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iGCSE biology edexcel May 17th predictions

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I found January 2016 really really easy..So June will probably be easier.
here is a link for the 2016 (JANUARY)paper:https://drive.google.com/folderview?id=0B23NLD5L6099bGIwSW1pSEp5RFE&usp=sharing&tid=0B23NLD5L6099QTRNMDI2Y0NaNzA
Reply 161
Original post by gameofno
what do we need to know about the menstrual cycle


All about hormones.

-Day 1, uterus lining is shed, menstrual blood and cells of the lining flow out of the vagina.
-Follicle stimulating cell is released by the pituitary, which helps develop and mature the egg cell. It stops being produced just before ovulation.
-Peak of luteinising hormone causes ovulation.
-While this is going on, (just before ovulation ) oestrogen is released which helps in repairing the lining of the uterus after menstruation. It slows down production of FSH and sitimulates secretion of LH.
-Released egg travels through the oviduct to the uterus, where fertilisation may happen.
- Follicle (it's where the egg develops) now changes into corpeus luteum.
-Corpeus luteum releases progesterone
-Progesterone completes the development of uterus lining, so the fertilised egg develops into an embryo.
-If no intercourse has taken place, unfertilised egg along with cells passes out of the vagina (period)
Original post by ahmbiology
haha truss me good luck :smile: x


thanks, you too xx :smile:
Original post by TheCe
All about hormones.

-Day 1, uterus lining is shed, menstrual blood and cells of the lining flow out of the vagina.
-Follicle stimulating cell is released by the pituitary, which helps develop and mature the egg cell. It stops being produced just before ovulation.
-Peak of luteinising hormone causes ovulation.
-While this is going on, (just before ovulation ) oestrogen is released which helps in repairing the lining of the uterus after menstruation. It slows down production of FSH and sitimulates secretion of LH.
-Released egg travels through the oviduct to the uterus, where fertilisation may happen.
- Follicle (it's where the egg develops) now changes into corpeus luteum.
-Corpeus luteum releases progesterone
-Progesterone completes the development of uterus lining, so the fertilised egg develops into an embryo.
-If no intercourse has taken place, unfertilised egg along with cells passes out of the vagina (period)


literally how are you so smart? like. i just. what.
Reply 164
Original post by gameofno
literally how are you so smart? like. i just. what.


Tell you what. I've sucked at the menstrual cycle the whole year. If you'd asked me what's menstrual cycle earlier in May, I'd have probably just said it's discharge of blood lol. But one day I was doing a past paper and there was a six marks question, asking to explain menstrual cycle. I was like what if it came in exam lol I'd be screwed. So I picked up the book and told myself I'm going to make this my favourite topic for today lol and it just sat quite well in my brain.

And as I say, don't insult smart people by calling me smart xD
(edited 7 years ago)
Original post by TheCe
Tell you what. I've sucked at the menstrual cycle the whole year. If you'd asked me what's menstrual cycle earlier in May, I'd have probably just said it's discharge of blood lol. But one day I was doing a past paper it and there was a six marks question, asking to explain menstrual cycle. I was like what if it came in exam lol I'd be screwed. So I picked up the book and told myself I'm going to make this my favourite topic for today lol and it just sat quite well in my brain.

And as I say, don't insult smart people by calling me smart xD


jesus man omfg i need to go look for menstrual cycle questions hahahaha i wish i was you D: its not even an insult, smart people would be flattered :biggrin:
Original post by TheCe
@themightysandu


If the ph probe in a fermenter stops working and the fermenter becomes acidic, how does this affect the production of human insulin?


No idea, do we even need to know the effect of that? I guess enzymes get denatured and bacteria stop reproducing, and the bacteria cells with the recombinant plasmids die. Then no human insulin is made and we have to result back to porcine insulin and people will die
Reply 167
Original post by gameofno
jesus man omfg i need to go look for menstrual cycle questions hahahaha i wish i was you D: its not even an insult, smart people would be flattered :biggrin:


PRSOM :frown:
Reply 168
Original post by themightysandu
No idea, do we even need to know the effect of that? I guess enzymes get denatured and bacteria stop reproducing, and the bacteria cells with the recombinant plasmids die. Then no human insulin is made and we have to result back to porcine insulin and people will die


Yep for edexcel. It's a past paper question
and thanks i think it makes sense i'll check the mark scheme though and tell you

From the mark scheme:-
1. less/no insulin / less production;
2. fewer bacteria / kill bacteria / eq;
3. enzymes;
4. (not) optimum pH;
5. denatured / changed active site / destroyed;
(edited 7 years ago)
Original post by TheCe
Yep for edexcel. It's a past paper question
and thanks i think it makes sense i'll check the mark scheme though and tell you


how many marks was it, I will see if I can make a legible answer
Reply 170
Original post by themightysandu
how many marks was it, I will see if I can make a legible answer


4...
Original post by TheCe
Yep for edexcel. It's a past paper question
and thanks i think it makes sense i'll check the mark scheme though and tell you

From the mark scheme:-
1. less/no insulin / less production;
2. fewer bacteria / kill bacteria / eq;
3. enzymes;
4. (not) optimum pH;
5. denatured / changed active site / destroyed;


isn't fermenter paper 2 ?
Reply 172
Original post by dance25
isn't fermenter paper 2 ?


huh?
Original post by TheCe
4...


Ok Step one, enzymes are probably involved somehow in reproduction of Bacteria or even proteings, because GMOs are created by using restriction endonucleases to cut the gene out of the DNA code and place them in the plasmids of bacteria as sticky ends, 'glued' together using DNA Ligases
Anyway, I think I just got carried away, back to topic
the proteins in the bacteria get denatured, then growth or something cant be catalysed. Therefore, less reproduction, and for some magic reason respiration cant happen so no energy, therefore less production, because of the low pH provided by the acid
Original post by dance25
isn't fermenter paper 2 ?


only yoghurt and some things, GMOs are paper 1 and so is Beer (the one I'm stuck on)
Original post by TheCe
Yep for edexcel. It's a past paper question
and thanks i think it makes sense i'll check the mark scheme though and tell you

From the mark scheme:-
1. less/no insulin / less production;
2. fewer bacteria / kill bacteria / eq;
3. enzymes;
4. (not) optimum pH;
5. denatured / changed active site / destroyed;



I was close..
Reply 176
Original post by themightysandu
I was close..


Very, actually, that's a 4/4 answer. Well done mate!
Original post by TheCe
Very, actually, that's a 4/4 answer. Well done mate!


Hell yeah! now to learn the beer stuff, I know the effects of lots of it, just need to reverse engineer that drinking, to remember how the hell it was made
Original post by dance25
isn't fermenter paper 2 ?


ImageUploadedByStudent Room1463425988.372180.jpg
The stuff on left is paper 2


Posted from TSR Mobile
Original post by themightysandu
only yoghurt and some things, GMOs are paper 1 and so is Beer (the one I'm stuck on)


ME TOO- this is kinda what i know but im really bad at explaining let me know if ive missed anything

Beer is made from barley seeds which is starch( it needs to broken down into smaller molecule).
in order to be broken down the barley seeds need to produce amalyse( which is the enzyme that breaks down starch).
amylase is produced by germinating the barley seeds- by soaking in water and leaving in a malt house.
then the amylase produced breaks down the starch into glucose. the yeast then anaerobically respires and breaks down the maltose into ethanol and co2.

ethanoll is alcohol which is beer

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