cell structure

• What are the two types of cells?

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

  Eukaryotic cells contain membrane-bound organelles and a nucleus, while prokaryotic cells do not.
• What is the composition of the prokaryotic cell wall?

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

  It is found free within the cytoplasm as chromosomal DNA and plasmid DNA.
• What are plasmids?

  Small, circular loops of DNA found free in the cytoplasm, separate from the main DNA.
• What is the function of plasmids in prokaryotic cells?

  They carry genes that provide genetic advantages, such as antibiotic resistance.
• What is order of magnitude?

  A power to the base 10 used to quantify and compare size.
• 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 are the additional cell components found in plant cells?

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

  It controls cellular activities.
• Describe the structure of the cytoplasm.

  It is a fluid component of the cell that contains organelles, enzymes, and dissolved ions and nutrients.
• What is the function of the cytoplasm?

  It is the site of cellular reactions and serves as a transport medium.
• What is the function of the cell membrane?

  It controls the entry and exit of materials into and out of the cell.
• What is the function of the mitochondria?

  It is the site of later stages of aerobic respiration in which ATP is produced.
• What is the function of the ribosomes?

  They join amino acids in a specific order during translation for the synthesis of proteins.
• What is the plant cell wall made of?

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

  It provides strength and prevents the cell from bursting when water enters by osmosis.
• What does the permanent vacuole contain?

  Cell sap, a solution of salts, sugars, and organic acids.
• What is the function of the permanent vacuole?

  It supports the cell, maintaining its turgidity.
• What is the function of chloroplasts?

  It is the site of photosynthesis.
• How are sperm cells in animals adapted to their function?

  • Haploid nucleus contains genetic information.
  • Tail enables movement.
  • Mitochondria provide energy for tail movement.
  • Acrosome contains enzymes that digest the egg cell membrane.
• How are nerve cells in animals adapted to their function?

  • Long axon allows electrical impulses to be transmitted all over the body.
  • Dendrites connect to and receive impulses from other nerve cells, muscles, and glands.
  • Myelin sheath insulates the axon and speeds up impulse transmission.
• How are muscle cells in animals adapted to their function?

  • Arrangement of protein filaments allows sliding for muscle contraction.
  • Mitochondria provide energy for contraction.
  • Merged cells in skeletal muscle allow contraction in unison.
• How are root hair cells in plants adapted to their function?

  • Large surface area to absorb nutrients and water.
  • Thin walls that do not restrict water absorption.
• How are xylem cells in plants adapted to their function?

  • No upper or lower margins between cells for continuous water flow.
  • Thick, woody side walls strengthen structure and prevent collapse.
• How are phloem cells in plants adapted to their function?

  • Sieve plates allow transport of dissolved amino acids and sugars.
  • Companion cells provide energy for active transport of substances.
• What is cell differentiation?

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

  It allows the production of different tissues and organs that perform various vital functions in the human body.
• At what point in their life cycle do most animal cells differentiate?

  Early in their life cycle.
• For 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 does a cell go through as it differentiates?

  It becomes specialized through the acquisition of different sub-cellular structures to enable a specific function.
• Define magnification.

  The number of times bigger an image appears compared to the size of the real object.
• Define resolution.

  The ability to distinguish two close objects as separate.
• What is the purpose of cell division in mature animals?

  Repair and replacement of cells