2 - Cells

• Cell


  Fundamental unit of life
• Tissue


  Group of cells with similar structure and function
• Organ


  Structure made up of a group of tissues that work together to perform a specific function
• Organ system


  Group of organs that work together to perform a major function
• Organism


  Living thing
• Plant cell


  • Cell wall made of cellulose
  • Contains chloroplasts with chlorophyll to trap light energy for photosynthesis
  • Contains large vacuole with cell sap
• Animal cell


  • Lacks cell wall
  • No chloroplasts
  • Smaller vacuoles
• Bacterial cell


  • Lacks nucleus
  • Has circular DNA
  • Has plasmids
• New cells are produced by division of existing cells
• Aerobic respiration occurs in mitochondria
• Cells with high rates of metabolism require large numbers of mitochondria to provide sufficient energy
• Specialised cells


  • Ciliated cells
  • Root hair cells
  • Palisade mesophyll cells
  • Nerve cells
  • Red blood cells
  • Sperm and egg cells
• Magnification


  Ratio of size of image to size of actual specimen
• Size of biological specimens


  Measured in millimetres and micrometres
• Photosynthesis is the process of making glucose in plants by combining carbon dioxide and water using light energy
• DNA in the nucleus controls the cell's activity and what proteins are made
• Ribosomes are where proteins are made by joining amino acids together
• Mitochondria release energy by aerobic respiration (breakdown of glucose with oxygen)
• Cells that use a lot of energy have a lot of mitochondria, e.g. muscle cells, nerve cells, heart cells
• Plant cell walls are made of cellulose
• Cell membrane controls the movement of substances in and out of the cell
• Cytoplasm is the jelly-like substance inside the cell where chemical reactions take place
• Nucleus contains DNA and controls the cell's activity
• Mitochondria supply energy to the cell by respiration
• Rough endoplasmic reticulum processes and transports proteins
• Ribosomes produce proteins
• Vesicles store and transport substances to and from organelles and cells
• Root hair cells


  • Finger-like structure
  • Large vacuole
  • Thin cell wall to give large surface area
• Xylem cells


  • No end wall
  • No cytoplasm
  • Hollow tube
  • Waterproof cell wall made of lignin
• Palisade cells


  • Lots of chloroplasts to maximise photosynthesis
  • Closely packed together to maximise photosynthesis
• Ciliated cells


  • Have mucus and tiny hair-like cilia to sweep mucus upwards and out
• Red blood cells


  • No nucleus
  • Biconcave shape for large surface area
  • Contain haemoglobin
• Sperm cells


  • Long tail/flagellum to swim towards ovum
  • Enzyme to digest jelly coat and enter ovum
  • Many mitochondria to provide energy
• Xylem cells


  • No end wall, no cytoplasm, hollow tube, waterproof cell wall by lignin
• Xylem cells


  Functions: to carry/transport water efficiently
• Palisade cells


  • A lot of chloroplast to maximize photosynthesis, closely packed together to maximize photosynthesis
• Ciliated cells


  • Mucus, tiny hair called cilia
• Ciliated cells


  Functions: To sweep up the mucus upward and out to the digestive system(to be killed by HCl in the stomach)
• Goblet cell


  Secrete mucus
• Mucus


  To trap the dust, bacteria in the air