Cell Structure

• What are the two types of cells?

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

  Eukaryotic cells have membrane-bound organelles
• How do prokaryotic cells compare in size to eukaryotic cells?

  Prokaryotic cells are much smaller
• What is the composition of the prokaryotic cell wall?

  Peptidoglycan
• How is genetic information stored in a prokaryotic cell?

  As chromosomal DNA and plasmid DNA
• What are plasmids?

  Small, circular loops of DNA
• What advantages do plasmids provide to bacteria?

  They can carry genes for antibiotic resistance
• What is order of magnitude?

  A power of ten used to compare sizes
• What is a centimetre (cm) in metres?

  1 x 10$-2$ metres
• What is a millimetre (mm) in metres?

  1 x 10$-3$ metres
• What is a micrometre (µm) in metres?

  1 x 10$-6$ metres
• What is a nanometre (nm) in metres?

  1 x 10$-9$ metres
• What is the difference in order of magnitude between a human hair (100 µm) and the HIV virus (100 nm)?

  The difference is 3 orders of magnitude
• What are the components of both plant and animal cells?

  • Nucleus
  • Cytoplasm
  • Cell membrane
  • Mitochondria
  • Ribosomes
• What additional components are found in plant cells?

  • Chloroplasts
  • Permanent vacuole
  • Cell wall
• What is the function of the nucleus besides storing genetic information?

  Controls cellular activities
• Describe the structure of the cytoplasm.

  Fluid containing organelles and nutrients
• What is the function of the cytoplasm?

  Site of cellular reactions and transport
• What is the function of the cell membrane?

  Controls entry and exit of materials
• What is the function of the mitochondria?

  Site of aerobic respiration producing ATP
• What is the function of ribosomes?

  Joins amino acids to synthesize proteins
• What is the plant cell wall made of?

  Cellulose
• What is the function of the plant cell wall?

  Provides strength and prevents bursting
• What does the permanent vacuole contain?

  Cell sap with salts and sugars
• What is the function of the permanent vacuole?

  Supports the cell and maintains turgidity
• What is the function of chloroplasts?

  Site of photosynthesis
• How are sperm cells adapted to their function?

  • Haploid nucleus for genetic information
  • Tail for movement
  • Mitochondria for energy
  • Acrosome with enzymes for egg digestion
• How are nerve cells adapted to their function?

  • Long axon for impulse transmission
  • Dendrites for receiving impulses
  • Myelin sheath for faster transmission
• How are muscle cells adapted to their function?

  • Protein filaments for contraction
  • Mitochondria for energy
  • Merged cells for coordinated contraction
• How are root hair cells adapted to their function?

  • Large surface area for absorption
  • Thin walls for easy water uptake
• How are xylem cells adapted to their function?

  • No margins for continuous water flow
  • Thick walls for structural support
• How are phloem cells adapted to their function?

  • Sieve plates for transporting substances
  • Companion cells for energy in transport
• What is cell differentiation?

  The process by which cells become specialized
• Why is cell differentiation important?

  It allows production of different tissues
• When do most animal cells differentiate?

  Early in their life cycle
• How long do plant cells retain the ability to differentiate?

  Throughout their entire life cycle
• What is the purpose of cell division in mature animals?

  Repair and replacement of cells
• What changes occur in a cell during differentiation?

  Acquisition of structures for specific functions
• Define magnification.

  Number of times bigger an image appears
• What changes does a cell undergo during differentiation?

  Becomes specialized with different sub-cellular structures