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Edexcel GCE Biology Unit 5 6BI05 June 2013

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Reply 1080
Feel so confident for this exam. The grade boundaries for each year are ridiculously low. :biggrin:

I also love this year's article, it's actually interesting!

Been getting full UMS in almost every past paper, so as long as the exam tomorrow doesn't suddenly turn into a chemistry paper, it should be plain sailing.
Original post by hussaincute
can sombody plz answer that in simple words:

explain why ATP production decreases when oxygen is low in the tissues?


With low O2, Aerobic Respiration cannot occur. However, glycolysis and Anaerobic respiration can. Anaerobic respiration produced only 2 molecules of ATP compared to the 36 produced by Aerobic respiration. So ATP production falls because there is less Aerobic Respiration and more anearobic respiration occurring.
Reply 1082
is action potential and potential difference the same thing? or action potential only occurs in at synapse? is can someone help me please thanks!
Reply 1083
Hey guys.

Ok I know this is very common, and everyone feels the same but literally I am terrified for tomorrow's exam. I am not exaggerating one bit but my heart is beating extremely fast and i'm getting really bad pain around my heart area LOOL . I do the same in the exam. I panic and I try really hard to brace myself. any tips on how to stop this? I get a lot of prep talks from friends and family but I'm worried that what i've done isn't enough. :frown: omgomgomg
Reply 1084
Original post by hussaincute
can sombody plz answer that in simple words:

explain why ATP production decreases when oxygen is low in the tissues?


more anaerobic repiration which is less efficent only 2 ATP produced compared to about 32 ATP for aerobic.
Reply 1085
Original post by Brad0440
More unit 5 questions:

Describe the structure of a muscle fibre. (4)

Spoiler



Explain how plants grow towards light. (6)

Spoiler



State two consequences of exercising too little and two consequences of exercising too little. (4)

Spoiler



Thx but isnt the second question too much off our spec, well yes a couple of points we should know, but isnt that a liitle too much detail
Reply 1086
Original post by Zahra333
Hey guys.

Ok I know this is very common, and everyone feels the same but literally I am terrified for tomorrow's exam. I am not exaggerating one bit but my heart is beating extremely fast and i'm getting really bad pain around my heart area LOOL . I do the same in the exam. I panic and I try really hard to brace myself. any tips on how to stop this? I get a lot of prep talks from friends and family but I'm worried that what i've done isn't enough. :frown: omgomgomg


You know the material, you've covered everything. Everything in that exam tomorrow (or 99.9% of it) you have already covered. So you know all the information, and when you read a question, that information will just start pouring out of your brain without any effort. You don't need to be worried. And if the exam is difficult, it will be difficult for everyone else too, so you won't be the only one.

Good luck. :smile:
Original post by Zahra333
Hey guys.

Ok I know this is very common, and everyone feels the same but literally I am terrified for tomorrow's exam. I am not exaggerating one bit but my heart is beating extremely fast and i'm getting really bad pain around my heart area LOOL . I do the same in the exam. I panic and I try really hard to brace myself. any tips on how to stop this? I get a lot of prep talks from friends and family but I'm worried that what i've done isn't enough. :frown: omgomgomg


It sounds like you are experiencing tachachardia :redface: lol

Same I'm so scared ... I can't concentrate - I just keep daydreaming :frown:
Deep breaths work for me - 5in hold 3 secs out 5 secs - try it :smile:
Reply 1088
Original post by tsr1
is action potential and potential difference the same thing? or action potential only occurs in at synapse? is can someone help me please thanks!


An impulse is a wave of action potentials down an axon. Potential difference is the charge across a membrane due to the movement of ions (in this context). Basically, a change in potential difference is what causes an action potential to be generated.
Reply 1089
Original post by Nathan@
Thx but isnt the second question too much off our spec, well yes a couple of points we should know, but isnt that a liitle too much detail


I agree. Some people go manic on the tiniest details that aren't even mentioned in the textbook. Makes me laugh sometimes, they spent so much effort learning something they don't need to.
Reply 1090
Original post by Mjwilson1988
I'm taking Chem 5 on Wednesday, that one isn't as frightening as Bio 5 though!

Also, in reply to your question, did you mean the production of Drugs by using GMOs (Plants, Microorganisms and Animals)?



Animals:

Genes coding for the desired protein are injected into a fertilised animal egg and this egg is implanted, so that the egg is carried to term and the animal produced has a genome coding for this protein.



Embryo - not egg. :smile:
Original post by iwantopas19
U asked a nice quesion related to the article, now i cant find it. can u please repost it? and did u get the answer?


Noone replied. I asked why the cells that were altered to contain cancer-causing genes were inserted into mice that had their immune systems compromised.
Reply 1092
Original post by Ziggy_72
Embryo - not egg. :smile:


Actually, i belive egg is fine since cgp book says Fertilised animal egg cell
Reply 1093
I don't know why but I don't feel no fear for exams.
Original post by I Hate Edexcel
Noone replied. I asked why the cells that were altered to contain cancer-causing genes were inserted into mice that had their immune systems compromised.


The mice will have had their immune systems compromised because in this situation you're trying to alter the DNA of the Mouse cells using the Vector of bacteria (? I'm assuming bacteria as you say you're using cells?) or virus. These things will be recognised by the immune system as Non-Self, and this will promote an immune response, thus causing the destruction (Phagocytosis etc) of the Vector. Suppressing the immune systems makes it more likely that the Vector will infect the desired cells.
Reply 1095
@Mjwilson1988

- if you think Bio 5 is scarier than Chem 5 you need your head checked!
Original post by Zahra333
Hey guys.

Ok I know this is very common, and everyone feels the same but literally I am terrified for tomorrow's exam. I am not exaggerating one bit but my heart is beating extremely fast and i'm getting really bad pain around my heart area LOOL . I do the same in the exam. I panic and I try really hard to brace myself. any tips on how to stop this? I get a lot of prep talks from friends and family but I'm worried that what i've done isn't enough. :frown: omgomgomg




lissen to opppaa gangam style :smile:
haha, stay cool, all the best!
Reply 1097
Original post by thegreenchildren
Yes I saw that one and it is helpful so thank you :smile:
However I was wondering about where the chemoreceptors are for the heart rate control and the breathing rate control :/


Breathing rate is controlled by:

1. Chemoreceptors in aortic and carotid bodies for low pH
2. The cerebrum (deciding to pant or hold your breath)
3. The stretch receptors in the lungs telling you when the are full - so stop inhaling now and let the exhale begin.
Reply 1098
Original post by Mjwilson1988
The mice will have had their immune systems compromised because in this situation you're trying to alter the DNA of the Mouse cells using the Vector of bacteria (? I'm assuming bacteria as you say you're using cells?) or virus. These things will be recognised by the immune system as Non-Self, and this will promote an immune response, thus causing the destruction (Phagocytosis etc) of the Vector. Suppressing the immune systems makes it more likely that the Vector will infect the desired cells.


Out of curiousity, will that suffice a 3 marker, anything else one could add?
Original post by Mjwilson1988
The mice will have had their immune systems compromised because in this situation you're trying to alter the DNA of the Mouse cells using the Vector of bacteria (? I'm assuming bacteria as you say you're using cells?) or virus. These things will be recognised by the immune system as Non-Self, and this will promote an immune response, thus causing the destruction (Phagocytosis etc) of the Vector. Suppressing the immune systems makes it more likely that the Vector will infect the desired cells.



this is what i thot too.

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