Edexcel IAL Biology Unit 1 June 2016 (WBI01/01)

Another question...How do you explain thrombosis? How is it different from atherosclerosis?

Atherosclerosis is the name for a condition that occurs when plaques form on the inner lining of the blood vessels. It is composed of fatty material which accumulates and can become calcified. Atherosclerosis forms in muscular arteries and the aorta. When atheromatous plaques break free (embolization) they commonly go to the brain and cause an aneurysm (if the plaque was located in the carotids). They form because of elevated cholesterols (LDL, VLDL)

A thrombus is the name for a blood clot that forms on the inner lining of your blood vessels-most commonly the deep legs veins. There are a number of causes, but the general cause is "blood stasis". When blood is unable to circulate (due to poor circulation, obesity, a long term hospital stay, long term immobility) it settles and forms clots. People with "hypercoagulable" states also form clots more easily that normal people. These clots can occlude a vessel can cause an infarction of tissue or an organ. If the clot breaks free (embolization), it most frequently goes to the lungs where it causes a pulmonary embolism.

I got a question...
The elastic fibres (in the aorta) stretch so that they can accommodate the greater volume of blood without being damaged. Between surges, these elastic fibres return to their original length, thus squeezing the blood and moving it in a continuous flow. This is known as elastic recoil.Alright, but does this elastic recoil raise or lower the blood pressure? If not, does it have any other role other than allowing the blood to move in a continuous flow?

How can atheromatous plaques break free (they're integrated into the endothelial lining after a point)? When you say 'embolisation', isn't it when a blood clot is immobilized in blood vessels and not when an atheromatous plaque breaks free?

its not that the whole atheroma breaks free
only little pieces of plaque break off and block small blood vessels
this applies to both of your questions
oh, and embolism could be due to a blood clot, fat globule, gas bubble or foreign material, in the bloodstream not necessarily a blood clot
good question btw

Thanks for the help! You ready for the exam?

yw
yeah i guess i'm ready. wbu?

Hmm try watching videos about it on YouTube and reading revision notes about it on physicsandmathstutor.com
It really helps


Posted from TSR Mobile

hey why is measuring the initial rate so important?

its important in reactions about enzymes because with the progress of reaction the rate of rxn decreases due to the decreasing substrate concentration and substrate concentration starts to become a limiting factor
so if you measure the initial rxn, at that point susbtrate concentration is not a limiting factor and there is only one variable changing which is time
i hope i made sense

Thanks

How was the exam people? What was the answer for the enzyme question.. Was the initial rate 0.5?

Couldn't find a thread for the unit 1 exam on the 26th of May so I've made one. Hope this is helpful!