Cell Biology

• What are the two types of cells in living organisms?

  Prokaryotic and eukaryotic
• What type of cells are animal and plant cells?

  Eukaryotic
• What are the main components of eukaryotic cells?

  • Cell membrane
  • Cytoplasm
  • Nucleus containing DNA
• What type of cells are bacterial cells?

  Prokaryotic
• What are the main components of prokaryotic cells?

  • Cell wall
  • Cell membrane
  • Cytoplasm
  • Single circular strand of DNA
  • Plasmids (small rings of DNA)
• What are organelles in a cell?

  Structures with different functions in a cell
• How do we use orders of magnitude to compare sizes?

  • 10 times bigger: $10^1$ times bigger
  • 1000 times bigger: $10^3$ times bigger
  • 10 times smaller: $10^{-1}$ times smaller
• Prefix:

  • Centi -> 0.01
  • Milli -> 0.001
  • Micro -> 0.000001
  • Nano -> 0.000000001
• Nucleus:

  • Contains DNA coding for a particular protein needed to build new cells.
  • Enclosed in a nuclear membrane.
• Cytoplasm:

  • Liquid substance in which chemical reactions occur.
  • Contains enzymes (biological catalysts, i.e. proteins that speed up the rate of reaction).
  • Organelles are found in it
• Cell Membrane:


  • Controls what enters and leaves the cell
• Mitochondria:

  • Where aerobic respiration reactions occur, providing energy for the cell
• Ribosomes:

  • Where protein synthesis occurs.
  • Found on a structure called the rough endoplasmic reticulum.
• Chloroplasts:

  • Where photosynthesis takes place, providing food for the plant
  • Contains chlorophyll pigment (which makes it green) which harvests the light needed for photosynthesis.
• Permanent vacuole:

  • Contains cell sap
  • Found within the cytoplasm
  • Improves cell’s rigidity
• Cell wall:

  • Made from cellulose
  • Provides strength to the cell
• Single circular strand of DNA

  • As they have no nucleus, this floats in the cytoplasm
• Plasmids:

  • Smal rings of DNA
• What does differentiation involve for a cell?

  Gaining new sub-cellular structures
• What are stem cells known for?

  Ability to differentiate their whole life
• How do plant cells differ in differentiation compared to animal cells?

  Many retain the ability to differentiate
• What is the primary function of sperm cells?

  To carry male DNA to the egg cell
• What adaptations do sperm cells have for swimming?

  Streamlined head and long tail
• Why do sperm cells have many mitochondria?

  To supply energy for movement
• What is the function of the acrosome in sperm cells?

  Contains digestive enzymes for egg cell
• What is the primary function of nerve cells?

  To transmit electrical signals quickly
• How does the axon of a nerve cell aid its function?

  It is long for carrying impulses
• What are dendrites in nerve cells responsible for?

  Forming branched connections with other cells
• Why do nerve endings have many mitochondria?

  To supply energy for neurotransmitter production
• What is the primary function of muscle cells?

  To contract quickly for movement
• What proteins are involved in muscle contraction?

  Myosin and actin
• Why do muscle cells have many mitochondria?

  To provide energy for contraction
• What chemical do muscle cells store for respiration?

  Glycogen
• How do striated muscle cells differ from smooth muscle cells?

  Striated muscles move bones, smooth muscles squeeze
• What is the primary function of root hair cells?

  To take up water and mineral ions
• How do root hair cells take up water?

  By osmosis from the soil
• What process do root hair cells use to absorb mineral ions?

  Active transport from the soil
• Where are root hair cells located?

  At the tips of roots
• Why do root hair cells have a large surface area?

  To allow more water to move in
• How does the large permanent vacuole affect water movement?

  It affects the speed of water movement