Edexcel 6BIO4 ~ 13th June 2014 ~ A2 Biology

Original post by billyfisher100

The lytic pathway is where viruses insert their (reverse transcribed) DNA into the host cell's genome and the viruses will bud out of that one cell and automatically cause cell lysis as a result.

The lysogenic pathway is where you end up with integrase inserting viral DNA into the host cell's genome, but the cell will divide by mitosis and undergo DNA replication up to the cell's Hayflick limit to create more cells so that the budding process is more efficient and the virus does not have to infect so many cells to proliferate and there is less risk of a T killer cell activating extrinsic apoptosis (which leads to cell lysis) to prevent budding of new viruses.

Although it is not directly on the specification, mention of "lytic" (and/or an explanation of it) on an HIV 4-6 mark question often gains a point.
(Also, if you can explain it properly, even if it is not on the mark scheme, it will impress the examiner, so they are more likely to give you the benefit of the doubt with other mark points on that question if you have not expressed them clearly).

Woah... Thanks for the information! :yy:

Reply 384

I've got some questions...

What is the difference between sense and antisense? Like which one's which? I get confused.

And what's the difference between lysosome and lysozyme?

:dontknow:

Reply 385

Peanut83

Original post by liomeeringca

I've got some questions...

What is the difference between sense and antisense? Like which one's which? I get confused.

And what's the difference between lysosome and lysozyme?

:dontknow:

The antisense strand is the one that forms the template for the mRNA.

And lysozyme is the enzyme; lysosome is the organelle within a cell, containing the enzyme.

Reply 386

Original post by Peanut83

The antisense strand is the one that forms the template for the mRNA.

And lysozyme is the enzyme; lysosome is the organelle within a cell, containing the enzyme.

Thanks, so do lysosomes release lysozymes? Cause that's what it said on the mark scheme of the paper I just did,

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Reply 387

Ahhhhh, I'm like seriously freaking out about this paper now... I need a B! Anyone else feel like this? :frown:

Reply 388

diggy

19

Original post by liomeeringca

Ahhhhh, I'm like seriously freaking out about this paper now... I need a B! Anyone else feel like this? :frown:

Yes, although I calculated that I need 2 C's for an A, so obviously I could lay back but i'm not just follow the specification and the assassin's notes

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Reply 389

13142vp

Original post by diggy

Yes, although I calculated that I need 2 C's for an A, so obviously I could lay back but i'm not just follow the specification and the assassin's notes

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really, u only need two C's to an A what u got in others(if u dont mind me asking)?
Im holding 2 Bs for courseworks and 2 C's atm, how likely do u think it is to get an A overall if get 2 As in two other units ?

Reply 390

Peanut83

Original post by liomeeringca

Thanks, so do lysosomes release lysozymes? Cause that's what it said on the mark scheme of the paper I just did,

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I think so, but not sure about the context. During phagocytosis the lysosome fuses with the vacuole containing a pathogen; then the lysozymes digest the pathogen.

I am totally panicking about this exam as well. I am doing the A level in a year, so I only did the AS exams last week and the week before. The level of precision, knowledge and everything else is so much harder for A2 so I'm really nervous about it.

Reply 391

13142vp

can anyone explain the structures in chloroplasts involved LD and LI reactions plss?

thanks

Reply 392

Original post by diggy

Yes, although I calculated that I need 2 C's for an A, so obviously I could lay back but i'm not just follow the specification and the assassin's notes

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That's a nice situation haha, and yeah I have/am, The Assassin is a literal hero in my eyes :mmm:

Reply 393

Original post by Peanut83

I think so, but not sure about the context. During phagocytosis the lysosome fuses with the vacuole containing a pathogen; then the lysozymes digest the pathogen.

I am totally panicking about this exam as well. I am doing the A level in a year, so I only did the AS exams last week and the week before. The level of precision, knowledge and everything else is so much harder for A2 so I'm really nervous about it.

Yeah sorry, should have said it was about phagocytosis, thank you for your help! :smile:

Dang, I'm really bad at biology so I'd find that 'doing it in a year' difficult D: You'll be fine I'm sure, your level if knowledge is high and just remember to keep a clear head :hugs: