Biology summary paper 1

• Plant cell

  • Cell membrane
  • Cell wall
  • Vacuole
  • Cytoplasm
  • Ribosomes
  • Chloroplasts
  • Mitochondria
  • Nucleus
• Animal cell

  • Cell membrane
  • Mitochondria
  • Ribosomes
  • Cytoplasm
  • Nucleus
• You'll notice there are several features of a plant cell that an animal cell doesn't share. For example, the cell wall, the vacuole, the chloroplasts.
• If you look up at these pages yourself, you can download them, the free-version guide from my website.
• Bacterial cell

  • Cell membrane
  • Cytoplasm
  • Chromosome
  • Flagella
  • Ribosomes
  • Cell wall
• Even though you have to learn the structure of a typical plant cell or a typical animal cell, there isn't really a typical type of cell because there are a wide range of differentiated specialized cells.
• Differentiation


  When various different genes will be turned on and turned off, and that's when it will start to specialize
• Microscopy techniques


  • From very basic lenses and focus, to more sophisticated lenses, to electron microscopes controlled by computer
• Magnification


  Equals image height over object height
• DNA


  A long strand of deoxyribonucleic acid, made of lots of letters: As, Ts, Cs and Gs, that twist round into a double helix
• Chromosome


  The double helix DNA further twists round and is located in the nucleus of a cell
• Mitosis


  1. DNA in the nucleus condenses into chromosomes

  2. Chromosomes line up down the middle

  3. Chromosomes pulled apart to either end of the cell

  4. New nuclei form

  5. Two identical daughter cells
• Stem cells


  Cells that have the potential to turn into any other type of cell
• Making stem cells


  1. Take nuclei out of an egg cell

  2. Take nuclei from patient's cell and insert into empty egg

  3. Egg develops into an embryo

  4. Stem cells removed from embryo and turned into new cells
• This does come with quite a lot of controversy because human embryos are going to be created and then destroyed.
• Diffusion


  Movement of things from a high concentration down the diffusion gradient to an area of low concentration
• Diffusion in the body

  • In the lungs (alveoli and capillaries)
  • In the gut (villi)
• Osmosis


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


  Movement across a membrane from a low concentration to a high concentration against the concentration gradient
• Tissue


  One type of cell carrying out one function
• Organ


  Made up from 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
• Digestive system


  • Mouth
  • Salivary gland
  • Liver
  • Gall bladder
  • Small intestine
  • Stomach
  • Pancreas
  • Large intestine
  • Rectum and anus
• Enzymes in digestive system

  • Lipase (breaks down fats)
  • Protease (breaks down proteins)
  • Amylase (breaks down starch)
• Enzyme activity


  • Optimal temperature
  • Denatured at high/low temperatures
  • Optimal pH
  • Denatured at high/low pH
• Respiratory system


  • Mouth/nose
  • Trachea
  • Bronchus
  • Bronchiole
  • Alveoli
  • Diaphragm
  • Intercostal muscles
  • Ribs
• Cardiovascular system


  • Right atrium
  • Right ventricle
  • Pulmonary artery
  • Pulmonary vein
  • Left atrium
  • Left ventricle
  • Aorta
  • Valves
• Veins carry deoxygenated blood, apart from the pulmonary vein. Arteries carry oxygenated blood, apart from the pulmonary artery.
• Blood vessels


  • Arteries (thick walls, thin lumen)
  • Capillaries (one cell thick)
  • Veins (thin walls, thick lumen)
• Blood components


  • Serum (liquid)
  • Red blood cells (no nuclei)
  • White blood cells (immune system)
  • Platelets (clotting)
• Cardiovascular disease


  • Fatty deposits build up in coronary arteries
  • Blood clots form
  • Blocks artery
  • Restricts oxygen to cells
  • Cells die
  • Heart can't function properly
• Risk factors for cardiovascular disease are smoking, high blood pressure, or having too much salts or fat in your diet.
• Blood


  Liquid component of the blood, cells give it its actual color
• Red blood cells


  • Have no nuclei so they have more space to carry oxygen, which is their main function
• White blood cells


  Part of the immune system
• Platelets


  Fragments of cells, important for clotting
• Cardiovascular disease


  Fatty deposits build up in coronary arteries around the heart, can lead to blood clots
• Blood clot blocking an artery

  Restricts oxygen to cells, causing them to die
• Many cells dying


  Can lead to heart attack if heart can't function or pump blood properly
• Risk factors for cardiovascular disease

  • Smoking
  • High blood pressure
  • Too much salt or fat in diet