I always thought diffusion was from high concentration to low concentration?
Is the first answer D? And I got confused at the second one aswel, I think it is because the other 2 are active transport. Or maybe diffusion has taken place from high to low until the concentrations have became equal? .. Not too sure
my teacher predicted: Unit1-Transcription/translation -Phogocytosis -Respiration Unit2-Mutation -Extinction/conservation -Coping with danger Unit3-Effect of light in growth -Water regulation -Monitoring population/density dependent and independent factors
These have all been essays in the past few years. Doubt they'll be essays again but will definitely come up in sections A & B
Is this true? I've never been told you can do that and I'm scared get penalised for it. Also, can you write essays in bullet points?
Yeah, most definitely, you can write all four if you have time and aren't sure which one you'd get most for You can only write the Write notes on....... questions. DO NOT write the Relevance and Coherance essays in bullet points, unless you want to lose the 2 marks fof relevance and coherance
I always thought diffusion was from high concentration to low concentration?
The first is D I think, because insecicides and herbicides would get rid of the loss of yield from insects and weeds, and the column in D has the most combined loss of yield from insects and weeds - 21 units. You can't just look at column height because that include loss due to disease too which won't be reduced.
For the second question, although you're right and diffusion does happen from a high to low concentration, the end result of diffusion is equal concentrations of a substance on either side because if there are any small fluctuations, the sides are made equal again as the side with more has some diffuse to the side with less. So yes, the answer is chloride.
I think it's because each parent passes on a characteristic on the X chromosome so the father would pass on the only one he has: the colour deficient gene and the mum would pass on a normal gene. The mother's is dominant so it will mask the fathers recessive gene and so the daughter will only be a carrier. If it was a son that was given the colour deficient gene he would be unable to mask it :P does that make sense?
I think it's because each parent passes on a characteristic on the X chromosome so the father would pass on the only one he has: the colour deficient gene and the mum would pass on a normal gene. The mother's is dominant so it will mask the fathers recessive gene and so the daughter will only be a carrier. If it was a son that was given the colour deficient gene he would be unable to mask it :P does that make sense?
Anyone able to explain why 2007 Section A qn 12 is B? I should know it, but my head's just gone completely
The mother is unaffected, so no matter what X chromosome she passes down, it will be recessive. The father passes the effected X to his daughter and the Y (which is neither effected nor unaffected as it is sex linked) to his son. The son can therefore never be effected & never be a carrier. However the daughter will be as she has to receive an affected X from her dad & unaffected from her mum. Daughter = carrier
I really bad at explaining things, I know. But hope it helped in some way
The mother is unaffected, so no matter what X chromosome she passes down, it will be recessive. The father passes the effected X to his daughter and the Y (which is neither effected nor unaffected as it is sex linked) to his son. The son can therefore never be effected & never be a carrier. However the daughter will be as she has to receive an affected X from her dad & unaffected from her mum. Daughter = carrier
I really bad at explaining things, I know. But hope it helped in some way
Anyone able to explain why 2007 Section A qn 12 is B? I should know it, but my head's just gone completely
It says in the question that photoperiodism allows plants to flower at the same time. This means that there will be a greater chance of a plant being able to sexually reproduce over asexual reproduction. This will provide genetic variation.
I kow, same :/ because last years paper wasn't too bad, so it'll get worse this year. Plus every other exam I've had so far has been so much harder than expected. But we can always hope biology will be better I suppose haha!
I have a quick question, For question 5e (Section B) on the 2009 paper... I'm absolutley clueless :P I know that they get bigger, but I don't see from the graph why?