3.3 Chapter 7- Mass Transport Flashcards
Give the key features of haemoglobin.
Many organisms have haemoglobin to transport oxygen and the type varies depending on their needs. Haemoglobin is highly adapted for transporting oxygen.
Describe the structure of haemoglobin.
- Group of chemically similar molecules found in many different organisms.
- Large proteins with a quanternary structure of four polypeptide chains
- Evolved to be efficient at loading oxygen in certain conditions and unloading it in others.
- Primary structure- the sequence of amino acids in the 4 polypeptide chains.
- Secondary structure- polypeptide chains coiled into a helix.
- Tertiary structure- haemoglobin folded into a precise shape to carry oxygen.
- Quanternary structure- four peptide chains linked together- each one associated with a haem group - iron ion of Fe2+- gives the haemoglobin its red colour- can combine with oxygen to form Fe3+ so 4 oxygen can be carried by a single human haemoglobin.
Describe briefly how oxygen and haemoglobin interact.
- Oxygen joins to haemoglobin in red blood cells to form oxyhemoglobin.
- Reversible reaction.
- Oxygen leaves near body cells.
Describe the key terms surrounding the action of haemoglobin and where these terms occur.
- Binding oxygen= loading/ association- occurs in human lungs
- Releasing oxygen= dissociation/ unloading- occurs in human tissue.
Why is haemoglobin important for the circulatory system?
- An important part of the circulatory system.
- Found in human red blood cells.
- Red blood cells and haemoglobin have a role of transporting oxygen around the body.
What is important about haemoglobin in different organisms?
- Many chemically similar types of haemoglobin in different organisms carry out the same function.
- Haemoglobin is found in many organisms from vertebrates to humans.
What does affinity mean in terms of haemoglobin (define affinity)?
- Affinity is the tendency for a molecule to bind with oxygen.
- Haemoglobin’s affinity varies depending on its conditions.
- Haemoglobin with a higher affinity for oxygen takes it up more easily, but releases it less easily and vice versa.
What role does haemoglobin have and what features mechanics does it have to achieve this?
- To be efficient at transporting oxygen haemoglobin has to readily associate with oxygen where gas exchange occurs and readily dissociate from oxygen at tissues.
- Does this by changing its affinity for oxygen at different conditions.
- Shape changes in the presence of e.g. CO2- binds more loosely with oxygen and releases oxygen more easily.
What is the oxygen disassociation curve? Draw it and explain.
- The graph of the saturation of haemoglobin with the partial pressure of oxygen.
- Affinity affects how saturated haemoglobin is.
- pO2 is high- e.g. the lungs- oxygen affinity increases- oxygen saturation increases.
- pO2 is low- e.g. respiring tissues- oxygen affinity decreases- oxygen saturation decreases.
- Saturation of haemoglobin affects affinity and shape, so the graph is S-shaped not a straight line.
How does hemoglobin’s affinity vary with regards to pO2?
- Haemoglobin’s affinity varies depending on the partial pressure of oxygen- pO2= measure of oxygen concentration.
- More oxygen = more pO2 = more affinity for oxygen.
- Areas of high pO2- oxygen loads onto haemoglobin to form oxyhaemoglobin
- Areas of low pO2- oxyhemoglobin unloads oxygen.
- Oxygen enters the blood at the alveoli in the lungs with a high pO2 so oxyhemoglobin is formed.
- Cells aerobically respire- use up oxygen- lower the pO2- oxyhaemoglobin in red blood cells unloads oxygen and haemoglobin returns to the lungs.
What happens at different partial pressures with haemoglobin?
At different partial pressures of oxygen haemoglobin loads, transports and unloads oxygen.
Describe step by step the oxyhaemoglobin dissociation curve and draw it.
Hint: 3 Steps
- The first haemoglobin finds it more difficult to bind as its 4 sites are close together. At a low PO2 (oxygen concentration) little oxygen binds.
- First O2 molecule associating- changes the quanternary structure of the haemoglobin- shape change uncovers second binding site- easier for oxygen to bind. Binding of the 1st molecule helps other molecules- takes a smaller pO2 increase to bind to the 2nd oxygen- positive cooperativity/ cooperative binding- makes it easier to bind to the 2nd molecule-** steeper curve**- small change in pO2 = more oxygen loading.
- Third molecule binds to haemoglobin- harder for oxygen to bind- less likely to find an empty site- gradient of the graph reduces and flattens.
Why does the shape of oxygen dissociation curves vary?
- Shape of the haemoglobin can change under certain conditions and/or between species.
- A wide variety of oxygen dissociation curves
What does an oxyhemoglobin curve moving left or right mean?
- Further to the left= greater affinity- haemoglobin loads oxygen easily but doesn’t find it easily easy to unload.
- Further to right = lower affinity.
Describe and name the effect of CO2 on haemoglobin include. the effect on the oxygen dissociation curve.
- The partial pressure of carbon dioxide- pCO2- a measure of CO2 concentration.
- Greater pCO2 produces acid due to the dissolving of CO2- decreases the pH- causes haemoglobin to change shape and release oxygen- dissociate.
- Haemoglobin- reduced affinity for oxygen in the presence of high pCO2= increased oxygen- the Bohr effect.
- Helps haemoglobin release more oxygen at times of high activity
- Increases oxygen association at the lungs- CO2 concentration low as it diffuses across the exchange surface and is excreted- affinity of oxygen increases- the loading of oxygen increases- oxygen dissociation curves shifts to the left.
- Respiring tissues- increased pCO2 decreases oxygen affinity- low pO2 and high pCO2- oxygen is readily unloaded to muscle cells- the oxygen dissociation curve is shifted to the right.
Why is the effect of CO2 on haemoglobin in organisms important?
- The effects of CO2 on haemoglobin helps haemoglobin release more oxygen in times of high activity.
- The Bohr effect increases dissociation of oxygen for aerobic respiration at the tissues in times of high activity.
Why might pCO2 per breath not change during intense exercise?
During periods of high exercise, pCO2 may not change per breath as breathing rate or tidal volume may increase instead.
Describe the gas exchange process of haemoglobin.
(Hint: 5 steps)
- At gas exchange surfaces CO2 is constantly removed.
- pH increases due to low concentration of CO2.
- Increased pH causes haemoglobin to change shape, making it have a higher affinity and more easily load oxygen.
- High affinity means the oxygen isn’t released while it’s being transported. CO2 is produced in the tissues and is acidic in solution- the pH in the blood around the tissues decreases.
- Changes the shape- quanternary structure- of the haemoglobin to have a lower affinity- increases oxygen dissociation.
- Haemoglobin releases oxygen into respiring tissues.
How does the gas exchange process change? And why is this important?
- Process is flexible to ensure there is always sufficient oxygen for respiring tissues.
- The more active the organism= more respiration occurs= higher pCO2 = lower pH= more haemoglobins shape changes= more oxygen is unloaded = more O2 is released for respiration.
- This ensures in times of high activity more oxygen reaches respiring cells for aerobic respiration to produce ATP.
Why is not all haemoglobin saturated and describe the saturation of haemoglobin at different stages?
- In humans haemoglobin is a saturated the lungs
- Not all is saturated as atmospheric pressure is usually 97%.
- When haemoglobin reaches a tissue with a low respiratory rate- 1 oxygen molecule is released, but blood is still 75% saturated with oxygen when it reaches the lungs.
- In high respiratory rates- 3 oxygen molecules are released.
What are the features of different haemoglobins in different organisms
- All haemoglobins are chemically similar and found in many different organisms.
- Slight differences between different organisms.
- Different types of haemoglobin within/ between species have different dissociation curves.
- Found in some vertebrates, worms, some insects and some bacteria.
Why are there different types of haemoglobin?
- Different types of haemoglobin with different oxygen transporting capacities and properties relating to the different organisms living conditions
What causes haemoglobin to have different properties and what are these properties?
- Different carrying capacity is related to the shape of the haemoglobin.
- Each organism has a haemoglobin with a slightly different amino acid sequence, so a different quanternary structure, binding capacity and affinity.
What determines the type of haemoglobin and organism has?
- The different types of haemoglobin are evolved adaptions related to an organism’s habitat, environment, size and activity to help it survive.
- e.g. A low pO2 environment= higher affinity haemoglobin.
Describe haemoglobin in low oxygen environments. Give examples and draw the dissociation curve relative to humans.
- Low oxygen environments- low pO2.
- Haemoglobin has a higher affinity for O2 than a human haemoglobin as little oxygen means more loading is needed to maintain oxygen for aerobic respiration.
- The oxyhaemoglobin dissociation curve shifts to the left.
- e.g. lug worms- live in burrows- get O2 from seawater- have to hold oxygen until the tide comes in again- they fully load their haemoglobin with oxygen despite little in environment.
- e.g. llamas live in higher altitudes- low oxygen environment- need specialised haemoglobin.
Describe the features of myoglobin.
Myoglobin has a higher affinity for O2 and holds oxygen for longer than normal haemoglobin to provide O2 when haemoglobin is unloaded in low oxygen environments.
Describe haemoglobin in high activity level organisms give examples and draw the dissociation curve relative to humans.
- High activity levels- high oxygen demand- low affinity is needed to unload oxygen so more is available to use for aerobic respiration.
- Oxyhaemoglobin dissociation curve shifts to the right.
- e.g. hawks- high activity so haemoglobin has to unload oxygen quickly to meet demand.
Describe haemoglobin in small organisms, give examples, draw the dissociation curve relative to humans and explain why it has its features.
- Smaller sized animals- increased SA:V- increased heat loss- need increased metabolic rate for warmth- increased oxygen demand.
- Need a lower affinity for oxygen as they need easier unloading
- Oxyhaemoglobin dissociation curve shifts to the right.
Describe foetal haemoglobin why it has its features and draw the dissociation curve relative to humans.
- Foetal haemoglobin has a higher affinity for oxygen than adult haemoglobin so it is better at loading oxygen.
- Important because the foetus has to unload oxygen from the mother from the mother for aerobic respiration- makes it easier, so it has to be better at binding to oxygen.
- The oxyhaemoglobin dissociation curve shifts to the right.
Why is mass transport important to certain organisms and name the specific organisms?
- Large multicellular organisms i.e. mammals have small SA:V, meaning not enough exchange occurs on their outer surfaces.
- All organisms need to exchange materials between outside and inside environments so mammals use specialised exchange systems and specialised mass transport systems to carry materials from exchange surfaces to cells and vice versa.
How have mammals evolved with regards to exchange?
Mammals have evolved to have more specialised organs and tissues making transport essential.
What are mammals mass transport systems called and what are their features?
- Mammelian specialised mass transport systems are circulatory systems.
- They may have a specialised transport medium and may have a pump.
What determines whether a mammals mass transport system has a pump?
- The surface area to volume ratio and the activity of the organism.
- Decreased SA:V and increased activity means the organism is likely to have a pump.
Why do some organisms not need mass transport?
Have short diffusion pathways and as mass transport is only needed if diffusion is not fast enough these organisms may not need mass transport.
What are the common features of mass transport systems?
(Hint: 8 features)
- A medium to carry materials- usually water based- because soluble and easy to move e.g. the blood, could also be a gas.
- Mass transport is more rapid than diffusion- the medium is moved in bulk over large distances.
- Usually a closed system in tubular vessels that contain the transport medium and branch out to all parts of organisms.
- Mechanism for moving the transport museum in vessels- usually pressure differences- maintained by animals using muscular contraction of body muscles or specialised organs such as the heart/ plants using passive processes such as evaporation
- Mechanisms that keep one direction of flow e..g. valves.
- Mechanisms to control the flow of transport mediums to different parts of the organism.
- Mechanisms for mass flow of water and gases e.g. intercostal muscles.
What type of circulatory system do mammals have and why?
- Closed double circulatory system.
- Blood is confined to vessels
- Passes twice through the heart in each circulation.
- Pressure after the lungs is low, so blood circulation would be very slow without the system.
- The heart boosts the pressure- important to speed up movement of blood- important due to high oxygen demand due to high aerobic resipration due to high body temperature and metabolism of mammals.
What is the circulatory system made up of and what are their roles?
- The circulatory system is the heart and blood vessels.
- Heart- pumps blood through the blood vessels to reach parts of the body.
- Blood vessels- arteries and arterioles, veins and capillaries.
- Pulmonary artery- heart to lungs.
- Pulmonary vein- lungs to heart.
- Aorta- heart to body.
- Vena Cava- body to heart.
- Renal artery- body to kidneys.
- Renal vein- kidneys to vena cava.
How does the mass transport system ensure swift transport?
- Transport systems move substances longer distances.
- Final exchange is by diffusion.
- Diffusion is rapid because of the large surface area, short distances and steep diffusion gradients maintained by the transport system.
What does blood transport?
- Respiratory gases
- Digestion products
- Wastes
- Hormones.
What does a double circulatory system mean?
The blood goes from the heart to the lungs, to the heart to the body, and passes through the heart twice.
Draw the cycle of the blood around the body to the kidneys, naming the specific vessels.
Blood moves from:
* the right atrium
* the right ventricle
* the pulmonary artery
* the lungs
* the pulmonary vein
* the left atrium
* the left ventricle
* the aorta
* Renal artery/ other arteries.
* Kidney/ body
* Renal veins/ other veins
* Vena Cava
* the right atrium.
How many pumps does the human heart have? What do they do and what do they contain?
- Two pumps.
- Left pumps- contain oxygenated blood- move it from the lungs to the body.
- Right pumps- contain deoxygenated blood- move it from the body to the lungs.
- Each pump contains an atria and a ventricle.
How many pumps does the heart have and why does it need them?
- The heart needs two pumps
- Make the pressure around the body stronger than in the lungs
- Ensures that oxygenated and deoxygenated bloods don’t mix.
How are the hearts pumps adapted to suit their function?
- Atria- elastic walls allow to stretch as they collect blood and thin walled as they only need to pump to the ventricles.
- Ventricles- thick and muscly- can pump blood along distance.
- Left ventricle- thicker than the right ventricle- powerful- enough pressure to pump blood around the body.
- Right ventricle- thick enough to get blood to the lungs.
What must you be careful of in heart diagrams?
The left and right sides are reversed.
What is the pattern of the heart pumps?
- The pumps pump in time with each other- the atria and then the ventricles.
- The same volume of blood each time.
What do the pumps ensure with regards to blood?
The oxygenated and deoxygenated blood do not mix after birth.
What do valves ensure, what types of valves are there and what are their features?
- Valves prevent backflow.
- Atroventricular valves- in the left and right atria and ventricles- link the atria and ventricles and stop backflow- chords attatch the atrioventricular valves to the ventricles to stop them being forced up the atria when ventricles contract.
- Semi-lunar valves- link ventricles to pulmonary arteries and aorta- stop backflow.
How many chambers are there in the heart and how are they connected?
The four chambers of the heart are connected by large blood vessels carrying blood towards and away from the heart.
Describe the chambers of the hearts.
- Atria- receive blood from the veins.
- Ventricles- pump blood away from the heart and into the arteries.
Name and describe the blood vessels in the hearts.
- Aorta- connect to left ventricle- carries oxygenated blood to all the body parts except the lungs.
- Vena Cava- connected to right atrium- carries deoxygenated blood from the tissue of the body except from lungs- lowest blood pressure.
- Pulmonary artery- connects to right ventricle- carries deoxygenated blood to the lungs- O2 is replenished and CO2 is removed- only artery that carries deoxygenated blood.
- Pulmonary vein- connects to left atria- carry oxygenated blood from the lungs to the heart- only vein that carries oxygenated blood.
- Coronary arteries (left and right)-
What are the roles of the coronary arteries and what is dangerous about issues with them?
- Branch off aorta- supply oxygen and blood to the heart.
- Blockage in these arteries can lead to a myocardial infaction or heart attack- heart muscles are deprived of oxygen and blood so can’t aerobically respire and die.
Draw and label the heart
Answer on revision card
Describe the movement of blood and how valves aid this.
- The pressure created by the heart keeps blood flowing in one direction.
- Blood always moves from a region of high pressure to a region of low pressure.
- Sometimes pressure differences cause blood to flow the wrong way, so valves are used to prevent backflow and maintain a unidirectional flow of blood from the heart, around the body and back to the heart again.
Describe what makes valves open and close and what this enables.
- Valves only open one way depending on pressure.
- High pressure behind valves causes them to open in the required direction.
- High pressure in front of valves causes them to close as the direction of blood isn’t desirable.
- Convex pressure> concave- valves open.
- Concave pressure > convex pressure- the blood collects in the ‘bowl’ to prevent the passage of blood.
Name and describe the different types of valves, their position, role and what causes them to open and close.
- Atroventricular valves- between the atria and the ventricles- prevent backflow when ventricles contract meaning their prressure is greater than atrial pressure- ensures blood moves into the aorta Atrial pressure > ventricles= open. Atrial pressure < ventricles =close.
- Semi-lunar Valves- between aorta, pulmonary arteries and the ventricles- prevent backflow into the ventricles when elastic walls of the vessels recoil, causing the aorta and pulmonary arteries to have a greater pressure than the relaxed ventricle walls.
- Pocket valves- in veins- veins are squeezed by muscle contraction- blood flows towards the heart and not away.
