Mass transport Flashcards

Question

Pressure in the heart two main facts

Answer 1

Blood circulation relies on the pressure gradients | Blood will always move down a pressure gradient - from high to low

Answer 2

High levels of salt raise BP High levels of saturated fat increase Low Density Lipoproteins (LDL) level hence increase blood cholesterol Antioxidants reduce risk of heart disease as does non starch polysaccharide/ dietary fibre

Answer 3

Can not change this fact can only manage lifestyle factors

Answer 4

High density lipoproteins (HDL) remove cholesterol from tissues and transport it to to the liver for excretion protect the artieries against heart disease LDL transport from liver to tissues including the artery walls which get infiltrated and lead to atheroma which leads to heart disease

Answer 5

Already high pressure in the arteries, the heart must work harder to pump blood into them, hence is more prone to failure High blood pressure within the arteries mean they are more likely to develop an anyerusm (wearing of the wall) and burst, causing haemorrhage To resist the higher pressure within them, the walls of the arteries become thicker and may harden, which could restrict blood flow

Answer 6

Smaller arteries that control blood flow from arteries to capillaries

Answer 7

Tiny vessels that link arterioles to veins and are small so permeate tissue to distribute metabolic material

Answer 8

Tough fibrous outer layer to resist both internal and external pressure Muscle layer to contract and control blood flow Elastic layer to maintain BP by streacthing and recoiling Endothelium (inner lining (thin)) is smooth to reduce friction and thin to allow easy diffusion Lumen is a centavo cavity through which blood flows

Answer 9

Fenster = window (German) | Windows for exchange of material like WBC in endothelium

Answer 10

Smaller in diameter as it slows blood flow in time for exchange Larger muscle layer and lumen allows for vasoconstriction and vasodilation to control blood flow Lower pressure than artery so relatively thinner elastic layer as not much recoil needed to control BP

Answer 11

Thicker muscle layer for constriction and dilation as volume of blood need to be controlled to reach tissues Thicker elastic layer as BP in artery is high and blood needs to reach extremities - this manages pressure surge es from heater because stretches at systole and recoils when hearts relaxes so diastole Thicker overall than veins because it needs to resist bursting under pressure No valves as there is high and constant pressure so unlikely back flow

Answer 12

Near muscle layer because carries blood away from tissues so vasoconstriction/vasodilation is unnecessary Thinner elastic layer because low BP in veins so low risk of bursting, hence no recoils action needed Overall thickness of wall is small because pressure is low so unlikely to burst also allows flattering by=muscles which aids blood flow Valves at intervals because low pressure means back flow could occurs

Answer 13

Muscles contract, which compresses veins, which pressurises the blood flow, hence the valve ensures the pressure only directs blood in one direction

Answer 14

To exchange metabolic materials (O2,CO2,C6H12O6) between blood and the cells of the body

Answer 15

Mostly inner lining layer (endothelium) = extremely thing so short diffusion distance (Fick’s Law) Numerous and highly branched so large SA for exchange and slows blood flow so there is more time for exchange to occur Narrow diameter means the tissue can permeated si no cell is far from a capillary = short diffusion distance Narrow lumen means RBC can just fit - walls are against side of capillary so there is a short diffusion distance as it is close to cell Fensters = allow WBC to escape to deal with any tissue infections

Answer 16

Every cell can’t be served directly by capillary so tissue fluid bathes cells

Answer 17

Is circuit of blood vessels to and from and in lungs have a large SA to reduce blood pressure and slows down flow of blood for diffusion to occur (resistance this is called) Lower pressure than the systemic circuit

Answer 18

Faster the flow of blood

Answer 19

55% plasma which has 90% water and 10% dissolves substances like plasma proteins and glucose 45% cell suspension which has RBC, WBC and platelets

Answer 20

Environment bathing all cells | Touches tissues directly in liver

Answer 21

Means by which substances are exchanges between cells and the blood Gives glucose and receives CO2 and waste products

Answer 22

Pressure created by the pumping of the heart

Answer 23

Fenestrations

Answer 24

From blood plasma out into tissues by ultra filtration then back into blood plasma by reabsorción or drains into lymph nodded and returns to blood plasma (from heart) by lymph vessels.

Answer 25

BP is high | Hydrostatic pressure is higher than the water potential into blood so fluid is filtered out

Answer 26

Blood pressure drops because or the friction/resistance of wall as and reduced blood volume Water potential in blood becomes lower (more negative) because the proteins become more concentrated The water potential gradient into the blood is higher than the hydrostatic pressure so tissue fluid is reabsorbed back into capillary.

Answer 27

Blockage in the lymphatic system causes excess tissue fluid to build up around the cells and in the lymph vessels leading up to the blockage, which can cause severe swelling

Answer 28

Contraction of muscles

Answer 29

``` Primary = sequence of amino acids in four polypeptide chains Secondary = each chain coils into a helix Tertiary = each chain folds into a precise 3D shape Quaternary = all four polypeptide chains link to form an almost spherical molecule. Each polypeptide chain is associated with a haem group (contains Iron II) (four haem groups total on haemoglobin so 4 O2 molecules carried at once) ```

Answer 30

Each Fe 2+ can combine with and one O2 molecule each, total of 4 O2 molecules can be carried by one haemoglobin molecule at once. Needed for transport of oxygen from surface of gas exchange to tissues that require O2. Efficient: readily associate with O2 at site of gas exchange and readily dissociate at respiring tissues

Answer 31

Haemoglobin binds with O2 | Lungs

Answer 32

Haemoglobin releases O2 | Respiring tissues

Answer 33

The degree to which a substance tends to combine with another

Answer 34

Oxygen binds to haemoglobin easily but is not released as easily

Answer 35

Under different conditions, shape changes occur in presence of other substances

Answer 36

High affinity (at site of gas exchange)

Answer 37

Low (at respiring tissues we want disassociation)

Answer 38

Low affinity (at respiring tissues)

Answer 39

High affinity (at site of gas exchange)

Answer 40

CO2 presence Causes tertiary structure change, resulting in a loose binding to O2 and hence O2 released at respiring tissues. CO2 reacts with H2O to form carbonic acid. Weak acid dissociates partially releasing hydrogen atoms causing a decrease in pH. Changes charges in protein causing change in tertiary structure (shifts graph to right)

Answer 41

Different sequence of amino acids, resulting in differences (small) to tertiary and quaternary structure and hence changes affinity to oxygen

Answer 42

Higher affinity, mostly covered by seawater (O2 diffuses from H2O into lungs) when tide goes out the burrow has less O2 hence high affinity means loaded with oxygen even in low concentration of oxygen

Answer 43

Higher affinity for oxygen, lives at high altitudes where there is a low partial pressure of O2 hence fully loaded haemoglobin with oxygen even in low partial pressure of oxygen

Answer 44

Live in root nodules and fix nitrogen into ammonia | Has high affinity with oxygen and keeps oxygen concentration low so increases efficiency of nitrogen fixation

Answer 45

One O2 molecule released at tissue with low respiratory rate | Very active tissues = 3O2 molecules released at once

Answer 46

Binding of first oxygen molecule causes a change in shape to geriatric and quaternary structure of haemoglobin, making it easier for second and third binding. (Positive cooperativity) Theoretically, fourth binding should be easier, however majority of binding sites are occupies so probability of binding is less likely

Answer 47

Hydrogen carbonate HCO3 - | Dissolved in plasma and taken to lungs

Answer 48

More active so higher rate of respiration. More CO2 produced . Reacts with water to form carbonic acid - more dissociation so more acidic blood so more O2 unloaded. Graph shifts to the right

Answer 49

Shape of haemoglobin molecule molecule in low concentration of O2 means hard for first O2 molecule to bind so graph is shallow, Binding of first O2 molecules causes change in quaternary structure of haemoglobin, which induces other subunits to bind to O2. Smaller increase in O2 kPa needed for second binding = positive cooperativity - each binding makes it easier for next binding so gradient is steep After third binding majority of sites are filled hence probability of fourth binding is lower as harder to find an empty site hence gradient reduces and graph plateaus.

Answer 50

Positive cooperativity

Answer 51

False but CO does

Answer 52

Greater the affinity because loads easily but unloading is difficult

Answer 53

Lower affinity as loading is hard unloaidng is easy

Answer 54

X= xylem Teardrops on outside = phloem Inner layer of meristems is known as pericycle Phloem always on outside

Answer 55

Active transport of minerals and absorption of water. Large surface area to volume ratio so via Fick’s law more efficient osmosis Many carrier proteins for active transport of ions also many mitochondria to produce ATP Lower (more negative) water potential in cells so water moves into cell

Answer 56

Deposits on membrane preventing exchange between cells, hence cells die and nucleus and organelles die - hence hollow tubes formed (xylem)

Answer 57

Lack of organelles - unrestricted flow of continuous stream of water Lignified walls - prevents collapse under pressure No end walls on cells - series of continuous, unbroken tubes of xylem Hollow - space for H2O to pass Spiral thickening for efficient support

Answer 58

Passive force (energy supplied from the sun) and is main driving force for drawing water up stem against gravity through xylem

Answer 59

Humidity of atmosphere is less than air spaces next to stomata, which forms a water potential gradient High WP (less negative inside) hence water loss from stomata Water lost by diffusion from air spaces is replaced by water evaporating from mesophyll cell walls Size of stomata controls rate transpiration - more open = quicker

Answer 60

Water lost from mesophyll cells via evaporation from cell walls is replaced by water from xylem. Mesophyll cells lose water to air spaces because of evaporation due to heat from sun Mesophyll cells have a lower (more neg) WP than neighbouring cells H2O enters via osmosis into mesophyll cells Neighbouring cells have a lower WP now across lead so water pulled up from xylem Movement between cells can be through symplastic pathway (through cytoplasm) or apoplastic pathway (through cell walls) (weird one)

Answer 61

Symplastic - osmosis through cytoplasm Apoplastic- through cell walk (follows line of cell wall till it hits casparin which is a waterproof layer and hence water enters via osmosis into the endodermis where it converges with symplastic pathway)

Answer 62

Phloem outside Xylem inside Cambium in middle - meristem cells incokvded in producing new phloem and xylem cells

Answer 63

H2O evaporates from mesophyll cells due to heat from sun leading to transpiration Due to the polarity of water, hydrogen bonds form between water molecules known as cohesion This forms an unbroken, continuous column of water across mesophyll calls and xylem As H2O molecules evaporate into air spaces near stoma, more are pulled up due to cohesion to replace water molecules lost. Hence transpiration pull causes a column of water to be pulled up xylem Hydrogen bonds also form between water molecules and the xylem walls, which assists in pulling water molecules up xylem. The transpiration pull creates a negative pressure on the xylem, which pulls xylem walls in together Hence known as cohesion-tension theory

Answer 64

Smaller diameter of tree trunks at hottest point of day, due to more heat from sun causing a higher rate of evaporation and hence transpiration, more negative pressure is created due to more tension, hence walls of xylem pulled towards each other and trunk shrinks in diameter. If a xylem vessel is broken and air enters, the CONTINUOUS COLUMN OF WATER is broken, hence the hydrogen bonds break and transpiration does not occur If xylem vessel were under pressure, than H2O woudl leak out when a xylem vessel is broken. As it does not and air is drawn in the idea of negative pressure is supported.

Answer 65

``` Unbroken, continuous column of water Transpiration pull Cohesion Adhesion Negative pressure Unrestricted flow ```

Answer 66

transport of organic molecules and mineral ions from sources (sites of production of sugars from photosynthesis) to sinks (where sugars can be stored or used.) and occurs in the phloem

Answer 67

Too fast to be diffusion

Answer 68

Manufactured from products of photosynthesis in cells containing chloroplasts Sucrose diffuses down conc gradient by facilitated diffusion from photosynthesising cells to companion cells. Active transport of hydrogen cells from companion cells into cell wall spaces Hydrogen ions then (facilitated) diffuse down a conc gradient through carrier proteins into sieve tube elements Sucrose molecules are the co - transported with hydrogen ions by co - transport proteins. (Hydrogen ions create an electrochemical gradient that pulls in sucrose molecules AGAINST sucrose concentration gradient) into sieve tube elements

Answer 69

At source: Active transport of sucrose out of source cells into sieve tubes lowers WP inside sieve tubes so water from xylem flows in via osmosis. Increases hydrostatic pressure near the source cells At sink: Active transport of sucrose from sieve tubes into sink cells increases WP in the phloem. Hence water leaves sieve tubes via osmosis, so decrease in hydrostatic oressure near the sink Hence passive mass flow of sucrose down hydrostatic gradient, but due to active transport of sugars is controlled by enzymes and therefore affected by temperature, pH and metabolic poisons etc

Answer 70

Storage Before entering sink cells (in middle of phase two explanation) Active transport by companion cells out of sieve tubes and into sink cells

Answer 71

Sap is releases when sieve tubes are cut, hence pressure within sieve tubes Conc of sucrose in leaves is higher than in the roots ( supports source and sink idea) Downward flow in phloem in daylight, but ceases in shade. less photosynthesis and supports movement to sinks An increase in sucrose levels at sinks are followed by an increase in sucrose levels in the phloem Metabolic poisons/ lack of O2 inhibit translocation in the phloem hence enzymes and active transport used. Companion cells possess many mitochondria and readily produce ATP that can be produced for the active transport of hydrogen ions for example and sucrose

Answer 72

Sieve plates function isn’t clear as they seem to hinder mass flow - may help prevent bursting under pressure? Not all solutes move at the same speed, which would occur if movement by mass flow Sucrose delivered at the same rate to all regions, rather than more quickly at ones with a lower sucrose concentration, as mass flow would suggest

Answer 73

If plant is brown in atmosphere with 14CO2 then 14C isotope will be present in sugars that are produced and can be tracked by radiography as they travel through a plant. Cross - sections of plant stem placed on X - ray film causes BLACKENING OF FILM where 14C is present and correspond to WHERE PHLOEM IS FOUND in tissues, and other tissues do not cause blackening hence ONLY THE PHLOEM CARRIES SUGARS. Supports mass flow

Answer 74

Remove section of circumference around stem, whilst attached to plant (removing phloem) Sugars of phloem will accumulate above the removed section, causing swelling Tissues will die due to interruption of translocation. (Samples of accumulation show high in sugars and organic substances) As xylem is not removed, phloem transports sugars. Supports mass flow hypothesis

Mass transport Flashcards

(100 cards)