Section 3:Mass transport Flashcards by Aaliyah Forbes

What is haemoglobin made up of?

Protein/polypeptide chains

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General protein structure

What is the structure of haemoglobin chains?

Primary=sequence of AAs
Secondary=in which each polypeptide chain is coiled into a helix
Tertiary=in which each polypeptide chain is folded into a precise shape
Quaternary=in which all polypeptide chains are linked together
Two β-polypeptide chains and two α-polypeptide chains

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What is associating/dissociating and where does it take place?

Associating=haemoglobin binds to oxygen and takes place in the lungs
Dissociating=haemoglobin releases its oxygen and takes place in the tissues

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What does it mean if haemoglobin has a high or low affinity for oxygen?

Haemoglobin with a high affinity for oxygen takes up oxygen more easily,but release it less easily

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What must haemoglobin do to be efficient at transporting oxygen?

Readily associate with oxygen at the surface where gas exchange takes place
Readily dissociate from oxygen at those tissues requiring it

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What is positive cooperativity?

The binding of the first oxygen molecule changes the quaternary structure of the haemoglobin. This induces the other subunits to bind to an oxygen molecule. Therefore, it takes a smaller increase in the partial pressure of oxygen to bind to the second oxygen molecule, than it did for the first oxygen molecule

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What does it mean if the oxygen dissociation curve is further to the left or right?

Left=haemoglobin has a higher affinity for oxygen
Right=haemoglobin has a lower affinity for oxygen

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How does the carbon dioxide concentration affect haemoglobin’s affinity for oxygen?

Haemoglobin has a reduced affinity for oxygen in the presence of carbon dioxide
* Lungs=low conc=increased affinity
* Muscles(respiring tissues)=high conc=decreased affinity

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How does a low concentration of carbon dioxde affect the structure of haemoglobin?

pH is raised due to the low conc
The higher pH changes the shape of haemoglobin into one that enables it to load oxygen readily
The shape also increases the affiinity of haemoglobin for oxygen~this means oxygen is not released while being transported in the blood to the tissues

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Six points

Explain why there is always enough oxygen for respiring tissues?

Excerise

Higher rate of respiration
More carbon dioxide produced
Lowers the pH
Greater the haemoglobin shape changes so decreases its affinity for oxygen
Oxygen is more readily dissociated
More oxygen is available for respiration

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Why do large organisms need a transport system?

Increasing size leads to decrease in SA:V for exchange. As a result it can no longer rely on simple diffusion and needs to develop specialist gas exchange systems

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What are good features of a transport system with examples within animals?

Suitable medium=to carry materials (Blood)
Closed system of tubular vessels=contains transport medium (Blood vessels)
Mechanism to maintain the mass flow in one direction(Valves)
Mechanism to control the flow of the transport medium(Valves)
Mechanism for moving the transport medium within vessels(Muscular contraction of the heart)

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How can you describe the mamilian circulatory system?

Closed double circulatory system

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Where do the different sides of the heart pump blood to?

Right=pumps blood to the lungs
Left=pumps oxygenated blood rapidly around the body at high pressures

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How does the structure of the atria relate to its function?

Thin muscular walls=only has to pump blood to the ventricles
Elastic walls=able to strech as it collects blood

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How does the structure of the ventricles relate to its function?

Thick muscular walls=has to pump blood a long way

Where does each heart vessel take blood?

Aorta=LV to the body
Pulmonary artery=RV to the lungs
Vena cava=body to the RA
Pulmonary veins=lungs to the LA
Coronary arteries=supply heart msucle

What is the function of valves and where can they be found in the heart?

Valves are present to prevent the backflow of blood
* Atrioventricular=between atria and ventricles
* Semi-lunar=in the arteries
Valves are held in place by valve tendons attached to muscles

What is the purpose of heart tendons?

To prevent valves from becoming inverted

What is the pathway of blood in the heart?

vena cava,RA,RV,pulmonary artery,pulmonary vin,LA,LV and aorta

What is meant by the heart is myogenic?

The heart contracts on its own without needing any nerve impulses

What is myocardial infarction and how is it caused?

Heart attack caused by the blockage of the coronary arteries=heart muscle is depriced of blood and therefore oxygen

What is cardiac cycle?

When the heart fill and empties with blood

What are the three stages of the cardiac cycle?

Atrial contraction (systole), ventricular contraction (systole) and relaxation (diastole)

What happens in the three stages of the cardiac cycle?

* Diastole=blood enters atria+ventricles from vena cava/atria relax fill with blood+ventricles relax(AV valves open) * Atrial systole=atria contract~push blood into ventricles(AV valves open) * Ventricular systole=atria rleax,ventricles contract~push blood away from heart via aorta+pulmonary arteries

What is the function and location of the atrioventricular, semi-lunar and pocket valves?

* Atrioventricular=between atria and ventricles~prevent back flow into atria when ventricles contract * Semi-lunar=aorta+pulmonary artery~prevent back flow into ventricles * Pocket=veins~ensures when veins are squeezed blood flow back towards the heart

How is cardiac output(cm3/m) calculated?

cardiac output=heart rate x stroke volume

# Three points How does the structure of the arteries relate to its function?

* Thicker overall wall=Resists the valve bursting due to high pressure * Thicker elastic layer=Streches as the heart beats then springs back when the heart relaxes * Thicker muscle layer=Smaller arteries an be constricted and dilate to control the flow of blood

# Two points How does the structure of the arterioles relate to their function?

* Muscle layer thicker than arteries=Contraction allows constriction of the lumen restricting the flow of blood * Less elastic layer than arteries=because the pressure is lower

What are cappiliries?

Tiny vessels linking arterioles to veins that excahange materials between body and blood

# Four points How does the structure of capillaries relate to their function?

* walls mostly lining layer=very thin, short diffusion pathway * Numerous and highly branched=increase SA * Narrow diameter=no cell is far from a capillary * Space between lining cells=WBCs can pass through to access infections in tissues

# Three points How does the structure of veins relate to their function?

* Valves=ensure back flow doesn't occur * Thinner elastic layer=lower pressure so they won't burst * Wall thickness small=Can be compressed when muscles contract

What is the pathway of blood from the heart and throught the blood vessels?

Heart,Artery,Arterioles,Capillaries,Venules and Veins

What is the role of tissue fluid?

Formed from metabloic substances. This bathes cells and allows the exchange of substances between the blood and cells

# Six points What susbtances are found in tissue fluid?

Water,glucose,amino acids,fatty acids,salts and oxygen

# Increasing How does temperature,humidity,air movement and light affect the rate of respiration?

* Temperature=Increase~Increase in KE * Humidity=Decrease~Decrease WP&Decrease diffusion * Air movement=Increase~Maintains WP gradient * Light=Increase~Stomata open more,more gas exchange needed

# Xylem Define transpiration

Evaporation of water from leaves through the stomata

Describe the structure of the xylem

* Xylem cells are dead,hollow and continuous tubes * Lignin found in cell walls and is a waterproof substance~cells die as nothing can move in and out * No cytoplasm or other organelles to restric water flow