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 bacterial 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: 10¹ times bigger
  • 1000 times bigger: 10³ times bigger
  • 10 times smaller: 10^-1 times smaller
• 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 role of ribosomes in a cell?

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

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

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

  Provides strength to the cell, made from cellulose
• How do bacterial cells differ from eukaryotic cells?

  • Bacterial cells are prokaryotic
  • Have no nucleus, single circular DNA, and plasmids
• What is differentiation in cells?

  Process where cells gain new structures to suit their role
• What are stem cells?

  Cells that can differentiate throughout life
• What is the role of sperm cells?

  • Carry male DNA to the egg
  • Streamlined head and long tail for swimming
• What is the function of nerve cells?

  • Transmit electrical signals quickly
  • Long axon for distance
• What is the role of muscle cells?

  • Contract quickly to move bones
  • Contain proteins for contraction
• What is the function of root hair cells?

  • Take up water and minerals
  • Large surface area for absorption
• What is the role of xylem cells?

  Transport water and minerals from roots to shoots
• What is the function of phloem cells?

  Carry products of photosynthesis to all parts of the plant
• What is the process of binary fission in bacteria?

  One bacterium splits into two, can occur every 20 minutes
• What is the formula to calculate the number of bacteria after a certain time?

  bacteria at beginning x 2^{number of divisions} = bacteria at end
• Why must Petri dishes and culture media be sterilised?

  To prevent contamination by unwanted microorganisms
• What is the purpose of sealing the Petri dish with tape?

  Stops airborne microorganisms from contaminating the culture
• Why should the Petri dish be stored upside down?

  To prevent condensation from disrupting growth
• Why is the culture incubated at 25 degrees?

  To prevent harmful bacteria from growing at higher temperatures
• What is the surface area to volume ratio?

  Size of surface area compared to its volume
• How do single-celled organisms transport molecules?

  Use diffusion due to a large surface area to volume ratio
• Why can't multicellular organisms rely solely on diffusion?

  They have a small surface area to volume ratio
• How does gas exchange occur in the lungs?

  Oxygen and carbon dioxide transfer across alveoli and capillaries
• What is the role of the small intestine in nutrient absorption?

  Facilitates the transfer of nutrients into the bloodstream
• Why do single-celled organisms not require specialized exchange surfaces?

  Because the rate of diffusion is sufficient for supplying and removing necessary gases.
• What is the surface area to volume ratio of a single-celled organism represented as?

  1. 1
• Why can single-celled organisms rely on diffusion for transport?

  They have a relatively large surface area to volume ratio and low metabolic demands.
• Why can't multicellular organisms rely solely on diffusion?

  They have a small surface area to volume ratio.
• What adaptations do multicellular organisms have for transport?

  • Specialized exchange surfaces
  • Organ systems for transport
  • Increased surface area for absorption