GCSE Biology

    Cards (130)

    • Eukaryotic cell

      cell with a nucleus e.g. animal/plant cells
    • Prokaryotic cell

      cell without a nucleus e.g. bacterial cell
    • Animal cell
      contains nucleus, cell membrane, cytoplasm, mitochondria and ribosomes
    • Plant cell
      contains nucleus, cell membrane, cytoplasm, mitochondria, ribosomes, cell wall, chloroplast and vacuole
    • Bacterial cell

      contains cell membrane, cell wall, plasmid, chromosomal DNA, slime coat and flagella
    • Nucleus
      Contains genetic info and controls all cell activities
    • Cell membrane
      controls what enters and leaves the cell
    • Cytoplasm
      where chemical reactions take place
    • Mitochondria
      where energy is released via aerobic respiration
    • Ribosomes
      site of protein synthesis
    • Cell wall
      made of cellulose to support and protect the cell
    • Chloroplast
      contains chlorophyll that traps sunlight energy for photosynthesis
    • Vacuole
      stores cell sap to keep cell firm and rigid
    • Chromosomal DNA
      contains the instructions for most of cell’s activities
    • Plasmid
      contains a small proportion of bacterium’s DNA
    • Flagella
      for movement
    • Slime coat
      for protection (not all bacteria have this)
    • Cell differentiation
      when cell becomes specialised to perform specific function
    • Sperm cell
      has nucleus, cell membrane, mitochondria, acrosome, streamlined shape and tail
    • Egg cell
      has nucleus, cell membrane, cytoplasm and jelly coat
    • Ciliated epithelial cell
      Has nucleus, mitochondria, cytoplasm and cilia
    • Specialised cell for digestion
      small intestine has many mitochondria (gives energy to muscle to squeeze food along)
      outer membrane is folded to make microvilli (increases sa for absorption)
      cells in pancreas has lots of ribosomes (to make protein enzymes)
    • Light microscope

      lower magnification, lower resolution and uses beams of light to see larger structures and living samples in colour (cheaper)
    • Electron microscope
      higher magnification, higher resolution and uses beams of electrons to see subcellular structures in dead samples in black and white (more expensive and harder to maintain temperature and pressure)
    • Stain
      to see specimen clearly
    • TOE
      total magnification = eye piece lens magnification x objective lens magnification
    • IAM
      image size = actual size x magnification
    • Field of view at new magnification (mm)

      current magnification / new magnification x distance shown by ruler (mm)
    • Preparation of slide
      • place specimen onto slide
      • add a drop of stain (iodine/methylene blue)
      • place coverslip carefully
      • remove excess liquid using paper towel
    • Preparation of microscope
      • place slide onto stage
      • switch on light source
      • set objective lens at lowest magnification
      • look through eyepiece lens
      • adjust coarse focusing wheel to move stage up/down for clear image
      • adjust fine focusing wheel to produce sharp and clearer image
      • move onto next higher objective lens magnification and refocus
    • Cilia
      contracts and causes wavy movements to move along substances
    • Ciliated epithelial cell

      found in oviduct and trachea
    • Acrosome
      contains enzymes to break down jelly coat of egg cell to burrow inside
    • Cell membrane for egg cell

      Hardens after fertilisation to ensure only one sperm enters
    • Cytoplasm for egg cell

      packed with nutrients to supply fertilised egg with energy and food for growth and development of embryo
    • Metre, centi, milli, micro, nano, pico
      x100, x10, x1000, x1000, x1000
    • Enzymes
      biological catalysts that speed up the rate of reaction without being used up
    • How an enzyme catalyses the breakdown of a substrate molecule

      • a solution of the enzyme is mixed with a solution containing substrate molecules
      • one substrate molecule fits neatly into the active site of the enzyme, like a key into a lock
      • some bonds in the substrate molecule break, causing the formation of two product molecules
      • the product molecules are a different shape to the substrate, so they no longer fit into the active site and are released from the site
      • the active site of the enzyme molecule is free to accept another substrate molecule
    • When enzyme denatures
      • shape of active site changes
      • shape of the protein fold is affected
      • substrate molecule can no longer lock onto the active site
      • enzyme can no longer catalyse the reaction
    • Breakdown of starch
      The digestive enzyme called amylase breaks the chemical bonds between the individual sugar molecules in each carbohydrate chain. It is found in saliva and small intestine.
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