1: Cell Biology

Cards (71)

  • Eukaryotes
    Cells that have a nucleus and membrane-bound organelles
  • Prokaryotes
    Cells that lack a nucleus and membrane-bound organelles
  • Components of animal and plant cells

    • Cell membrane
    • Cytoplasm
    • Nucleus containing DNA
  • Components of bacterial cells
    • Cell wall
    • Cell membrane
    • Cytoplasm
    • Single circular strand of DNA and plasmids
  • Orders of magnitude
    Used to understand how much bigger or smaller one object is from another
  • Prefixes used to show multiples of units
    • Centi (0.01)
    • Milli (0.001)
    • Micro (0.000,001)
    • Nano (0.000,000,001)
  • Structures found in animal and plant cells
    • Nucleus
    • Cytoplasm
    • Cell membrane
    • Mitochondria
    • Ribosomes
  • Structures found only in plant cells
    • Chloroplasts
    • Permanent vacuole
    • Cell wall
  • Structures found in bacterial cells
    • Cytoplasm
    • Cell membrane
    • Cell wall
    • Single circular strand of DNA
    • Plasmids
  • Adaptations of Sperm cells
    • Streamlined head and long tail to aid swimming
    • Many mitochondria to supply energy
    • Acrosome with digestive enzymes to break down egg cell membrane
  • Adaptations of Nerve cells
    • Long axon to transmit impulses
    • Many dendrites to form branched connections
    • Mitochondria to supply energy for neurotransmitter production
  • Adaptations of Muscle cells
    • Special proteins (myosin and actin) to cause contraction
    • Many mitochondria to provide energy
    • Can store glycogen for respiration
  • Adaptations of Root hair cells
    • Large surface area for water and mineral ion uptake
    • Large vacuole to affect water movement
    • Mitochondria to provide energy for active transport
  • Adaptations of Xylem cells
    • Lignin deposition to form hollow tubes for water transport
    • Lignin spirals to withstand water pressure
  • Phloem cells
    • Sieve plates to allow movement of substances
    • Rely on mitochondria in companion cells for energy
  • Cell differentiation
    Process where stem cells switch on/off genes to become specialised cells
  • In animals, most cells differentiate early and lose ability to differentiate further
  • In plants, many cells retain ability to differentiate throughout life
  • Light microscope
    Has two lenses, objective and eyepiece, to magnify and view tissues, cells and large sub-cellular structures
  • Electron microscope
    Uses electrons instead of light to form high magnification (up to 2,000,000x) and high resolution (0.2nm) images of sub-cellular structures
  • Calculating magnification of light microscope
    Magnification of eyepiece lens x magnification of objective lens
  • Calculating size of object
    Size of image / magnification = size of object
  • Standard form
    Expressing very large or small numbers as a number between 1 and 10 multiplied by a power of 10
  • Components of culture medium
    • Carbohydrates
    • Minerals
    • Proteins
    • Vitamins
  • Growing microorganisms in nutrient broth
    1. Make suspension of bacteria and mix with sterile nutrient broth
    2. Stopper flask with cotton wool to prevent contamination
    3. Shake regularly to provide oxygen
  • Growing microorganisms on agar plates
    1. Spread bacteria suspension on agar surface
    2. Seal plates to prevent contamination
    3. Incubate at optimum temperature for growth
  • Culturing microorganisms
    • Microorganisms are very small, so scientists need to grow many of them in the lab using nutrients
  • Components of culture medium
    • Carbohydrates for energy
    • Minerals
    • Proteins
    • Vitamins
  • Growing microorganisms in the lab
    1. In nutrient broth solution
    2. On an agar gel plate
  • Making an agar gel plate involves pouring hot sterilised agar jelly into a sterilised Petri dish, letting it cool and set, then inoculating with a microorganism and incubating
  • Sterilisation
    Petri dishes and culture media must be sterilised before use, often by autoclave or UV light, to prevent contamination
  • Inoculating loops
    Wire loops used to spread microorganisms over the agar, which must be sterilised by passing through a flame
  • Sealing Petri dish
    The lid should be sealed but not completely, to prevent airborne contamination while allowing oxygen entry
  • Storing Petri dish
    Upside down to prevent condensation from the lid disrupting growth
  • Incubation temperature

    25 degrees, to prevent growth of bacteria harmful to humans
  • Testing antibiotic effectiveness
    Soak paper discs in antibiotics, place on agar plate with bacteria, measure inhibition zone after incubation
  • The formula to calculate cross-sectional area is πr^2, where r is the radius
  • Chromosomes
    Contain coils of DNA, with each chromosome carrying many genes
  • There are 23 pairs of chromosomes in each body cell, and 23 chromosomes in each sex cell
  • Cell cycle and mitosis
    1. Interphase: cell growth, organelle increase, DNA replication
    2. Mitosis: chromosome alignment and separation
    3. Cytokinesis: formation of two daughter cells