Biology paper 3

[Yousif Mukkhtar]

hey, how does dialysis machine work?
im sooooooooooooooooooooooooooooooooooooo stressed i have biology and french continuous writing on the same day!! my hand will fall off!!!!

Don't stress yourself. You will lead yourself to more confusion. Take it easily.

See, for dialysis machine it is more like "artificial kidney" it filters and removes the urea and salt by this principle:
The blood coming out of the vein is directed the dialysis machine. The dialysis machine contains dialysis fluid, which is in such a compositon that allows urea and salts to diffuse into but not water and use molecules like glucose. Because blood has higher concentration of urea and salts, they diffuse from blood to the dialysis fluid. So the blood now has less urea and salt concentration. This is returned to a chamber that removes blood clots and maintains the temperature , this prevents the person having some kind of shock when blood returns to him. So now the blood is returned back to his vain, in a more purified form.

 

[Yousif Mukkhtar]

Oh me too please, those are my worst topics..

Nitrogen fixation is done by bacteria present in root nodules of plants. The bacteria convert the nitrogen in the soil to a more reactive form such ammonia or nitrate. The plants then absorb these fixed nitrogen compounds and make proteins.

Animals then feed on the plant and obtain proteins. When both plants and animals die, decomposers feed on them and convert it to ammonia. Nitrification is when bacteria converts ammonia to nitrate, which plants can use again.

 

[TheBaller23]

Nitrogen fixation is done by bacteria present in root nodules of plants. The bacteria convert the nitrogen in the soil to a more reactive form such ammonia or nitrate. The plants then absorb these fixed nitrogen compounds and make proteins.

Animals then feed on the plant and obtain proteins. When both plants and animals die, decomposers feed on them and convert it to ammonia. Nitrification is when bacteria converts ammonia to nitrate, which plants can use again.

Take note that they don't award you for stating where the symbiotic bacteria are located.. Saw in a past paper M.S. "Ignore - reference to root nodules"
Also nitrifying bacteria first convert atmospheric nitrogen to nitrites then nitrates to be specific

 

[ZainH]

Nitrogen fixation is done by bacteria present in root nodules of plants. The bacteria convert the nitrogen in the soil to a more reactive form such ammonia or nitrate. The plants then absorb these fixed nitrogen compounds and make proteins.

Animals then feed on the plant and obtain proteins. When both plants and animals die, decomposers feed on them and convert it to ammonia. Nitrification is when bacteria converts ammonia to nitrate, which plants can use again.

Thanks a ton.

 

[Yousif Mukkhtar]

Thanks a ton.

Anytime.

 

[salvatore]

Nitrogen from the air is usually in an nonreactive form.. changing nitrogen gas from the air into a more reactive form is called nitrogen fixation. This can be done by:
1 - Lightning - Which makes nitrogen gas in air combine with oxygen, forming nitrogen oxide. When these oxides dissolve in rain, they are washed into the soil where they from nitrates.
2 - A nitrogen-fixing bacteria (Rhizobium) lives in the soil & uses nitrogen gas from the air spaces in the soil to make ammonium ions which the plant uses to make protein!

Nitrification is whereby the the ammonia, which is broken down from dead plants/animals, is converted to nitrates.. which the plants can use. This is usually carries out by nitrifying bacteria

 

[whitetiger64]

Nitrogen fixation is done by bacteria present in root nodules of plants. The bacteria convert the nitrogen in the soil to a more reactive form such ammonia or nitrate. The plants then absorb these fixed nitrogen compounds and make proteins.

Animals then feed on the plant and obtain proteins. When both plants and animals die, decomposers feed on them and convert it to ammonia. Nitrification is when bacteria converts ammonia to nitrate, which plants can use again.

Thank you bt i hav one more doubt! So the nitrifying bacteria and nitrogen fixing bacteria are completely differant?

 

[Yousif Mukkhtar]

Thank you bt i hav one more doubt! So the nitrifying bacteria and nitrogen fixing bacteria are completely differant?

Yeah completely different. Because nitrogen fixing bacteria convert nitrogen to nitrate/ammonia directly. Nitrifying only converts ammonia to nitrate.

 

[whitetiger64]

Yeah completely different. Because nitrogen fixing bacteria convert nitrogen to nitrate/ammonia directly. Nitrifying only converts ammonia to nitrate.

kk thnx

 

[whitetiger64]

Can anyone plz explain the role of villi in digestion???

 

[Jspake]

Nitrogen from the air is usually in an nonreactive form.. changing nitrogen gas from the air into a more reactive form is called nitrogen fixation. This can be done by:
1 - Lightning - Which makes nitrogen gas in air combine with oxygen, forming nitrogen oxide. When these oxides dissolve in rain, they are washed into the soil where they from nitrates.
2 - A nitrogen-fixing bacteria (Rhizobium) lives in the soil & uses nitrogen gas from the air spaces in the soil to make ammonium ions which the plant uses to make protein!

Nitrification is whereby the the ammonia, which is broken down from dead plants/animals, is converted to nitrates.. which the plants can use. This is usually carries out by nitrifying bacteria

Thanx man.. clear as crystal!

 

[Jspake]

Can anyone please explain negative feedback?? I will appreciate the definition and one example..

 

[Yousif Mukkhtar]

Can anyone plz explain the role of villi in digestion???

A villi is a finger like structure present in the small intestine, there are many of them giving a large surface area for diffusion. A villi has both capillaries and lacteal in it. S o a villi is basically a structure that absorbs digested food. Glucose and amino acids diffuse in to the caplliaries, and so the capillaries carry them. The capillaries join up together and forms a vein called the hepatic portal vein, which takes the digested food to the liver. The liver then decides what to do. Excess glucose is converted to glycogen and amino acids to proteins. The excess part is destroyed.

Lacteal absorbs fatty acids and glycerol and takes it to the lymphatic system.

 

[dana xP]

this one is strainght out of the notes out of http://www.xtremepapers.com/community/threads/igcse-physics-chemistry-biology-notes.14611/
"Negative feedbackis where, when the hypothalamus has made your skin take action to increase heat loss, info about this is fed back as the drop in blood temperature is sensed, so the hypothalamus stops the skin taking action to lose heat.""

thanx alot it was a greatb help ya know !!

 

[dana xP]

A villi is a finger like structure present in the small intestine, there are many of them giving a large surface area for diffusion. A villi has both capillaries and lacteal in it. S o a villi is basically a structure that absorbs digested food. Glucose and amino acids diffuse in to the caplliaries, and so the capillaries carry them. The capillaries join up together and forms a vein called the hepatic portal vein, which takes the digested food to the liver. The liver then decides what to do. Excess glucose is converted to glycogen and amino acids to proteins. The excess part is destroyed.

Lacteal absorbs fatty acids and glycerol and takes it to the lymphatic system.

can u plz tell me how does the lacteal join up with the lymphatic system and what happens to the fatty acids and glycerol ??
it would mean a lot to me

 

[Yousif Mukkhtar]

can u plz tell me how does the lacteal join up with the lymphatic system and what happens to the fatty acids and glycerol ??
it would mean a lot to me

Actually that part isn't in our syllabus.

Lacteal is basically an extension coming out of the lymphatic system. For example an artery separates and makes capillaries. The lymph vessels separate and makes an extension called the lacteal. A lacteal is joined and connected to the lymph vessels.

 

[dana xP]

Actually that part isn't in our syllabus.

Lacteal is basically an extension coming out of the lymphatic system. For example an artery separates and makes capillaries. The lymph vessels separate and makes an extension called the lacteal. A lacteal is joined and connected to the lymph vessels.

hhhhhhhhhhhhh ok sorry for that !!

 

[Maz]

can someone please explain to me what's ATP?

 

[dana xP]

what is the deanimation process ??

 

[Yousif Mukkhtar]

can someone please explain to me what's ATP?

First of all, ATP is Adenosene Triphosphate. It is the basic source of energy, so during respiration energy is released in the form of ATP. ATP can be used for storing and releasing energy. When energy is released, one phosphate molecule is removed from the ATP so it is called Adenosene disphosphate. ATP can also be used to store energy, by adding a phosphate ion to the Adenonese diphosphate giving you ATP (Adenonese triphosphate)

If that wasn't clear read:
ATP is a source of energy
It can be used to store energy when one phosphate ion is added to Adenonesene diphosphate which gives ATP.
ATP can release energy by releasing a phosphate ion.