AQA BIOL5 Biology Unit 5 Exam - 22nd June 2011

Can someone help me with this?

One of my biology books say that "high blood pressure is detected by baroreceptors, then impulses are sent to the medulla oblongata, sending impulses along parasympathetic newurons, which secrete acetylecholine, which then binds to receptors on the SAN"

Whereas my other biology book says that " high blood pressure is detected by baroreceptors, then impulses are sent to the center in the medulla oblongata that decreases heart rate, which then increases the frequency of impulses to the SAN via the parasympathetic nervous system"

What should I say in my exam then?? :/

hey in genetic fingerprinting is all the dna cut up into fragments?

all i know is pcr replicates smaller amounts than in vivo, which has the ability to replicate large amounts of DNA

Embryonic stem cells (at the 16 cell stage) are totipotent - each cells is capable of regenerating to all the cells in the body, including the umbilical cord (and therefore a new foetus)

Once they become pluripotent, they can only differentiate into one of the 3 tissue types - digestive organs, skeletal system or nervous system. They cannot develop into umbilical tissue, hence incapable of forming a new foetus.

Adult stem cells are multipotent, hence not as powerful as embryonic stem cells

Here is a website which explains this quiet well:

http://biomed.brown.edu/Courses/BI108/BI108_2002_Groups/pancstems/stemcell/stemcellsclassversatility.htm

hahahahahahhahhhahha... that always gets me

Specimen paper Q5ai) The mark scheme says:

"Sodium ions move out of axon;
By diffusion/down concentration gradient;
Through sodium ion channels/sodium ion channels open;"

This this a typo? Or have I had it the wrong way round the whole time??

Specimen paper Q5ai) The mark scheme says:

"Sodium ions move out of axon;
By diffusion/down concentration gradient;
Through sodium ion channels/sodium ion channels open;"

This this a typo? Or have I had it the wrong way round the whole time??

thank you very much is adrenaline an enzyme then? i thought it was a hormone?

This confused me today too. It's a mistake definitely.

Typo! Have a liitle faith in yourself!

Its a neurotransmitter - neither a hormone nor an enzyme

The cells used in research are pluripotent - you take them from the inner mass of the blastocyst - hence you destroy the embryo.

Embryonic stem cells are pluripotent - not totipotent.

http://en.wikipedia.org/wiki/Embryonic_stem_cellm

Actually it is both a neurotransmitter and a hormone

how come adrenaline forms a substrate receptor complex with the receptor on the CSM then? i thought that only applied to enzymes when their active site binds to a substrate

Actually it is both a neurotransmitter and a hormone

Question!!!
Some organisms are adapted for living in hot, dry environments.
Explain what causes the activity of reptiles living in a desert to vary greatly over a twenty-four hour period.

What is?

im really confused about pcr use in genetic fingerprinting, NT text book says it amplifies th edna sample and then uses restriction endonucleases to break the sample up, so in pcr how big is the sample that is amplified? how do they choose it? and if it just a section of dna, in parent fingerprinting wont you need two dna sections, one from each chromosome?