AQA BIOL5 ~ 17th June 2013 ~ A2 Biology

plans and mark schemes for all essays or you narrowed them down?

Oestrous Cycle

-FSH, secreted from pituitary gland, stimulates follicle development

-Oestrogen is released from the follicle and the ovaries

-Oestrogen stimulates the uterus lining to thicken and inhibits FSH

-As Oestrogen concentration increases, it stops inhibiting and stimulates the pituitary gland to secrete LH and FSH (LH surge)

-LH surge causes ovulation where the follicle ruptures and an egg is released

-LH stimulates the follicle to become the corpus luteum

-Progesterone secreted by corpus luteum

-Progesterone maintains the uterus lining and inhibits LH and FSH

If no embryo implants

-Corpus luteum breaks down

-Progesterone no longer released

-FSH concentration increases because it is no longer inhibited by progesterone

-Cycle starts again



Remember you're not a flop at Biology, you're a F.O.L.P.!

Hope this helps!

So sorry to keep repeating myself

but, what have you got for ATP essay plan? Is this enough?

- Produced in Aerobic and Anaerobic respiration.
- Produced in light dependent and independent reactions
- Produced by phosphocreatine ssytem
- Used for Muscle contraction
- Used for active transport
- Used to create second messenger when adrenaline binds
- Used for sodium potassium pump
- Good as it's simple one step reaction
- Can be regenerated
- Does not affect osmotic potential of cell like glucose would.
- Produces energy in managable amounts.

anyone thin chemical co-ordination in animals and plants could come up as an essay? or something like communication between cells, tissues and organs?

Yep.

Maybe talk about the role of ATP on the receptors of the postsynaptic neurone?

You don't need any. This isn't required. That's just extra. I did this exam last year and got 23/25 on the essay without including any off spec topics.

I would say that its used up in photosynthesis to create glucose or other products, Dont know if im right on that tho

Potassium voltage-gated channels are closed during depolarisation, and open during repolarisation (at around +40 mV).

I THINK; can anyone clarify?

Someone else posted there plan to that question, there you are
Use in plants
- Water uptake in roots - apoplastic (cell wall) /symplastic (cytoplasm)
- minerals build up in root due to low water potential
- causes root pressure, evidenced by guttation

- Transpiration - is the loss of water from plant surface due to evaporation
- dependent on water potential in leaf and in air
- transpiration stream is continous flow of water from root to leaf
- Cohesion-Tension (water pulled up by transpiration replaced by more water

- Photosynthesis - water used in photolysis of water, molecule splits into
- H+ ions reduce NADP
- electrons replace electrons lost from PSII in non-cycli phosphorylation
- oxygen released as waste gas

- Xerophytic adaptions - thick waxy cuticle reduces evaporation
- close stomata in daylight to reduce transpiration
- succulent leaves store water
- smaller leaves, reduced SA:V ratio slows diffusion

Reproduction
- sexually reproducing organisms use water to bring male and female gametes together in fertilisation
- in mammals foetus develops in water filled sac which provides thermal and physical stability

Hydrolysis and condensation
- ATP -> ADP + Pi
- restriction endonucleases use hydrolysis
- hydrolysis/condensation reactions of biopolymers (polysaccharides, polypeptides, nucleic acids)

Osmosis
- movement of water molecules from a high water potential to low water potential through partially permeable membrane
- water potential in cells (if isotonic no net diffusion, if in hypotonic soln cell swells/plant cell turgid, if in hypertonic soln cell crenates/plant cell undergoes plasmolysis)

Blood Glucose

- Blood glucose conc too high - water potential too low
- causes water to leaves surrounding cells to increase water potential, cells my dehydrate/die
- Diabetes - blood has lower water potential, leads to thirst, copious urine produced due to XS water in blood, poor vision due to osmotic loss of water from eye, blood pH falls leading to acidosis

Cholera
- bacterial cell adheres to epithelia and secretes exotoxin, which enters cell and opens chloride ion channels
- chloride ions diffuse out of cells into lumen, lowering lumen's water potential
- water osmotically diffuses into lumen, produces diarrhoea
- treat with ORS salts

Cystic Fibrosis
- in healthy cells CFTP protein carries Cl ions out of cell, increases water potential of cytoplasm
- water leaves cell by osmosis, makes mucus watery
- CFTP protein absent due to genetic mutation
- Cl ions cannot leave cell, water remains in cell
- produces thick sticky mucus which blocks airways, leads to coughing, wheezing, bacterial infection

OTHER TOPICS could be considered
- water as a habitat (oceans, lakes, rivers) for marine life (fish gills, counter-current exchange)
- adaptions of hydrophytic plants
- Role of water in thermoregulation
- Osmoregulation (TBH this is quite complicated)

Oestrous Cycle

-FSH, secreted from pituitary gland, stimulates follicle development

-Oestrogen is released from the follicle and the ovaries

-Oestrogen stimulates the uterus lining to thicken and inhibits FSH

-As Oestrogen concentration increases, it stops inhibiting and stimulates the pituitary gland to secrete LH and FSH (LH surge)

-LH surge causes ovulation where the follicle ruptures and an egg is released

-LH stimulates the follicle to become the corpus luteum

-Progesterone secreted by corpus luteum

-Progesterone maintains the uterus lining and inhibits LH and FSH

If no embryo implants

-Corpus luteum breaks down

-Progesterone no longer released

-FSH concentration increases because it is no longer inhibited by progesterone

-Cycle starts again



Remember you're not a flop at Biology, you're a F.O.L.P.!

Hope this helps!

what could you write for that?

also what would you include if hey asked about the importance of hydrogen bonds?