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safis
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#3921
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#3921
(Original post by Tasha_11)
I have a question I've just been doing the specimen paper for biology and stuck on a question about action potentials. I thought that when an action potential is started, sodium ions move into the neurone and potassium to move out, in the mark scheme though it says that sodium ions move out and potassium in. This has really confused me so I would appreciate if anyone could help. Thanks


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Ignore specimen paper. Action potential arrives sodium ion channels open sodium ions enter depolarisation.

Specimen is weird.
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LitGeek94
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#3922
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#3922
(Original post by FuddyMucker)
Dont think there would be enough topics from 3 of the units, i can only think of diffusion and neurotransmission
You can also write about nitrogen cycle/ calcium ions and muscle contraction/ photosynthesis and hydrogen
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Mesutozil
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#3923
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#3923
3.5.4 of spec

'the second messenger model of adrenaline and glucagon action'

I know about adrenaline.. what is it about glucagon though?
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F1's Finest
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#3924
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#3924
(Original post by Dorkins)
Before:
----------

Partial:
----------
-----
---
--


After:
-----
---
--


The restriction enzyme action takes time, so a partially digested solution will contain a bit of everything (even strands of completely untouched DNA)
Oh I see, so when you're putting the pieces back together, you use gel electrophoresis to determine the size of the fragments and hence you won't find long fragments like this:

----------

??

I get it now, haha.
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_jamie
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#3925
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#3925
(Original post by FuddyMucker)
Dont think there would be enough topics from 3 of the units, i can only think of diffusion and neurotransmission
There is quite a few:
Na+/K+ in nerve impulse
Na+ in the transmission across a synapse
Ca2+ in the transmission across a synapse
Ca2+ in Muscle contraction
H+ in Hydrolysis in the light dependant reaction and its importance in the formation of co-enzymes such as NADPH and FADH2 in respiration and also it's importance in the electron transport chain
Ammonium, Nitrites and Nitrates within the Nitrogen cycle are also ions
Could discuss Cholera and perhaps Cystic fibrosis and how normal functioning of ion channels is important for an organism
Co-transport of glucose
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Opasniipocik
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#3926
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#3926
Remeber that when we touch something really hot , we take away our fingy from it without actually thinking , its like a reflex !!!
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samfreak
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#3927
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#3927
can someone please help me on the topics to write about in the following essays?

how the structures of different polymers are related to their functions?
transfers through ecosystems?
energy transfers which take place in living organisms
condensation and hydrolysis and their importance in biology?


thanks in advance :-)

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Scienceisgood
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#3928
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#3928
I am getting annoyed with AQA now and their constant examinations of rectums! Seriously, have they nothing better to look at other than a rat's ass?!
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Mocking_bird
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#3929
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#3929
Is it just me or is June 2011 horrible?
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rommy123
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#3930
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#3930
Really dont know which essays to actually make plans on, and prepare for HELP :confused:
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_jamie
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#3931
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#3931
Just remember that you don't actually need anything that is considered outside the specification to score well on the essay you only need it to score 25/25. You can still get 23/25 without mentioning anything from outside the A level specification.
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gingerandice
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#3932
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#3932
(Original post by Mocking_bird)
Is it just me or is June 2011 horrible?
it is horrible!!!
1
Mocking_bird
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#3933
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#3933
(Original post by gingerandice)
it is horrible!!!
Ok good! Its making me feel completely unprepared!
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stoppy123
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#3934
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#3934
Simple reflex arc:

Stimulus
Receptor
Sensory neurone to CNS
Motor neurone, from CNS
effector
Reponse
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gingerandice
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#3935
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#3935
(Original post by Scienceisgood)
I am getting annoyed with AQA now and their constant examinations of rectums! Seriously, have they nothing better to look at other than a rat's ass?!
LOOOOOOOOOOOOOOOOOOOOOOOOOOL, fluctuations less with changes in the external environment, and the other thing the *******s want us to say it that its not exposed to the external environment.
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FuddyMucker
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#3936
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#3936
(Original post by _jamie)
There is quite a few:
Na+/K+ in nerve impulse
Na+ in the transmission across a synapse
Ca2+ in the transmission across a synapse
Ca2+ in Muscle contraction
H+ in Hydrolysis in the light dependant reaction and its importance in the formation of co-enzymes such as NADPH and FADH2 in respiration and also it's importance in the electron transport chain
Ammonium, Nitrites and Nitrates within the Nitrogen cycle are also ions
Could discuss Cholera and perhaps Cystic fibrosis and how normal functioning of ion channels is important for an organism
Co-transport of glucose
Some of them are stretching it to fit them in, and most are from the same units... i think thats pushing it
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DELETED ACCOUNT
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#3937
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#3937
(Original post by Opasniipocik)
Remeber that when we touch something really hot , we take away our fingy from it without actually thinking , its like a reflex !!!
Yep
stimulus-->receptor----> sensory neurone-----> relay/intermediate neurone in spinal cord------> motor neurone-----> effector----> reponse

The response would be taking away our finger from it without actually thinking.
Why is this reflex arc important in us humans? (1mark)
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gingerandice
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#3938
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#3938
(Original post by Mocking_bird)
Ok good! Its making me feel completely unprepared!
hopefully it will be more like june12 and actually have bio 5 questions!
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Scienceisgood
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#3939
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#3939
(Original post by gingerandice)
LOOOOOOOOOOOOOOOOOOOOOOOOOOL, fluctuations less with changes in the external environment, and the other thing the *******s want us to say it that its not exposed to the external environment.
You call it science, I call it pervy scientists just like they were looking at snakes getting it on for unit 2...
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Anaiza
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#3940
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#3940
These essay plans were posted quite a while back, thought id post them if somebody hasn't seen them:


How the structure of cells is related to their function.
· Prokaryotic bacteria specialised to cause disease and resist antibodies
· White blood cells to kill bacteria
· Alpha and Beta cells and glucose regulation
· Nerve cells to transport action potentials
· Any cell with many mitochondria: Link reaction, Krebs cycle and Electron transport chain
· Epithelial cells for diffusion
· Microvilli in the intestine for absorption
· Red blood cells contain haemoglobin and large surface area
· Muscle cells, actin and myosin for muscle contraction
· Rod and cone cells
· Xylem and phloem in cohesive tension theory

The control of living organisms and control within living organisms.
· Thermoregulation
· Heart rate
· Oestrogen cycles
· Glucose regulation
· Synapses and muscle contraction
· Antibodies
· Absorption of starch
· Diffusion and affinity of haemoglobin
· Tropisms
· Biological and chemical controls of population

Negative Feedback and its importance in biology.
· Return to normal levels
· Thermoregulation
· Heart rate
· The oestrus cycle
· Glucose regulation
· Population control
· Control of ventilation
· Metabolic pathways

The different ways in which organisms use ATP.
· Respiration - Glycolysis
· Photosynthesis – GP to TP
· Muscle contraction
· Protein carriers and active transport
· Cell division
· Energy transfer in the food chain

Inorganic ions include those of sodium, phosphorus and hydrogen. Describe how these and other inorganic ions are used in living organism.
· Nerve impulses (sodium/potassium ions in action potential)
· Fertilisers
· ATP created by phosphorus
· Absorption in the small intestine
· Nitrogen cycle (nitrates and ammonium ions)

The movement of substances within living organisms / transport systems within living organisms
· Protein transport out of cells
· Digestion and absorption
· Haemoglobin – the blood system – the heart
· Gas exchange in lungs
· Nerve system – Pacinian corpuscle
· Diffusion
· Plants (transpiration) cohesion tension theory

Enzymes and their importance in plants and animals
· Structure:
· Polypeptide chain of hydrogen, carbon, oxygen and nitrogen
· Catalysts that lower activation energy
· DNA Polymerase and DNA Helicase
· Amylase, Maltase, Lactase, Sucrase
· RNA Polymerase
· Restriction Endonuclease
· Reverse transcriptase
· DNA ligase
· Effect of competitive and non-competitive inhibition
· Enzymes and the breakdown of ATP
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