Topic 1 IAL edexcel biology

LDL:HDL

the ratio LDL:HDL determines if person is healthy HDL .transport cholesterol to liver to be expelled .reduce cholesterol levels .the more present the better .made of unsaturated fats and proteins. LDL .transport cholesterol to arteries and build up forms plaque .increases cholesterol levels .the less present the better .made of saturated fats and proteins.

Blood clotting

thromboplastin catalyses conversion of prothrombin to thrombin thrombin catalyses conversion of fibrinogen to fibrin and fibrin creates mesh with platelts to trap RBC and forms scab to stop bleeding/blood loss.

glycerol + 3 fatty acids

ester bond is o \\ c-o know how to draw glycerol and fatty acid chains with and without water. know how to draw glucose

difference between fibrinogen and fibrin

fibrinogen .soluble .large .globular (round/spherical) fibrin .insoluble .small .fibrous (long and narrow)

Risk factors of CVD how to reduce it

genetics and age diet and somoking and inactivity you can reduce it by less smoking , less alcohol , less salt intake ,more exercise

How disaccharide form

glucose+glucose=maltose glucose+galactose=lactose glucose+fructose=sucrose all held by glycosidic bonds by condensation , production of water can be broken by hydrolysis , use of water

carbon 1 and carbon 4

if alpha glucose both oh on bottom. if beta glucose carbon 1 will have (h )on bottom carbon 4 will have (h) on top

inhalation and exhalation

inhalation .Diaphragm contract .volume increase .pressure decrease exhalation .Diaphragm relax .volume decrease .pressure increases

How structure of mammalian heart adapted for rapid gas exchange

many alevolis thin capillary -short diffusion .alveoli covered with network of capillary so large surface area and maintains concentration gradient

Monosaccharides and disaccharide

mono is single , di is 2 both are sweet and small and soluble and simple

why double circulation is better?

oxygenated and deoxygenated bloods are separate. allow higher metabolic rate. oxygen rich blood.

obesity indicator

.BMI .WASIT TO HIP RATIO

Atherosclerosis

1)damage to endothelium lining 2)inflammatory response - due to high risk of blood clotting moves WBC to artery. 3)build up and harden leading to plaque formation 4)build up leads to narrowing of artery - restricting blood flow so oxygen doesn't reach heart cells.

difference between saturated and unsaturated?

1. Saturated fatty acids have no carbon-carbon double bonds, whereas unsaturated fatty acids have at least one carbon-carbon double bond 2. Saturated fatty acid chains are straight, whereas unsaturated fatty acid chains are not straight

Treatments of CVD

Antihypertensives .lowers blood pressure .pro : effective and inexpensive .con : nausea , dizziness ,constipation Statins .lowers cholesterol levels , reduces build up of plaque .pro : relaxes blood vessel , that lowers blood pressure ,that prevents CVD. con : nausea , muscle pain , joint ache Anticoagulants .prevent blood clots , prevents platelets from sticking .pro : reduce blood clot that cause thrombosis and reduce blood flow .con : if blood vessel is damaged , internal bleeding happens , stroke too Platelet inhibitors .interrupt blood clot , reduces it and slows it from forming .pro : prevent formation of blood clot in area anticoagulants cant. con : internal bleeding

Blood vessels structure and functions arteries, capillaries , veins

Arteries .one cell thick wall to withstand high pressure .elastic walls to expand stretch and recoil .smooth endothelium to reduce friction Capillaries .numerous capillaries so its highly branched and have a large surface area .wall is one cell thick so short diffusion happens .narrow diameter to reach close to every cell veins .Thin walls that carry blood at low pressure .valves to prevent backflow .wide lumen that maximise blood flow to heart

transport of gases in blood

As partial pressure increases , hemoglobin has higher affinity for oxygen factors 1- saturation : changes it shape so its easier for oxygen to bind to hemoglobin and form oxyhemoglobin 2-fetal hemoglobin : more oxygen affinity to survive low pressure 3- Bohr effect : co2 decreases oxygen affinity

cardiac cycle

Atrial systole - atria contracts so atrioventricular valves open and semilunar valves close and blood flows to ventricles ventricular systole -ventricles contracts so atrioventricular valves close and semilunar valves open and blood goes to arteries diastole - both atria and ventricles relax and fill with blood. .

structure of heart and function

Heart has 4 chambers left and right ventricles (receive blood into the heart) left and right atrium (push blood out of heart into the arteries to go to the lungs or the body) 1)Blood first enters the heart into the right atrium via vena cava. 2)first time blood leaves the heart from the right ventricle via pulmonary artery to the lungs were it becomes oxygenated. 3)blood then returns to the heart via pulmonary vein into the left atrium 4)second time blood leaves heart from left ventricle via aorta where blood now flows to the rest of the body

definitions of risk , correlation and causation

Risk- probability that an event will occur correlation - relationship between 2 variables causation - one variable causes another

Starch and glycogen used in storage

similarities : both insoluble compact branched for quick sugar release differences : starch in plant , glycogen in animals starch 2 polysaccharides (amylose and amylopectin ), glycogen only 1 polysaccharide. Amylose- alpha helix , 1-4 glycosidic bond, unbranched, helical. amylopectin - alpha helix , 1-4 and 1-6 glycosidic bond branched.