real size of an onion cell if its image size is 1.14 mm?

  Real size = 1.14 mm / 570
• What are common features of animal cells?

  Nucleus, cytoplasm, cell membrane
• What additional structures do plant cells have compared to animal cells?

  Cellulose cell wall, chloroplasts, vacuole
• What is the function of chloroplasts in plant cells?

  Photosynthesis
• What is the function of a permanent vacuole in plant cells?

  Helps keep the cell rigid
• What is the size range of animal cells?

  Around 10 µm to 30 µm
• What is the role of mitochondria in animal cells?

  Energy production through respiration
• What is the genetic material in eukaryotic cells contained in?

  A nucleus
• What distinguishes prokaryotic cells from eukaryotic cells?

  Prokaryotes lack a distinct nucleus
• What is the shape of bacterial cells?

  Various shapes
• What is the function of plasmids in prokaryotic cells?

  Extra small rings of DNA
• How do bacteria reproduce?

  By fission
• What is the order of magnitude of a large plant cell compared to a small animal cell?

  10 times bigger
• What happens to cells as an organism develops?

  Cells differentiate to form different types
• What are examples of specialised animal cells?

  Nerve cells, muscle cells, sperm cells
• Why do muscle cells contain many mitochondria?

  To transfer energy for movement
• What is the main function of root hair cells?

  To absorb water and minerals
• What is the function of photosynthetic cells?

  To make food through photosynthesis
• What do xylem cells transport?

  Water and mineral ions
• What is the role of phloem cells?

  To transport food made by photosynthesis
• What is diffusion?

  Movement from high to low concentration
• What is osmosis?

  Diffusion of water across a membrane
• How does the concentration gradient affect diffusion?

  Affects the rate of diffusion
• What is the significance of a concentration gradient?

  It drives the movement of particles