Topic 1- complete Flashcards
why do small organisms not need a mass transport system?
their surface area to volume ratio is high enough for diffusion to be effective enough on its own
why is mass transport needed?
because cells need a constant supply of reactants (oxygen and glucose) for metabolism
why do larger organisms need a mass transport system?
low surface area to volume ratio, large diffusion distance, high energy requirement due to high metabolic rate (so more reactants needed)
what is included in a mass transport system?
a network to move through (vessels),
a medium for movement (blood),
controlled movement (pressure from heart and controlled by valves),
maintenance of speed (contraction of heart and elastic recoil of arteries maintain blood pressure and therefore speed)
define mass transport
the bulk movement of gases or liquids in one direction usually by a system of vessels and tubes
what are the benefits of a mass transport system?
moves substances quickly, maintains diffusion gradients, ensures effective cell activity by supplying reactants and removing waste products
define cohesive
the attraction between molecules of the same type (water)
what are the 5 properties of water?
solvent- disolves polar
transport medium
metabolite- made and used in metabolic reactions
high heat capacity- reliable habitat
high heat of vaporisation- sweating is affective without losing lots of water
what are the stages of the cardiac cycle?
atrial systole, ventricular systole, cardiac diastole
describe atrial systole
atria contract, atrial pressure increases and volume decreases, blood enters ventricles, slight increase in ventricular pressure
describe ventricular systole
atria relax, ventricles contract, ventricular pressure increases and volume decreases, pressure in ventricles higher than in atria and atrioventricular valves close, pressure continues to increase (now higher than pulmonary artery) semi lunar valves open, blood forced out
describe cardiac diastole
ventricles and aria relax, pressure in ventricles drop and semilunar valves close, pressure in vena cava and pulmonary vein higher than in the atria, blood enters atria, atria contracts, atrial pressure increases and volume decreases, atrioventricular valves open
what are the 4 main blood vessels of the heart?
pulmonary vein, pulmonary artery, vena cava, aorta
what is the function of the septum?
prevents oxygenated and deoxygenated blood mixing
why does the left ventricle have thicker walls than the right ventricle?
the left needs to pump blood all around the body so needs a more powerful contraction
why does the right ventricle have thinner walls than the left ventricles?
the right only needs to pump blood to the lungs which are nearby
why do the ventricles have thicker walls than the atria?
the atria only have to pump blood to the ventricles but the ventricles have to pump blood out of the heart
how are the atria adapted to their function?
thin, elastic walls to allow for stretching when filled with blood
what supplies the cardiac muscle with blood?
coronary arteries
why do the veins have valves?
lower pressure than arteries so valves stop back flow of blood
describe how the features of the arteries show they are adapted to their function
thick-walled (provides strength), muscular, elastic tissue (expands and contracts) to cope with high pressure (away from heart), endothelium is folded to allow artery to expand, narrow lumen, outer walls contain collagen for protection
describe features of the veins
wide lumen, thin muscle tissue, valves, low pressure (back towards heart), blood flow helped by contraction of body muscles surrounding them
describe how features of the capillaries show they are adapted to their function
smallest, endothelium 1 cell thick to lower diffusion distance, capillary beds increase surface area, where metabolic exchange occurs, narrow lumen means red blood cells flow single file which reduces speed so more time for diffusion, cells in walls have pores which allow white blood cells or plasma to leak out
what are the ethical issues with using invertebrates in research?
cannot give consent, cannot express pain
what are the ways of limiting ethical issues when using invertebrates in research?
handled gently, examination periods kept as short as possible, returned promptly to holding tank, extreme ranges of variables shouldn’t be tested (extreme temps. or caffeine concs.)
why might using invertebrates for research be more acceptable than using vertebrates such as monkeys?
use invertebrates as less sophisticated nervous system so could feel less pain
what are the stages of atherosclerosis?
damage to endothelium of arteries (due to high bp), inflammatory response (when blood cells move into the area), white blood cells and lipids clump together under the endothelium to form fatty streaks, connective tissue and platelets join and form a fibrous plaque called an atheroma, atheroma narrows lumen
what has to be damaged for an atheroma to form?
the endothelium
what response is triggered by damage to the endothelium?
the inflammatory response
what are the fatty steaks in the formation of the atheroma made of?
white blood cells and lipids clumped together
what are atheromas made of?
white blood cells, calcium salts, cholesterol, lipids and connective tissue
why do atheromas increase blood pressure?
plaque partially blocks the lumen of the artery and restrict blood flow
what is the process of an atheroma hardening?
calcification
what is atherosclerosis?
the hardening of the arteries caused by atheromas
what is endothelium dysfunction?
when the endothelium is damaged and it cannot function normally
how can atheromas increase risk of thrombosis?
the atheroma can rupture, causing a blood clot to form at the rupture site (thrombosis=blood clotting)
what are the enzymes in the blood clotting cascade?
thrombin and thromboplastin
what is a blood clot made of?
fibrin, platelets, red blood cells
what 3 things are needed to convert prothrombin to thrombin?
thromboplastin (released from platelets), vitamin K and calcium ions
how can a blood clot cause heart attacks?
a clot can block a coronary artery which stops blood supply to the heart muscles. this can cause damage and death of heart muscles
what is a stroke?
a rapid loss of brain function due to a disruption in the blood supply to the brain
what is deep vein thrombosis?
the formation of a blood clot in a vein deep inside the body
what are the causes of deep vein thrombosis?
prolonged inactivity (flights) and risk increases with age
what are the 7 factors that can increase risk of CVD?
diet, inactivity, smoking, high blood pressure, genetics, age, gender
how does diet increase risk of CVD?
a diet high in saturated fats increases blood cholesterol which increases atheroma formation. A diet high in salt also increases risk of high blood pressure
how does high blood pressure increase risk of CVD?
increases risk of damage to artery walls which increases risk of atheroma formation
what lifestyle factors increase high blood pressure?
excessive alcohol consumption, stress, diet
how does smoking increase risk of CVD?
CO in cigarettes reduces oxygen supply which can cause a heart attack if heart muscle is starved of oxygen
nicotine increases agglutination of platelets so risk of thrombosis increases
how can inactivity increase risk of CVD?
increases blood pressure
what lifestyle factors increase risk of CVD?
diet, smoking and inactivity
how can genetics increase risk of CVD?
different alleles mean some people are more likely to have high cholesterol or high blood pressure
how can age increase risk of CVD?
risk of CVD increases with age, this is partially due to plaque build up and blood vessels becoming fragile over time
how can gender increase risk of CVD?
men are 3x more likely to have CVD than pre-menopausal women, this may be due to hormones (estrogen increases levels of HDL)
why might people overestimate the risk of developing CVD?
(they believe the risk is greater than it actually is) might have known someone who smoked and died from CVD so now think anyone who smokes will die from CVD, constant exposure to articles about links between lifestyle factors and CVD can make people constantly worried
why might people underestimate the risk of developing CVD?
(they believe the risk is lower than it actually is) could be due to lack of information making them unaware of the factors that increase CVD
what are the 3 types of drugs which can treat CVD?
antihypertensives, statins and anticoagulants
how do antihypertensives treat CVD?
reduce high blood pressure so less chance of damage to the endothelium (less risk of atheroma’s)
what are the types of antihypertensives?
beta-blockers, diuretics and vasodilators
how do beta- blockers reduce high blood pressure?
reduce the strength of the heart beat
how do diuretics reduce high blood pressure?
reducing the amount of sodium which is reabsorbed by the blood in the kidneys. this means less water is retained which reduces blood volume
how do vasodilators reduce blood pressure?
widen the blood vessels
what are the benefits of antihypertensives?
can be used in combination with each other as they work differently
what are the risks of antihypertensives?
palpitations, allergic reactions and depression
how do statins treat CVD?
reduce blood cholesterol by reducing LDL (bad) produced in the liver, this lowers atheroma formation
what are the benefits of statins?
reduce the levels of LDL and increase the levels of HDL so lowers atheroma risk
what are the risks of statins?
side effects such as muscle and joint pain and liver damage, and need to be taken long term to be effective
how do anticoagulants treat CVD?
reduce blood clotting so clots less likely to form at sites of damaged blood vessels and restrict blood flow
what are the benefits of anticoagulants?
can be used to treat people with existing clots or CVD as they prevent from growing
what are the risks of anticoagulants?
if injured excessive bleeding may occur, damage to fetus if taken in pregnancy
give two examples of anticoagulants
warfarin and heparin
how do platelet inhibitory drugs treat CVD?
type of anticoagulant so prevent platelets clumping together to form a blood clot
what are the risks of platelet inhibitory drugs?
excessive bleeding if injured which can cause fainting and death
define energy budget
describes the amount of energy taken in by an organism and the amount of energy used up by an organism
why does weight gain occur?
if energy intake is higher than energy output the excess energy is turned to fat reserves by the body
why does weight loss occur?
if energy intake is lower than energy output the body turns some of its fat reserves into energy
what is the formula for energy budget?
energy input-energy output= energy budget
what reaction joins two monosaccharides together?
condensation
what bond holds two monosaccharides together?
glycosidic
what is a glycosidic bond?
when two hydroxyl groups on two different monomers react to together to form a covalent bond
what bond is between the glucose and fructose in sucrose?
alpha 1,2- glycosidic bond
what bond is between the glucose and galactose in lactose?
beta 1,4- glycosidic bond
give 4 examples of monosaccharides
alpha and beta glucose, galactose and fructose
give 3 examples of disaccharides
lactose, sucrose, maltose
are disaccharides soluble in water?-why?
yes due to presence of larger number of hydroxyl groups
give 3 examples of polysaccharides
amylose, amylopectin, glycogen
what is the main energy storage material in plants?
starch
what are the 2 structures of starch?
amylose and amylopectin
what monomer is starch made of?
alpha glucose
describe the structure of amylose
1-4 glycosidic bonds, coiled structure, unbranched, compact
describe the structure of amylopectin
1-4 and 1-6 glycosidic bonds, coiled structure with branches, side branches allow molecule to be quickly hydrolysed as more enzymes can bind to the many terminal ends
is starch soluble in water?
no. this means it doesn’t cause water to enter cells via osmosis which would make them swell so starch is good for storage
what is the main energy storage material in animals?
glycogen
what is the monosaccharide glycogen is made of?
alpha glucose
describe the structure of glycogen
1-4 and 1-6 glycosidic bonds, many branches, compact, insoluble, large so lots of energy, alpha glucose
where is glycogen stored in animals?
most in liver some in muscles
what are triglycerides a type of?
lipid
what are triglycerides made of?
one glycerol and 3 fatty acids
what are fatty acids made of?
a long hydrocarbon chain with a carboxylic acid group
are fatty acids hydrophilic or hydrophobic?- what does this mean?
hydrophobic so lipids are insoluble in water
how are triglycerides formed?
by condensation reactions between 3 fatty acids and 1 glycerol, 3 water is released and 3 ester bonds form
where are saturated fats found?
in animal fats
where are unsaturated fats found?
in plants
which type of lipids melt at lower temperatures?
unsaturated
which fats increase risk of CVD?
saturated
which type of fats are ‘good’?
unsaturated
what type of fats are ‘bad’?
saturated
what is cholesterol a type of?
lipid (made in the body)
what are the uses of cholesterol in the body?
cell membrane fluidity regulation, sex hormone structure, synthesis of bile
describe the role High Density Lipoproteins
transport cholesterol from body tissues to the liver where it is recycled or excreted
what are high density lipoproteins made of?
unsaturated lipids/fats and proteins
mainly proteins
which type of lipoprotein decreases blood cholesterol levels?
high density lipoproteins
which type of lipoprotein increases blood cholesterol levels?
low density lipoproteins
describe the role of Low Density Lipoproteins
transport cholesterol from liver to blood where it circulates until its needed by cells
what are low density lipoproteins made of?
saturated fats/lipids and proteins
mainly lipids
what is the healthy ratio of LDL:HDL?
3:1
what is the equation for BMI?
weight in kg/height squared m
what is the threshold BMI for obesity?
30
how is the waist hip ratio calculated?
waist cm/ hip cm
what value of waist to hip ratio shows a health risk?
a value above 1
