F215 - Revision thread 13th June 2011

With Apoptosis, do we need to know the process? My textbook only outlines what it's used for, eg. tadpoles losing their tales due to the cells undergoing apoptosis, and then digested by phagocytes. Or webbing between fingers. Doesn't actually state how apoptosis occurs.

Reply 1321

786girl

Original post by heartskippedabeat

a long ethics question on the lac operon? :eek:

well i guess we could talk about how it is very immoral of the repressor protein to bind to the operator region which stops RNA polymerase binding to it and hence stopping transcription of the genes. jk

Reply 1322

ajenkins

since we reckon apoptosis is going to come up, would anyone care to explain the process to me?! ALSOOOO, I am thinking there is going to be a lot of genetics on this paper, at least one of those square things - probs a dihybrid and a chi squared with it maybe - i say this because there was next to no genetics on the january paper which i did for my mock!

Reply 1323

heartskippedabeat

10

Original post by 786girl

well i guess we could talk about how it is very immoral of the repressor protein to bind to the operator region which stops RNA polymerase binding to it and hence stopping transcription of the genes. jk

Haha yeah, poor RNA polymerase has a right to bind to it and we have a moral responsibility to let it do so....

Reply 1324

Waqar Y

11

Original post by ajenkins

since we reckon apoptosis is going to come up, would anyone care to explain the process to me?! ALSOOOO, I am thinking there is going to be a lot of genetics on this paper, at least one of those square things - probs a dihybrid and a chi squared with it maybe - i say this because there was next to no genetics on the january paper which i did for my mock!

1) Enzymes break down the cell cytoskeleton and the cellular contents, e.g ribosomes/nucleus etc are condensed and tightly packed

2) This cell surface membrane forms 'blebs' which are inner foldings of the membrane.

3) The cell is then split into vesicles

4) Phagocytes take in the vesicles by phagocytosis (endocytosis of the vesicle) which is then digested by enzymes and the cellular debris is disposed off

Reply 1325

ekta9

Original post by ajenkins

since we reckon apoptosis is going to come up, would anyone care to explain the process to me?! ALSOOOO, I am thinking there is going to be a lot of genetics on this paper, at least one of those square things - probs a dihybrid and a chi squared with it maybe - i say this because there was next to no genetics on the january paper which i did for my mock!

Process for apoptosis:
- Enzymes break down the cell cytoskeleton
- Cytoplasm becomes dense, with organelles tightly packed
- The cell surface membrane changes and small bits called blebs form.
- Chromatin condenses and the nuclear envelope breaks. DNA breaks into fragments.
- The cells break into vesicles that are taken up by pahgocytosis (endocytosis of large molecules)

Just memorise those steps :biggrin:

Basically, what the person above just posted ^

I'm dreading this.

Original post by ViralRiver

I'm dreading this.

Me too. x 10000000 :frown:

Reply 1328

Jhyzone

13

Someone help me to understand epistasis - Antagonistic and complementary fashion. ESP how to do the Punnett Square.
A good analogy, visual type would be helpful too.
Thanks.

Reply 1329

guitarmike456

9

Original post by Kaph

With Apoptosis, do we need to know the process? My textbook only outlines what it's used for, eg. tadpoles losing their tales due to the cells undergoing apoptosis, and then digested by phagocytes. Or webbing between fingers. Doesn't actually state how apoptosis occurs.

Remember that the first stages of meiosis 1 in prophase 1 also happen in apoptosis - chromatin condenses and nuclear envolope breaks down :smile:

But the order of events has been posted above - you just need to learn them.
But if they do use an example I'd presume it would be webbing of toes/feet :smile:

EDIT: Don't forget the opposite - necrosis which is uncontrolled cell death - and when this occurs then harmful hydrolitic enzymes are released hence why apoptosis is needed as it prevents these enzymes being produced.
Also nitrogen oxide dissipates the proton gradient in mitochondria which begins the process of apoptosis.

(edited 12 years ago)

Reply 1330

ajenkins

Me three. The only thing getting me through this is knowing I have both my r.s exams on monday morning as well and then also geography the next da...OH WAIT NO THAT MAKES IT SOOOO MUCH WORSE. F-M-L.

Reply 1331

guitarmike456

9

Original post by Jhyzone

Someone help me to understand epistasis - Antagonistic and complementary fashion. ESP how to do the Punnett Square.
A good analogy, visual type would be helpful too.
Thanks.

I posted about 6 pages back definitions of recessive and dominant epistasis which should gain you all the marks.

Reply 1332

Jhyzone

13

I've always wondered how they make the paper look as if it had already covered all the topics in the textbooks, in terms of the question they asks.

(edited 12 years ago)

Reply 1333

heartskippedabeat

10

Anyone still up revising? :redface:

Reply 1334

sillysal

9

Original post by heartskippedabeat

Anyone still up revising? :redface:

me! just going though the spec

Reply 1335

heartskippedabeat

10

Original post by sillysal

me! just going though the spec

I'm finishing off typing my notes up on here, thought it would help it all stick in my mind a bit better :redface:

and it's soo much quicker than writing them out again.
i might have to switch to maths soon though cos i have my tutor in the morning :frown:

arghhh i hate exams haha

Reply 1336

Suren_x

Original post by heartskippedabeat

Anyone still up revising? :redface:

Yup, have to finish module 3 today. Its so boring -_-

Reply 1337

sillysal

9

Original post by heartskippedabeat

I'm finishing off typing my notes up on here, thought it would help it all stick in my mind a bit better :redface:

and it's soo much quicker than writing them out again.
i might have to switch to maths soon though cos i have my tutor in the morning :frown:

arghhh i hate exams haha

tell me about it, i hate balancing out revision, so hard to sort out what's priority lol, im retaking f214 and have hardly done any revision for that although it doesnt look half as bad as what it did first time round :P

Reply 1338

ManPowa

7

Original post by sillysal

tell me about it, i hate balancing out revision, so hard to sort out what's priority lol, im retaking f214 and have hardly done any revision for that although it doesnt look half as bad as what it did first time round :P