Edexcel BIOLOGY Doubts!!!!

[hissyfit]

Samia 99 on The student Room made this,just wanted to share it with others as an example...


Cut Equal sized pieces of tissue Then rinse under water 2 remove all the pigment released by cutting .Place the pieces in Equal volumes of Distilled water using a range Of Temp & leaving for Equal time
Remove pieces carefully & shake each solution gently 2 disperse any pigment. Assess amount of pigment lost using a colorimeter 2 measure da absorbance/transmission value of Solution & FINALLy plot Results on graph . Temp on x-axis & Absorbance on y ...


Effect of temperature on cell membrane (beetroot)Control-using different temperatures

Organism- using the same beetroot,with the same surface area for all temperatures

Repeat-experiment repeated twice+average taken

Measure-measuring pigment leakage(arbitrary units) over time (mins) @ diff. temperatures (degress celcius).

Same-keeping temp as constant as possible.

If there are any mistakes please post.
Thanks

[hissyfit]

How can a mutation in a gene switch cause anatomy to evolve,without the gene changing?
I don t get this, if there is a change in the gene switch the gene won t be transcribed normally,so the gene will change,no?

[sasha7amad]

Can we discuss the practical 3b yet?

[The Golden Girl =D]

You're NOT allowed to discuss anything unless 24 HOURS have passed.

[Uchia]

if that is the case I would then care for the discussion cz we have to forget about the paper to focus on the other exams

[The Golden Girl =D]

This is one of this site's Rules. You will remember at least the things we have doubt in

[sasha7amad]

lot more than 24 hours have passed
so guys how did you find the unit 3b bio in general?

[Parthenon]

When they ask us to draw the best fit line through the points ... and the points are in the shape of a curve ...

Do we draw a smooth curved line through the points OR do we join consecutive points with individual straight lines?




One more question ...

Jan 2011 Bio3B paper ... Who represented the mineral deficiency table in what graphical form? ... I did a bar graph

[Amelia]

How can a mutation in a gene switch cause anatomy to evolve,without the gene changing?
I don t get this, if there is a change in the gene switch the gene won t be transcribed normally,so the gene will change,no?

A gene switch is a protein (such as a hormone) that switches on or off the expression of one or more genes. A single gene switch can affect the expression of multiple genes.

For example, a switch can control when a gene that produces bone tissue is turned on and off. This switch can make bones longer or shorter without any change to the bone-generating gene at all.

For a more extreme example, in fruit flies, a regulatory protein named 'Ey' can tun on or off the entire set of genes that produces an eye. When expressed in the larvae of fruit flies in the location that goes on to become a leg, the resulting fruit fly ends up with a misplaced eye on its leg.
(Illustration: http://www.ncbi.nlm.nih.gov/books/NBK268… )

[hissyfit]

thanks,it s a bit late as I already sent the homework for the question.It s not on the curriculum(too much detail) anyway.I wrote what I could from my textbook.Sorry,funny about the fruit fly though

[Amelia]

thanks,it s a bit late as I already sent the homework for the question.It s not on the curriculum(too much detail) anyway.I wrote what I could from my textbook.Sorry,funny about the fruit fly though

Better late then never. It took me time to research about the gene switch.

[hissyfit]

sorry about that I should have edited my post/removed it. Hopefully you got something out of this.Sorry

[Amelia]

sorry about that I should have edited my post/removed it. Hopefully you got something out of this.Sorry

Do stop apologizing. 

[Hissa]

I have some few questions from unit 4 (A-level):
- Suggest two enviromental conditions that could increase the rate of oxygen production in plants
- Describe how a forest could be managed sustainably in order to ensure a continual supply of timber for the future
-Name a method by which global sea temperatures can be monitored
-Some recovery in the great barrier reef may be taking place at present. Suggest a possible explanation for this, other than change in sea temperature
-HIV positive people were excluded from the data (ie data about number of new TB cases). If they have been included suggest how the data would differ. Give an explanation to your answer.
-Give one example of physical evidence that could be retained from the original investigation of a crime scene and explain why the sample is suitable for a DNA test to be carried out.

SOrry for being thick, answer what u can if u please thanks alot

[abuelzouz]

hey wt about the quadrat/transect experiment? i knw nothin how 2 do it!