Cell biology

• What is a key difference between plant and animal cells?

  Plant cells have a cell wall.
• What structures are found in a typical animal cell?

  Nucleus, cytoplasm, cell membrane, mitochondria, ribosomes.
• What is the function of the nucleus in an animal cell?

  It controls cell activities and contains genetic material.
• Where do most chemical reactions occur in an animal cell?

  In the cytoplasm.
• What is the role of mitochondria in an animal cell?

  They are where aerobic respiration takes place.
• What additional structures do plant cells have compared to animal cells?

  Cell wall, permanent vacuole, chloroplasts.
• What is the function of chloroplasts in plant cells?

  They absorb light to make food through photosynthesis.
• What are the two main types of cells?

  • Prokaryotic
  • Eukaryotic
• What distinguishes prokaryotic cells from eukaryotic cells?

  Prokaryotic cells lack a nucleus.
• What is the genetic material structure in prokaryotic cells?

  A single DNA loop and plasmids.
• What is the role of plasmids in bacterial cells?

  They allow gene transfer between cells.
• What shapes can bacterial cells take?

  Round, rod-shaped, spiral.
• What replaces mitochondria and chloroplasts in bacterial cells?

  The cytoplasm takes over their roles.
• What is the typical size of a plant cell?

  About 0.1 mm in diameter.
• What is the typical size of a prokaryotic cell?

  About 0.002 mm long.
• What are the units used to describe cell sizes?

  • Centimetre (cm)
  • Millimetre (mm)
  • Micrometre (µm)
  • Nanometre (nm)
• What is resolution in microscopy?

  The ability to see separate objects clearly.
• When was the light microscope developed?

  In the late 16th century.
• What is the advantage of using an electron microscope?

  It provides much better resolution.
• What can be studied using an electron microscope?

  Structures inside mitochondria and chloroplasts.
• What is the process of mitosis?

  1. DNA replicates.
  2. Chromosomes align in the center.
  3. Chromosomes are pulled to opposite ends.
  4. Nucleus divides.
  5. Cytoplasm divides to form two identical cells.
• Why is mitosis important?

  It produces new cells for growth and repair.
• What are stem cells?

  Undifferentiated cells that can become specialized.
• Where are embryonic stem cells found?

  In human embryos.
• What is therapeutic cloning?

  Creating embryonic stem cells from an adult.
• What are the benefits of using stem cells?

  They can replace damaged cells in diseases.
• What is diffusion?

  • Net movement of particles from high to low concentration.
  • Continues until evenly spread out.
• What factors affect the rate of diffusion?

  Concentration gradient, temperature, surface area.
• What is osmosis?

  Diffusion of water through a partially permeable membrane.
• What is active transport?

  • Movement of substances against a concentration gradient.
  • Requires energy from respiration.
• How do plants absorb mineral ions?

  Through active transport in root hairs.
• How do sugar molecules enter the blood?

  By active transport from the gut.
• Compare diffusion, osmosis, and active transport.

  • Diffusion: Movement from high to low concentration.
  • Osmosis: Diffusion of water across a membrane.
  • Active Transport: Movement against a concentration gradient, requires energy.