AQA BIOL2 Biology Unit 2 Exam - 26th May 2011

How can a mutation cause cancer to develop?

I was waiting for this thread

Have some note babes:

http://www.mediafire.com/?sunk9g8vdowk5ds

Mitosis - phases
Genetic Comparisons: DNA and proteins
Biodiversity
Antibiotics: mechanism +resistance
Starch, Glycogen, Cellulose
Haemoglobin (basic)
Courtship behaviour - why is it necessary?


Directly from NT aqa textbook, everything we need to know for those topics

So vertical gene transmission does not involve conjugation? Makes sense, the textbook doesn't really specify though.

I actually don't know the answer to this.
Care to share?

Hmm
Do you use the NT book?
If so, it doesn't specify in that either!

And for the Cancer, i think it's about the mutation as in the development of abnormal cells, effecting the cell cycle, making it an 'uncontrollable growth' or something.

Explain step of Mitosis in very specific detail (8 Marks) Ill answer this later

Try and answer these questions as if in an exam, some of the previous answers look as though they are directly copied from the textbook

Cheers and please quote any answers

So vertical gene transmission does not involve conjugation? Makes sense, the textbook doesn't really specify though.

anyone got the AQA AS Biology Unit 2 18th January 2011 markscheme?

"Explain why the increased use of antibiotics leads to strains of bacteria resistant to multiple antibiotics."

Antibiotic kill the bacteria which doesnt have the resistance gene
bacteria which survive has resistance gene these survive and replicate passing on their R plasmid (vertical gene transmission)
R plasmid can be passed on by horizontal gene transmission to bacteria which doesnt have the R plasmid by conjugation.

Explain "the formation of tissue fluid and its return to the circulatory system" ( much detail as possible)

Tissue fluid bathes the tissue cells outside the capillaries. Tissue fluid is forced out of capillaries due to high hydrostatic pressure at the arteriole end of the capillaries. Plasma proteins are too large to pass through the capillary wall, thus their concentration increases in the capillaries. Tissue fluid moves back into the capillary due to osmosis, as the WP gradient in the capillaries is lower than that outside. The hydrostatic pressure at the venule end of capillaries also forces tissue fluid back in. The tissue fluid that cannot be returned directly is returned to a vein via the lymph vessels, which carry the fluid when muscles contract and squeeze them.


What are the three components of biodiversity and what do they each mean?

Ecosystem diverity - range of different habitats
genetic diversity - variety of different genes possessed by individuals that make up any species
Species diversity - number of different species and the number of individuals of each species within a community


Explain the gas exchange system in fish and how maximum exchange is possible (6)

Water enters through the mouth and is forced over the gills. The rate of diffusion of O2 from the water into the blood is increased due to numerous gill filaments and numerous gill lamellae. The gill lamellae have a single thin epithelium cell, so diffusion pathway is short. Conc gradient is maintained by the constant introduction of water with a high O2 concentration, and the constant removal of blood with a high O2 conc. Countercurrent flow, in which the conc of O2 is always higher in the water than in the waters equivalent section of blood, allows diffusion gradient to be maintained over the entire length of the gill.

Describe the structure of haemoglobin

Tissue fluid bathes the tissue cells outside the capillaries. Tissue fluid is forced out of capillaries due to high hydrostatic pressure at the arteriole end of the capillaries. Plasma proteins are too large to pass through the capillary wall, thus their concentration increases in the capillaries. Tissue fluid moves back into the capillary due to osmosis, as the WP gradient in the capillaries is lower than that outside. The hydrostatic pressure at the venule end of capillaries also forces tissue fluid back in. The tissue fluid that cannot be returned directly is returned to a vein via the lymph vessels, which carry the fluid when muscles contract and squeeze them.


What are the three components of biodiversity and what do they each mean?

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How is the structure of cellulose related to its function in cell walls?

Are you guys sitting unit 1 aswell?

I was waiting for this thread

Have some note babes:

http://www.mediafire.com/?sunk9g8vdowk5ds

Mitosis - phases
Genetic Comparisons: DNA and proteins
Biodiversity
Antibiotics: mechanism +resistance
Starch, Glycogen, Cellulose
Haemoglobin (basic)
Courtship behaviour - why is it necessary?


Directly from NT aqa textbook, everything we need to know for those topics