heart

• Oxygenated blood


  Blood that has picked up oxygen from the lungs and delivered it to the body's tissues
• Arteries


  Blood vessels that carry oxygenated blood away from the heart to the rest of the body
• Capillaries


  Tiny blood vessels that allow for the exchange of oxygen and nutrients with waste products between the blood and body tissues
• Capillaries


  Extremely small blood vessels with thin walls that facilitate the exchange of oxygen and nutrients with waste products
• Arteries


  Larger blood vessels with thicker walls that carry oxygenated blood away from the heart to the rest of the body
• Oxygenated Blood vs. Deoxygenated Blood

  Key differences include oxygen content, color, and function
• Oxygenated Blood


  Blood that has picked up oxygen from the lungs and delivered it to the body's tissues
• hydrochloric acid breaks down proteins into amino acids
• enzymes break down carbohydrates into simple sugars
• lipase breaks down fats into fatty acids and glycerol
• bile emulsifies lipids so enzymes can work on them more easily
• small intestine is where most absorption occurs
• the liver produces bile which is stored in the gallbladder until needed
• the small intestine absorbs nutrients through villi and microvilli
• large intestine absorbs water from food waste to form faeces
• active transport requires energy (ATP)
• Cells

  All life can be seen with a normal light microscope, but subcellular structures are only visible with an electron microscope which has better resolving power and higher resolution
• Calculating cell size


  1. Magnification = image size / object size

  2. Rearrange to measure actual cell size = image size / magnification
• Cell types


  • Eukaryotic cells (have a nucleus)
  • Prokaryotic cells (no nucleus, DNA in a ring)
• Subcellular structures


  • Cell membrane
  • Cell wall (in plant cells and bacteria)
  • Cytoplasm
  • Mitochondria
  • Ribosomes
  • Chloroplasts (in plant cells)
  • Vacuole (in plant cells)
• Binary fission


  How bacteria multiply
• Practical: Producing a bacterial culture

  1. Use aseptic technique

  2. Incubate at 25°C

  3. Calculate culture size from area or initial drop
• Diploid


  Cells with 23 pairs of chromosomes
• Haploid


  Cells with 23 unpaired chromosomes
• Mitosis


  1. Genetic material duplicated

  2. Nucleus breaks down

  3. Chromosomes pulled to opposite sides

  4. New nuclei form in each new cell
• Specialised cells


  • Nerve
  • Muscle
  • Root hair
  • Xylem
  • Phloem
• Stem cells


  Unspecialised cells that can differentiate into different cell types
• Diffusion


  Movement of molecules/particles from high to low concentration, down the concentration gradient, without energy input
• Osmosis


  Diffusion of water across a semi-permeable membrane
• Practical: Investigating osmosis


  1. Cut equal potato cylinders

  2. Weigh and place in sugar solutions

  3. Reweigh after a day

  4. Calculate percentage change in mass

  5. Plot against sugar concentration to find no change point
• Active transport


  Using energy to move substances against a concentration gradient
• Tissues


  • Heart
  • Digestive
• Enzymes


  Biological catalysts that are specific to certain substrates, work at an optimum temperature and pH
• Practical: Investigating enzyme activity

  1. Mix amylase and starch at different temperatures or pH

  2. Test for starch every 10 seconds with iodine

  3. Plot time to complete reaction against temperature or pH
• Food tests


  • Iodine for starch
  • Benedict's solution for sugars
  • Biuret reagent for proteins
  • Ethanol for lipids
• Respiratory system structures


  • Trachea
  • Bronchi
  • Bronchioles
  • Alveoli
• Circulatory system


  Double circulatory system, with deoxygenated blood entering right side of heart, going to lungs, then oxygenated blood entering left side and going to body
• Heart structure


  Right atrium and ventricle, left atrium and ventricle<|>Thicker walls in left ventricle to pump blood around body
• Blood vessels


  Arteries carry oxygenated blood away from heart, veins carry deoxygenated blood towards heart<|>Arteries have thicker walls, veins have valves
• Coronary artery


  Supplies heart muscle with oxygen and nutrients