Edexcel Biology Unit 4(ALL OPTIONS) June 2009 (Old Spec)

I was unsure of that question, I think I said that turbidity increased as the bacteria numbers increased absorbing more light (i.e increasing turbidity). I thought it might have something to do with diaxic growth but the values of turbidity doesn't seems to support that very much.

thats sorta what i said:
bacterial cells normal at beginning - turbidity constant for first hour - nothing happening as enzymes being snthesisd.
bacteria numbers increased - exponential phase - more bacteria, higher turbidity
got stagnant again - turbidity the same - diauxic growth so new enzymes being synthesised to hydrolyse second carbon source
increased again- turbidity increased - more bacteria - exponential phase
stagnant at end - turbidity constant - no more substrate left to respire

sorta what i wrote but with alot more waffling in between.

Anyone do the Food science module, was pretty straight forward i think few questions yo had to think about.

Q1) R pointing at lamella (Outer segment)
a) The idea that rhodopsin is bleached in bright light and that cones used for acute vision so in high intensity light and rods for sensetive vision so dim light.

Q2) Sensory neurone (Impule Upwards)

Action potential just when membrane permeability chages so more Na+ moves in and thus axon becomes depolarised may have mentioned the actual values cant remember.

Q3) Yeast one i think so idea or O2 does not reach zero because yeast begin to respire anaerobically and no oxygen needed, Bi-product or Ethanol is produced instead to oxidise NADH + H+ so NAD can be recycled.

Q4) the glucose one, percentade was 83.xx% the older men has desensitised cells to do not respond to insulin as efficiently. Glucagon stimulate cells in liver to break down glycogen to glucose, promote amino acids and fatty acids to not only be used as respiratory subtrates but be converted to glucose (gluconeogenesis) and as well as inhibiting insulin production. Other hormone is Adrenaline.

Q5) Loop of Henle i drew the structure and explained counter current multiplier system, and hoe decending limb is permeable to water and accending limb is impermeable. Chloride pumps which cause the loop to bath in concentrated solution so draws water our of filtrate by osmosis and leaving behind concentrated filtrate thus concentrated urine (along thos lines basically)

b) ADH released by Posterior Pituitary gland (Messed up because i said anterior), Osmoreceptors in brain detect low levels of water in blood so ADH secretion occurs which travels in the blood to the collecting ducts where they act on aquaproteins. Thes proteins open thus more water reabsorbed efectively leaving behind concentrated urine.

FOOD SCIENCE

6a) Cant remember everything but Vit C absorbs oxygen so reducing spoilage and growth of aerobic bacteria. Fermentation of lactic acid reduces pH and so unfavorable environment for bacteria growth. Pasterisation i wasnt sure i just said involved heating and so sterilisation??

7) Was a graph question i think with the idea of choleterol and HCL??
Healthy balance diet to reduce chance of coronary heart disease (CHD)
if diet has more fat this means more cholesterol so reduced flow through coronary arteries due to build up of plaque (arteriosclerosis) so individual suffers from angina pertoris then eventually heart attack.

Fibre reduced transit time so potential carcinogenic substances are not in contact with the walls of the intestine to reduced chance of colon cancer. Also idea of fibe making stool softer due to more water uptake so again individual does not suffer from constipation. (Forgot to mention about build up of pressure and possible pouches that form in the colon and the idea that increase in fibre consumption reduced cholesterol)

8) Male and Female energy expenditure, Males are larger and more muscular so greater energy expenditure. Also idea that men have less metabolically active adipose tissue compared to females and so more energy expenditure. As for the comparing the graph i just said greatest energy usage for swimming least in walking and greatest difference i think was swimming. Mentioned figures and stuff also.

Q9) Last but not least ingrediants for saurcraut were cabbages and brine i think.

Bacteria were entrobacter plantarium and i mentioned lactobacillus bulgarius. These were wrong as the answer was Entrobacter cloaca and Leuconostoc plantarium .

pH falls as fructose converted to lactic acid in respiration as conditions are anaerobic.

the stuff is packaged on day 21, i said it was because the had to make sure taste and ph was contant and bacteria were all dead "no idea" dont think i did too good in this question.

All in all a pretty long ass post but these were my answers anyone care to comment lol

Anyone do the Food science module, was pretty straight forward i think few questions you had to think about.

Q1) R pointing at lamella (Outer segment)
a) The idea that rhodopsin is bleached in bright light and that cones used for acute vision so in high intensity light and rods for sensetive vision so dim light. etc...

Q2) Sensory neurone (Impule Upwards)

The neurone itself generates an impulse due to a stimulus i.e placing your hand on a hot surface and as a result the stimulus tracels from the receptors in the skin through the sensory neurone to the central nervous system.
Action potential just when membrane permeability chages so more Na+ moves in and thus axon becomes depolarised may have mentioned the actual values cant remember.

Q3) For the Yeast one i think i mentioned the idea that O2 does not reach zero because yeast begin to respire anaerobically and no oxygen needed, Bi-product or Ethanol is produced instead to oxidise NADH + H+ so NAD can be recycled.

Q4) the glucose one, percentage was 83.xx% the older men has desensitised cells to do not respond to insulin as efficiently. Glucagon stimulate cells in liver to break down glycogen to glucose, promote amino acids and fatty acids to not only be used as respiratory subtrates but be converted to glucose (gluconeogenesis) and as well as inhibiting insulin production. Other hormone is Adrenaline.

Q5) Loop of Henle i drew the structure and explained counter current multiplier system, and how decending limb is permeable to water and accending limb is impermeable. Chloride pumps which cause the loop to bath in concentrated solution so draws water our of filtrate by osmosis and leaving behind concentrated filtrate thus concentrated urine (along thos lines basically)

b) ADH released by Posterior Pituitary gland (Messed up because i said anterior), Osmoreceptors in brain detect low levels of water in blood so ADH secretion occurs which travels in the blood to the collecting ducts where they act on aquaproteins. These proteins open thus more water reabsorbed efectively leaving behind concentrated urine.

FOOD SCIENCE

6a) Cant remember everything but Vit C absorbs oxygen so reducing spoilage and growth of aerobic bacteria. Fermentation of lactic acid reduces pH and so unfavorable environment for bacteria growth. Pasterisation i wasnt sure i just said involved heating and so sterilisation??

7) Was a graph question i think with the idea of choleterol and HCL??
Healthy balance diet to reduce chance of coronary heart disease (CHD)
if diet has more fat this means more cholesterol so reduced flow through coronary arteries due to build up of plaque (arteriosclerosis) so individual suffers from angina pertoris then eventually heart attack.

Fibre reduced transit time so potential carcinogenic substances are not in contact with the walls of the intestine so reduced chance of colon cancer. Also idea of fibe making stool softer due to more water absorbtion by fibre so again individual does not suffer from constipation. (Forgot to mention about build up of pressure and possible pouches that form in the colon and the idea that increase in fibre consumption means reduced cholesterol)

8) Male and Female energy expenditure, Males are larger and more muscular so greater energy expenditure. Also idea that men have less metabolically active adipose tissue compared to females and so more energy expenditure. As for the comparing the graph i just said greatest energy usage for swimming least in walking and greatest difference between male and female i think was swimming. Mentioned figures and stuff also.

Q9) Last but not least ingrediants for saurcraut were cabbages and brine i think.

Bacteria i mentioned were entrobacter plantarium and lactobacillus bulgarius. These were wrong as the answer was Entrobacter cloaca and Leuconostoc plantarium .

pH falls as fructose converted to lactic acid in respiration as conditions are anaerobic.

The saurkraut is packaged on day 21, i said it was because the had to make sure taste and ph was contant and bacteria were all dead "no idea" dont think i did too good in this question.

All in all a pretty long ass post but these were my answers anyone care to comment lol (Not 100% right i no so dont just go by my answers) Good luck to all doing the Synoptic on Wednesday.

Not sure about the bacteria as i was taught differently but you could be right, yes the ingrediants are Salt and Cabbage not Brine, and Fibre youve mentioned pretty much the same stuff as above.

I WROTE PSUEDOUNIPOLAR as it was so damn blatant...hope its right

this browser was open for so long lol....popped up when i was shuting down

good luck ppl for unit 6b

u guys are not gona belive wat i rote for that stupid yeist question!! the forst thing i thought was that it repsires ANAROBICALLY!! so i started rattling on bout how oxygen is high because the etc cant work as its respires anarobiclly so atp is only generated by glycolysis!! i fuked up sooo baddddd how stupid am iiiiiiiiiii!!

Just realised I did that too...
No idea why - guess I just thought it was a good reason for there to be oxygen left....

EDIT: Ahh ok, after reading the rest of the thread it doesn't seem such a stupid thing to do

Although I have just realised I wrote that ADH increases the permeability of the loop of Henle and the DCT ooops

with the anarobic oxygen stuff r u talkin bout the first part of the yeast cells quesiton
if so i wrote that too! lol

last question
bacteria were defo lactobacillus and leoconstoc check ur book!

also ingrediants were salt and cabbage

brine is is SOYA SAUCE
and as for fibre

increases size of stools
so they move faster and less time for carcinogenic substances to have an effect on mucosa of gut wall
increase transit time
and fibre also absorbs carcinogenic substance (saw it in another markshceme)
and then talked about problems like constipation ect