AQA AS Biology Unit 2 - 1 June 2015

Then I'm 100% baffled. In a past paper it pointed to the cross section of a root and asked you to label the features. It pointed to what i thought was the endodermis yet the mark scheme specifically said "reject Endodermis" and only accept endothelium. So i went back into my book and looked at the exact same diagram with the exact same labeling and they called it endodermis too. Ugh.

Hahaha I am generally worried now

What is a genetic bottleneck and founder's effect?

Ahaha I'm incredibly worried too ;(.
Dont worry-you'll be okay. Just take your time reading every question properly and just be positive bc you can totally do it aha!


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What would you write for selective breeding if it was a 6 marker?

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Selective breeding is the deliberate breeding breeding of animals and plants with desired characteristics /traits in order to perpetuate certain characteristics/or eliminate others.
Advantages
It produces high yielding animals and plants.
Animals and plants can be bred to have increased tolerance of bad conditions.

It can be used.to produce animals that have increased resistance to disease, so less antibiotics and pesticides have to be used.
Disadvantages
It can cause health problems.
It reduces genetic diversity,which results in increased incidence of genetic disease and increased susceptibility to new diseases because of a smaller gene pool and higher allele frequency of any mutated gene responsible for a genetic illness.

What paper was that?

When does crossing-over occur? Metaphase 1?

can explain what they would write for a 6 marker on osmotic lysis

At the moment i am doing the june 2012 and actually quite enjoying it hope the paper is nice like this one!

Heres my effort:

* Antibiotic inhibit synthesis of peptide cross linkage in cell walls
* preventing them from making cell walls
* which weakens the cell walls and cant withstand pressure
* so they are unable to prevent water entering
* they would burst- osmotic lysis

can only think of 5 main points and I dont think they will ask this for 6 marks, maybe they will add another part to the questions like how antibiotics dont work for certain bacteria in which case, youll have more to write about

Heres my effort:

* Antibiotic inhibit synthesis of peptide cross linkage in cell walls
* preventing them from making cell walls
* which weakens the cell walls and cant withstand pressure
* so they are unable to prevent water entering
* they would burst- osmotic lysis

can only think of 5 main points and I dont think they will ask this for 6 marks, maybe they will add another part to the questions like how antibiotics dont work for certain bacteria in which case, youll have more to write about

thank u so much

Ahh- well that's great ahah!- I might try it out if I have time. Hopefully you'll find it to be the same way, yes.

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PLEASE CAN SOMEONE EXPLAIN Q A??

THE ANSWER IS 'X IS BETWEEN ZYGOTE AND SPORES' bUT I THOUGHT IT WAS BEFORE GAMETE