Cell Biology

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

  Prokaryotic and 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 and plasmids
• What are organelles?

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

  • 10 times bigger: \(10^1\)
  • 1000 times bigger: \(10^3\)
  • 10 times smaller: \(10^{-1}\)
• What are the prefixes used in measurements and their values?

  • Centi: \(0.01\)
  • Milli: \(0.001\)
  • Micro: \(0.000001\)
  • Nano: \(0.000000001\)
• What is the function of the nucleus in a cell?

  • Contains DNA coding for proteins
  • Enclosed in a nuclear membrane
• What is the role of cytoplasm in a cell?

  • Liquid substance for chemical reactions
  • Contains enzymes and organelles
• What is the function of the cell membrane?

  Controls what enters and leaves the cell
• What occurs in mitochondria?

  Where aerobic respiration reactions occur, providing energy
• What is the function of ribosomes?

  Where protein synthesis occurs
• What is the role of chloroplasts in plant cells?

  • Where photosynthesis takes place
  • Contains chlorophyll for light absorption
• What is the function of a permanent vacuole in plant cells?

  • Contains cell sap
  • Improves cell rigidity
• What is the structure and function of the cell wall in plant cells?

  • Made from cellulose
  • Provides strength to the cell
• How do bacterial cells differ from eukaryotic cells in terms of organelles?

  Bacterial cells do not share as many similarities in organelles as animal and plant cells do
• What is cell specialization?

  Cells undergo differentiation to gain new sub-cellular structures suited to their role
• How do stem cells differ from other cells in terms of differentiation?

  Stem cells can differentiate throughout their life, while most animal cells only differentiate once
• What are the specialized functions of sperm cells?

  • Carry male DNA to the egg
  • Streamlined head and long tail for swimming
  • Many mitochondria for energy
  • Acrosome with enzymes to penetrate the egg
• What are the specialized functions of nerve cells?

  • Transmit electrical signals quickly
  • Long axon for distance
  • Many dendrites for connections
  • Mitochondria for neurotransmitter production
• What are the specialized functions of muscle cells?

  • Contract quickly to move bones or squeeze
  • Special proteins for contraction
  • Many mitochondria for energy
  • Store glycogen for respiration
• What are the specialized functions of root hair cells?

  • Take up water and minerals
  • Large surface area for absorption
  • Large vacuole for water movement
  • Mitochondria for energy in active transport
• What are the specialized functions of xylem cells?

  • Transport water and minerals
  • Hollow structure for continuous flow
  • Lignin for strength under pressure
• What are the specialized functions of phloem cells?

  • Carry products of photosynthesis
  • Sieve plates for substance movement
  • Energy supplied by companion cells
• What is the role of stem cells in animals?

  Stem cells can replace specialized cells that cannot divide
• How do plants retain the ability to differentiate?

  Many plant cells can differentiate throughout life when they reach their final position
• What is the purpose of microscopy?

  To enlarge extremely small structures like cells for observation
• Who first observed cells in cork and when?

  Robert Hooke in 1665
• What are the components of a light microscope?

  • Two lenses: objective and eyepiece
  • Illuminated from underneath
  • Maximum magnification of \(x2000\)
  • Resolving power of 200nm
• What is the difference between scanning and transmission electron microscopes?

  • SEM creates 3D images
  • TEM creates 2D images
• What is the maximum magnification of an electron microscope?

  Up to \(x2,000,000\)
• What is the formula for calculating magnification in a light microscope?

  Magnification = magnification of eyepiece lens x magnification of objective lens
• How do you calculate the size of an object using a microscope?

  Size of object = size of image / magnification
• What is standard form and why is it useful in microscopy?

  Standard form helps manage very large or small numbers in calculations
• What is the culture medium for growing microorganisms?

  • Contains carbohydrates, minerals, proteins, and vitamins
• What are the two methods for culturing microorganisms?

  1. Nutrient broth solution
  2. Agar gel plate
• Why must Petri dishes and culture media be sterilized?

  To prevent contamination by unwanted microorganisms
• How do bacteria multiply in culture?

  Bacteria multiply by binary fission, splitting every 20 minutes
• What is the formula for calculating the number of bacteria after a certain time?

  Bacteria at end = bacteria at beginning x \(2^{\text{number of divisions}}\)
• What is the purpose of testing antibiotics on bacteria?

  To determine the effectiveness of different antibiotics on bacterial growth