A level Biology: Post your doubts here!

[Irfan1995]

Isn't oxygen debt the lack of oxygen in the tissues?

We know that there is lack of oxygen. If there wasn't any lack of oxygen, then anaerobic respiration wouldn't have started in the first place.

Oxygen debt is how much oxygen you need to break down the toxic products (lactic acid) of anaerobic respiration. The longer anaerobic respiration has been continuing, the greater oxygen required (hence the greater the oxygen debt is).

 

[Noor Ahmad]

Okay, let's say you're sick, so you need to take an antibiotic. We know that antibiotics are useless if bacteria are resistant to it.
During the process of genetic engineering, we made plasmids that have an antibiotic-resistant allele.
If you take insulin that's made from these plasmids, then the insulin you're taking has the antibiotic-resistant allele.
When the antibiotic-resistant allele is expressed, it will give a protein that counteracts the antibiotic you're taking.
So the antibiotic you're taking is useless.

THANK YOUUU

 

[narutogirl]

Guys, I don't understand anything about polyploidy >.<
Do I have to memorize the wheat example, and how species bred and formed a hybrid that are sterile and then by chance, polyploidy took place forming a fertile tetraploid that could mate , etc etc..do I have to memorize the number of chromosomes and connect this with autopolyploidy and allopolyploidy ?
How would I ever answer that if it came in section B ;_;
Can someone give a brief explanation ^^"

 

[knowitall10]

Guys, I don't understand anything about polyploidy >.<
Do I have to memorize the wheat example, and how species bred and formed a hybrid that are sterile and then by chance, polyploidy took place forming a fertile tetraploid that could mate , etc etc..do I have to memorize the number of chromosomes and connect this with autopolyploidy and allopolyploidy ?
How would I ever answer that if it came in section B ;_;
Can someone give a brief explanation ^^"

First of all, my friend, I've never seen crop plant questions come in Section B. Second of all, don't memorize, understand. Understanding is the best way to grasp the context of what's happening. this way, you can even answer the Section B questions in your own words and be absolutely epic at it...try understanding the topic, if u don't get it, ask again, I'll explain it to you inshAllah

 

[dornam]

which chapters are likely to come up in sectoin B?

 

[cyclone94]

which chapters are likely to come up in sectoin B?

gary221 any idea???

 

[butterMAROfly796]

does anyone know what we should focus on most?

 

[knowitall10]

Yo guys...what's up? I'm surprised we're discussing these for a theory paper....
Anyway, for what we should be focussing on: THE WHOLE COURSE no short cut
and for what might come in section B: everything that requires explanation: Adaptations of a C4 plant (rare), Photosystems..absorption and action spectra, homeostasis-coordination and control-, respiration...

I hope i cleared your confusion...

 

[knowitall10]

cyclone94 here you go

 

[cyclone94]

cyclone94 here you go

i din't c ur post above n i waz gna ask u "wer 2 go "
lol
btw Jazakallah

 

[knowitall10]

i din't c ur post above n i waz gna ask u "wer 2 go "
lol
btw Jazakallah

Wa iyyaki..

 

[narutogirl]

First of all, my friend, I've never seen crop plant questions come in Section B. Second of all, don't memorize, understand. Understanding is the best way to grasp the context of what's happening. this way, you can even answer the Section B questions in your own words and be absolutely epic at it...try understanding the topic, if u don't get it, ask again, I'll explain it to you inshAllah

Hehe, thank you for the kind offer.
I am a bit frightened as they changed the syllabus for 2013, they will include things from application. I am not even well prepared for the core topics, so scared to be stuck explaining these things.
I am very scared they might get from the AS, I read briefly the biological molecules, the enzymes and immunity. Do I need to read anything else? I'm kind of in a panic mode but trying to calm myself down because I wasted too much time panicking. Caused to myself synaptic fatigue xD

 

[knowitall10]

Hehe, thank you for the kind offer.
I am a bit frightened as they changed the syllabus for 2013, they will include things from application. I am not even well prepared for the core topics, so scared to be stuck explaining these things.
I am very scared they might get from the AS, I read briefly the biological molecules, the enzymes and immunity. Do I need to read anything else? I'm kind of in a panic mode but trying to calm myself down because I wasted too much time panicking. Caused to myself synaptic fatigue xD

Chill Dude..chill!
Yea from AS, you need to know the structure of the antibody, i saw a question on that in p4..and in nov 2012, they even ask to describe transcription and translation..but if u have any problems at all, please feel free to ask, even if that makes u inbox me a billionn times ina day I'm pleased to help!

 

[kingos3111]

First of all, my friend, I've never seen crop plant questions come in Section B. Second of all, don't memorize, understand. Understanding is the best way to grasp the context of what's happening. this way, you can even answer the Section B questions in your own words and be absolutely epic at it...try understanding the topic, if u don't get it, ask again, I'll explain it to you inshAllah

this is just perfect i was thinkkin of sane thing always understand nd u can easily create ur own notes fascinating btw i wanna do alevel bio this oct nov im studin now respiration

 

[narutogirl]

Would you be kind to explain the null hypothesis. ( I love how I discover things right before the exam :'D )
I don't quite understand the phrase: if the probability is less than 0.05 then the null hypothesis is correct and we reject it....why would we reject it if it's correct "

 

[kingos3111]

why is there today alevel bio

 

[sashaleon]

Can someone explain stabilising seletion & all other selections.....

 

[mariyam95]

First of all, my friend, I've never seen crop plant questions come in Section B. Second of all, don't memorize, understand. Understanding is the best way to grasp the context of what's happening. this way, you can even answer the Section B questions in your own words and be absolutely epic at it...try understanding the topic, if u don't get it, ask again, I'll explain it to you inshAllah

dude section b before it included the core syllabus only but this year application syllabus will be included in section b... check out the syllabus !

 

[mariyam95]

Can someone explain stabilising seletion & all other selections.....

so there are 3 types of natural selction \
1-directional selection : in which an environmental change causes a change in the gene pool of a population favoring one characterstict over the others e e.g. the peppered mot example
2-stablising selection : in which the environmental factor is stable and so is the characteristics
e.g. the newborn weight its stable since the human being was made because the too heavy or too light babies wont survive
3-disruptive selection in which two extremes characteristic are favored
e.g. malaria and sickle cell anaemia

 

[backtodev]

dude section b before it included the core syllabus only but this year application syllabus will be included in section b... check out the syllabus !

Can you tell me which page on the syllabus says this?
Sigh Section B will be tough this year then