Biology; Chemistry; Physics: Post your doubts here!

[Umar Ilyas]

http://www.xtremepapers.com/papers/...onal O Level/Biology (5090)/5090_s07_qp_1.pdf
Q19 please its confusing, answer in marking scheme is C

 

[snoonono]

http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Biology (5090)/5090_s07_qp_1.pdf
Q19 please its confusing, answer in marking scheme is C

its correct bcz you should straighten ur hands contracting tricep and relaxing bicep

 

[A star]

http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Chemistry (5070)/5070_s10_qp_42.pdf

listen it has to do with limiting reactant increasing the concentration of the limiting reactant will not only increase the rate of reaction but also the amount of product because more moles of limiting reactant are present.this question is a repeat and i did it in 1 min.

 

[A star]

6 A student added 10.0 cm3
of 0.100 mol/dm3
hydrochloric acid to an excess of zinc. The
volume of hydrogen produced was recorded at intervals until no more gas was produced.
This was experiment P.
The experiment was repeated with a different acid solution, again using an excess of zinc.
This was experiment Q.
The graphs of the two experiments are shown on the grid below.
volume of
hydrogen
/ cm3
time/ s
P
Q
Which acid solution would give the graph for experiment Q?
(a) 10 cm3
of 0.050 mol/dm3
hydrochloric acid
(b) 10 cm3
of 0.200 mol/dm3
hydrochloric acid
(c) 20 cm3
of 0.100 mol/dm3
hydrochloric acid
(d) 20 cm3
of 0.200 mol/dm3
hydrochloric acid


i cannot find anything about powder form in this question?

please view my comment

 

[stareaj]

Pls help ASAP biology mcq
november2006 que 14 paper mcq
June2009 que 13 paper m q
Same question on cardia. Cycle but diff answer :-/ and to 2009 is A and 2006 is B please help

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

Assalam-o-alaikum wr wb...
Biology doubt:
October/November 2011 Q5 (d)
izzit or not??

 

[snoonono]

Assalam-o-alaikum wr wb...
Biology doubt:
October/November 2011 Q5 (d)
izzit or not??

yes it is because the allele is carried but the trait isnt shown, as in u have the allele, but the cells dont have a sickle shape i think

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

yes it is because the allele is carried but the trait isnt shown, as in u have the allele, but the cells dont have a sickle shape i think

but 50% is trait? 25% is normal and the other 25% is sickle cell anaemia..
co dominance is basically neither is dominant over the other...right?

 

[snoonono]

but 50% is trait? 25% is normal and the other 25% is sickle cell anaemia..
co dominance is basically neither is dominant over the other...right?

i guess it z :?

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

i guess it z :?

i also think the same thing
well...this is written in the mark scheme...i got the first 2 points...but what does the third point (bold one) mean?

idea that

both alleles / HbA and HbS, are expressed
;


both alleles make two different forms of haemoglobin

;
if dominant / recessive, then only one form of
haemoglobin in heterozygous people

;
three phenotypes (not two) / sickle cell trait is a different
phenotype from normal and sickle cell anemia

;

 

[Tharindu]

What is Antimatter?

 

[ayeshaK]

Please explaiin nitrogen cycle in short ?

 

[ayeshaK]

What is Antimatter?

In particle physics, antimatter is the extension of the concept of the antiparticle to matter, where antimatter is composed of antiparticles in the same way that normal matter is composed of particles. But this is nt in our syllabus :/

 

[snoonono]

Please explaiin nitrogen cycle in short ?

t
THERE U GO, the siplest drawing

 

[Tharindu]

In particle physics, antimatter is the extension of the concept of the antiparticle to matter, where antimatter is composed of antiparticles in the same way that normal matter is composed of particles. But this is nt in our syllabus :/

I kno it's

In particle physics, antimatter is the extension of the concept of the antiparticle to matter, where antimatter is composed of antiparticles in the same way that normal matter is composed of particles. But this is nt in our syllabus :/

not in our syllabus..jus kidding

 

[ayeshaK]

t
THERE U GO, the siplest drawing

Thankyou

 

[snoonono]

Thankyou

welcome at anytime

 

[sedanx]

Q) phagocytes and lymphocytes are the same in size then why cant lymphocytes squeeze out of capillary walls in tissue fluid ?

circulating phagocytes produce surface glycoprotein receptors that increase their ability to adhere to the inner surface of capillary walls, enabling them to squeeze out of the capillary and be attracted to the site of infection.

 

[sedanx]

What is oxygen debt ?

oxygen debt the extra oxygen that must be used after a period of strenuous exercise to reconvert lactic acid to glucose and decomposed ATP and creatine phosphate to their original states.

 

[luckywang]

Are there any different between bacteria and bacterium?

 

[Fallen316]

Are there any different between bacteria and bacterium?

bacterium: singular
bacteria: plural