[TheBlueNowhere]

(Original post by Picture~Perfect)
I'm planning out an essay 'The ways in which organisms use ATP'
Would it be relevant to discuss in detail the ways in which ATP is synthesised? As in the photophosphorylation of ATP during photosynthesis and the production of ATP during respiration.

You could mention that ATP form photophosphorylation is used in the calvin cycle and for respiration how ATP is used in glycolysis but I wouldn't get too sidetracked on the synthesis as there are only those two uses really.

[sam_23]

(Original post by jessplease)
Oh if only, but the fact she predicted last years, is pretty amazing aha. Did she mention any others that could come up?

Not that I remember. I'm on study leave so I havent been at school to ask if there are any other predictions.

[sam_23]

(Original post by jessplease)
Thanks! I wonder how sure she is, because its quite hard to predict really, do you have any idea how she predicted last year, or was it just a guess? i hope shes right aha

Yeah it was a guess. There's no way they can get access to the papers and if they do they'll be screwed over by AQA

[Akbar2k7]

(Original post by James A)
cool! i have family in reading so i could visit them too, it's pretty handy.

And of course, its only 20 minutes by train into Paddington station which is real handy.

Oh, i see you live in Walthamstow, im not too far from you.... i live in enfield

Nice!

[EffKayy]

(Original post by ecokid)
Did you get your biol4 paper remarked and did you get the script back? I only need a B in Biology, but I know my EMPAs will drag me down.

I found task 3 of the EMPA awful

[ashleyp]

im seeing comments like 2 marks for each paragraph for the essay, can someone please explain this?! i understand its 16/25 for scientific content..

[Granger]

im confused, is pre RNA the same as mRNA? Or is it something else?

[Bright.Inspiration.]

(Original post by Granger)
im confused, is pre RNA the same as mRNA? Or is it something else?

Pre-mRNA contains introns (non-coding DNA)
but splicing takes place to remove the introns and make mRNA, which is then translated

[Granger]

(Original post by Bright.Inspiration.)
Pre-mRNA contains introns (non-coding DNA)
but splicing takes place to remove the introns and make mRNA, which is then translated

oh really thanks

[JJMick]

(Original post by EffKayy)
I found task 3 of the EMPA awful

I much prefer ISAs, I managed to get 46/50 in both unit 3 and unit 6

[BodybuildinPassion]

Can someone explain cone cells and rod cells? dont know how much of it to learn, Thanks

[ChocolatePearl]

(Original post by BodybuildinPassion)
Can someone explain cone cells and rod cells? dont know how much of it to learn, Thanks

In a nutshell.
Rods and Cones are photo-receptors found in the eyes. Your eyes contain circa. 120million Rods that enable you to see black and white images. Cones enable you to see colours and are found concentrated in the fovea. You only have around 6-7million Cones. You can't see colour at night because unlike Rods, Cones are not as sensitive to light and only 'work' with bright light.

These are some of the marking points you need according to AQA,
Rods and cones

• no rods at blind spot or fovea;
• greater distribution of rods at edge
• rods have high sensitivity / show retinal convergence /summation occurs with rods / converse
• for cones;
• rhodopsin .bleached. at low light intensities / iodopsin .bleached at high light intensities;
• higher frequency of rods;
• better vision in dim light;
• lower visual acuity;

Hope it helped!

[JJMick]

(Original post by BodybuildinPassion)
Can someone explain cone cells and rod cells? dont know how much of it to learn, Thanks

Rod cells

• Exhibit high sensitivity due to the fact that many rod cells are attached to one neurone - spatial summation occurs so small generator potentials combine to reach the threshold value and create an action potential.

• because many rod cells are attached to one neurone two different spots of light close to each other cannot be distinguished as only one impulse is sent to brain.

• are spread evenly round more towards the edges of the retina.

Cone cells

• Have high visual acuity as each cone cell is attached to one neurone so different close light spots have separate impulses

• Have low sensitivity as no summation occurs

• Are concentrated at the fovea

[JJMick]

(Original post by ChocolatePearl)
In a nutshell.
Rods and Cones are photo-receptors found in the eyes. Your eyes contain circa. 120million Rods that enable you to see black and white images. Cones enable you to see colours and are found concentrated in the fovea. You only have around 6-7million Cones. You can't see colour at night because unlike Rods, Cones are not as sensitive to light and only 'work' with bright light.

These are some of the marking points you need according to AQA,
Rods and cones

• no rods at blind spot or fovea;
• greater distribution of rods at edge
• rods have high sensitivity / show retinal convergence /summation occurs with rods / converse
• for cones;
• rhodopsin .bleached. at low light intensities / iodopsin .bleached at high light intensities;
• higher frequency of rods;
• better vision in dim light;
• lower visual acuity;

Hope it helped!

Beat me to it, but I don't think we need to know the names of the specific pigments do we?

[ChocolatePearl]

(Original post by JJMick)
Beat me to it, but I don't think we need to know the names of the specific pigments do we?

Its in the markscheme and my teacher mentioned it quite a few times, so yup sadly we do

[TheBlueNowhere]

(Original post by ChocolatePearl)
Its in the markscheme and my teacher mentioned it quite a few times, so yup sadly we do

Which mark scheme? Pretty sure we don't have to know the names of pigments.

[ChocolatePearl]

(Original post by TheBlueNowhere)
Which mark scheme? Pretty sure we don't have to know the names of pigments.

Ahh, whoops! Old spec

[umair.khan]

(Original post by JJMick)
Beat me to it, but I don't think we need to know the names of the specific pigments do we?

It could only help you get marks if you learn the names of the pigments, especially for the essay

[handsome7654]

(Original post by JJMick)
Rod cells

• Exhibit high sensitivity due to the fact that many rod cells are attached to one neurone - spatial summation occurs so small generator potentials combine to reach the threshold value and create an action potential.

• because many rod cells are attached to one neurone two different spots of light close to each other cannot be distinguished as only one impulse is sent to brain.

• are spread evenly round more towards the edges of the retina.

Cone cells

• Have high visual acuity as each cone cell is attached to one neurone so different close light spots have separate impulses

• Have low sensitivity as no summation occurs

• Are concentrated at the fovea

Doesn't temporal summation occurs with cones??

[handsome7654]

(Original post by BodybuildinPassion)
Few questions for the biology wizards, who gets A's/A*

Can someone tell me the marking points for transcription/translation?

Can someone also clarify the role of RNA polymerase in transcription, does it form hydrogen bonds between the RNA nucleotides bases and the exposed bases or does it join the nucleotides together to form pre mRNA single strand?

And in translation, does ribosome join at one end of the mRNA then do complementary tRNA molecules attach? Help appreciated

What do you mean marking points? Do you mean like the starting points? Or the end post transcriptional and translational modification?

RNA forms phosphodiester bonds between a phosphate group and pentose sugars and joins the nucleotides together.

A ribosome attaches to the mRNA at an initiation codon (typically AUG). It doesn't have to be in the end, it may be somewhere within the sequence.
Then tRNA anticodon attaches to the first mRNA codon by complementary base pairing

Btw I'm not a biology wizard or anything so if anyone can correct any mistakes or fill the gaps in my knowledge I would really appreciate, thankyou!