topic 1 cell biology

    Cards (65)

    • 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 to show multiples of units
      • Centi (0.01)
      • Milli (0.001)
      • Micro (0.000,001)
      • Nano (0.000,000,001)
    • Structures in animal and plant cells
      • Nucleus
      • Cytoplasm
      • Cell membrane
      • Mitochondria
      • Ribosomes
    • Additional structures in plant cells
      • Chloroplasts
      • Permanent vacuole
      • Cell wall
    • Structures in bacterial cells
      • Cytoplasm
      • Cell membrane
      • Cell wall
      • Single circular strand of DNA
      • Plasmids
    • Cell specialisation
      The process where cells gain new sub-cellular structures to be suited to their role
    • Specialised animal cells

      • Sperm cells
      • Nerve cells
      • Muscle cells
    • Specialised plant cells

      • Root hair cells
      • Xylem cells
      • Phloem cells
    • Cell differentiation
      The process where stem cells switch on/off genes to produce different proteins and acquire new sub-cellular structures
    • In animals, most cells differentiate early and lose ability to differentiate, but some like red blood cells are replaced by adult stem cells
    • In plants, many cell types retain ability to differentiate throughout life
    • Light microscope
      Has two lenses (objective and eyepiece), illuminated from underneath, max magnification x2000, resolving power 200nm
    • Electron microscope
      Uses electrons instead of light, two types (scanning and transmission), max magnification x2,000,000, resolving power 10nm (SEM) and 0.2nm (TEM)
    • 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
      Used to represent very large or small numbers by multiplying a number between 1 and 10 by a power of 10
    • Culture medium
      Contains carbohydrates, minerals, proteins and vitamins to grow microorganisms
    • Growing microorganisms in nutrient broth
      Make suspension of bacteria, mix with sterile nutrient broth, stopper with cotton wool, shake regularly
    • Standard form
      Multiplying a certain number by a power of 10 to make it bigger or smaller, with the 'number' being between 1 and 10
    • Standard form examples
      • 1.5 x 10^-5 = 0.000015
      • 3.4 x 10^3 = 3400
    • 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
    • Steps in making an agar gel plate
    • Reasons for sterilisation
      To prevent contamination with other microorganisms that could compete for nutrients and space, or be harmful
    • Reason for sealing Petri dish lid
      To stop airborne microorganisms from contaminating the culture, but not completely to allow oxygen entry
    • Reason for storing Petri dish upside down
      To prevent condensation from the lid landing on the agar surface and disrupting growth
    • Reason for incubating at 25 degrees

      To prevent growth of bacteria that could be harmful to humans, as their optimum temperature is near 37 degrees
    • Testing antibiotic effectiveness
      1. Soak paper discs in antibiotics and place on agar plate with bacteria
      2. Leave plate for 2 days
      3. Measure zone of inhibition around discs
    • Formula for calculating cross-sectional area
    • Chromosomes
      Contain coils of DNA, with each chromosome carrying many genes
    • Number of chromosomes
      46 in body cells, 23 in sex cells
    • Cell cycle and mitosis
      1. Interphase: cell growth, organelle increase, DNA replication
      2. Mitosis: chromosomes line up and separate
      3. Cytokinesis: cytoplasm and cell membranes divide to form two daughter cells
    • Importance of mitosis
      • Growth and development, replacing damaged cells, asexual reproduction
    • Stem cells
      Undifferentiated cells that can divide to produce more similar cells, some of which will differentiate
    • Types of stem cells
      • Embryonic
      • Adult (e.g. in bone marrow)
      • Meristems in plants
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