POST YOUR BIO AND CHEM PAPER 1 DOUBT HERE !!!!

[Tekno-M]

It's D! Check the marking scheme again..

Checked, it's B.

 

[salvatore]

Checked, it's B.

Ur checking the wrong ms.. i guess!

 

[Tekno-M]

Ur checking the wrong ms.. i guess!

No. 16!! :O Sorry I mistyped it.

 

[salvatore]

No. 16!! :O Sorry I mistyped it.

No probs.. this question is regarding diastole, whereby blood enters the left/right ventricle while it is relaxing. The aortic valve (semi-lunar) should remain closed so as to prevent blood from flowing back into the ventricle while it is leaving through the aorta.. and the bicuspid valve should remain open in order to allow blood to flow from the atrium into the ventricles!

 

[FATIMAH]

you should not heat the crystals as they are very delicate and they break easily..also the water will be evaporated from it so "heat the crystals" is point 3..and as u see in the choices A,B and C they all have the number 3..so none of them and the answer will be D..

thank you sooo much

 

[ameeron]

Chemistry, O/N 2009 Paper 1, Q13 ???

 

[FATIMAH]

Chemistry MCQ doubt:​

​

Q: In some countries, ethanol, rather than petrol, is used as a fuel for cars. Which gas is not present in the exhaust from cars that burn ethanol?​

​

A Carbon dioxide​

B Nitrogen​

C Oxides of nitrogen​

D Sulphur dioxide​

do you know the right answer ???

 

[Tekno-M]

No probs.. this question is regarding diastole, whereby blood enters the left/right ventricle while it is relaxing. The aortic valve (semi-lunar) should remain closed so as to prevent blood from flowing back into the ventricle while it is leaving through the aorta.. and the bicuspid valve should remain open in order to allow blood to flow from the atrium into the ventricles!

Are you sure this is diastole? Because diastole is when all muscles relax so blood flows into the heart. I think it's called ventricular systole. Thanks for your explanation btw.

 

[Tekno-M]

Though, in ventricular systole, the semi-lunar valves are open due to the pressure by the blood, and the atrioventricular valve is shut to prevent blood to move back to the atrium.

 

[Rania MD]

can someone answer this question please.

 

[Rania MD]

do you know the right answer ???

D?!

 

[salvatore]

Are you sure this is diastole? Because diastole is when all muscles relax so blood flows into the heart. I think it's called ventricular systole. Thanks for your explanation btw.

Oh sorry.. i ws kinda confused. This is artrial systole whereby the atria contract and the ventricles relax to allow flow of blood into the ventricles. The tricuspid and bicuspid valves open up to allow blood flow between the atria and ventricles. The semi-lunar valves remain closed to prevent the back flow of blood.
Btw ventricular systole is when the ventricles contract and blood is forced out of the ventricles and into the aorta!

 

[Rania MD]

This one too, pleassseeee.

 

[Tekno-M]

Oh sorry.. i ws kinda confused. This is artrial systole whereby the atria contract and the ventricles relax to allow flow of blood into the ventricles. The tricuspid and bicuspid valves open up to allow blood flow between the atria and ventricles. The semi-lunar valves remain closed to prevent the back flow of blood.
Btw ventricular systole is when the ventricles contract and blood is forced out of the ventricles and into the aorta!

That's exactly the question, ventricles contract, and blood flows into the aorta, so it's ventricular systole.

 

[FATIMAH]

do you know the right answer ???

another member in the forum explained this question !! here is the answer

IT IS D BECUZ ethanol produces CO2 and water when combusted and that oxides of nitrogen and nitrogen arent affect by the fuel used, they will always be available. only sulfur dioxide is affected by the fuel used and ethanol as i said before doesnt release sulfur dioxide when combusted and so it is sulfur dioxide.

 

[Tekno-M]

Btw guys, are you sure that all the marking schemes are 100% correct? Since sometimes I'm 100% assured of an answer and it's still wrong according to the marking schemes.

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

Assalam-o-alaikum wr wb...

why is the answer D?

 

[Dsilentkila]

what da?

 

[Rania MD]

what da?

One X chr.

 

[сᴏᴏʟ сяуѕтᴀʟѕ]

This one too, pleassseeee.

Assalam-o-alaikum wr wb...
the answer is C i guess...bcoz the question says 'human sewage'! what is that suppose to mean? that nitrogen containing compounds move from animals to soil....