Biology A edexcel paper 2 11th June 2018

Blood clot leads to tissue death, as less oxygen and glucose reaches tissue cells so they cannot respite aerobically to produce ATP, so they die.

Flexors was hamstrings, contract when extensors relax to bend the knee (move soon towards hamstring), extensors (quads).contract when flexors relax to extend the lower leg. They are antagonistic.

Glucose moves into cells down concentration gradient through a gated channel protein, as it is large and not lipid based (facilitated diffusion)

Starch is long chain polysaccharide, so a rich source of glucose for energy. Branched so glucose side chains can be rapidly hydrolysed. Compact so no osmotic effect on cells. Stored in liver and muscles.

Glucose binds to receptors on beta cells - - induces second messenger molecule which binds to promoter of insulin gene alone with RNA polymerase to form transcription initiation complex whoch transcribes mRNA which is translated to produce insulin protein.

Brain: multiple choice was front part (visual cortex)

fMRI follows oxygen uptake; active areas have more oxyhaemoglobin so do not absorb signal, and light up on the machine. Non active areas have deoxyhaemoglobin, which absorbs the radio waves.

Visual cortex critical period: light - - impulse from retina along optic nerve to thalamus, then continued along axons that grow towards cells of visual cortex. Repeated stimulation = increase in synapse strength = visual development. Vice versa.

Bacteria spreads in bloodstream as it divides via binary fission using free nucleotides and glucose and oxygen in blood. ATP from respiration of glucose to give energy for division. Semi conservative replication.

Can't remember 5.

Testosterone causes increase in triceps growth compared to placebo.

Ratio of cholesterol to HDL with testosterone = 6:1

6 marker: more testosterone = less HDL and more cholesterol, so less HDL to transport cholesterol to liver to be broken down - - blood clot (due to narrower lumen) - - increased risk of CVD.
Also inhibits enzyme that breaks down cholesterol, so less collisions, less enzyme substrate complexes etc. - - CVD (same reason as above).

Acid binds to active site of lysine in condensation, forming peptide bond, so active site has altered shape and plasmid cannot bind it.

All three adaptations.

Lipid only (with 7.7)

For calculations: converted the Cm3 into dm3 by dividing by 1000

For 850 grams, worked out change, times by 850 then times by 24 (did not divide by 1000, should I have?) and added negative sign. got three thousand something.

Lysosomes lack G enzyme, so do not function and die.

Can't remember the rest.

Harder than 1 imo, lost at least 16 marks due to time and not knowing wtf the Q was on about.

you were meant to divide by 1000 because it asked fr dm3
also for the testosterone question i read it as the cholestrol is activley synthesised rather than the enzyme is inhibited. so i read it as testosterone increases the amount of enzyme that syntheisises cholestrol

I swear the question asked about glycogen not starch

Channel or carrier protein? I put channel but other people I know put carrier.

First question about glucose, I spoke about carrier proteins, and going from a high to low conc down conc gradient

For the testosterone question I spoke about atherosclerosis formation and possibility of blood clotting leading to CHD

For the multiple choice I put that it was only lipids

For the last 6 marker, I followed the basis of their experiment they described but changed it for the two things they told us to do. I said incubate at 25 degrees and do in aseptic conditions and allow oxygen to get in

For the personalized medicine on I said how it only looks at one mutation of enzyme G and therefore is very specific and not many people will have that mutation

For the wakened muscles due to GHB I said about how the na+/k+ pump has to work across the whole axon because can’t do salutatory conduction, therefore less ATP available for breaking cross bridge

For the small animal experiment I said to add koh to absorb co2 and then record the volume of oxygen consumed per unit time and the scale up to one hour and measure mass of the animal

For weakened muscles I talked about lack of myelin sheath, so impulses are not insulated and propagation is slower, so less impulses reach muscles (effector) so they cannot contract as much or with as much force

Blood clot leads to tissue death, as less oxygen and glucose reaches tissue cells so they cannot respite aerobically to produce ATP, so they die.

Flexors was hamstrings, contract when extensors relax to bend the knee (move soon towards hamstring), extensors (quads).contract when flexors relax to extend the lower leg. They are antagonistic.

Glucose moves into cells down concentration gradient through a gated channel protein, as it is large and not lipid based (facilitated diffusion)

Glycogen is long chain polysaccharide, so a rich source of glucose for energy. Branched so glucose side chains can be rapidly hydrolysed. Compact so no osmotic effect on cells. Stored in liver and muscles.

Glucose binds to receptors on beta cells - - induces second messenger molecule which binds to promoter of insulin gene alone with RNA polymerase to form transcription initiation complex whoch transcribes mRNA which is translated to produce insulin protein.

Brain: multiple choice was front part (visual cortex)

fMRI follows oxygen uptake; active areas have more oxyhaemoglobin so do not absorb signal, and light up on the machine. Non active areas have deoxyhaemoglobin, which absorbs the radio waves.

Visual cortex critical period: light - - impulse from retina along optic nerve to thalamus, then continued along axons that grow towards cells of visual cortex. Repeated stimulation = increase in synapse strength = visual development. Vice versa.

Bacteria spreads in bloodstream as it divides via binary fission using free nucleotides and glucose and oxygen in blood. ATP from respiration of glucose to give energy for division. Semi conservative replication.

Can't remember 5.

Testosterone causes increase in triceps growth compared to placebo.

Ratio of cholesterol to HDL with testosterone = 6:1

6 marker: more testosterone = less HDL and more cholesterol, so less HDL to transport cholesterol to liver to be broken down - - blood clot (due to narrower lumen) - - increased risk of CVD.
Also inhibits enzyme that breaks down cholesterol, so less collisions, less enzyme substrate complexes etc. - - CVD (same reason as above).

Acid binds to active site of lysine in condensation, forming peptide bond, so active site has altered shape and plasmid cannot bind it.

All three adaptations.

Lipid only (with 7.7)

For calculations: converted the Cm3 into dm3 by dividing by 1000

For 850 grams, worked out change, times by 850 then times by 24 (did not divide by 1000, should I have?) and added negative sign. got three thousand something.

Lysosomes lack G enzyme, so do not function and die.

Can't remember the rest.

Harder than 1 imo, lost at least 16 marks due to time and not knowing wtf the Q was on about.

Multiple choice:
For locus I put the one about the position on gene
The adaptation I put all
Enzyme lowers activation energy
I said non protein was opsin

Question with environmental factors - talked about how LDL causes higher BMI - example of phenotype and epigenetic changes

Thermoregulation 4 mark - hypothalamus detects changes from receptors and effectors Work to return to norm level via negative feedback. I mentioned sweating and hairs lie flat.

Why is the amino acid not able to bind - different primary structure means different 3D shape different active site no condensation

Question on RNA short sequence being produced - restriction enzymes and PCR

I think it was retinal that's the non protein one

Damn.
What did you put for the RNA short sequence?