Cell Biology

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

  Prokaryotic and eukaryotic
• What are the components of eukaryotic cells?


  • Cell membrane
  • Cytoplasm
  • Nucleus containing DNA
• What are the components of prokaryotic cells?


  Cell wall, cell membrane, cytoplasm, single circular strand of DNA, and plasmids
• What is the function of organelles in a cell?


  They perform different functions necessary for the cell's survival and operation
• How do we express the size difference between objects using orders of magnitude?


  If an object is 10 times bigger, it is said to be 10$^1$ times bigger
• What does the prefix 'centi' represent in measurements?


  It represents multiplying the unit by 0.01
• What are the prefixes used in measurements and their corresponding values?


  • Centi: 0.01
  • Milli: 0.001
  • Micro: 0.000001
  • Nano: 0.000000001
• What is the role of the nucleus in a cell?


  It contains DNA coding for proteins needed to build new cells
• What is the function of cytoplasm in a cell?


  It is the liquid substance where chemical reactions occur and contains enzymes
• What is the function of the cell membrane?


  It controls what enters and leaves the cell
• What is the role of mitochondria in a cell?


  They are where aerobic respiration occurs, providing energy for the cell
• What is the function of ribosomes?


  They are the site of protein synthesis
• What is the role of chloroplasts in plant cells?


  They are where photosynthesis takes place, providing food for the plant
• What is the function of the permanent vacuole in plant cells?


  It contains cell sap and improves the cell's rigidity
• What is the function of the cell wall in plant cells?


  It provides strength to the cell and is made from cellulose
• 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
• How can you calculate the size or area of sub-cellular structures?


  By finding a shape that resembles it and applying the appropriate area formula
• What is cell differentiation?


  • The process by which cells gain new sub-cellular structures
  • Suited to their specific roles
  • Can occur early in development or throughout life (stem cells)
• What is the function of sperm cells?


  To carry the male's DNA to the egg cell for reproduction
• How are nerve cells specialized for their function?


  They have a long axon and many dendrites for transmitting signals quickly
• What is the role of mitochondria in muscle cells?


  They provide energy from respiration for muscle contraction
• What is the function of root hair cells?


  To take up water and mineral ions from the soil
• How do xylem cells function in plants?


  They transport water and mineral ions from the roots to the shoots
• What is the role of phloem cells?


  They carry the products of photosynthesis to all parts of the plant
• What is the process of differentiation in stem cells?


  • Stem cells undergo differentiation to form specialized cells
  • Involves switching genes on or off
  • Produces different proteins for specific functions
• What happens to most animal cells after differentiation?


  They lose the ability to differentiate further
• How do plant cells differ in their ability to differentiate compared to animal cells?


  Many plant cells retain the ability to differentiate throughout their life
• Who first observed cells and in what year?

  Robert Hooke in 1665
• What is the maximum magnification of a light microscope?


  x2000
• What is the resolving power of a light microscope?


  200 nm
• What is the difference between a scanning electron microscope and a transmission electron microscope?


  SEM creates 3D images, while TEM creates 2D images
• What is the formula for calculating magnification in a light microscope?


  Magnification = magnification of eyepiece lens x magnification of objective lens
• What is the formula for calculating the size of an object?


  Size of object = size of image / magnification
• What is standard form and how is it used?


  • A way to express very large or small numbers
  • Involves multiplying a number by a power of 10
  • The number must be between 1 and 10
• What is the culture medium for growing microorganisms?


  It contains carbohydrates, minerals, proteins, and vitamins
• What is the purpose of sterilizing Petri dishes and culture media?


  To prevent contamination by unwanted microorganisms
• How do bacteria multiply in a suitable environment?


  By binary fission, which can occur every 20 minutes
• What is the formula for calculating the number of bacteria at the end of a growth period?


  Bacteria at beginning x 2$^{\text{number of divisions}}$ = bacteria at end
• What is the purpose of soaking paper discs in antibiotics during an experiment?


  To test the effectiveness of different antibiotics on bacterial growth
• What does the size of the inhibition zone indicate in an antibiotic effectiveness test?


  The larger the zone, the more bacteria are killed, indicating higher effectiveness