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AS LEVEL BIOLOGY > Mass transport > Flashcards

Mass transport Flashcards

1
Q

structure of Haemoglobin molecules

A
  • primary structure: sequence of amino acids in the four polypeptides chain
  • secondary: each chain is coiled into a helix
  • tertiary: each chain is folded in a specific shape to carry oxygen
  • quarternary: four polypetides are linked to form an almost spherical molecule
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2
Q

Loading and unloading oxygen

A
  • when haemoglobin releases its oxygen is called unloading or dissociating
  • when haemoglobin bind with oxygen is called loading or associating
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3
Q

The role of haemoglobin

A

its role is to transport oxygen
Haemoglobin must:
- readily associate with oxygen at the surface where gas exchange takes place
- readily dissociate from oxygen at those tissues requiring it
- haemoglobin changes it’s affinity for oxygen under different conditions
- it changes its shape in the presence of carbon dioxide
- in the presence of carbon dioxide, haemoglobin binds to oxygen more loosely so it then releases it

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4
Q

Why are there different haemoglobins?

A
  • each species produces a haemoglobin with slightly different amino acid sequence
  • each species’ haemoglobin has different tertiary and quarternary structure so thus has different binding properties
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5
Q

Effects of carbon dioxide concentration

A
  • haemoglobin has a reduced affinity for oxygen in the presence of carbon dioxide
  • the greater the concentration of carbon dioxide, the more readily the haemoglobin releases it oxygen
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6
Q

Loading, transport and unloading of oxygen

A
  • at the gas- exchange surface carbon dioxide is constantly being removed
  • the pH is slightly raised due to low concentration of CD
  • the higher pH changes the shape of haemoglobin into one that enables it to load oxygen readily
  • the shape also increases the affinity for haemoglobin for oxygen so its not released
  • in the tissues, CD is produced by respiring cells
  • CD is acidic in solution so the pH of the blood within the tissues is lowered
  • the lower pH changes the shape of haemoglobin into one with a lower affinity for oxygen
  • Haemoglobin releases its oxygen into the respiring tissues
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7
Q

The more active a tissue the more oxygen is unloaded:

A
  • the higher the rate of respiration –> the more CD the tissues produce –> the lower the pH –> the greater the haemoglobin change –> the shape change –> the more readily oxygen is unloaded –> the more oxygen is available for respiration,
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8
Q

Lugworm

A
  • oxygen diffuses into the lugworm’s blood from the water and it uses haemoglobin to transport oxygen
  • dissociation curve shifted far to the left of that of a human meaning the haemoglobin is fully loaded with oxygen
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9
Q

Llama

A
  • it lives in high altitudes so the atmospheric pressure is lower and so the partial pressure is lower so its difficult to load haemoglobin with oxygen. Llama also have a type of haemoglobin that has a higher affinity for oxygen than human one so it has shifted to the left on the curve
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10
Q

plants rely on natural, passive processes such as the evapouration of water:

A
  • a mechanism to maintain the mass flow movement in one direction for example valves
  • a means of controlling the flow of the transport medium to suit the changing needs of different parts of the organism
  • a mechanism for the mass flow of water or gases e.g intercoastal muscles and diaphragm during breathing
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11
Q

Circulatory systems in mammals

A
  • they have a closed, double circulatory system in which blood is confined to vessels and passes twice through the heart for each complete circuit
  • the blood is passed through the lungs and its pressure is reduced
  • blood is returned to the heart to boost its pressure before being circulated to the rest
  • so that’s why mammals have a high temperature and metabolism
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12
Q

The vessels that make up the circulatory system of a mammal are divided into three types:

A
  • artieries
  • veins
  • capillaries
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13
Q

Each pump has two chambers

A
  • atrium: thin walled and elastic so as it stretches it collects blood
  • ventricle: has a much thicker muscular wall as it has to contract strongly to pump blood some distance to either lungs or rest
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14
Q

Right ventricle pumps blood to where

A
  • only to the lungs because it has a thinner muscular wall
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15
Q

The left ventricle pumps blood to where

A
  • it has a thicker muscular wall allowing it to contract to contract to create enough pressure to pump blood to the rest of the body
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16
Q

Between each atrium are valves that prevent the backflow of blood into the atria when the ventricles, such as:

A
  • left atrioventricular valve

- right atrioventricular valve

17
Q

Roles of chambers and ventricles and atria

A
  • each 4 chambers is connected to large blood vessels that carry blood towards or away from heart
  • The ventricles pump blood away from heart and into arteries
  • atria recieve blood from veins
18
Q

Vessels connected to four chambers:

A
  • aorta is connected to left ventricle which carries oxygenated blood to rest of body not lungs
  • vena cava is connected to right atrium and brings deoxygenated blood back from tissues of the body
  • pulmonary artery: is connected to right ventricle and carries deoxygenated blood to lungs where CD is removed from blood
  • pulmonary vein is connected to left atrium and brings oxygenated blood back from lungs
19
Q

Coronary arteries

A

the heart is supplied by its own blood vessels called coronary arteries which branch off the aorta shortly after it leaves the heart
- blockages of these artieries e.g by blood clot leads to myocardial infarction e.g heart attach where an area of the heart is deprived of blood

20
Q

Relaxation of the heart

A
  • blood returns to the atria of the heart through pulmonary vein (from the lungs) and the vena cava (from the body)
  • Diastole, in the cardiac cycle, period of relaxation of the heart muscle, accompanied by the filling of the chambers with blood. … Initially both atria and ventricles are in diastole, and there is a period of rapid filling of the ventricles followed by a brief atrial systole
21
Q

Contraction of the atria (atrial systole)

A
  • the contraction of atrial walls along with the recoil of the relaxed ventrical walls, forces the remaining blood into the ventricles from the atria
  • throughout this stage the muscle of the vetricle walls remains relaxed
22
Q

Contraction of the ventricles (ventricular systole)

A

the contraction, or period of contraction, of the heart, especially of the ventricles, during which blood is forced into the aorta and pulmonary artery.
- Systole, period of contraction of the ventricles of the heart that occurs between the first and second heart sounds of the cardiac cycle

23
Q

cardiac output

A

= heart rate x stroke volume

24
Q

Structure of blood vessels

A
  • arteries carry blood away from the heart and into arterioles
  • arterioles are smaller arteries that control blood flow from arteries to capillaries
  • capillaries are tiny vessels that link arterioles to veins
  • veins carry blood from capillaries back to the heart
25
Q

Arteries, Arterioles and Veins all have the same basic layer structure

A
  • tough fibrous out layer: which resists the pressure from both within and out
  • muscle layer: that can contract and so control the flow of blood
  • elastic layer: helps maintain blood pressure by stretching and springing back
  • Inner lining (endothelium) which is smooth to reduce friction and thin to allow diffusion
  • Lumen is not an actual layer but the central cavity of the blood vessel through which blood flows
26
Q

Artery structure and function:

A
  • muscle layer is thick com
    pared to veins meaning smaller arteries can be constricted and dilated in order to control the volume of blood passing through them
  • elastic layer is relatively thick compared to veins because blood pressure in arteries is kept high
  • Overall thickness of the wall is great: resists the vessel bursting under pressure
  • There are no valves because blood is under constant pressure

AS LEVEL BIOLOGY (9 decks)

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