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AS BIO - C1, 2,3 AND 4 > C3 - EXCHANGE AND TRANSPORT SYSTEMS > Flashcards

C3 - EXCHANGE AND TRANSPORT SYSTEMS Flashcards

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Biology 101 flashcards
1
Q

why is an exchange transport system needed

A
  • every organism needs to take in substances and release other substances in order to survive
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2
Q

what affects how quickly the absorbance and release of substances takes place

A
  • size
  • surface area = SA
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3
Q

describe the exchange of substances with the environment

A
  • every organism needs to exchange things with its environment
  • cells needs to take in oxygen for aerobic respiration and nutrients
  • need to excrete waste products like carbon dioxide and urea
  • most organisms need to stay at roughly the same temperature, so heat needs to be exchanged
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4
Q

SA:VR relationship

A
  • affects how quickly substances are exchanged
  • smaller organisms : higher SA : VR, compared to larger organisms
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5
Q

exchange organs and mass transport systems

A
  • an organism needs to supply every one of its cells with substances like glucose and oxygen for respiration
  • it also needs to remove waste products from every cell, to avoid the cell damaging itself
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6
Q

how do single celled organisms exchange and transport substances

A
  • substances can diffuse directly into/out of the cell, across the cell surface membrane
  • diffusion rate = quick, because the distance the substance needs to travel = small
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7
Q

how do multi-cellular organisms exchange and transport substances

A
  • diffusion across the outer membrane is too slow BECAUSE :
  • some cells are deep within the body and there is a big distance between them and the outside environment
  • AND larger animals have a low SA:VR and this means its difficult for there to be enough substances exchanged to supply a large volume of animal, through a relatively small outer surface
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8
Q

instead of using diffusion, how do multi-cellular organisms absorb and excrete substances

A
  • using specialised exchange organs, ex - lungs
  • need mass transport systems to carry substances to and from their individual cells
  • in mammals, mass transport = the circulatory system which uses blood to carry oxygen and glucose around the body, also carries around hormones, antibodies and waste like CO2
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9
Q

how does mass transport work in plants

A
  • the transport of water and solutes in the xylem and phloem
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10
Q

describe the process of heat exchange

A
  • metabolic activity in the cells creates heat
  • staying at the right temp is heavily influenced by size and shape
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11
Q

how does body size affect heat exchange

A
  • rate of heat loss is dependent on SA
  • if the organism is small, then its relative SA is large which means it loses heat easily
  • smaller organisms need a relatively high metabolic rate so they can generate enough heat to stay warm
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12
Q

how does body shape affect heat exchange

A
  • animals of any size with a COMPACT shape have a SMALL SA relative to V = minimised heat loss from their surface
  • animals with a LESS COMPACT shape, ex - have bits that stick out, have a LARGER SA relative to their V = increased heat loss from their surface
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13
Q

how is the arctic dox adapted so it reduces heat loss

A
  • small ears
  • round head
  • these 2 features reduce its SA : VR and therefore reduces its heat loss
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14
Q

how is the african bat eared fox adapted so it reduces heat loss

A
  • large ears
  • more pointed nose
  • these 2 features increases its SA:VR and therefore increases its heat loss
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15
Q

how is the european fox adapted so it can match the temp of its environment

A
  • aims to match the temp of its environment
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16
Q

name the behavioural and physiological adaptations to aid exchange for ANIMALS WITH A HIGH SA:VR

A
  • tends to lose more water as it evaporates from their surface
  • big problem especially for animals living in hot regions where water evaporates quickly
  • some dessert mammals have kidney structure adaptations so that they produce less urine to compensate
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17
Q

name the behavioural and physiological adaptations to support the high metabolic rate of small mammals

A
  • needed to support high metabolic rates
  • small mammals living in cold regions need to eat large amounts of high energy foods like seeds and nuts
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18
Q

name the behavioural and physiological adaptations to maintain the internal temperature of small mammals

A
  • may have thick layers of fur OR hibernate when the weather gets really cold
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19
Q

name the behavioural and physiological adaptations to cool down large organisms

A
  • larger organisms which live in hot regions, like elephants and hippos, find it hard to keep cool as their heat loss is relatively slow
  • elephants : developed large flat ears which increase their SA - allows them to lose more heat
  • hippos : spend much of the day in the water - behavioural adaptation to help them lose heat
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20
Q

why do plants and animals have adaptations to aid gas exchange

A
  • because they are large organisms and gas exchange isn’t easy for them due to them having a LARGE gas exchange surface
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21
Q

how does gas exchange take place

A

it occurs over a gas exchange surface

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22
Q

what is a gas exchange surface

A

a boundary between the outside environment and internal environment of an organism

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23
Q

what are the 2 gases that need to diffuse across the gas exchange surface as quickly as possible

A
  • oxygen
  • carbon dioxide
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24
Q

what are the 2 things most gas exchange surfaces have in common, which are there to increase the rate of diffusion

A
  • have a large SA
  • they are thin = one layer of epithelial cells, this provides a SHORT DIFFUSION PATHWAY across the GE surface
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25
Q

what else does the organism do to increase the rate of diffusion

A
  • maintain a steep conc gradient of gases across the exchange surface
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26
Q

describe the process of gas exchange in single celled/unicellular organisms

A
  • absorb and release gases by diffusion through their CELL SURFACE MEMBRANES
  • have a relatively large SA, thin surface and a short diffusion pathway
  • therefore, there is no need for a specialised gas exchange system
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27
Q

what does having a short diffusion pathway mean

A

it means that oxygen can take part in biochemical reactions as soon as it diffuses into the cell

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28
Q

describe the basis of how gas exchange works in fish

A
  • lower conc of oxygen in water than in air
  • fish have special adaptations to get enough oxygen
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29
Q

what is the gas exchange surface for fish

A

the gills

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30
Q

describe the structure of gills

A
  • water, which contains oxygen, enters the fish through its mouth and passes through the gills
  • each gill is made of lots of thin plates called GILL FILLAMENTS
  • gill fillaments have a large SA for exchange of gases = increases the rate of diffusion
  • gill fillaments are covered in lots of tiny structures called LAMELLAE = increases the SA even more
  • lamellae have lots of blood capillaries and a thin layer of cells = speeds up diffusion of oxygen between water -> blood
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31
Q

describe the counter-current system

A
  • takes place in the gills of a fish = GAS EXCHANGE SURFACE
  • blood flows through the lamellae in one direction, and water flows over them in the OPPOSITE direction = counter current system
  • CC system means that the water with a relatively HIGH oxygen conc ALWAYS flows next to blood with a LOWER conc of oxygen
  • a steep conc gradient maintained between the water and blood = ensures as much as oxygen possible diffuses from water -> oxygen
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32
Q

how does gas exchange take place in dicotyledonous plants take place

A
  • plants need CO2 for photosynthesis, this produced O2 as a WASTE GAS
  • the O2 produced as a waste gas is needed for RESPIRATION
  • main gas exchange surface = surface of MESOPHYLL CELLS in the leaf
  • have a large SA = well adapted
  • the mesophyll cells are inside the leaf
  • gases move in and out through pores in the epidermis
  • these pores = STOMATA
  • stomata can open = allow exchange of gases
  • they can also close = if the plant is losing too much water
  • GUARD CELLS control the opening and closing/movement of the stomata
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33
Q

how does gas exchange take place in insects

A
  • terrestrial insects have microscopic air-filled pipes = TRACHEA, these are used for GE
  • air moves INTO the trachea through pores on the surface
  • the pores on the surface = SPIRACLES
  • oxygen travels down the conc gradient, towards the CELLS
  • trachea branch off into smaller TRACHEOLES
  • tracheoles have thin, permeable walls and go to individual cells = means that O2 diffuses directly into the respiring cells = no transport of O2
  • CO2 from cells moves down its conc gradient -> SPIRACLES = to be released into the atmosphere
  • insects use rhythmic abdominal moevements to move air in and out out of the spiracles
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34
Q

what is the consequence of gas exchange for plants and insects

A

they lose water

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35
Q

have plants and insects evolved adaptations to reduce the extent of water loss

A

yes

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36
Q

how are insects adapted to not losing too much water

A
  • use their muscles to close their spiracles
  • have a waterproof, waxy cuticle all over their body = reduces evaporation
  • have tiny hairs around their spiracles = reduces evaporation
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37
Q

how are plants adapted to not losing too much water

A
  • their stomata are usually kept open during the day = allows GE
  • water enters guard cells = makes them turgid = opens stomatal pore
  • if the plants starts to become dehydrated, the guard cells lose water = become flaccid = closes pore
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38
Q

what is the name of plants that are specially adapted for life in warm, dry or windy (where water loss is a massive problem)

A

xerophytes

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39
Q

give some examples of xerophytic adaptations

A
  • stomata is sunk in pits to trap water vapour, reduces the conc gradient of water between LEAF and AIR = reduces evaporation of water from leaf
  • has a layer of ‘hairs’ on the epidermis to trap water vapour around the stomata
  • curled leaves with the stomata INSIDE = windy conditions increase the rate of diffusion and evaporation
  • reduced number of stomata = fewer places for water to escape
  • has thicker, waxy, waterproof cuticles on leaves and stems = reduces evaporation
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40
Q

what is the purpose of GE for humans

A
  • humans need O2 in their blood
  • they need to get rid of CO2 = made by respiring cells
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41
Q

describe the structure of the GE system in humans

A
  • inhalation
  • as you breathe in, air enters the trachea
  • trachea slips into 2 bronchi, each bronchus leads to each lung
  • each bronchus branches off into smaller tubes = bronchioles
  • bronchioles end in alveoli = small air sacs
  • GE surface = alveoli
  • ribcage, intercostal muscles and diaphragm all work together to move air in and out/ in the process of inhalation and exhalation
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42
Q

describe the role of intercostal muscles in gas exchange in humans

A
  • found between the ribs
  • 3 sets, only need to know 2 = internal intercostal muscles and external intercostal muscles
  • internal intercostal muscles = inside of the external intercostal muscles
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43
Q

describe the basics of the process of ventilation

A
  • consists of inspiration and expiration
  • controlled by the movements of the diaphragm, internal and external intercostal muscles and ribcage
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44
Q

describe the process of inspiration = breathing in

A
  • external intercostal muscles and diaphragm = contract
  • ribcage = moves upwards and outwards
  • diaphragm = flattens and increases in volume
  • volume of thoracic cavity = increases
  • lung pressure = decreases to below atmospheric pressure
  • air flows from an area of higher pressure -> an area of lower pressure (down the pressure gradient)
  • air flows down the trachea -> lungs
  • inspiration = active process = requires energy
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45
Q

describe the process of expiration = breathing out

A
  • external intercostal muscles and diaphragm = relaxes
  • ribcage = moves down and in
  • diaphragm = curves up, becomes dome shaped again
  • volume of thoracic cavity = decreases
  • air pressure = increases above atmospheric pressure
  • air is forced down the pressure gradient and out the lungs
  • passive process = doesn’t require energy
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46
Q

what is forced expiration, explain this and give an example

A
  • expiration can be forced, ex - if you blow out candles on a birthday cake
  • during forced expiration, the external intercostal muscles RELAX and internal intercostal muscles CONTRACT = pulls ribcage down and in
  • movement of the internal and external intercostal muscles is antagonistic = opposing
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47
Q

what are the alveoli and what are their role in GE

A
  • lungs contain millions of microscopic air sacs = alveoli = where GE occurs
  • alveoli are surrounded by a network of capillaries
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48
Q

describe the structure of alveoli

A
  • wall of each alveolus is made from a single layer of thin, flat cells = ALVEOLAR EPITHELIUM
  • walls of capillaries = made from CAPILLARY ENDOTHELIUM
  • walls of the alveoli contain a protein called ELASTIN
  • elastin = elastic, helps alveoli to return/recoil to their normal shape AFTER inhaling and exhaling
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49
Q

describe the basics in the movement if O2 and CO2 through the GE system

A
  • air, containing O2, moves down the trachea, bronchi, bronchioles into the alveoli = movement happens DOWN a pressure gradient
  • oxygen moves into blood = can be transported around the body = happens down a diffusion gradient
  • CO2 moves down its own diffusion and pressure gradients
  • moves down in the OPPOSITE direction to O2 = so it can be breathed out
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50
Q

describe how GE takes place in the alveoli

A
  • O2 diffuses out of the alveoli, across alveolar epithelium and capillary endothelium, into haemoglobin in the blood
  • CO2 diffuses into the alveoli from the blood
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51
Q

summarise the complete movement of oxygen in the GE system

A

trachea -> bronchi -> bronchioles -> alveoli -> alveolar epithelium -> capillary endothelium -> blood

trachea -> bronchioles = pressure gradient and O2 is from the air

alveolar epithelium -> blood = diffusion gradient and O2 is in the haemoglobin

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52
Q

name and explain the factors which affect the rate of diffusion

A
  • a thin exchange surface = the alveolar epithelium is only one cell thick = short diffusion pathway
  • large SA = there are millions of alveoli = large SA for GE
  • there is also a steep conc gradient of O2 and CO2 between the alveoli and the capillaries = increases the rate of diffusion = constantly maintained by the flow of blood and ventilation
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53
Q

what does lung disease effect

A
  • ventilation
  • gas exchange
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54
Q

give examples of lung diseases

A
  • tuberculosis
  • fibrosis
  • asthma
  • emphysema
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55
Q

what are the 4 measures of lung function

A
  • tidal volume
  • ventilation rate
  • forced expiratory volume / FEV1
  • forced vital capacity/ FVC
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56
Q

define tidal volume

A
  • volume of air in each breath
  • usually between 0.4 dm3 to 0.5 dm3
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57
Q

define ventilation rate

A
  • the number of breaths per min
  • healthy person should have a rate of 15 breaths per min
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58
Q

define forced expiratory volume/FEV1

A
  • max volume of air which can be breathed out in 1 second
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59
Q

define forced vital capacity

A
  • max volume of air it is possible to breathe forcefully out the lungs, after a very deep breath in
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60
Q

what is tuberculosis

A
  • TB is a lung disease caused by bacteria
  • when someone gets infected with TB bacteria, their immune system cells build a wall around the bacteria in the lungs
  • forms small and hard lumps : tubercles
  • infected tissue in the tubercles dies AND the gas exchange surface is damaged = tidal volume decreases
  • TB causes fibrosis = further reduces the tidal volume
  • low tidal volume = less air inhaled in each breath
  • because tidal volume is low, patients will have to breathe faster
  • common symptoms : persistent cough, coughing up blood/mucus, chest pains, shortness of breath and fatigue
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61
Q

what is fibrosis

A
  • formation of scar tissue in the lungs
  • could be due to result of an infection OR exposure to substances like asbestos or dust
  • scar tissue = thicker and less elastic than normal lung tissue
  • formation of scar tissue means the lungs are less able to expand = cant hold as much air = tidal volume reduced = FVC reduced
  • reduced rate of gas exchange BECAUSE diffusion is slower across a thicker scarred membrane
  • patients have a faster ventilation rate than normal so they can get enough air into their lungs, so they can oxygenate their blood
  • common symptoms : shortness of breath, a dry cough, chest pain, fatigue and weakness
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62
Q

what is asthma

A
  • respiratory condition where the airways become inflamed and irritated
  • usually because of an allergic reaction to substances like pollen and dust
  • during an asthma attack, the smooth muscle lining the bronchioles contracts and a large amount of mucus is produced
  • causes constriction of the airways, making it difficult for the sufferer to breathe properly
  • air flow in and out of lungs is SEVERELY reduced = less oxygen enters the alveoli and moves into the blood
  • reduced air flow means FEV1 is severely reduced
  • common symptoms : wheezing, tight chest, shortness of breath
  • during an asthma attack the symptoms come on very suddenly
  • they can be relieved by drugs, often in inhalers, which cause the muscle in the bronchioles to relax = opening up the airways
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63
Q

what is emphysema

A
  • caused by smoking or long term exposure to air pollution - foreign particles in the smoke or air become trapped in the alveoli
  • causes inflammation, which attracts phagocytes to the area
  • phagocytes produce an enzyme that breaks down elastin, this is a protein found in the walls of the alveoli
  • elastin = elastic, helps the alveoli to return to their normal shape after inhaling and exhaling air
  • loss of elastin = alveoli cant recoil to expel air as well, it remains trapped in the alveoli
  • leads to destruction of the alveoli walls = reduces SA of alveoli = rate of gas exchange decreases
  • common symptoms : shortness of breath and wheezing
  • patients have a increased ventilation rate as they try to increase the amount of air, containing O2, reaching their lungs
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64
Q

the effect of lung diseases on gas exchange

A
  • TB, fibrosis, asthma and emphysema all reduce the rate of GE in the alveoli
  • less O2 is able to diffuse into the blood stream = body cells receive less O2 = rate of aerobic respiration decreases = less energy released and sufferers often feel tired and weak
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65
Q

define a risk factor

A
  • factors which increase someones likelihood of getting that disease
  • all diseases have risk factors
  • ex, smoking is a risk factor for developing lung cancer
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66
Q

define correlation

A

a link between 2 things

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67
Q

does correlation indicate cause

A
  • no
  • correlation does not mean that one thing causes another
  • correlation is not causation
  • ex, smokers have an INCREASED risk of developing cancer but that does NOT mean that smoking causes cancer
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68
Q

how do you carry out a dissection for a level biology

A
  • could be a dissection of a gas exchange system or a mass transport system, or an organ in those systems, in either an animal or plant
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69
Q

what are dissection tools

A
  • scalpels
  • have a very sharp detachable blade
  • can be used for making very fine cuts
  • dissecting scissors
  • used for precise cutting
  • safer to use than scalpels = blades are less likely to snap under pressure
  • can be easier to avoid damaging the tissue underneath when using scissors
  • dissecting pins
  • can be used with wax filled dissection tray to pin a specimen in place during the dissection
  • tweezers
  • useful for holding and manipulating the smaller parts of the specimen
  • all dissecting tools should be clean, sharp and free from rust
  • blunt tools dont cut well and can be dangerous
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70
Q

what is digestion in very simple terms

A
  • food molecules are broken down BY ENZYMES into smaller molecules
  • these molecules can be absorbed into the bloodstream
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71
Q

describe the basics of digestion

A
  • large biological molecules, like starch and proteins, in food are too BIG to cross cell membranes = can’t be absorbed from the gut -> blood
  • during digestion, these LARGE MOLECULES are BROKEN DOWN into SMALLER MOLECULES, like glucose and amino acids
  • the smaller molecules CAN move across cell membranes
  • they can be easily absorbed from the gut -> blood = allows them to be transported around the body
  • aim of transport is so they can be used by the body cells
  • large bio molecules = POLYMERS
  • polymers -> monomers via HYDROLYSIS REACTIONS
  • hydrolysis reactions break bonds through the addition of water
  • carbohydrates = hydrolysed -> DISSACHARIDES -> MONOSACCHARIDES
  • fats = FATTY ACIDS and MONOGLYCERIDES
  • proteins -> AMINO ACIDS
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72
Q

describe the role of digestive enzymes

A
  • used to break down biological molecules in food
  • variety of different digestive enzymes are produced by SPECIALISED CELLS in the digestive systems of mammals
  • enzymes are released to mix with food, with the aim of breaking them down
  • because enzymes are specific and only work with their specific substrate, different enzymes are needed to catalyse the breakdown of different food molecules
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73
Q

how does amylase digest carbohydrates

A
  • amylase : digestive enzyme which catalyses the breakdown of starch
  • starch : a mixture of 2 polysaccharides, both of which are made from long chains of A glucose molecules
  • amylase catalyses hydrolysis reactions which break the glycosidic bonds in starch -> produces MALTOSE (disaccharide)
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74
Q

where is amylase produced and released

A
  • produced by SALIVARY GLANDS
  • releases amylase into MOUTH
  • produced by PANCREAS
  • releases amylase into SMALL INTESTINE
75
Q

describe the action of membrane bound dissacharides

A
  • they are enzymes which are attached to the cell membranes of epithelial cells which line the ileum
  • help break down disacchararides -> monosaccharides
  • ^ involves hydrolysis of glycosidic bonds
76
Q

what enzymes breaks down disaccharides

A

a disaccharidase which is complementary to the specific disaccharide

77
Q

what is the disaccharide for sucrose, maltose and lactose

A

sucrose - sucrase

maltose - maltase

lactose - lactase

78
Q

what are the monosaccharides that make up sucrose, maltose and lactose

A

sucrose - glucose and fructose

maltose - glucose and glucose

lactose - glucose and galactose

79
Q

how are monosaccharides transported

A
  • transported across the epithelial cell membranes in the ileum via specific transporter proteins
80
Q

how are lipase enzymes involved in the digestion of lipids

A
  • they catalyse the breakdown of lipids -> monoglycerides and fatty acids
  • done through the hydrolysis of ester bonds in lipids
81
Q

where are lipases made and released

A
  • mainly made in the PANCREAS
  • secreted into the SMALL INTESTINE
82
Q

what is the role of bile salts in the digestion of lipids

A
  • produced by the LIVER
  • role EMULSIFYING lipids : causes lipids to form small droplets
  • bile salts are NOT enzymes, but they have an important role in lipid digestion
83
Q

why is it important that bile salts make a big lipid droplet -> a small lipid droplet, in terms of lipid digestion

A
  • bile salts cause a big lipid droplet to emulsify and this leads to the formation of many smaller lipid droplets
  • greatly increases the SA of the lipid available for lipases to work on
84
Q

what happens to lipids in lipid digestion after lipase hydrolyses lipids

A
  • the monoglycerides and fatty acids (produced from the breakdown of lipids) stick with BILE SALTS
  • when they stick with bile salts, they form tiny structures called MICELLES
  • micelles help the products of lipid digestion to be absorbed
85
Q

describe the basics of the digestion of proteins

A
  • proteins are broken down by many different peptidases
  • peptidases : enzymes that catalyse the conversion of proteins -> amino acids BY hydrolysing the PEPTIDE BONDS between amino acids
86
Q

describe the action of endopeptidase

A
  • hydrolyses peptide bonds within a protein
  • endo : think of IN THE, so within
87
Q

name some endopeptidases and their action

A
  • trypsin AND chymotrypsin are both ENDOpeptidases
  • made in PANCREAS
  • secreted/released in SMALL INTESETINE
  • pepsin is an ENDOpeptidase
  • released into stomach via cells in the stomach lining
  • pepsin only works in ACIDIC conditions
  • acidic conditions provided by hydrochloric acid in stomach
88
Q

describe the action of exopeptidase

A
  • act to hydrolyse peptide bonds at the ENDS of proteins
  • remove single amino acids from proteins
  • EXO : think of EXIT, so end of
89
Q

describe the action of dipeptidase

A
  • are exopeptidases
  • work specifically on DIPEPTIDES
  • act to separate the 2 amino acids which make up a dipeptide
  • separate them by hydrolysing the PEPTIDE bond between them
  • often located in the cell surface membrane of EPITHELIAL CELLS in the SMALL INTESTINE
90
Q

how are monosaccharides, the product of carbohydrate digestion, absorbed

A
  • glucose is absorbed by ACTIVE TRANSPORT with sodium ions via a co-transporter proteins
  • galactose is absorbed the same way with the same co-transporter protein
  • fructose is absorbed via facilitated diffusion through a different transporter protein
91
Q

how are monoglycerides and fatty acids, the products of lipid digestion, absorbed

A
  • micelles help to move monoglycerides and fatty acids
    -> epithelium
  • micelles constantly break up and reform, so they can ‘release’ monoglycerides and fatty acids : allows them to be ABSORBED
  • whole micelles are NOT taken up across the epithelium
  • monoglycerides and fatty acids are LIPID SOLUBLE, so they CAN diffuse directly across the epithelial cell membrane
92
Q

how are amino acids, the products of protein digestion, absorbed

A
  • absorbed via co-transport
  • sodium ions are actively transported OUT of the ileum epithelial cells -> the blood
  • ^ creates a sodium ion conc gradient
  • sodium ions can then diffuse from the lumen of the ileum -> epithelial cells VIA sodium dependent transporter proteins AND they carry the amino acids with them
93
Q

describe the role of haemoglobin (HM)

A
  • mass transport systems, like the circulatory system in animals ensure efficient movement of substances throughout the organism
  • haemoglobin : an important part of the circulatory system
  • human HM is found in red blood cells
  • role is to carry oxygen around the body
  • different organisms have their own type of HM
94
Q

describe the structure of HM

A
  • large protein
  • has a quaternary structure
  • made of 4 polypeptide chains
  • each chain has ONE haem group, which contains a iron ion and gives HM its red colour
  • each molecule of human HM can carry 4 oxygen molecules
95
Q

describe the formation and action of oxyhaemoglobin

A
  • happens in the lungs
  • oxygen joins to HM in RBC -> forms oxyhaemoglobin
  • reversible reaction
  • near the body cells, oxygen leaves oxyhaemoglobin and this causes it to go back to haemoglobin
96
Q

what is the name for when an oxygen molecule joins haemoglobin

A

ASSOSCIATION/LOADING

97
Q

what is the name for when an oxygen molecule leaves haemoglobin

A

DISSOCIATION/UNLOADING

98
Q

what is one of the factors that haemoglobin affinity for oxygen is impacted by

A

the partial pressure of oxygen/ pO2

99
Q

what is the partial pressure of oxygen

A
  • a measure of oxygen concentration
  • the greater the conc of dissolved oxygen in cells = higher the partial pressure of oxygen
100
Q

what is the effect of increasing pO2 on the affinity of HM

A

it increases

101
Q

what is the effect of oxygen loading and unloading at a high and low pO2

A
  • oxygen loads onto HM to form oxyhaemoglobin at a HIGH pO2
  • oxygen unloads its oxygen where there’s a LOWER pO2
102
Q

talk about the behaviour of HM in the alveoli in the lungs

A
  • alveoli : in lungs
  • high O2 conc
  • high pO2
  • high affinity
  • oxygen LOADS
103
Q

talk about the behaviour of HM in the respiring tissue

A
  • respiring tissue
  • low O2 conc
  • low pO2
  • low affinity
  • oxygen UNLOADS
104
Q

talk about high pO2 in dissociation curve graphs

A
  • pO2 tends to be high in the lungs
  • HM has a high affinity for O2
  • HM has a high saturation of O2
105
Q

talk about low pO2 in dissociation curve graphs

A
  • pO2 tends to be low in respiring tissues
  • HM has a low affinity for O2
  • HM has a low saturation of O2
106
Q

why is the line on a dissociation curve not straight

A
  • is ‘S - shaped’
  • due to the saturation of HM affecting affinity
107
Q

how is the curve of the line on the dissociation curve graph affected by HM binding

A
  • when HM is joined with its first O2 molecule, its shape changes in a way that makes it easier for other O2 molecules to join (cooperative binding)
  • as the HM become more saturated, it becomes harder for more O2 molecules to join
  • ^ because of this, the curve has a steep bit in the middle where its EASY for O2 molecules to join
  • the shallow bits at the end is where O2 molecules find it harder to join
  • when the curve is steep (where it is EASY for O2 molecules to join HM), a small change in pO2 can cause there to be a BIG change in the amount of O2 carried by the HM
108
Q

what is pCO2

A
  • partial pressure of carbon dioxide
  • measure of the concentration of CO2 in a cell
109
Q

what does pCO2 affect

A

oxygen unloading

110
Q

how does having a high pCO2 affect oxygen dissociation

A

oxygen is given up more readily at a high pCO2

111
Q

describe the bohr effect

A
  • when cells respire, they produce CO2 -> raises the pCO2
  • ^ increases the rate of O2 unloading (more oxyhaemoglobin -> oxygen + haemoglobin)
  • causes the dissociation curve to shift to the right
  • saturation of blood with O2 is lower for a given pO2, means more O2 is released
112
Q

describe the different types of haemoglobin

A
  • different organisms have different types of HM with different O2 transporting capacities
  • HM depends on things like where they live, how active they are and their size
  • having a certain type of HM is an adaptation that helps the organism to survive in a particular environment
113
Q

how does HM change in low oxygen environments

A
  • organisms that live in environments with a low concentration of O2 have HM HIGHER AFFINITY of O2 than human HM
  • ^ this is because there isn’t much O2 available, so the HM has to be very good at loading any available O2
  • dissociation curve of their HM is to the LEFT of ours
114
Q

how does HM change in high activity levels

A
  • organisms that are very active and have HIGH O2 DEMAND have HM with a LOWER AFFINITY OF O2
  • ^ this is because they need their HM to EASILY UNLOAD O2, more availability for them to use
  • dissociation curve of their HM is to the RIGHT of ours
115
Q

give an example of an animal which has HM which is adapted to a low oxygen environment

A
  • lugworm
  • lives in burrows beneath the sand where there is a LOW O2 conc
  • its HM has to be able to pick up as much O2 as possible
  • HIGH affinity of O2
116
Q

give an example of an animal which has HM which is adapted to a high activity level

A
  • hawk
  • high respiratory rate
  • lives where there is plenty of O2
  • its HM has to be able to UNLOAD O2 quickly
  • because it needs to meet the HIGH O2 demand
  • LOW affinity of O2
117
Q

how does size affect HM

A
  • small mammals tend to have a higher SA:V, than larger mammals
  • ^ causes them to lose heat quickly, so they have a HIGH metabolic rate to help keep them warm = HIGH O2 DEMAND
  • mammals smaller than humans have HM with a LOWER affinity of O2 than human HM
  • ^ because they need their HM to EASILY UNLOAD to meet their HIGH O2 DEMAND
  • dissociation curve of their HM is to the RIGHT of the human one
118
Q

give an example of an animal and how its size leads to its HM being adapted

A
  • a rat
  • higher SA:V than a human
  • its HM needs to unload O2 easily to meet the HIGHER O2 DEMAND
  • LOWER affinity for O2
  • dissociate curve of their HM is to the RIGHT of the human one
119
Q

what is the function of the circulatory system

A
  • multicellular organisms, like mammals, have a LOW SA:V
  • ^ this means they need a specialised mass transport to carry raw materials from specialised exchange organs to their body cells : circulatory system
120
Q

structure of the circulatory system

A
  • made of the heart and blood vessels
  • heart pumps blood through blood vessels (arteries, arterioles, veins and capillaries) to reach different parts of the body
121
Q

where does the PULMONARY ARTERY carry blood from and carry blood to

A
  • carries blood from the HEART
  • carries blood to the LUNGS
122
Q

where does the PULMONARY VEIN carry blood from and carry blood to

A
  • carries blood from the LUNGS
  • carries blood to the HEART
123
Q

where does the AORTA carry blood from and carry blood to

A
  • carries blood from the HEART
  • carries blood to the BODY
124
Q

where does the VENA CAVA carry blood from and carry blood to

A
  • carries blood from the BODY
  • carries blood to the HEART
125
Q

where does the RENAL ARTERY carry blood from and carry blood to

A
  • carries blood from the BODY
  • carries blood to the KIDNEYS
126
Q

where does the RENAL VEIN carry blood from and carry blood to

A
  • carries blood from the KIDNEYS
  • carries blood to the VENA CAVA
127
Q

how does the blood transport raw materials around the body

A
  • blood transports RESPIRATORY GASES, PRODUCTS OF DIGESTION, METABLOIC WASTES AND HORMONES around the body
  • one circuit takes blood from the heart -> lungs, then back to the heart
  • other loop takes blood around the rest of the body
  • therefore, the blood has to go through the heart TWICE to complete one FULL circuit of the body
128
Q

what is the hearts own supply of blood

A
  • left and right CORONARY ARTERIES
129
Q

describe the structure and function of the ARTERIES

A
  • carry blood from heart -> rest of body
  • walls are THICK and MUSCULAR
  • walls have ELASTIC TISSUE : ability to STRETCH and RECOIL as heart beats -> helps MAINTAIN HIGH PRESSURE
  • inner lining (endothelium) is FOLDED : allows artery to STRECH -> helps MAINTAIN HIGH PRESSURE
  • all arteries carry OXYGENATED blood except PULMONARY ARTERIES
  • PA takes DEOXYGENATED blood to the lungs
130
Q

describe the structure and function of the ARTERIOLES

A
  • arteries divide into smaller vessels ARTERIOLES
  • ARTERIOLES form a NETWORK throughout the body
  • BLOOD is directed to different areas (of demand) in the body by muscles inside the ARTERIOLES
  • muscles in ARTIERIOLES CONTRACT to RESTRICT the blood flow
  • muscles in ARTIERIOLES RELAX to ALLOW full blood flow
131
Q

describe the structure and function of the VEINS

A
  • take blood back to the HEART under LOW PRESSURE
  • they have a WIDER LUMEN than arteries
  • very LITTLE elastic or muscle tissue
  • contain VALVES : stop the blood flowing backwards
  • blood flow through the VEINS is helped by the CONTRACTION of the body muscles surrounding them
  • all VEINS carry DEOXYGENATED blood (as oxygen has been used up by body cells)
  • apart from PULMONARY VEINS, which carry OXYGENATED blood to the heart -> lungs
132
Q

describe the structure and function of the CAPILLARIES

A
  • ARTERIOLES branch into CAPILLARIES, which are the SMALLEST of the blood vessels
  • substances, glucose and oxygen, are exchanged between cells and capillaries : ADAPTED FOR EFFICENT DIFFUSION
  • always found very near cells in exchange tissues (alveoli in the lungs) : VERY SHORT DIFFUSION PATHWAY
  • there are a LARGE number of CAPILLARIES = increases SA for exchange
  • networks of capillaries in tissue are called - CAPILLARY BEDS
  • endothelium : 1 cell thick
133
Q

what is tissue fluid made of

A
  • the fluid that surrounds cells in tissues
  • made from small molecules that LEAVE the blood plasma, ex : OXYGEN, WATER and NURTIENTS
  • tissue fluid DOES NOT contain RED BLOOD CELLS or BIG PROTEINS
  • ^ because they are too large to be pushed out through the capillary walls
  • cells TAKE IN OXYGEN and NURTIENTS from the tissue fluid
  • cells RELEASE METABOLIC WASTE into the tissue fluid
134
Q

how do substances move out of the capillaries and into the tissue fluid in a capillary bed

A
  • substances move out of the capillaries and -> the tissue fluid IN A CAPILLARY BED by PRESSURE FILTRATION
135
Q

explain the formation of tissue fluid

A
  • at the ARTERIOLE END of capillaries
  • there is HIGHER HYDROSTATIC PRESSURE in the CAPILLARIES, compared to the hydrostatic pressure in the TISSUE FLUID
  • this forces WATER and DISSOLVED SUBSTANCES out of the CAPILLARIES
  • LARGE PLASMA PROTEINS REMAIN in the CAPILLARY
136
Q

explain the return of tissue fluid to the circulatory system

A
  • at the VENULE END of capillaries
  • hydrostatic pressure REDUCES as fluid LEAVES the capillary
  • because of water loss, an INCREASING concentration of plasma proteins LOWERS the WP in the capillary
  • water enters capillaries FROM the tissue fluid via OSMOSIS, DOWN a WP gradient
  • excess water is taken up by LYMPH CAPILLARIES and RETURNED to the circulatory system through VEINS
137
Q

what are the 2 causes of excess tissue fluid accumulation

A
  • low concentration of protein in blood plasma/ high salt concentration
  • high blood pressure -> high hydrostatic pressure
138
Q

explain how low concentration of protein in blood plasma/ high salt concentration causes excess tissue fluid accumulation

A
  • WP in capillary is not as low = WP gradient is reduced
  • causes more tissue fluid to be formed at the ARTERIOLE end/ LESS water absorbed (via osmosis) at the VENULE end
139
Q

explain how high blood pressure -> high hydrostatic pressure causes excess tissue fluid accumulation

A
  • INCREASES outward pressure from ARTERIOLE end and REDUCES pressure from the VENULE end
  • MORE tissue fluid formed at ARTERIOLE end = LESS water absorbed at VENULE end (via osmosis)
  • lymph system may not be able to drain excess fast enough
140
Q

what is the function of the right side of the heart

A
  • pumps DEOXYGENATED blood
    -> LUNGS
141
Q

what is the function of the left side of the heart

A
  • pumps OXYGENATED blood -> WHOLE BODY
142
Q

name the parts of the heart

A

RIGHT SIDE
- pulmonary artery
- superior vena cava
- inferior vena cava
- right atrium
- semi lunar valve
- right atrioventricular valve
- right ventricle

LEFT SIDE
- aorta
- pulmonary vein
- left atrium
- semi lunar valve
- left atrioventricular
- cords
- left ventricle

143
Q

what is the function of the RIGHT side of the heart

A
  • vena cava
  • right atrium
  • atrioventricular valve
  • right ventricle
  • semilunar valve
  • pulmonary artery
144
Q

what is the function of the LEFT side of the heart

A
  • pulmonary vein
  • left atrium
  • atrioventricular valve
  • left ventricle
  • semilunar valve
  • aorta
145
Q

what is the importance of a DOUBLE circulatory system

A
  • prevents the mixing of oxygenated and deoxygenated blood : blood pumped to the body is FULLY saturated with oxygen for AEROBIC RESPIRATION
  • blood can be pumped to body at a higher pressure : substances taken to/removed from body cells quicker/more efficiently
146
Q

name the blood vessels entering and leaving the heart and LUNGS

A
  • vena cava : deoxygenated blood from body tissues -> heart
  • pulmonary artery : deoxygenated blood from heart -> lungs
  • pulmonary vein : oxygenated blood from lungs -> heart
  • aorta : oxygenated blood heart -> respiring body tissues
147
Q

name the blood vessels entering and leaving the kidneys

A
  • renal arteries : oxygenated blood -> kidneys
  • renal veins : deoxygenated blood from kidneys -> vena cava
148
Q

why is the wall of the left ventricle of the heart thicker than the right ventricle of the heart

A
  • thicker muscle to contract with greater force
  • to generate higher pressure to pump blood around the ENTIRE body
149
Q

why are the ventricles thicker than the atria

A
  • walls of the ventricles are thicker than the walls of the atria
  • allows them to push blood out the heart, compared to the atria which only blood a short distance (INTO THE VENTRICLES)
150
Q

how are the AV valves adapted to do their job efficiently

A
  • link atria to ventricles
  • stop blood flowing back into atria when ventricles contract
151
Q

how are the SV valves adapted to do their job efficiently

A
  • link ventricles to pulmonary artery and aorta
  • stop blood flowing back into the heart when ventricles contract
152
Q

how are the cords adapted to do their job efficiently

A
  • attach AV valves to ventricles to stop them being forced into ATRIA when ventricles contract
153
Q

what is the cardiac cycle

A
  • ongoing sequence of contraction and relaxation of the atria and ventricles that keeps blood continuously circulating around the body
  • volume of the atria and ventricles changes as they contract and relax
  • pressure changes also occurs due to changes in chamber volume
154
Q

what are the 3 stages of the cardiac cycle

A
  • atrial systole
  • ventricular systole
  • diastole
155
Q

what takes place in atrial systole, in the cardiac cycle

A
  • atria contract, volume decreases, pressure increases
  • AV valves open when the pressure in the atria > pressure in the ventricles
  • SV valves remain shut, because pressure in arteries > pressure in the ventricles
  • blood is pushed into the VENTRICLES
156
Q

what takes place in ventricular systole, in the cardiac cycle

A
  • ventricles contract, volume decreases, pressure increases
  • AV valves shut when pressure in the ventricles > pressure in the atria
  • SV valves open when pressure in ventricles > pressure in arteries
  • blood is pushed out of the heart through ARTERIES
157
Q

what takes place in diastole, in the cardiac cycle

A
  • atria and ventricles relax, this causes volume to increase and pressure to decrease
  • SV valves shut when pressure in arteries> pressure in ventricles
  • AV valves open when pressure in atria> pressure in ventricles
  • blood fills atria, via the veins, and it flows PASSIVELY to the ventricles
158
Q

what is the equation for cardiac output

A

cardiac output = stroke volume x heart rate

159
Q

what is cardiac output

A

the volume of blood pumped out of the heart per min

160
Q

what is stroke volume

A

the volume of blood pumped in each heart beat

161
Q

what is heart rate

A

the number of beats per min

162
Q

what is a risk factor, in terms of cardiovascular disease

A
  • an aspect a persons lifestyle or substances in a persons body/environment
  • have been showed to increased rate of C disease
163
Q

give examples of a risk factor for C disease

A
  • age
  • diet high in salt/saturated fat
  • smoking
  • lack of exercise
  • genes
164
Q

what is the function of the xylem tissue

A

transports water and mineral ions through the STEM, up the plant
-> LEAVES of plants

165
Q

how is xylem tissue adapted for its function

A
  • cells are joined with NO END WALLS = continuous tube -> water flows as a continuous column
  • cells contain NO CYTOPLASM/NUCLEUS
    -> easier water flow/no obstructions
  • thick cell walls with LIGNIN -> provides support/withstand tension/prevents water loss
  • pits in side walls -> allows lateral water movements
166
Q

explain the cohesion-tension theory of water transport in the xylem

A

leaf
- water lost from the leaf by TRANSPIRATION -> water evaporated from mesophyll cells into air spaces and water vapour evaporates through open stomata
- reduces the WP of mesophyll cells
- water is drawn out of the xylem DOWN a WP gradient

xylem
- TENSION is created in the xylem
- hydrogen bonds cause in cohesion between water molecules, so water is pulled up as a CONTINOUS COLUMN
- water also adheres (sticks to) to walls of xylem

root
- water enters roots via OSMOSIS

167
Q

name the different environmental variables which affect the rate of TRANSPIRATION

A
  • light intensity
  • temperature
  • wind intensity
  • humidity
168
Q

what is the effect of increasing light intensity

A

increases the rate of transpiration

169
Q

what is the effect of increasing temperature

A

increases the rate of transpiration

170
Q

what is the effect of increasing wind intensity

A

increases the rate of transpiration

171
Q

what is the effect of increasing humidity

A

decreases the rate of transpiration

172
Q

explain how increasing light intensity leads to an increased rate of transpiration

A
  • stomata OPEN in light to let in CO2 for photosynthesis
  • allows more water to EVAPORATE faster
  • stomata close when its dark = low transpiration rate
173
Q

explain how increasing temperature leads to an increased rate of transpiration

A
  • water molecules gain KINETIC ENERGY as temp increases
  • water evaporates faster
174
Q

explain how increasing wind intensity leads to an increased rate of transpiration

A
  • wind blows away water molecules from around the stomata
  • decreases WP of air around the STOMATA
  • increases WP gradient = water evaporates faster
175
Q

explain how increasing humidity leads to a decreased rate of transpiration

A
  • more water in air = higher WP gradient
  • decreasing WP gradient from leaf to air
  • water evaporates slower
176
Q

describe the function of phloem tissue

A

transports organic substances, like sucrose, in plants

177
Q

suggest how phloem tissue is adapted for its function

A

sieve tube elements
- NO NUCLEUS/ FEW ORGANELLES -> maximise space for/easier flow of organic substances
- end walls between cells perforated (sieve plate)

companion cells
- MANY mitochondria -> HIGH rate of transpiration to make ATP for active transport of solutes

178
Q

what is translocation

A
  • movement of assimilates/solutes, ex - sucrose, from source cells to sink cells by MASS FLOW
  • source cells = where the solutes are made
  • sink cells = where used/stored
179
Q

give an example of a source cell

A

leaves

180
Q

give an example of a sink cell

A

roots

181
Q

explain the mass flow hypothesis for translocation in plants

A
  • at source, sucrose is ACTIVELY TRANSPORTED, into phloem sieve tubes/cells by COMPANION CELLS
  • ^ this LOWERS WP in sieve tubes so water enters from the xylem, by osmosis
  • ^ this INCREASES hydrostatic pressure in sieve tubes (at source)/ creates a hydrostatic pressure gradient
  • allows mass flow to occur (movement from the source -> sink)
  • at sink, sucrose is removed by ACTIVE TRANSPORT to be used by respiring cells OR stored in storage cells
182
Q

describe the use tracer experiments to investigate transport in plants

A
  • leaf is supplied with a RADIOACTIVE TRACER, like CO2 which contains C14 (radioactive isotope)
  • radioactive carbon is incorporated into organic substances during photosynthesis
  • these move around the plant by TRANSLOCATION
  • the movement is tracked using AUTORADIOGRAPHY or a GEIGER COUNTER
183
Q

describe the use of ringing experiments to investigate transport in plants

A
  • remove/kill phloem, eg -> remove a ring of bark
  • bulge forms on the source side of the ring
  • fluid from bulge has a HIGHER conc of sugars than below, shows sugar is transported in the phloem
  • tissues BELOW the ring die because they cant get organic substances
184
Q

what points should be considered when interpreting evidence from tracer and ringing experiments AND evaluating evidence for/against the mass flow hypothesis

A
  • is there evidence to suggest the phloem is involved, instead of the xylem?
  • if there evidence to suggest respiration/active transport is involved?
  • is there evidence to show movement is from the source -> sink ?
  • is there evidence to suggest movement is from a high -> low hydrostatic pressure?
  • could movement be due to another factor, like gravity?

AS BIO - C1, 2,3 AND 4 (4 decks)

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