A level Biology: Post your doubts here!

[Mohammed salik]

q40-statementA is valid since in ecosystem Y the dominant producer is large and woody, so would not be easily consumed. StatementB is valid since there is a smaller fluctuation of temperature in marine aquatic ecosystems and also there is less oxygen. Statement C is also valid, since with lower energy losses between trophic levels the ecosystem X can support more trophiclevels. Therefore the answer is statement D.
Q39-same.So it will be B.

Q40 is D and 39 is D but Ms is Wrong for 40 I think

 

[princeali97]

Q40 is D and 39 is D but Ms is Wrong for 40 I think

Q39 will be B na.Its in the ms too :/

 

[joanna omar]

What's the difference between Tidal volume and vital capacity ?

 

[Mohammed salik]

What's the difference between Tidal volume and vital capacity ?

Tidal Volume is .. Volume Breathed in At rest (Normal breathing)
Vital capacity is the maximum amount of air a person can exhale from the lungs after a maximum inhalation!

 

[Mohammed salik]

Q39 will be B na.Its in the ms too :/

http://papers.xtremepapers.com/CIE/...nd AS Level/Biology (9700)/9700_s13_ms_13.pdf Q39 is D !

 

[joanna omar]

Could someone list down the reasons why Africans are so susceptible to diseases such as aids and cholera?

Cholera:
1)Poor sanitation
2)Malnutrition
3)no sewage treatment
4)over population
5)people live faraway from vaccination centres and health

AIDS:
1)many people dont go for Hiv testing due to personal freedom
2)they dont know they are carriers of the disease
3)testing HIV is expensive and difficult to organize
4)increased no. of high risk groups
5)Lack of education abt AIDS
6) In rawanda it was also high as it was used as a genicidal weapon in the civil War

 

[joanna omar]

Tidal Volume is .. Volume Breathed in At rest (Normal breathing)
Vital capacity is the maximum amount of air a person can exhale from the lungs after a maximum inhalation!

thanks but in M.s they say vital capcity is the volume of air that can be exchanged during one breath in and out
I guess u have said all abt inspiratory reserve volume !

I still don't understand difference !

 

[Mohammed salik]

thanks but in M.s they say vital capcity is the volume of air that can be exchanged during one breath in and out
I guess u have said all abt inspiratory reserve volume !

I still don't understand difference !

That Is for Tidal volume !
Which M.s.. Could plz give me Link..
Look at this diagram then ... http://en.wikipedia.org/wiki/File:Lungvolumes.svg

 

[princeali97]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_s13_ms_13.pdf Q39 is D !

that is strange!.I will write B if this question comes in the exam

 

[princeali97]

Which M.s.. Could plz give me Link..
Look at this diagram then ... http://en.wikipedia.org/wiki/File:Lungvolumes.svg

Acha salik there was a question in the past paper that asked for the method/experiment by which vital capacity can be measured.Can u pls explain me the experiment.

 

[princeali97]

thanks but in M.s they say vital capcity is the volume of air that can be exchanged during one breath in and out
I guess u have said all abt inspiratory reserve volume !

I still don't understand difference !

Vital Capacity is exactly the maximum volume of air that can be breathed in and then breathed out of the lungs.Sum of supplementary and complementary air.Average abt 4.6dm-3.

 

[Mohammed salik]

Acha salik there was a question in the past paper that asked for the method/experiment by which vital capacity can be measured.Can u pls explain me the experiment.

assk The Person To Inhale Completely so His Lungs are fully inflated.. then Ask him to Exhale Fully then Use spirometer to Measure These volumes and look at the Graph We Get i mentioned Earlier..!

 

[princeali97]

assk The Person To Inhale Completely so His Lungs are fully inflated.. then Ask him to Exhale Fully then Use spirometer to Measure These volumes and look at the Graph We Get i mentioned Earlier..!

So do we describe what happens in the spirometer?.Like,when the person inhales, the o2-containing chamber falls and rises when exhales and that the kymograph records the movement of the chamber.its in the book.

 

[Mohammed salik]

So do we describe what happens in the spirometer?.Like,when the person inhales, the o2-containing chamber falls and rises when exhales and that the kymograph records the movement of the chamber.its in the book.

No.. Just 2 marks Yaar! Not in Our sylabus Though!

 

[Mohammed salik]

Cholera:
1)Poor sanitation
2)Malnutrition
3)no sewage treatment
4)over population
5)people live faraway from vaccination centres and health

AIDS:
1)many people dont go for Hiv testing due to personal freedom
2)they dont know they are carriers of the disease
3)testing HIV is expensive and difficult to organize
4)increased no. of high risk groups
5)Lack of education abt AIDS
6) In rawanda it was also high as it was used as a genicidal weapon in the civil War

Point 6 about Aids was Hilarious...!!
R u serious? did u see than in M.s?

 

[princeali97]

No.. Just 2 marks Yaar! Not in Our sylabus Though!

Not 2...3 marks Dude!

 

[princeali97]

Point 6 about Aids was Hilarious...!!
R u serious? did u see than in M.s?

Yes i've seen it. It was in the m.s

 

[Mohammed salik]

Haha.. Ok! If u can understand and memorize then do memorize from Book!!

Not 2...3 marks Dude!

 

[Mohammed salik]

Yes i've seen it. It was in the m.s

xD!!!

 

[princeali97]

Haha.. Ok! If u can understand and memorize then do memorize from Book!!

Biology requires memorising tendency only to be honest