Physics, Chemistry and Biology: Post your doubts here!

[My Name]

haha same here
Anyone else who's got this messed up thing figured out?

♣♠ Magnanimous ♣♠
can u help!

 

[Bilal ashraf]

someone help
i dont understand how platelets help in blood clotting..
They just conver fibronegon to fibrin...thats it?

 

[Counter Logic Gamer]

i have a doubt in this question
CaCo3+2Hcl>>CaCl2+CO2+H2O
one piece of marble 0.3g was added to 5cm3 of Hcl concentration 1.00 mol/dm3 which reagent is in excess?
mass of 1 mol of CaCO3=100g
no. of mol of CaCO3=?
no.of mol of Hcl=?
reagent in excess=...............
reason=.........................
calculate maximum no.of volume of CO2 produces=.....
pls solve and explain if you ca as asoon as possible....

 

[My Name]

someone help
i dont understand how platelets help in blood clotting..
They just conver fibronegon to fibrin...thats it?

When an injury causes a blood vessel wall to break, platelets are activated. They change shape from round to spiny, stick to the broken vessel wall and each other, and begin to plug the break.


The platelets also interact with fibrinogen, a soluble plasma protein, to form insoluble fibrin. Calcium is required for that.

Fibrin strands form a net that entraps more platelets and other blood cells (red cells and white cells), producing a clot that plugs the break.

 

[Lola_sweet]

the contraceptive method of Intra Utrine Device (IUD) where is it placed in the female reproductive system?

 

[Mai(M4!)]

the contraceptive method of Intra Utrine Device (IUD) where is it placed in the female reproductive system?

in the uterus
it is shaped like T and its head should be placed against the top uterus wall to stop implantation

 

[Lola_sweet]

in the uterus
it is shaped like T and its head should be placed against the top uterus wall to stop implantation

thnk u!
can u clear this doubt i ve
co-dominance: an example could be a red flower with white spots
incomplete dominance: an example could be a pink flower! with the alleles of a red and white flower!

 

[Akshajistari]

the contraceptive method of Intra Utrine Device (IUD) where is it placed in the female reproductive system?

It prevents the a blastula( formed after the zygote has multiplied several times after fertilisation) from implanting in the uterine wall

 

[Lola_sweet]

another qs: why is glucose converted into glycogen rather than kept as glucose inside the cells?

 

[Akshajistari]

another qs: why is glucose converted into glycogen rather than kept as glucose inside the cells?

Because glucose is soluble in water and would affect the concentration gradient for osmosis. If there was too much glucose in a cell, water would diffuse in but as animal cells do not have a cell wall, the cells will burst( cytolysis)

 

[Lola_sweet]

Because glucose is soluble in water and would affect the concentration gradient for osmosis. If there was too much glucose in a cell, water would diffuse in but as animal cells do not have a cell wall, the cells will burst( cytolysis)

thnk u thnk u sooooo much!

 

[Akshajistari]

thnk u thnk u sooooo much!

You're welcome!

 

[ibzer275]

Pass?

Chem: http://igcse.at.ua/index/igcse_chemistry_notes_arranged_by_topic/0-40
Phy: http://www.physicsatweb.com/index_rev.php?id=igcse

i always get 30 out of 80 in both chemistry and physics and thank you for the revision notes

 

[Ameena Eesa]

i always get 30 out of 80 in both chemistry and physics and thank you for the revision notes

haha........ this time better?

 

[ibzer275]

haha........ this time better?

my paper 3 exams are next week so hopefully this time ill do better

 

[Abdel Moniem]

http://papers.xtremepapers.com/CIE/Cambridge IGCSE/Physics (0625)/0625_s11_qp_31.pdf
Question 6bi and 6biii

 

[Mai(M4!)]

the ones that took exam today
how was it ????

 

[Lola_sweet]

easy but long

the ones that took exam today
how was it ????

 

[Faiza Anwar]

Assalam-o-Alaikum.
Post your Physics, Chemistry and Biology doubts in here and members, along with me will try their best to help you out.

can any one help me with M/J 2011 p-31 Q 3b (iv)

 

[Lola_sweet]

can any one help me with M/J 2011 p-31 Q 3b (iv)

biology?