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Author Topic: Edexcel BIOLOGY Doubts!!!!  (Read 132278 times)

Offline ksitna

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #15 on: May 10, 2010, 04:12:40 pm »
HEY UM WHAT ARE DEPENDENT AND INDEPENDENT VARIABLES AGAIN?
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Offline Assi1993

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #16 on: May 10, 2010, 04:25:52 pm »
the dependent variable is the one you get as a result from your experiment.. on the y axis
the independent variable is the one u can control.. on the x axis
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Offline Tammy

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #17 on: May 10, 2010, 07:28:32 pm »
Quote from: Summer :] on May 09, 2010, 05:19:30 pm
All the practicals in unit 1 and 2
-daphnia's experiment
-cell permeability experiment
-vitamin c experiment
-enzyme controlled reactions experiments
-root tip squash experiment (observing mitosis)
-investigating totipotency in plants (tissue culture)
-mineral ions deficiency experiment
-antimicorbial properties of plants experiment
- plant fibres experiment
thats all
and some background of some unit 1 information such as CVDS and their risks, Genetic diseases (like CF) and genetic diagrams, what else..
genetic screening
(scan through)
for unit 2, basically you're taking the exam now in june so you know the information/facts there..

Yeah thanks.... I almost did that... and I just read through the information in unit 1 & 2....

Good Luck tomorrow everyone... Hope the second question is an easy one!!!!!!!!!!  ;D
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Offline Blizz_rb93

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #18 on: May 10, 2010, 08:06:06 pm »
Quote from: Assi1993 on May 10, 2010, 03:30:40 pm
Suggest why Daphnia needs a heart and circulatory system
I think so it can be able to pump the blood around the circulatory system so the person testing on daphnia will be able to observe the heart beats
basically i guess with the heart as a pump and the circulatory system as a transportation for the blood

im not 100% accurate but i think it's something like that, if not plz someone correct me :)
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Offline Uchia

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #19 on: May 10, 2010, 08:54:58 pm »
daphnia needs a heart system because it has a low surface area to volume ratio and diffusion it self wouldn't be effective to transport substances inside and outside so a heart system is needed to make susbtances as near as possible to diffuse this is done by the fluid transported through the body (transport medium which is the blood) with the help of the heart a transporter
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Offline Blizz_rb93

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #20 on: May 10, 2010, 09:11:52 pm »
Here's a question I got on Beetroot...
This question is from May/June 2009

Question 1. a) iii)
The dependent variable in this experiment is the degree of redness. Describe how the degree of redness could be measured.



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Offline Uchia

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #21 on: May 10, 2010, 09:14:19 pm »
use a colorimeter
use a pipetter to measure a certain amount of water usually a 1 cm cube
mark the absorbance as 0 to the water
calculate the absorbance of the dye by the solution
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Offline Blizz_rb93

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #22 on: May 10, 2010, 09:19:58 pm »
Quote from: damlaj on May 10, 2010, 09:14:19 pm
use a colorimeter
use a pipetter to measure a certain amount of water usually a 1 cm cube
mark the absorbance as 0 to the water
calculate the absorbance of the dye by the solution
thank you man! :) rep for u
i cant wait for tomorrow!! tomorrow is the unit 3 external lol
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Offline ksitna

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #23 on: May 10, 2010, 09:34:56 pm »
Quote from: Psyclax on May 10, 2010, 09:19:58 pm
thank you man! :) rep for u
i cant wait for tomorrow!! tomorrow is the unit 3 external lol

u cant wait???? dude im freaking out!!! :o
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Offline Blizz_rb93

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #24 on: May 10, 2010, 09:44:20 pm »
Quote from: ksitna on May 10, 2010, 09:34:56 pm
u cant wait???? dude im freaking out!!! :o
lol yeah i wanna do good!! ive been studying so hard and i feel like im ready to ace that exam :D besides 20 minutes left for it to be tomorrow :p
so yeah i wanna finish with this and get it over with
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Offline Blizz_rb93

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #25 on: May 10, 2010, 09:48:08 pm »
How does High temperatures affect the beetroot's membrane permeability?? i know how low temperatures affect but i just dont know how to put the one for high temperatures in a acceptable form lol
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Offline ksitna

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #26 on: May 10, 2010, 09:51:48 pm »
the higher the temp the more pigment comes out
except for zero, i dunno why tho
yep and at 70 degrees the pigment is destroyed or all the pigment has gone out aand not a lot left so a very small amount of pigment comes out

correct me if im wrong tho :/


and tell mee Psyclax
what did u study
like just the core practicals?
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Offline Uchia

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #27 on: May 10, 2010, 10:37:33 pm »
higher temperatur more kientic energy cells might get damaged more allowing more dye pigment to move/leak out and as there is high temperature the membrane becomes more permeable so more dye will move at a specific amount of time

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Offline Uchia

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #28 on: May 10, 2010, 10:39:42 pm »
and right at 0 it could be a control for comparison no kienitic energy so less cells will get damaged resulting in no dye leaking out good luck for both of us. God help us to get aces
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Offline Blizz_rb93

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Re: Edexcel BIOLOGY Doubts!!!!
« Reply #29 on: May 11, 2010, 03:09:20 am »
so far all good, i studied alot..
yeah i studied all the practicals and i answered alot of questions on each
so inshaallah i do good =)
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