UNIT 2 - Biology

• Cell


  Smallest and most basic unit of life that displays the 5 characteristics of living things
• Things most cells have

  • Plasma cell membrane
  • Cytoplasm
  • Mitochondria
  • Vacuoles
  • Nucleus
• 5 features of living things

  • Has a lifespan
  • Grows in size, reproduce & repairing themselves
  • Senses and responds to changes in environment
  • Requires energy
  • Produces waste
• Organelles


  Cell structures that perform specific individual functions for the cell
• Plasma cell membrane


  Membrane that protects the inside of a cell from the outside environment, and regulates movement of substances in and out of the cell
• Cytoplasm


  Gelatinous liquid that fills the inside of a cell, holds organelles in place, aids in metabolism and provides structure to the cell
• Mitochondria


  The main source of chemical energy for the entire cell, site of cellular respiration and produces ATP
• Vacuoles


  Help isolate & get rid of waste products within the cell, store water, nutrients and waste products
• Nucleus


  Contains genetic information, like DNA and 46 chromosomes, controls the cell's activities
• Nucleolus


  Darker structure within the nucleus, involved in the production of ribosomes
• Chromatin


  Material in the nucleus that contains all of the cell's genetic information
• Cell wall


  Provides structural support and protects the rest of the cell from mechanical/osmotic stress
• Nuclear membrane


  Separates the nucleus from the cytoplasm and controls the passage of materials
• Ribosomes


  Produced in the nucleus, site of protein synthesis
• Centrioles


  Involved in cell division (in animal cells) and organizing microtubules (in plant cells)
• Rough E.R.


  Covered in ribosomes, involved in protein synthesis and transport
• Golgi apparatus


  Modifies, sorts and packages proteins & lipids for secretion or delivery to other parts of the cell
• Chloroplast


  Site of photosynthesis, producing glucose, contains chlorophyll
• Lysosome


  Contains digestive enzymes, breaks down waste material and cellular debris
• The 3 functions of cell division

  1. Growth

  2. Repair

  3. Reproduction
• Diffusion


  Transport mechanism for moving chemicals in and out of the cell, from an area of high concentration → area of low concentration
• Osmosis


  Movement of a fluid, usually water, across a membrane towards an area of high solute concentration
• Reasons a cell would stay in interphase and refuse to divide

  • Signals from neighbouring cells tells it not to divide
  • Not enough nutrients able to provide for more cells
  • DNA inside the nucleus has not replicated yet
  • The DNA is damaged
• Cytokinesis


  Phase of the cell cycle where the cytoplasm divides to form two identical cells; last segment of cell division
• Tumour


  Result of uncontrolled cell division: division continues despite messages from the body to stop
• Types of tumour


  • Benign (non-cancerous)
  • Malignant (cancerous)
• Benign tumour


  Tumour that does not affect surrounding tissues other than by physically crowding them
• Malignant tumour


  Tumour that interferes with the functioning of surrounding cells; a cancerous tumour
• Carcinogens


  Substance or a set of conditions that are known to increase the risk of cancer
• Examples of carcinogens


  • Tobacco smoke
  • Radiation (x-ray & uv ray)
  • Viruses (hepatitis b & hpv)
  • Certain chemicals in plastics
• Ways to detect cancer

  • Cancer screening (checking for cancer even if there are no symptoms)
  • Skin checks
  • Endoscope
  • X-rays
  • MRI scan
• Ways to treat cancer

  • Surgery
  • Chemotherapy
  • Radiation
• Specialized cells


  Cells that perform a specific function, have physical and chemical differences to allow them to perform one specific job very well
• Types of stem cells

  • Embryonic
  • Adult/tissue
• 4 main types of tissues

  • Epithelial tissue
  • Connective tissue
  • Muscle tissue
  • Nerve tissue
• Organs


  Structure in the body made up of several different cells and tissues that are specialized to perform a certain task for the body's benefit, function and survival
• Organ systems


  Group of organs that work together to achieve a common goal
• Hierarchy of structure


  Organization of living organisms from simple to complex
• Prophase


  1. Condensed chromosomes are in the shape of an "x"

  2. They are called sister chromosomes since the DNA was previously replicated during interphase

  3. Each side of the duplicated chromosome is called a chromatid, and they are attached at a structure called a centromere
• Metaphase


  1. Chromosomes line up at the metaphase plate

  2. Each sister chromatid is attached to a spindle fibre originating from opposite poles