mock revision topic 1 Flashcards
1
Q
why do larger organisms require a mass transport system compared to single celled organisms
A
- single celled organisms can gain oxygen and glucose directly from their surroundings and the molecules can diffuse to all parts of the cell quickly due to short diffusion distances
- larger organisms: made of many layers of cells, so time taken for substances to diffuse to every cell in body would be too long
- diffusion distances involved are too great
- larger organisms also have high energy requirements, and the delivery of reactants for metabolisms needs to happen quickly.
2
Q
mass transport definition
A
bulk movement of gases or liquids in one direction via a system of vessels and tubes
3
Q
what does mass transport system help to do
A
- bring substances quickly from one site to another
- maintain diffusion gradients at exchange sites and between cells and their fluid surroundings
- ensure effective cell activity by supplying reactants and removing waste products
4
Q
what is a dipole
A
separation of charge due to electrons in the covalent bond being unevenly shared
5
Q
why is water flowy in liquid state
A
- has hydrogen bonds due to dipole nature of water molecule
- hydrogen bonds are weak
- they constantly break and reform
6
Q
what is cohesion
A
attraction of water molecules to each other
7
Q
what is adhesion
A
hydrogen bonding of water molecules to other molecules
8
Q
why is cohesion and adhesion in water a good property of water
A
- the forces of cohesion and adhesion allows water molecules to pull other water molecules along and itsself, which means that it flows easily
9
Q
how is water a solvent
A
- its a polar molecule so many ions and covalently bonded polar substances will dissolve it
- water molecules surround the charged particles so +ve part attracted to -ve particles and vice versa
- the surrounded molecules break apart and so the ions surrounded by water molecules have dissolved
10
Q
why is water being a solvent good
A
- allows chemical reactions to happen in cells as dissolved solutes are more chemically reactive wen theyre free to move about
- allows for metabolites to be transported efficiently
11
Q
describe a closed circulatory system
A
the blood is pumped around the body and is always contained within a network of closed blood vessels
12
Q
decribe an open circulatory system
A
the blood or blood equivalent is inside the body cavity and bathes the organs
13
Q
double vs single circulatory system
A
- double circulatory system has two loops - one to the lungs and one to the body
- single has one loop that includes the lungs and the body
14
Q
left ventricle structure
A
- thicker muscle than right ventricle for strong contraction to pump blood all the way around the body
- the right ventricle in comparision has to only pump blood to nearby lungs
15
Q
why are ventricle walls thicker than that of atrial walls
A
- as they pump blood out of the heart, they have thicker walls, the atria in comparision only pump blood to the ventricles
16
Q
AV (atrioventricular valves) function and structure
A
- to prevent backflow of blood from ventricles into atria
17
Q
semi lunar valves function and structure
A
- prevent backflow of blood from the aorta or pulmonary artery into ventricles
18
Q
structure of arteries and how it relates to its function
A
- endothelium (tunica intima) is one cell thick, lines the lumen of all blood vessels. it is v smooth, reduces friction so free blood flow
- highly folded endothelium enabling it to expand under pressure
- smooth muscle and elastic tissue (tunica media) is very thick
- thick muscles strengthen arteries to withstand high bp
- enables to constrict and narrow lumen for reduced blood flow, useful for diverting blood away from certain locations.
- elastic tissue helps maintain blood pressure (stretches and recoils to even out any fluctuations in pressure)
- tunica adventita contains collagen which is a strong protein that protects blood vessels from damage by over stretching
- narrow lumen which helps maintain high bp
19
Q
structure of veins and how it relates to its function
A
- smooth muscle and elastic layer is much thinner in veins than arteries as they do not need to withstand high pressure
- very wide lumen to ensure large volumes of blood per unit time returns to heart at an adequate speed.
- large lumen reduces friction between blood and endothelium of the vein.
- contain valves which prevent backflow of blood helping blood return to heart
20
Q
structure of capillaries and how it relates to its function
A
- thin walls which are permeable allowing substances to leave the blood and reach the body’s tissues
- can form networks called capillary beds which are important exchange surfaces within the circulatory system
- narrow lumen to allow rbc to pass through in a single file which forces blood to travel slowly which provides more time for diffusion to occur
- wall of capilary is single layer of endothelial cells ( one cell thick) which reduces diffusion distance for oxygen and carbon dioxide between blood and tissues of body
- have pores which allow blood plasma to leak out and form tissue fluid
- wbc can combat infection in affected tissues by squeezing through pores in capillary walls
21
Q
describe the steps of atrial systole
A
- walls of atria contract
- atrial volume decreases
- atrial pressure increases
- pressure in atria rises above tht in ventricles, forcing av valves to open
- blood is forced into ventricles
- theres slight increase in ventricular pressure and chamber volume as ventricles recieve the blood from atria
- ventricles r relaxed atp, ventricular dyastole coincides with atrial systole
22
Q
what happens during ventricular systole
A
- walls of ventricles contract
- ventricular volume decreases
- ventricular pressure increases
- pressure in ventricles rises above tht in atria
- forces AV valves to close, preventing backflow of blood
- pressure in ventricles rises above tht in aorta and pulmonary artery
- ## forces the semilunar valves to open so blood is forced into the arteries and out of the heart
23
Q
what happens during diastole
A
- ventricles and atria are both relaxed
- pressure in ventricles drops below tht in the aorta and pulmonary artery, forcing the sl valves to close
- atria continues to fill w blood and blood returns to heart via vena cava and pulmonary vein
- pressure in atria rises above tht in the ventricles, forcing AV valves open
- blood flows passively into the ventricles without need of atrial systole
24
Q
PAG
A
25
Q
steps involved in atherosclerosis
A
- damage caused to endothelium
- inflammatory response happens when wbc such as macrophages accumulate in the damaged area
- lipids and cholesterol clump together wuth the machrophages under the endothelium and form fatty streaks
- platelets can add to the fatty deposit
- accumilation of all of this, forms a plaque, known as an atheroma
-the atheroma narrows the lumen of the artery, reducing and restricting blood flow, and thereby raising blood pressure - overtime, the plaque can calcify and harden, reducing elasticity of the artery wall and further increasing blood pressure.
26
Q
steps involved in blood clotting (thrombosis)
A
- damage to wall occurs
- platelets stick to damaged wall and to each other, forming a platelet plug
- protein called thromboplastin is released
- calcium ions from the plasma, along with thromboplastin triggers the conversion of soluble prothrombin protein into the enzyme thrombin
- thrombin catalyses the conversion of soluble fibrinogen to insoluble protein fibrin
- fibrin fibres mesh together and tangle together, trapping platelets and rbc forming a clot
27
Q
how can blood clot lead to stroke
A
- blood clot leads to blockage of arteries
- leads to reduced blood flow and delivery of oxygen to cells of the brain, reducing respiration
- cells in affected part of the brain cannot produce ATP and function is reduced
(this is an ISCHEMIC stroke)
28
Q
define risk factor
A
factor that can be linked to an increased risk of a disease
29
Q
types of medication of CVD
A
- antihypertensives
- statins
- anticoagulants
- platelet inhibitors
30
Q
how do antihypertensives work?
A
- lower bp
- high bp is known as hypertension
- lowering bp = reduced risk of arterial endothelial damage and so reduces risk of atheroma and thrombosis
31
Q
what are 3 types of antihypertensives
A
- beta blockers
- vasodilators
- diuretics
32
Q
how do beta blockers work
A
- prevent increases in heart rates
33
Q
how do vasodilators work
A
- increase diameter of blood vessel so blood flows at lower pressure
34
Q
- how do diuretics work
A
- reduce blood volume
- decrease amount of sodium reabsorbed into the blood by kidneys
- decrease volume of water reabsorbed into the blood
35
Q
how do statins work
A
- lower blood cholesterol, by blocking enzyme in liver needed to make cholesterol
- lowers LDL conc, so reduces risk of atheroma formation
36
Q
how do anticoaulants work
A
- reduce blood clotting
- reduced formation of blood clots decreases likelyhood of thrombosis and therefore reduces risk of blood vessels being blocked by blood clots
37
Q
what are a type of anticoagulant and how does this work
A
- platelet inhibitors
- prevent clumping together of platelets, so prevent formation of blood clot (aspirin)
38
Q
benefits and risks of antihypertensives
A
- they reduce blood pressure, and blood pressure can be monitored at home to check drugs r working
- have many side effects like headaches, drowsieness, heart palpitations, swelling and cough so patients may stop taking medication due side effect
39
Q
benefits and risks of statins
A
- reduce LDL cholesterol in blood, so reduces risk of atheroma developing.
- increases HDL which aids further LDL removal
- can take a while to be effective so need to be taken long term
- side effects such as muscle and joint pain, liver damage.
40
Q
benefits and risks of anticoagulants/patelet inhibitors
A
- reduces formation of blood clots and so risk of blood vessel blockage
- can cause exessive bleeding if injury happens
- can cause side effects
41
Q
what is a monosaccharide
A
- single sugar unit with a general formula of (CH2O)n where n is number of carbon atoms
42
Q
give examples of hexose sugars
A
- glucose, galactose, fructose
43
Q
why are monosaccharides not good for storage
A
- they are soluble
- require little or no change before being used in cellular respiration
- have influence on process of osmosis
44
Q
how are disaccharides or polysaccharides formed
A
- when two hydroxyle groups on diff monosaccharides interact to form strong covalent bond called glycosidic bonds
45
Q
what type of reaction is it when a glycosidic bond is formed
A
- condensation reaction as one water molecule is released for every glycosidic bond formed
46
Q
how is maltose formed
A
- two molecules of glucose
- 1,4 glycosidic bond
47
Q
how is sucrose formed
A
- glucose and fructose
- 1,2 glycosidic bond
48
Q
how is lactose formed
A
- glucose and galactose
- 1,4 glycosidic bond
49
Q
disaccharide
A
- when two single sugar units can join together to form this
50
Q
hydrolysis reaction
A
- when the glycosidic bond is broken when water is added
- for example the digestion of food and breakdown of stored carb in muscle and liver for cellular respiration
51
Q
function of disaccharides
A
- provides body with quick release source of energy
- make up 2 sugar molecules, so easily broken down by enzymes
- they have many hydroxyle groups so easily soluble w water as they form hydrogen bonds w water molecules
52
Q
examples of polysaccharides
A
- starch, glycogen, cellulose
53
Q
advantage of a branched polysaccharide
A
- it increases the rate at which a polysaccharide can be broken down because more TERMINAL ends
- so these ends make it easier to be hydrolysed for use during cellular respiration OR added for storage.
54
Q
why might a polysaccharide be straight or coiled
A
- straight = molecules can construct cellular structures (cellulose)
- coiled = molecule is more compact and suitable for storage (amylose in starch)
55
Q
why are starch and glycogen useful as storage polysaccharides
A
- theyre compact so large quantities can be stored
- theyre insoluble so have no osmotic effect, unlike glucose which would increase solute conc of cell and cause water to move in by osmosis
56
Q
structure of starch and how its structure relates to its function
A
- made up of a mixture of two molecules: amylopectin and amylose
- amylose: unbranched, helix shaped chain with 1,4 glycosidic bonds between alpha glucose. HELIX = more compact and so more can be stored
- amylopectin: branched molecule with 1,4 and 1,6 glycosidic bonds between alpha glucose. branches result in many terminal glucose molecules that can be easily hydrolysed for use during cellular respiration, or added to fat for storage
57
Q
what is glycogen
A
- storage polysaccharide of animals and fungi
58
Q
structure and how this relates to the function of glycogen
A
- highly branched and not coiled, with 1,4 and 1,6 glycosidic bonds
- more branched than amylopectin = more terminal glucose molecules = so quicker adding or removing by hydrolysis = allows the quick storage or release of glucose to meet the high energy demands of animal cells as theyre very metabolically active
- compact = stored in small place
59
Q
where and how is glycogen found mainly in
A
- liver and muscle cells have high conc of this
- its very compact
- its present as visible granules which enables high cellular respiration rate.
60
Q
triglyceride structure
A
- 3 fatty acids
- 1 glycerol joined
- condensation reaction when they join
61
Q
why are unsaturated fats liquid at room temp
A
- have double bonds
- these cause a kink in the hydrocarbon chain
- these kinks prevent unsaturated hydrocarbon from packing closely together
- increasing distant between molecues weakens intermolecular forces between unsaturated triglycerides, resulting in oils that are liquid at room temp
62
Q
what is a saturated fat and its properties
A
- long straight hydrocarbon chain, with no double bonds in the chain
- no more hydrogen can be added to it
- they can pack closely together as theyre straight, forming strong intermolecular forces and are solid at room temp
63
Q
are lipids polar or non polar
A
- non polar
- hydrophobic
- insoluble in water
64
Q
reaction that triglycerides are formed by
A
- esterification
- an ester bond is formed between the hydroxyl group of the glycerol and the carboxyl group of the fatty acid
- its also a condensation reaction, as 3 fatty acids join to one glycerol, theres 3 ester bonds, and 3 water molecules are released
65
Q
what are lipoproteins
A
- molecules composed of lipid and protein
66
Q
what are HDLs
A
- high density lipoproteins
- contain unsaturated fat, cholesterol and protein
67
Q
function of HDLs
A
- transport cholestrol from body tissues to liver to be recycled or excreted
- responsible to reduce blood cholesterol levels and contribute to removal of cholesterol from fatty plaques
68
Q
what is the structure and function of LDLs
A
- contain saturated fat, cholesterol and protein
- moves cholesterol from liver to blood stream where it remains till its required by cells.
- binds to receptors on cell surface membranes, so they can be taken up by the cell that needs them
- high levels of LDLs can lead to blockage of membrane receptors and can cause blood cholesterol to rise
69
Q
PAG 2
A
70
Q
A
