As biology unit 1 21/5/2014 panic thread

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hii!!

can anyone please summarise the enzyme & rate of reaction experiment!

Caffeine affects the heart rate because its a stimulant. Caffeine stimulates receptors located in cells within the heart which results in an increased heart rate

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Reply 182

myrmeco12

Enzyme & Rate of reaction experiment:

1. Use range of substrate concentrations i.e; 0.1, 0.2, 0.3...(same volume).
2. Mix enzymes with substrate conc to form enzyme/substrate complex.
3. Make sure to there is a suitable temp and pH (kept the same).
4. Measure initial rate of reaction for specific time period, say 1 min.
5. Repeat experiment without enzyme to compare and contrast, also serves as a control.
6. Series of repeats to discount and discard any anomalous results and to be able to take an average.

I think that's pretty much it, however, do link the answer specifically to the question as this is just a general answer :smile:

Hope this helps!

Reply 183

La231

please can someone explain CF and how the CFTR channel not working effects water in mucus, and does water leave mucus via osmosis?

Reply 184

Tahera2013

Original post by haappy17

I don't think this is in the specification! Is it? Because I don't really understand it either!

My lousy teacher was mumbling about it. So this is what i have down. Think its off CGP.

So we know that oxygen binds to Haemoglobin forming oxyhaemoglobin, (HB + 4O2 (reversible reaction arrows) HBO8

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Haemoglobin Saturation depends on the partial pressure of O2 (PO2)

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PO2 Is a measure of of Oxygen concentration

The greater the concentration of dissolved oxygen in cells the higher the partial pressure :smile:

I could continue to go more indepth about HB's affinity but I'll focus on the actual curve.

Sorry about the diagram,

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the Y axis: When the curve is on 100% saturation thats how you know 4 haemoglobins have bound to the O2 and is carrying all 4. When its at 0% it's carrying none.

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the x axis: Where Partial pressure of O2 (PO2) is high (in the lungs) haemoglobin has a high affinity for O2 so have high saturation. Thats why it picks up all 4. When PO2 is low HB has low affinity for 02 thats why none are picked up.

The Graph is S shaped because when the HB combines with the O2 molecule the shape alters in a way that makes it easier for other molecules to join too.
AS HB becomes more saturated it gets harder for o2 molecules to join so thats why in the middle of the diagram or the middle of the S is steep so its easier for the o2 molecules to join. The shallow bits the ends of the s are harder to join to.

Reply 185

fictioned

I got it!
Thank you :3

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Reply 186

Fattyma97

Good luck everyone :smile:

))

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Reply 187

Katiekatie1

How you have you guys measured reaction rate for enzyme conc core practical? Not using hydrogen peroxide? Ahh

Reply 188

Lorri97

Done the exam. Went well I must say :smile:

Reply 189

fictioned

It did.
Actually.

Guys, please no discussion on here, or else the grade boundary will only go up

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Reply 190

Lorri97

Yeah lol we dont want them to be higher than they already will be xD

Reply 191

MissBCM17

Original post by Lorri97

Yeah lol we dont want them to be higher than they already will be xD

Hello guys! It was an okay paper, not very hard!! Will anyone post a mark scheme tomorrow ? :smile:

Reply 192

Fattyma97

It was good but please lock this thread till tomorrow!. Did anyone leave a question because of time issue not gonna say which one though...

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