Topic Two - Organisation

Cards (94)

  • Define catalyst
    A catalyst is a substance that increases the speed of the reaction without being changed or used up in the reaction.
  • What are enzymes?
    Large proteins made of chains of amino acids, that act as biological catalysts for reactions in living organisms.
  • Describe the Lock and Key theory
    Enzymes usually only catalyse one type of reaction. The enzyme has an active site with a unique shape that fits onto the substrate of the reaction. For the reaction to work the substrate has to fit into the enzymes active site.
  • What do digestive enzymes do?
    Convert food into small soluble molecules that can be absorbed into the bloodstream.
  • What do carbohydrases break down?
    Carbohydrates to simple sugars
  • What is amylase?
    Amylase is a carbohydrase which breaks down starch into glucose and other sugars like maltose.
  • Where is amylase found?
    It is found in the salivary glands, the pancreas, and the small intestine.
  • What do proteases do?
    Proteases break down proteins to amino acids
  • Where are proteases produced?
    In the stomach (where it is called pepsin), the pancreas and the small intestine.
  • What do lipases do?
    Lipases break down lipids (fats) to glycerol and fatty acids
  • Where are lipases produced?

    In the pancreas and the small intestine.
  • What are the products of digestion used for?
    They are used to build new carbohydrates, lipids, and proteins. Some glucose is used in respiration.
  • Where is bile found?
    Bile is made in the liver and stored in the gall bladder
  • What is bile's function?
    It is alkaline to neutralise hydrochloric acid from the stomach. It also emulsifies fat to form small droplets which increases the surface area. The alkaline conditions and large surface area increase the rate of fat breakdown by lipase.
  • Why do enzymes need the correct temperature?
    If the temperature is too high some of the bonds holding the enzyme together break, changing the shape of the active site, denaturing the enzyme.
  • Why do enzymes need the correct pH?
    If the pH in an enzyme is too high or too low it interferes with the bonds holding the enzyme together, changing the shape of the active site and denaturing the enzyme.
  • Describe the heart?
    A pumping organ that keeps the blood flowing around the body, its walls are mostly made of muscle tissue.
  • Why does the heart have valves?
    It has valves to make sure that the blood flows in the right direction and prevent it flowing backwards.
  • Describe the double circulatory system
    The heart pumps blood around the body in a double circulatory system. The right ventricle pumps blood to the lungs where gas exchange takes place. The left ventricle pumps blood around the rest of the body.
  • How does the blood flow through the heart?
    Blood flows into the two atria from the vena cava and the pulmonary vein. The atria contract, forcing the blood into the pulmonary artery and the aorta, then out of the heart. The blood then flows into the organs.
  • What is the function of coronary arteries?
    To supply oxygenated blood to the heart itself, they branch off the aorta.
  • Where are the ventricles, the top or bottom of the heart?
    The ventricles are on the bottom, atria at the top.
  • What is important to remember when looking at diagrams of the heart?
    Diagrams of the heart are reversed; it is a diagram of someone facing you. The right side is deoxygenated, left oxygenated.
  • Where are the lungs?
    The lungs are in the thorax (which is separated from the rest of the body by the diaphragm), they are protected by the rib cage and surrounded by the pleural membranes.
  • How do we breathe?
    The intercostal muscle contract (the ribs go up and out) and the diaphragm flattens when you breath in, the intercostal muscles and diagram relax when exhaling.
  • What is the trachea?
    windpipe
  • What is the bronchus?
    Bronchi split off from the trachea into the two lungs, then themselves split into bronchioles that attach to small bags called alveoli.
  • What are alveoli?
    Alveoli are sacs surrounded by a network of blood capillaries, where gas exchange happens. Oxygen diffuses out of the alveolus from a high concentration into the blood (low concentration), carbon dioxide diffuses out of the blood into the alveolus (from high to low).
  • What happens when the blood reaches body cells?
    When the blood reaches the body cells oxygen is released from the red blood cells (high concentration) to the body cells (low concentrations) co2 does the opposite.
  • What controls our heartbeats?
    The natural resting heart rate is controlled by a group of cells located in the right atrium that act as a pacemaker. Artificial pacemakers are electrical devices used to correct irregularities in the heart rate.
  • Arteries
    Arteries carry blood away from the heart. The heart pumps blood out of the heart at high pressure, so artery walls are strong and elastic, The walls are thick compared to the lumen and contain thick layers of muscle to make them strong and elastic fibres to allow them to stretch and spring back.
  • veins
    Veins carry blood to the heart. The pressure is lower, so the walls rent as thick, and they have a bigger lumen then arteries. They also have valves to help keep the blood flowing in the right direction.
  • capillaries
    Capillaries are involved in the exchange of substances in the tissue. They are very small, have small lumen and one cell thick walls. The walls are permeable so that substances can diffuse in and out. They supply food and oxygen and take away waste like CO2. The walls being one cell thick increases rate of diffusion as distance it happens over is decreased.
  • How are blood vessels connected?
    Arteries branch out into capillaries; capillaries join up to form veins.
  • How can valves in the heart be damaged?
    Valves in the heart can be damaged or weakened by heart attacks, infection, or old age. This damage causes the valves to stiffen, so it wont open properly. Or a valve may become leaky, allowing blood to flow in both directions.
  • How can valves in the heart be replaced?
    The valves can be replaced by ones taken from humans or other mammals. It is a much less drastic procedure than a whole heart transplant, but it is still a major surgery and there can be problems with blood clots.
  • What is plasma?

    Plasma is a pale straw-coloured liquid that carries everything in the blood. It carries blood cells, platelets, nutrients like glucose and amino acids, carbon dioxide, urea, hormones, proteins, antibodies, and antitoxins
  • What are red blood cells?
    Red blood cells carry oxygen from lungs to the cells of the body. It is biconcave to provide a large surface area for absorbing o2. They don't have a nucleus so there is more space for carrying oxygen.
  • How do red blood cells carry o2?
    They contain a red pigment called haemoglobin. In the lungs it binds to oxygen to become oxyhaemoglobin, in body tissues the reverse happens, releasing oxygen in the cell.
  • What are white blood cells?
    White blood cells defend against infection, some through phagocytosis, others produce antibodies and antitoxins. They do have a nucleus.