topic 1 - lifestyle and risk Flashcards
explain a water molecule…
including charges, bonding when two H2o’s attach and what this bonding does
hydrogen atoms = partially positive
oxygen atoms = partially negative
- this separation of charge is called a DIPOLE
- polar molecule as one end is negative and the other is positive
- hydrogen bonding
- H bonding creates cohesion and adhesion, enabling effective transportation
explain why water is a good solvent. what does it dissolve in?
- chemicals dissolve easily in water due to dipole nature
- ionic substances dissolve easily. negative ions attracted to positive end of H20 and positive ions attracted to negative ends of H20. ions become surrounded by water molecule and dissolve
- polar molecules dissolve easily. polar groups become surrounded as they are hydrophilic
- this allows chemical reactions to occur within cells as the dissolved solutes are more chemically reactive when they are free to move about
- hydrophobic substances dont dissolve.
explain waters thermal properties and why this is useful in organisms
- specific heat capacity is very high
- because lots of energy needed to break H bonds
- large input of energy also increases temp a little
- useful in organisms as helps to avoid rapid changes
why have a heart and circulation? what are the differences in circulatory system between uni and multicellular organisms?
to move substances around the body.
unicellular:
- use diffusion as only short distance
multi:
- as size increases SA to V ratio decreases
- diffusion insufficient so mass transport used
- MT is used to carry raw materials from specialised organs to the body cells and to remove metabolic waste.
name four features of a mass transport system
- network to move through
- medium for movement
- controlled direction
- maintenance of speed
arteries
- function and adaptations
- carry oxygenated blood away from the heart to body
- small lumen to maintain high blood pressure
- smooth endothelium so less resistance
- endothelium folded to allow artery to expand
-lots of collagen fibres for strength and support - thick walled to cope with high pressure
veins
function and adaptations
- carry deoxygenated blood back to heart
- large lumen to reduce resistance to flow
- wider with little elastic tissue as lower pressure
- valves to prevent backflow
explain the three stages of the cardiac cycle
- atrial systole: atria contracts increasing pressure of chambers and decreasing volume. valves open and blood flows to ventricles
- ventricular systole: ventricles contract forcing atrioventricular valves to close, semi lunar to open. blood leaves the left ventricle via aorta and right via pulmonary artery
- cardiac diastole: atria and ventricles relax. pressure decreases and SL valve closes. blood returns to heart and atria fills.
atherosclerosis
- define.
- explain how it happens
- the hardening of arteries caused by building up of fibrous plaque
- endothelium becomes damaged. this could happen via smoking, high BP etc
- inflammatory response. white blood cells move into artery.
- over time, white blood cells, cholesterol, calcium salts and fibres build up leading to plaque.
- artery wall loses its elasticity
- plaque build up restricts blood flow
how do blood clots form
- endothelium damage exposes collagen fibres
- platelets attach to exposed collagen fibres
- platelets release thromboplastin protein
- thromboplastin activates an enzyme that catalyses prothrombin to thrombin. in order for this to occur, calcium ions and vit k must be present
- thrombin catalyses conversion of soluble fibrinogen into fibrin
- mesh of fibrin traps platelets and red blood cells and clot forms
what are the consequences of blood clots
- angina: narrowing of coronary arteries limits amount of oxygen rich blood reaching heart
- heart attack: plaque in coronary arteries. heart muscle does not receive blood.
- stroke
- deep vein thrombosis
seven factors that increase risk of CVD
- diet - sat fat increases plaque build up. high salt increases bp
- high bp - increases damage to artery walls which increases atheroma formation
3, smoking -
- carbon monoxide binds with haemoglobin and reduces amount of oxygen carried
- nicotine makes platelets sticky and narrows arteries
- decreases amount of antioxidents in blood - inactivity
- genetics
- age: arteries become less elastic
- gender: oestrogen makes arteries more elastic
explain LDL and HDL
LDL: mainly lipid, transport cholesterol from liver to blood. increases blood cholesterol
HDL: mainly protein, transports cholesterol from body tissues to liver. deceases blood cholesterol
antihypertensives
- function
-examples
- benefits and risks
- reduce blood pressure
- beta blockers (prevent increases in heart rate), and vasodilators (widen vessels), and diuretics (reduce water absorption)
- can be given in combination. bp monitored at home
- palpatations. fainting
statins
-function
-risks
- reduce amount of LDL cholesterol
- nausea, inflammation
anticoagulants
- function
- example
- benefits
-risks
- reduce formation of blood clots
- eg warfarin
- can be used with people who have CVD already
- excessive bleeding. can damage foetuses
platelet inhibitors
-function
-benefits
-risks
- make platelets less sticky reducing atheromas
- can be used with people who have CVD already
- excessive bleeding, stomach bleeding
carbohydrates general formula
Cn(H20)n
three main monosaccharides
- glucose
- galactose
- fructose
what is sucrose made from and what is bond
- alpha glucose and fructose
-1,2 glycosidic
what is maltose made of and bond
- alpha and alpha
- 1,4 glycosidic
what is lactose made of and bond
- galactose and glucose
- 1,4 glycosidic
starch
- what is it
- made of?
- soluble?
- main energy storage in plants
amylose: straight chain of glucose molecules. spiral shape. 1,4 bonds. compact.
amylopectin: 1,4 and 1.6 bonds. side branches allow enzymes to break down glucose easily. - insoluble. compact structure and insolubility makes it good at storage
cellulose
- made of?
- monomer
- properties
10,000 glucose molecules
forms straight chain
no branches
hydrogen bonds
end up with microfibrils
monomer= beta glucose
bond= 1,4
strong and insoluble. only found in plant cell walls
glycogen
- used for
- structure
-properties
animals store excess glucose as glycogen
- 1,4 and 1,6 with side branches so can be released quickly
- compact and large, good for storage
- insoluble
- alpha glucose
saturated fats
- long and straight
- no double bonds
- strong IMB so solid at room temp
unsaturated fats
- double bond forms kink in chain which prevents molecules packing close together
- thus IMF are weak so liquid at room temp
- made solid by adding hydrogen
lipid properties
- fatty acid tail is hydrophobic so insoluble
- very compact
- non polar and insoluble = good for storage
- provide thermal insulation as conduct heat slowly
what will happen to additional energy if a person takes in more than required
it will be stored as fat in body cells
causal relationship definition
a change in one variable directly results in the change of another
why does the structure of glycogen allow it to be an energy store
- polymer of glucose
- branched for rapid hydrolysis
- compact to allow large amount of energy stored in small place
- insoluble therefore does not affect osmosis
a platelet is….
a cell fragment that releases thromboplastin
fibrinogen is…
a soluble plasma protein
how does a blood clot lead to stroke/heart attack etc
- reduced blood flow so less oxygen rich blood
- less aerobic respiration so less ATP produced
- lactic acid produced from anaerobic respiration
- lactic acid is toxic
capillaries
- adaptations
- one cell thick which reduces diffusion distance for oxygen and carbon dioxide between blood and tissues
- pores which allow blood plasma to leak out and form tissue fluid. white blood cells can also combat infection by squeezing out from the pores
- narrow lumen providing more time for diffusion to occur
- no collagen
- thin permeable walls, allowing substances to leave the blood to reach body tissues
what is the vessel transporting blood at highest pressure
aorta
which chamber of the heart has the highest pressure
left ventricle
name one function of glycoproteins in cell membrane
cell recognition
why is ATP required for facilitated diffusion
- being moved against a conc gradient using active transport
how does change in primary structure affect enzyme
different primary structure results in different sequence of amino acids
change in R group changes
substrate cannot bind
stopping…..
Compare diffusion and active transport
Similarities
both move molecules through the {phospholipid bilayer / cell surface membrane} (1)
(in both) molecules can move through proteins (1)
Differences
diffusion occurs down a concentration gradient whereas active transport occurs against a concentration gradient (1)
diffusion is {passive / does not require ATP} whereas active transport requires ATP (1)
Why is water an ideal transport medium
water is a solvent (1)
because water molecules surround { polar molecules / ions } / hydrogen bonds form between water molecules and solute molecules (1)
water is liquid so has the ability to flow (1)
Which side of the heart has lower pressure
The right as blood is transported from heart to lungs