bio

• Plant cell


  • Cell membrane - determines what goes in and out
  • Cell wall - provides structure
  • Vacuole - provides structure
  • Cytoplasm - where most reactions take place
  • Ribosomes - responsible for protein synthesis
  • Chloroplasts - where photosynthesis occurs
  • Mitochondria - where energy is produced
  • Nucleus - control centre
• Animal cell


  • Cell membrane - determines what goes in and out
  • Mitochondria - where energy is produced
  • Ribosomes - spots for protein synthesis
  • Cytoplasm - where reactions take place
  • Nucleus - where DNA is held and controls the cell
• There is no such thing as a 'typical' cell as there is a wide range of differentiated, specialised cells
• Cells start off looking the same and then specialise through the turning on and off of different genes
• Tissue


  One type of cell carrying out one function
• Organ


  Made up of lots of different types of cells carrying out a joint function
• Organ system


  A group of organs that work together to carry out a function
• Hierarchy of biological organisation

  • Cells
  • Tissues
  • Organs
  • Organ systems
• Microscopy techniques


  • From very basic lenses and manual focus to highly sophisticated electron microscopes controlled by computers
• Magnification


  Calculated as image height / object height
• Units of measurement


  • Meter (m)
  • Centimeter (cm)
  • Millimeter (mm)
  • Micrometer (μm)
  • Nanometer (nm)
  • Picometer (pm)
• Diffusion


  The movement of gases or dissolved particles from an area of high concentration to an area of low concentration
• Osmosis


  The movement of water through a partially permeable membrane from an area of high water concentration to an area of low water concentration
• Active transport


  The movement of substances across a membrane from an area of low concentration to an area of high concentration, against the concentration gradient
• Enzymes


  • Have a specific active site that only certain substrates can fit into
  • Form an enzyme-substrate complex
  • Break apart or join together substrates
  • Are unchanged and can be used again
• Temperature affects enzyme activity

  Enzyme activity increases up to an optimal temperature, then decreases as the enzyme becomes denatured
• pH affects enzyme activity


  Enzyme activity is optimal at a certain pH, decreasing at very high or very low pH as the enzyme becomes denatured
• Substrate concentration affects enzyme activity

  Enzyme activity increases as substrate concentration increases, until all active sites are full and activity cannot increase further
• Catalysis


  Enzymes increase the rate of a reaction without being consumed or permanently altered
• Respiration is an exothermic reaction that releases energy
• Aerobic respiration


  Glucose + Oxygen -> Carbon dioxide + Water
• Anaerobic respiration


  Glucose -> Lactic acid + Energy (less than aerobic)
• Anaerobic respiration in yeast

  Glucose -> Ethanol + Carbon dioxide
• Respiratory system


  • Air enters through mouth/nose -> Trachea -> Bronchi -> Bronchioles -> Alveoli (gas exchange)
  • Diaphragm and intercostal muscles control breathing
  • Heart pumps blood around body
• Testing for biological molecules

  1. Fats - Emulsion or filter paper test

  2. Starch - Iodine test

  3. Sugars - Benedict's test

  4. Proteins - Biuret test
• Digestive system


  • Mouth - mechanical breakdown
  • Saliva - enzymatic breakdown
  • Stomach - acid and enzymes
  • Small intestine - absorption
  • Large intestine - water absorption and waste removal
• Digestive enzymes


  • Lipase - breaks down fats
  • Protease - breaks down proteins
  • Amylase - breaks down starch
• Metabolism


  The rate of chemical reactions in the body, involving energy from respiration
• Cardiovascular system


  • Double circulatory system - blood pumped from heart to lungs and back, then to rest of body
  • Valves control one-way flow of blood
  • Right side pumps to lungs, left side pumps to body
  • Veins carry deoxygenated blood, arteries carry oxygenated blood (except pulmonary vessels)
• Pacemakers can be used to help regulate an abnormal heart rhythm
• Arteries have thick walls and a narrow lumen to withstand high blood pressure, capillaries are very thin to allow efficient gas exchange
• Vowels


  Allow blood flow
• Right side of heart


  • Pumps blood to the lungs which aren't very far away
• Left side of heart

  • Pumps blood to the rest of the body, a much longer distance
• Blood flow


  • Veins carry deoxygenated blood (except pulmonary vein)
  • Arteries carry oxygenated blood (except pulmonary artery)
• Pacemakers


  Artificial devices that can be introduced to help the heart keep time if it isn't functioning properly
• Arteries


  • Have very thick walls because they are carrying blood under high pressure, which means they have a thin lumen (gap in the middle)
• Capillaries


  • Are very small, only one cell thick, to allow for diffusion
• Capillaries


  Generally go around in a mesh network around things like the guts, villi, and alveoli to have a large surface area
• Veins


  • Carry deoxygenated blood back to the heart, have valves, and have thin walls and a thick lumen because they are carrying blood under low pressure