mass transport

    Cards (34)

    • When do animals need a mass transport system?
      Have a fairly high respiration rate and a small surface area to volume ratio
    • What 6 things does an efficient mass transport system need?
      1. A medium that can hold and release chemicals as and when needed
      2. A way to move the transport medium around in bulk
      3. A closed system that will not lose the transport medium and will reach every part of the animal
      4. A way of moving the transport medium around this system continuously
      5 a way of ensuring one direction of flow
      6. A way of controlling this flow
    • Why is blood good for transporting chemicals?
      Water based so good solvent, red blood sells contain haemoglobin which is good for transporting oxygen
    • What are the 3 main blood vessels?
      arteries, capillaries, veins
    • Describe arteries ( 7 points)
      Carry blood away from heart
      Thick muscular elastic walls
      Internal diameter small
      Carry oxygenated blood (except pulmonary artery)
      Blood at high pressure
      No valves
      Round regular shape due to high pressure
    • Describe the veins ( 7 points)

      Carry blood toward the heart
      Thin inelastic walls
      Internal diameter is large
      Carry deoxygenated blood ( except pulmonary vein)
      Blood is at low pressure
      There are valves to prevent backflow
      Shape changes according to pressure
    • Describe capillaries (5 points)
      Carry blood between cells of the tissues
      Have walls a single cell thick
      Very narrow
      Medium pressure
      Carry useful substances to cells and take waste away
    • Describe the structure of haemoglobin (4 points)
      Large conjugated protein molecule with a quaternary structure.
      Comprised of 4 polypeptide chains: 2 alpha chains and 2 beta chains
      Structure varies from species to species
      Each polypeptide is joined to a haem group ( inorganic molecule that contains one atom of iron)
    • How many haem groups does a molecule of haemoglobin contain and how many oxygen molecules can it transport?
      4 so can transport up to 4 oxygen molecules
    • What is the amount of oxygenation that occurs in haemoglobin directly related to?
      The pressure of oxygen in its surroundings
    • What is partial pressure?
      Pressure exerted by each part of a mixture such as air
    • If AIR pressure is 30 pascals and oxygen makes up 20% of the air, then the partial pressure of oxygen is ..........
      6 pascals (20% of 30)
    • Explain the Bohr shift
      Where there is more CO2, more hydrogen ions in red blood cells, oxyhaemoglobin releases more oxygen
    • What does it mean if the oxygen disassociation curve for haemoglobin shifts to the right?
      There is more CO2 - giving up more oxygen for respiring cells
    • What is co2 converted to in red blood cells?
      Hydrogen carbonate ions HCO3
    • Hydrogen carbonate ions in the red blood cells are split in a reaction catalysed by carbonic anhydrase. What is the result of this reaction.

      Hydrogen carbonate ions created and diffuse into the blood plasma, hydrogen ions are produced in red blood cells which then react with the haemoglobin to produce haemoglobinic acid - production of this causes the haemoglobin to unload remaining oxygen - THE BOHR SHIFT
    • Explain the oxygen disassociation curve of haemoglobin of an organism living in anaerobic conditions
      Shifted to the left compared to human haemoglobin
    • Which part of the heart brings deoxygenated blood from the body and empties into the right atrium? Veins from head and upper body feed into here.
      Superior vena cava
    • Which part of the heart receives deoxygenated blood from the superior vena cava?
      Right atrium
    • Which part of the heart brings deoxygenated blood from the legs and lower body into the right atrium?
      Inferior vena cava
    • What part of the heart transports deoxygenated blood from the right ventricle to the lungs?
      Pulmonary artery
    • Which part of the heart brings oxygen rich blood from the lungs to the left atrium?
      Pulmonary vein
    • What happens in the left atrium?
      Receives oxygen rich blood from pulmonary vein, the contraction of the sinoatrial node progresses through atria the blood passes through the mitral valve into the left ventricle
    • What happens when they left ventricle is filled with blood?
      Contracts- mitral valve closes and aortic valve opens to allow blood to flow into aorta
    • Which part of the heart carries oxygen rich blood from the left ventricle to the body?
      Aorta
    • what are coronary arteries?
      arteries that branch from the aorta to supply oxygenated blood to heart muscles
    • what are the capillaries of the coronary arteries responsible for?
      transporting red blood cells which provide oxygen and nutrients to the cardiac muscle tissue and bond with co2 and other waste products taking them away from the heart for disposal through lungs, kidney and liver
    • What causes myocardial infarction?
      Cholesterol plaque accumulates and blocks the flow of blood through the coronary artery so the cardiac tissue fed by it is deprived oxygen and nutrients and then stops functioning properly causing damage to the cardiac muscle tissue.
    • Explain what root hair cells in plants are responsible for , their structure and where they are located?
      Uptake of water and vital minerals. Very large surface area and very short diffusion distance, found very close to top of the root and extend into soil
    • When conditions are damp, the soil contains .............. concentration of mineral and nutrients that the concentration of minerals in the root hair cells themselves. This means that the water potential of the soil is much ............. than that of the root hair cell. Water moves ............. the root hair cell by ................. , .......... this water potential ...............
      LowerHigherIntoOsmosisDownGradient
    • Once inside the root, water moves towards the centre and the xylem by which two methods?
      The apoplastic pathwayThe symplastic pathway
    • Explain the apoplastic pathway
      Water moves through the water filled spaces between the cells of the root-occurs because as water is drawn through cells it creates a tension with extra cellular water due to the cohesion properties of the water molecules = continuous stream of water
    • Explain the symplastic pathway
      Root cell gains water- water potential increases to higher than neighbouring cell-water will move in to next cell by osmosis - happens again into next cell- always heads towards centre of the root because as root hair cell loses water to its neighbour, its water potential lowers so more water comes into it from soil = continuous water potential gradient is set up between the centre of the root and the root hair
    • The endodermal cells of the root use ............... ........................ to move salts and mineral ions into the xylem.
      Active transport