AS Biology P1 MCQs Preparation Thread

[Alicee]

But resolution= wavelength / 2. So the resolution of a 600nm wavelength should give a 300nm resolution. And since resolution is the ability to distinguish between 2 points then 2 membranes 300 nm apart should be seen as separate points..
Right?

nope...the membranes are 7nm....how can you see them with 300nm resolution? even though they are 300nm apart they it dsnt matter if you cant see them how can you distinguish them as seperate points?

 

[kingos3111]

help may june 2007 q4

 

[1357911]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_s11_qp_12.pdf q6,8,9,21,30,35, anyone plz ?????/

q-6 this is something which u hav to learn.

q-8
Remember this also. Only tertiary and quartanary structures contain ionic bonds.

q-9
quaternary structure has more than 2 polypeptide chains. Myoglobin has only one. Learn this

 

[1357911]

help may june 2007 q4

I too hav a doubt in the same question

 

[HubbaBubba]

Mm, I don't usually have questions in biology, but can somebody explain the heart graph thing to me? When does the semi lunar valve open/atriolventricular valve open, etc?

 

[1357911]

://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Biology (9700)/9700_s11_qp_12.pdf q6,8,9,21,30,35, anyone plz ?????/

q-21 see the table. on the ryt hand side anticodons on the tRNA are written. First write the amino acid sequence while seeing the anticodon.
For ex the first one is UUA. the amino acid which will fit in the active site of this tRNA is AAU. and then there is a point that the sequence of the amino acid in the active site of the tRNA is same as the sequence in the DNA molecule.Only the U is replaced by G.
Hope u understand.

 

[HubbaBubba]

help may june 2007 q4

Calibrate it first. Each division is 0.1mm and there are 50 EPG units for each 0.1mm division. Therefore one eyepiece graticule unit is (0.1/50) 0.002mm. (2 micrometers). Take the seed that is growing vertically. On the left picture the bud is at 25 EPG units. It grows to 35 EPG units. That's a difference of 10 EPG units. (10 * 2) = 20 micrometers in 4 hours. So 20/4 = 5 micrometers/hour

 

[Ikram Khaliq]

Which symptoms may be seen in a person affected by chronic obstructive pulmonary disease
(COPD)?
1 persistent cough
2 less elastic alveoli
3 increased risk of lung infection
4 shortness of breath

 

[HubbaBubba]

Which symptoms may be seen in a person affected by chronic obstructive pulmonary disease
(COPD)?
1 persistent cough
2 less elastic alveoli
3 increased risk of lung infection
4 shortness of breath

2. Less Elastic Alveoli, because Emphysema is part of COPD
4. Shortness of breath

 

[Ikram Khaliq]

2. Less Elastic Alveoli, because Emphysema is part of COPD

you have to choose more than one. wait i'll post the whole question.
here you go:

Which symptoms may be seen in a person affected by chronic obstructive pulmonary disease
(COPD)?
1 persistent cough
2 less elastic alveoli
3 increased risk of lung infection
4 shortness of breath

A 1 and 4 only
B 1, 2 and 3 only
C 2, 3 and 4 only
D 1, 2, 3 and 4

 

[1357911]

Which year is this ques from?????

you have to choose more than one. wait i'll post the whole question.
here you go:

Which symptoms may be seen in a person affected by chronic obstructive pulmonary disease
(COPD)?
1 persistent cough
2 less elastic alveoli
3 increased risk of lung infection
4 shortness of breath

A 1 and 4 only
B 1, 2 and 3 only
C 2, 3 and 4 only
D 1, 2, 3 and 4

 

[Ikram Khaliq]

Which year is this ques from?????

O/N12 p13

 

[1357911]

o/n 2011 varient 11
QUestions 14,30,36,40
Can any1 help???

 

[HubbaBubba]

you have to choose more than one. wait i'll post the whole question.
here you go:

Which symptoms may be seen in a person affected by chronic obstructive pulmonary disease
(COPD)?
1 persistent cough
2 less elastic alveoli
3 increased risk of lung infection
4 shortness of breath

A 1 and 4 only
B 1, 2 and 3 only
C 2, 3 and 4 only
D 1, 2, 3 and 4

Yeah I realised after I posted sorry
Uhm now that I think about it, all of them are symptoms of COPD. 2, and 4 caused by Emphysema and 1, 3 caused by chronic bronchitus

 

[Ikram Khaliq]

Yeah I realised after I posted sorry
Uhm now that I think about it, all of them are symptoms of COPD. 2, and 4 caused by Emphysema and 1, 3 caused by chronic bronchitus

but are all of them SYMPTOMS WHICH CAN BE SEEN?

 

[HubbaBubba]

but are all of them SYMPTOMS WHICH CAN BE SEEN?

Well doctors see them, don't they? I still think answer is D, what year is this from?

 

[Alicee]

would anyone be kind enough to write a short summary of what happens as a pathogen enters our body including the function of B and T lymphocytes ?

 

[Ikram Khaliq]

O/N12 p13 the answer is D btw i don't get it waisay. how can less elastic alveoli be seen? xD

 

[HubbaBubba]

would anyone be kind enough to write a short summary of what happens as a pathogen enters our body including the function of B and T lymphocytes ?

èWhen a macrophage engulfs a pathogen, it can expose the antigen to a T-helper cell which releases cytokines.
èThis stimulates the B cells to divide into plasma cells and secrete antibodies. Other B cells become memory cells.

èKiller T-Cells search for foreign antigens on cells, and attach to it, releasing toxic substances.

 

[HubbaBubba]

O/N12 p13 the answer is D btw i don't get it waisay. how can less elastic alveoli be seen? xD

Mm, doctors make the person who's sick breath into a spirometer to check how much air he can inhale/exhale. Usually small volumes indicate that fibres are not elastic