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A Level Biology > Organism Exchange Substances And Mass Transport > Flashcards

Organism Exchange Substances And Mass Transport Flashcards

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1
Q

What is Metabolism?

A

Sum of all chemical reactions in the body

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2
Q

Explain the relationship between size and SA:V ratio and explain impact on diffusion?

A

Smaller cells have a high SA:V ratio which means that diffusion is quicker and more efficient as diffusion pathway is short.

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3
Q

How do larger organisms adapt to having a small SA:V ratio and give examples?

A

They will have some sort of transport system:
Microvilli for SI
Alveoli
Cristae in Mitochondria
Root hair cells and blood cells

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4
Q

Explain the equation of Ficks law of Diffusion?

A

SAx Diff in conc of gas on either side of membrane/thickness of respiratory surface

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5
Q

Explain some features that increase SA:V ratio

A

Thin skin
Folded skin
Lots of capillaries
Outward projection of skin

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6
Q

Why do some animals not need a transport system

A

Has a high SA:V ratio so diffusion pathways are shorter
This means lower metabolic rate and less metabolic demand so less oxygen for respiration and less ATP required

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7
Q

What is Bergmans Rule?

A

At colder temps,Animals will have a greater body mass which means a smaller SA:V ratio which is easier to maintain heat

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8
Q

Explain the effect of SA:V ratio on heat?

A

The Higher SA:V ratio,the smaller the organism so it loses heat quicker and thus requires more oxygen for respiration as respiration releases heat

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9
Q

Explain adaptations for gas exchange in Fishes and why does it need it?

A

There’s a low concentration of oxygen in water than in air

Each gill is made up of lots of thin gill filaments which allow for a short diffusion pathway
Gill Filaments are covered in lamealle which increases the SA
Lots of blood capillaries and thin surface layer to speed up diffusion

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10
Q

Process Of Inspiration?(Breathing in)(Include all muscles involved)

A

The external intercostal and diaphragm contract
This causes ribcage to move up and down and diaphragm flattens increasing thoracic activity
Volume of air increases,lung pressure decreases
Air flows from a higher pressure to a lower pressure so air flows from trachea to lungs
This requires energy

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11
Q

Process of expiration?(Breathing out)

A

The external intercostal muscles and diaphragm relax
Ribcage moves downwards and diaphragm is more curved
Volume of thoracic activity decreases causing air pressure to increase
Air is forced down pressure gradient and out of lungs

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12
Q

Adaptations of Gas exchange in the alveoli?

A

Single celled walls-means shorter diffusion pathway so diffusion is quicker and easier
Rich blood supply-increases concentration gradient
Lots of alveoli which increases SA and thus greater rate of gas exchange

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13
Q

Explain function and adaptations of Trachea?

A

Contains C shaped cartilage to withstand pressure changes when air flows in the body
It is c shaped so oesophagus is not blocked and can push food down by peristalsis

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14
Q

Structure of fish filaments and effect on diffusion?

A

Fish have many gill filaments, each covered in many lamellae providing a large surface area for gas exchange. The blood in the capillaries flows in the opposite direction to the water.

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15
Q

Explain the effect of goblet cells and where they are found?

A

Goblet cells produce mucus which catches pathogens and particulates
Releases a protein called mucin which mixes with water

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16
Q

What is the function of ciliated epithelial cells?

A

Ciliated epithelial cells will move mucus upwards so it can be disposed off

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17
Q

Explain what cells are the alveoli are composed of and what’s the function?

A

They are composed of squamous epithelial cells which is a single layer of flattened cells which shortens diffusion distance and makes diffusion quicker

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18
Q

What are smooth muscle cells and its purpose?

A

Found in arteries and veins with the purpose for the regulation of blood pressure and blood flow which is responsible for contraction
Relaxing smooth muscle increases bronchioles diameter

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19
Q

Which part of the lungs are goblet cells and epithelial cells found?

A

Bronchioles

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20
Q

What are chondrocytes and its function?

A

Responsible for cartilage formation,maintains cartilaginous matrix by the production of collagen
Chondrocytes support the airway to prevent collapse

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21
Q

Function of cilia?

A

Hair like structures on the surface of cells which sweeps Hair,mucus and trapped dust and bacteria back to the throat

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22
Q

Explain why counter current flow is more efficient than co current flow

A

Water and blood flow in the opposite direction this means that:
Because the blood continues to pass water which has a higher oxygen concentration, so the concentration gradient is maintained along the whole length of the gill filament

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23
Q

Explain the steps of fish ventilation?

A

Mouth opens
The buccal cavity(mouth cavity) is lowered
This increases the volume and decreases the pressure of buccal cavity
This creates a pressure gradient where water rushes down
The mouth is closed and the operculum opens
The buccal cavity is raised
Pressure inside the buccal cavity is higher than operculum cavity

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24
Q

What is the trachea made of and its function in insects?

A

Trachea in insects is made of the polysaccharide chitin and its function is allowing sir to enter the insect and spiracles

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25
What are spiracles and its function in insects?
Spiracles are respiratory openings found on the thorax and abdomen of insects and allow oxygen and co2 to diffuse into the body of the insect Allows air to enter trachea
26
Spiracles can open and close what is the effect of this?
Prevents water loss Aids ventilation Creates a pressure gradient
27
What do the spiracles lead to and what is the function of tracheae and structure?
The spiracles lead to a network of tubes called a tracheae They are reinforced with chitin,which prevents the insect from collapsing
28
What are tracheoles function in insects and structure and how it helps gas exchange?
They are a single cell and very narrow,hollow branches which increases SA and has a lot of CO2 which provides and maintains an O2 gradient Narrow trachoeles allow for a very small diffusion pathway leading to rapid oxygen diffusion directly in cells Co2 also diffuses rapidly out of insect and in air They contain a fluid called tracheal fluid which is often used in anaerobic respiration This produces lactic acid and decreases water potential of cells
29
What is the tracheoles?
Tracheoles are respiratory tubes of the trachea and they convey oxygen directly to cells and muscles while allowing co2 to diffuse out
30
Function of tracheal fluid?
Tracheal fluid prevents water loss by closing the spiracles however this means more water stored in Tracheoles which reduces SA
31
What is the hemolymph and explain the function in insects?
Essentially the blood of insects(Don't write this in the exam) They are a major extracellular fluid and is a transport medium for exchange of materials between cells They surround tissues
32
Explain how insects control water loss?
Closing spiracles stops water loss They also have a waterproof waxy cuticle and thin hairs which reduce evaporation
33
Explain how insects exchange gases by moving and other ways?
Insects use their rhythmic abdominal movements to move air in and out of spiracles This allows oxygen to diffuse down a conc gradient directly into respiring cells
34
What is the function of bronchioles and structure?
Has inner folding to allow expansion during breathing Bronchioles have cartilage
35
What is a closed circulatory system and what are some advantages?
This system means that vessels are constantly having blood creating a constant pressure gradient so maintaining pressure so blood can travel further around the body,so a smaller diffusion distance Concentration gradient is maintained
36
Function and describe arteries?
Arteries carry blood from the heart to the rest of the body They have thick muscular walls with elastic tissue to stretch and recoil to help maintain a high pressure and to prevent artery bursting They have folded inner linings allowing arteries to stretch Arteries carry oxygenated blood except pulmonary artery which carries deoxygentaed blood to lungs Elastic fibres smooth out pressure Muscular tissue contracts to prevent bloodflow to an area
37
What are arterioles and describe its function?
Arteries divide into smaller branches called arterioles They can constrict to restrcit blood flow or relax to allow blood flow Thick muscular wall to restrict blood flow into the capillaries
38
Describe the passage of blood through the human heart?
Depxygenated blood entered the RA through the VC Deoxygenated blood is pumped from the RA to the RV The RV pumps depxygenated blood out of the heart to lungs through pulmonary artery The blood is oxygenated and goes back into the heart via pulmonary vein The blood passes the LA than the LV which than passes the blood out of Aorta where all blood is transferred across the body
39
Why is the left side of the heart thicker than the right side?
The left side of the heart has more muscle because the LV has to pump oxygenated blood out of Aorta and around the body whereas the RA pumps blood to RV so there is more pressure on left side
40
Why is the heart described as myogenic?
During heartbeat the muscular walls contract,increasing pressure and forcing blood to other areas of the body The heart muscle is myogenic as the heart triggers its own beat without any signals
41
Describe what is the Sino Atrial Node and atrial systole and function?
The SAN is another word for pacemaker cells The cells in the SAN depolarise(becomes electrical with charge) This causes a wave of electrical excitation causing atria to contract Atria contraction is atrial systole
42
Where are the semilunar valves and function?
Links ventricles to the Aorta and pulmonary artery And stops blood flowing back into the heart after ventricle contraction
43
Where are the atrioventricular valves and what types of AV valves are there and location and function?
They are located between atria and ventricles,stop blood flowing back into the atria when the ventricles contract Bicuspid on the left side Tricuspid on the right
44
What are valves and function?
They are located in the heart to prevent backflow of blood and allow blood to flow in one direction
45
Explain the steps of the cardiac cycle?
Blood from the body arrives at the heart via the VC and PV The atria contract(atrial systole) This causes higher pressure in the atria than ventricles which opens the AV valves(bicuspid and tricuspid) The ventricles contract(ventricular systole) This causes higher pressure in the ventricles compared to atria which causes the AV valves to close and SL valves to open The Atria and ventricles relax(diastole) Lower pressure in Ventricles compared to Aorta and PA cause SL valve to close
46
Explain what valves open when atrial pressure is greater than ventricular pressure?
Bicuspid valves opens,and when ventricular pressure is greater bicuspid valves close
47
Explain why the aortic pressure is maintained?
This is due to the elastic recoil of the aorta
48
Explain pathway of blood when ventricles relax and atria contract?
Atrial systole increases pressure and decreases volume forcing blood to move from the atria to the blood
49
Explain what happens when the ventricles contract and atria relaxes? Talk about valves
Ventricular systole increases pressure and decreases volume This forces AV valves to shut to prevent backflow of blood in ventricles Pressure in ventricles is greater than aorta and pulmonary vein which opens SL valves
50
Describe the function and structure of veins?
Veins take blood back to the heart under low pressure Wider lumen,little elastic tissue Contains valves to stop backflow of blood Relies on surrounding skeletal muscles pushing against them to push blood back to heart All veins carry deoxygenated blood
51
Explain what the septum is?
Barrier in the heart separating the left and right side
52
Explain fully the control of the Cardiac Cycle?
The cardiac cycle is initiated by nerve impulses in a region at the top of RA called SAN These nerve impulses spread through the atria causing them to contract Theses waves of electrical impulses are drawn to a tissue called AVN They then move through the Purkyne fibres which run through the septum which then moves through the ventricles causing ventricular systole
53
What is the function and describe the capillaries?
Around 0.01mm in diameter Blood in capillaries is lower in arteries but higher in veins They form networks around organs called capillary beds The endothelium is one cell thick for easy gas exchange
54
Why is there higher rise and fall in blood pressure in aorta compared to smaller arteries?
Closer linked to the heart so the pressure is higher Has elastic tissue which stretches and recoils
55
What is tissue fluid and how is it caused?
Pressure from the heart causes the capillaries to leak This creates the interstitial or tissue fluid which surrounds the cell,where exchange of molecules occur 90% of fluid is reabsorbed into the blood due to plasma proteins lowering water potential
56
What is hydrostatic pressure and how does it link to tissue fluid?
Hydrostatic pressure is the pressure of heart contractions,it forces fluid out of the capillaries This fluid moves out through tiny gaps in capillary walls Dissolved gases and nutrients move with it
57
What is osmotic pressure and its link with tissue fluid?
A net loss of water from the capillaries(due to hydrostatic pressure)
58
Explain how to calculate tissue fluid movement and whether it forms or removes tissue fluid?
Tissue fluid is calculated by a net figure of hydrostatic pressure and osmotic pressure Hydrostatic pressure is higher at arterial end than venous end At arterial end,tissue fluid is formed but at venous end tissue fluid is removed
59
What is lymph and why do we have it?
Lymph is the excess tissue fluid drained into the vessels of the lymphatic system This is because not all fluid passes back into the capillaries This excess output needs to be collected to avoid tissue swelling
60
3 main functions of the lymphatic system?
Aid reabsorption of fluid into blood capillaries Part of the immune system Absorption of lipids in small intestine
61
Explain the role of capillaries in transporting lymph?
Lymph flows in blind ended capillaries that have valves to only allow fluid to move from tissue fluid into the lymph vessels
62
What is the 2 jobs of Haemoglobin?
To Bind to oxygen to form oxyhaemoglobin To then release/take in oxygen for respiring muscles/tissues
63
Describe the structure of Haemoglobin?
Made up of 4 polypeptide chains(2 alpha helix and 2 beta pleated sheets) Also have 4 haem groups which are 4 non protein components that contain iron and bind to one oxygen molecule
64
Explain how Heamoglobin changes shape and why it does?
Heamoglobin changes shape with each binding of oxygen The first binding of oxygen leads to a conformational change so its easier to bind to 3 other oxygen molecules This allows oxygen to be taken up quickly and released in regions of low and high oxygem
65
Explain why it is difficult for the first and fourth oxygen molecule to bind to heamoglobin in comparison to 2nd and 3rd?
At low partial pressures of oxygen,heamoglobin has a low affinity for oxygen For the 4th oxygen molecule to bind,this is hard as 3 are already binded meaning partial pressure must be high so saturation increases and an oxygen can collide with a heam group
66
Explain how tissue fluid leaves the capillary at the arterial end?
Fluid such as water moves out due to hydrostatic pressure being greater than osmotic pressure so there is a net movement of tissue fluid leaving
67
Explain the role of the heart in the formation of tissue fluid?
Ventricular systole forces fluid out of capillaries causing hydrostatic pressure This causes greater HS pressure so greater net movement out of capillary Forces water/fluid out at arterial end
68
What does a leftward shift mean in the oxygen/heamoglobin dissociation curve?
It means the organism has a higher percentage saturation at lower partial pressures so a higher affinity to oxygen so can load more oxygen
69
What does a rightwards shift mean in oxygen hemoglobin dissociation curve? Will it release or load oxygen
This means lower affinity as there is saturation of Haemoglobin at higher partial pressure of oxygen This means that it is easier to release oxygen at any pressure so oxygenated blood will move to cells and tissue for aerobic respiration
70
Describe the effect of having more Co2 in blood on saturation of heamoglobin?
Blood with CO2 leads to rightwards shift so lower affinity so easier to release oxygen at any pressure for aerobic respiration Vice versa for leftwards shift
71
Explain how the effect of carbonic acid on heamoglobin(caused by co2 reacting with plasma)impacts the shape of heamoglobin?
Carbonic acid lowers the pH This causes less attraction for the tertiary level binding such as Ionic and will cause shape of tertiary structure to change
72
Explain how CO2 is transported?
CO2 is transported in the plasma(5%) 10% joins heamoglobin to form carbaminoheamoglobin 85% is transported as hydrogencarbonate ions This is catalysed by Carbonic Anhydrase
73
Veins contain what type of blood in contrast with arteries?
Deoxygenated blood and moves blood to the heart Arteries have oxygenated blood and moves away from the heart
74
Role of coronary arteries?
Supply blood to the heart muscle as it needs oxygen to function
75
Explain the formation of tissue fluid?
Blood enters the capillaries from the arterioles,resulting in high hydrostatic pressure at the arterial end Molecules like glucose amino acids urea ions fatty acids are forced out forming Tissue Fluid Large molecules like proteins remain in capillaries lowering water potential At the venous end there is low WP and HP so water re-enters by osmosis Remaining tissue fluid absorbed by lymphatic system

A Level Biology (7 decks)

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