OCR Biology F215 Control, Genomes and Environment Fri 15 June 2012

Reply 380

Subbed.

Original post by sas25

Might have been mentioned before.. but do you only use somatic nuclear transfer and embryo splitting in reproductive cloning as they both produce an organism? or can they be used in non-reproductive cloning where you use it for reproduction of cells/tissues/organs?

nuclear transfer and embryo splitting is to obtain totipotent cells that can become an entire organism later on. Non-reproductive cloning would use cells that are already specialised in order to grow into the organ needed. You wouldn't want to obtain an entire organism just so that you can use just one organ.

Reply 382

The Illuminati

4

Original post by Raj K

anyone help me with the sliding filament model pleaseee..i have a strong feeling this may come up :P

MUSCLE CONTRACTION
Impulse arrives at the neuromuscular junction causing vesicles of ACh to fuse with presynaptic membrane and release ACh onto synapse via exocytosis. ACh diffuses across synapse, binds to receptors site on the sarcolemma (sarcolemma has large SA) causing depolarisation
Wave of depolarisation travels down transverse tubule. T system depolarisation causes Ca2+ to be released from the sarcoplasmic reticulum.

Sliding filament model
The Ca2+ binds to the troponin, changing it’s shape causing the tropomyosin to move away from the binding site of the actin exposing the actin-myosin binding sites so that the myosin head can attach to form a cross bridge.
Power stroke: myosin head tilts 45 degrees via the hydrolysis of ATP to ADP and Pi. The actin filaments are drawn closer together so that there is more of an overlap between the thin and thick filaments. ATP binds to the myosin head breaking the cross bridge.
The ATP is hydrolysed to ADP and Pi so the myosin head moves backwards and forms a cross bridge with the adjacent actin molecule.
Millions of cross bridges are continuously made and broken, shortening the entire length of the muscle.

During muscle contractions The A band stays the same length.
The H zone and I zone remain the same size.

(edited 11 years ago)

musclestructure.jpg77.9KB

Reply 383

Raj K

9

Original post by The Illuminati

MUSCLE CONTRACTION
Impulse arrives at the neuromuscular junction causing vesicles of ACh to fuse with presynaptic membrane and release ACh onto synapse via exocytosis. ACh diffuses across synapse, binds to receptors site on the sarcolemma (sarcolemma has large SA) causing depolarisation
Wave of depolarisation travels down transverse tubule. T system depolarisation causes Ca2+ to be released from the sarcoplasmic reticulum.

Sliding filament model
The Ca2+ binds to the troponin, changing it’s shape causing the tropomyosin to move away from the binding site of the actin exposing the actin-myosin binding sites so that the myosin head can attach to form a cross bridge.
Power stroke: myosin head tilts 45 degrees via the hydrolysis of ATP to ADP and Pi. The actin filaments are drawn closer together so that there is more of an overlap between the thin and thick filaments. ATP binds to the myosin head breaking the cross bridge.
The ATP is hydrolysed to ADP and Pi so the myosin head moves backwards and forms a cross bridge with the adjacent actin molecule.
Millions of cross bridges are continuously made and broken, shortening the entire length of the muscle.

During muscle contractions The A band stays the same length.
The H zone and I zone remain the same size.

hey thankyou! (:

Reply 384

Sasha193

Does anyone have a copy of the January 2012 paper and mark sheme? :smile:

xx

Reply 385

The Illuminati

4

Original post by Sasha193

Does anyone have a copy of the January 2012 paper and mark sheme? :smile:

xx

I do!

F215-01Jan12.pdf207.9KB

F215_MS_Jan12.pdf313.3KB

Reply 386

banana-milkshake

7

Original post by Raj K

here you go https://docs.google.com/leaf?id=0By84nmCmJZnWMU5EN2RDcmtBU2s :smile:

Thanks for uploading this- it's really useful :smile:

Reply 387

andrewpeters

1

I find biotechnology the most confusing, im trying to get all the ideas linked in my head? Could anyone summarise the chapter?

Reply 388

Raj K

9

Original post by banana-milkshake

Thanks for uploading this- it's really useful :smile:

no problem.. someone uploaded it before me lol

Reply 389

andrewpeters

1

Does someone have a list of all the definitions we're required to know?

Reply 390

Beffnaay

Is it just me or is this module near enough impossible?

Reply 391

Funky_Munky

Original post by PrettyLittleLiars

Hmm you sound like you go to my college. We did it in the exact order, so what did you do about it? Have yo done your own individual revision?

i have tried, but it is seriously confusing

it'll take me at least 2 hours to completely get my head round a
double spread page

and then when i look at the time, i can see how much time i've wasted and then i just go depressed :frown:

Reply 392

Revent

10

I need like 147 in this exam :erm:

Reply 393

im so fresh

12

Original post by Revent

I need like 147 in this exam :erm:

that wold be amazing. Are you aiming for an A or A* overall?
i need like 135. :cry:

Reply 394

Beffnaay

I need 120! It's not even going to happen at this rate. How do your schools do in the coursework by the way? Our school never does well and we have to resit and still do poo?!

Reply 395

Raj K

9

yesssss...this module is impossible ..for me anyway.

Reply 396

sumsum123

2

Original post by Revent

I need like 147 in this exam :erm:

I need like 126 for an A and 143 for an A* "/. I need the A* to make up for my upcoming fail in maths. Any idea how many raw marks you need for 147 or full ums?

(edited 11 years ago)

Reply 397

S_Azizi

Original post by sumsum123

I need like 126 for an A and 143 for an A* "/. I need the A* to make up for my upcoming fail in maths. Any idea how many raw marks you need for 147 or full ums?

In most cases 80-85/100 is 100% UMS.

Reply 398

Revent

10

Original post by im so fresh

that wold be amazing. Are you aiming for an A or A* overall?
i need like 135. :cry:

A*

So not happening though :frown:

135 for an A or *?

Original post by sumsum123

I need like 126 for an A and 143 for an A* "/. I need the A* to make up for my upcoming fail in maths. Any idea how many raw marks you need for 147 or full ums?