1.1

Cards (31)

  • Features common to plant and animal cells
    • Cytoplasm
    • Cell membrane
    • Nucleus
    • Mitochondria
  • Cytoplasm
    Where chemical reactions that make up life take place
  • Cell membrane
    Controls what enters and exits the cell
  • Nucleus
    Contains DNA
  • Mitochondria
    Carries out aerobic respiration, supplies cells with energy
  • Plant cells
    • Have cell wall made of cellulose
    • Have central vacuole filled with sap
  • Plant cells
    • Have chloroplasts that absorb light for photosynthesis
  • Sperm cells
    • Have little cytoplasm and a tail to swim fast toward the egg
  • Red blood cells
    • Have lost their nuclei and are packed with haemoglobin to carry oxygen around the body
  • Xylem cells
    • Form tubes which carry water to the plant, cell walls are thick, cytoplasm dies off to leave a hollow tube
  • Levels of organization
    • Cell
    • Tissue
    • Organ
    • Organ system
    • Organism
  • Tissue
    A group of similar cells with similar functions
  • Organ
    A collection of tissues that do specific functions
  • Organ system
    A collection of several organs that work together
  • Organism
    The whole animal or plant
  • Diffusion is the passing movement of substances down a concentration gradient
  • Cell membrane forms a selectively permeable barrier that allows diffusion of water
  • Active transport is an active process by which substances can enter cells against a concentration gradient
  • Enzymes
    Proteins made by living cells which catalyse the rate of chemical reactions
  • High temperatures and extremes can denature an enzyme
  • Enzyme catalysis
    1. Enzyme and substrate collide
    2. Enzyme-substrate complex forms
    3. Catalysis occurs
    4. Products are released
  • Substrate
    The substance that an enzyme acts upon
  • Prokaryotic cells

    a cell which does not have a nucleus - the DNA strands are free in the cytoplasm
  • Eukaryotic cells
    a cell which has a nucleus, eukaryotic cells also have other structures in the cytoplasm which have membranes around them
  • Stem cells
    embryonic stem cells - undifferentiated, have potential to turn into any cell
    adult stem cells - found in bone marrow, can only form a certain cell ( eg blood cells )
  • Uses of stem cells
    • replaces faulty blood cells
    • making insulin producing cells
    • making nerve cells
  • Bacterial cells
    • Prokaryotic cells
    • contain a plasmid
    • cell splits into two
  • For embryonic stem cell research
    • curing patients with stem cells are more important than the rights of embryos
    • they are only using unwanted embryos from fertility clinics, which would normally be destroyed
  • Against embryonic stem cell research
    • embryos are human life
    • scientists should find other sources of stem cells ( eg adult stem cells )
  • Stem cells in plants
    • found in meristem
    • produce clones of plants
    • can grow crops with specific features ( eg disease resistant )
  • Examples of tissues, organs and organ systems
    • tissue - bone muscle, blood, xylem, epidermis
    • organs - kidney, brain, heart, leaf, flower
    • organ systems - digestive system, nervous system, shoot system