Author Topic: CHEM AND BIO HELP AND TIPS HERE  (Read 345824 times)

Offline The Golden Girl =D

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #495 on: May 02, 2010, 03:56:25 pm »
um how do i revise for paper 6 and 1 chem  IGCSE  on the night/day  before the Eaxm itself?
and
 um how do i revise for paper  1 biology IGCSE  on the night/day  before the Eaxm itself?


thx in advance
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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #496 on: May 02, 2010, 05:27:00 pm »
um how do i revise for paper 6 and 1 chem  IGCSE  on the night/day  before the Eaxm itself?
and
 um how do i revise for paper  1 biology IGCSE  on the night/day  before the Eaxm itself?


thx in advance

Past-papers...Past-papers

Of course if you have time, revise your notes first, then just keep on doing past-papers,even if you have done them before.
« Last Edit: May 02, 2010, 08:43:56 pm by ~ A.F.N.M ~ »

Offline The Golden Girl =D

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #497 on: May 02, 2010, 07:49:30 pm »
thx A.F.

Verily, in the remembrance of Allah do hearts find rest(13:28)

Please, Don't forget to Include GG in your Prayers =D

Offline CatAly$t

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #498 on: May 02, 2010, 08:39:09 pm »
Whoah, you dont need to know that much, simple that they dont work on viruses, because virusesbacteria do not show the characteristics of viruses. You will not be asked this question though, in the CIE spec.

You will be given questions like why has penicillin becomes less effective??

Because strains of Bacteria become more resistant to it.

thx to both of you....
InshaAllah 8 A* in IGCSE....Ameen.....

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Offline K_M

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #499 on: May 03, 2010, 09:52:08 am »
any notes for
- outline the use of microorganisms and fermenters to manufacture the antibiotic
penicillin
- describe the role of the fungus Penicillium in the production of antibiotic penicillin
and
- discuss the adaptations of the leaf, stem and root to three contrasting environments, to include pond, garden and desert, with emphasis on local examples (where appropriate) and the factors described in the core.


The fermenters are used to manufacture antibiotics to provide a sterile environment and optimum conditions ie optimum temperature and pH. Microorganisms speed up the process of producing antibiotics.

Adaptations of plants:
POND: eg: canadian pondweed
- stomata present on upper surface only to absorb carbon dioxide and give out oxygen easily and transpiration is not a problem as water is in abundance.
- The upper epidermis contains chlorophyll as absorbing light energy through the water is difficult therefore it increases photosynthesis
- leaves are thing and ribbon-like in order not to get ruptured by water currents
- the stem contains air spaces to provide buoyancy and to allow diffusion of gases throughout the plant. This provide energy to absorb nutrients by active uptake as they respire aerobically
- stems are flexible and ribbon-like
- roots are virtually absent as water is in abundance hence they do not need to absorb water from the soil.

DESERT: eg: cactus
- leaves are reduced to spines to protect the plant from being eaten and to reduce water loss and in order not to get ruptured by strong desert winds
- stem contains chlorophyll to carry out photosynthesis, it is covered in cutilce to prevent water loss
- stem stores water and nutrients
- stem is short and juicy in order not to get ruptured by strong desert winds
- roots are long to provide anchorage and to reach the water table deep underground

Offline K_M

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #500 on: May 03, 2010, 09:55:24 am »
can someone please give me the answer to the following questions:

1. describe the passage of water from blood in the aorta to its excretion via the urethra

2. outline a treatment of sewage which would produce re-usable water

3.suggest how the build up of sticky mucus would affect a sufferer of cystic fibrosis

4. suggest how a high salt intake can be dangerous to a person's health

thankyou in advance!
« Last Edit: May 03, 2010, 10:24:26 am by K_M »

nid404

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #501 on: May 03, 2010, 11:25:10 am »
can someone please give me the answer to the following questions:

1. describe the passage of water from blood in the aorta to its excretion via the urethra

2. outline a treatment of sewage which would produce re-usable water

3.suggest how the build up of sticky mucus would affect a sufferer of cystic fibrosis

4. suggest how a high salt intake can be dangerous to a person's health

thankyou in advance!

5 hrs

Offline saleemsamer

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #502 on: May 03, 2010, 11:32:05 am »
The fermenters are used to manufacture antibiotics to provide a sterile environment and optimum conditions ie optimum temperature and pH. Microorganisms speed up the process of producing antibiotics.

Adaptations of plants:
POND: eg: canadian pondweed
- stomata present on upper surface only to absorb carbon dioxide and give out oxygen easily and transpiration is not a problem as water is in abundance.
- The upper epidermis contains chlorophyll as absorbing light energy through the water is difficult therefore it increases photosynthesis
- leaves are thing and ribbon-like in order not to get ruptured by water currents
- the stem contains air spaces to provide buoyancy and to allow diffusion of gases throughout the plant. This provide energy to absorb nutrients by active uptake as they respire aerobically
- stems are flexible and ribbon-like
- roots are virtually absent as water is in abundance hence they do not need to absorb water from the soil.

DESERT: eg: cactus
- leaves are reduced to spines to protect the plant from being eaten and to reduce water loss and in order not to get ruptured by strong desert winds
- stem contains chlorophyll to carry out photosynthesis, it is covered in cutilce to prevent water loss
- stem stores water and nutrients
- stem is short and juicy in order not to get ruptured by strong desert winds
- roots are long to provide anchorage and to reach the water table deep underground
thx :D

Offline sarasa

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #503 on: May 03, 2010, 02:41:09 pm »
WHere in the car is a catalytic converter fitted in a vehicle?

Offline $H00t!N& $t@r

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #504 on: May 03, 2010, 03:41:10 pm »
Quote
WHere in the car is a catalytic converter fitted in a vehicle?

The Catalytic Converter is a device fitted in the exhaust system of your car that effectively reduces the harmful exhaust gases entering the atmosphere.

"If A equals success, then the formula is:
A=X+Y+Z, X is work. Y is play. Z is keep your mouth shut"- Albert Einstein

nid404

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #505 on: May 03, 2010, 05:44:01 pm »
can someone please give me the answer to the following questions:

1. describe the passage of water from blood in the aorta to its excretion via the urethra


Blood is got to the kidney via renal artery. The renal artery divides into a great number of arterioles and capillaries, mostly in the cortex. Each arteriole leads to a glomerulus. The pressure in the glomerulus causes part of the blood plasma to leak the capillary walls. The RBC's and proteins in plasma r too big to pass out. The fluid that moves out contains mainly water with dissolved salts, urea, glucose and uric acid. The process by which the fluid is filtered out of the blood by the glomerulus is called ultrafiltration. The filtrate from the glomeruls collects in the renal capsule and trickles down the renal tubule. As it does so, the capillaries which surround it absorb the substance the body needs. All the glucose is absorbed, with much of the water(depends on the state of hydration). The some salts r taken back to keep the correct con in the blood. This process of taking back the required substances is called selective reabsorption.

Substances that r not needed pass further down to the collecting duct into the pelvis of the kidney. From here the fluid, now called urine, passes down the ureter to the bladder.


Nephron- A single glomerulus with its renal artery, renal tubule and blood capillaries

visit the site for a good animation http://www.biologymad.com/resources/kidney.swf

nid404

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #506 on: May 03, 2010, 06:01:58 pm »
can someone please give me the answer to the following questions:

2. outline a treatment of sewage which would produce re-usable water



http://www.ehow.com/about_5368260_sewage-water-treatments.html

I dunno how much of it you wanted....i you told me the marks, i would've written down a good answer

nid404

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #507 on: May 03, 2010, 06:03:24 pm »
can someone please give me the answer to the following questions:


3.suggest how the build up of sticky mucus would affect a sufferer of cystic fibrosis


Cystic fibrosis is an inherited disease which affects the lungs and digestive system. It results from mutation in a gene responsible for making a protein which is involved in the transport of ions across cell boundaries.

The effect is to produce a sticky mucus which clogs the lungs and can lead to serious infection. A similar sticky mucus also blocks the pancreas (a part of the digestive system) which provides enzymes for breaking down food. This gets in the way of the processes which convert the food into molecules which can be absorbed by the body.

Offline $H00t!N& $t@r

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Re: CHEM AND BIO HELP AND TIPS HERE MOLESS!!!!
« Reply #508 on: May 03, 2010, 06:34:20 pm »
Hi, can you please help me solve the following question

0.5 g of magnesium is added to a solution containing 3.0 g of ethanoic acid. Which is the limiting reagent and how many moles of the other reagent are left unreacted?             

Mg + 2CH3COOH ---> (CH3COO)2Mg + H2

Please explain fully with all the steps.

And can you please give an excellent website on moles?
Thanks in advance!
"If A equals success, then the formula is:
A=X+Y+Z, X is work. Y is play. Z is keep your mouth shut"- Albert Einstein

Offline haris94

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Re: CHEM AND BIO HELP AND TIPS HERE
« Reply #509 on: May 03, 2010, 07:16:25 pm »
first find the number of moles of each reactant
no. of moles = mass/molecular mass
so mg=0.5g and ch3cooh=3g
and ram of mg=24   and   rmm of ch3cooh=60

moles of mg=0.5/24               moles of ch3cooh=3/60
                =0.02                                         =0.05

now use mol ratio to find the number of moles used
(take the lower value from your answer of the no. of moles)

mg   :   ch3cooh
1     :    2
0.02 :   x
x=2*0.02
x=0.04 moles

so ultimately your limiting reagent will be mg cause it was all used up in the reaction
and out of the 0.05 moles of ch3cooh, 0.04 were used up

hope i was able to help
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