IGCSE Biology Paper 3

[shafiq_92libra]

chem was definately better dan bio for me ><

[hdbkiwi]

dey dint ask wich enzyme was used
dey asked how blood clotting happend and dey sed an enzyme is used
i wrwote about platelets clumping and dey contai fibrinogen wich is changed into fibrin by an enzyme wich hardens and froms a blood clot

oh I just did the platelets part-good job for the fibrinogen part that's full marks for you^^

[hdbkiwi]

Amphibians are the only ones that have smooth skin
Fish and reptiles are the only ones with scales (reptile-dry; fish-wet)
Birds and Mammals have No scales-birds have feathers and mammals have no feathers
Mammals are the only ones that have mammary glands (hence the name mammary ) and external ears.

[sheshee]

heyy yayyy i got the dry mass one correct
and yeah abt the enzyme bacteria thing i ddnt know wt to write so i just wrote that we put it in the fermenter feedstock then filtration hpoes its correct
yeah one more thing how did u guys do in the very last question abt energy? uhh god i ws solving nd then i saw a question abt acid i ws woow wt acid rain has to do with energy ?

[sweetie]

hey guys,
4 da animal feed que. wasnt da energy in feed more dan energy in wheat??
but in da que. dey said 'why is da energy in feed less???
soooooooooo
plz help  

[sheshee]

chem was definately better dan bio for me ><

uhhhh rlyyy nooo for me bio ws much easier than chem omg chem ws somthin different 

[aquarian93]

i sed when there's a cut, platelets and damaged tissues secrete chemicals which converts a soluble protein fibrinogen to insoluble fibrin which forms fibres, and a mesh which forms a clot.

[girl_92]

the water that the plants have taken up is not the only wet mass they have. The water has to be removed completely

Yeah I know.
But as they used the same raddish for 6weeks. We cannot dry it. So the Best option Would be what we wrote.
 

who said the radish used is the same for the weeks. It's not possible...and im sorry cuz to find out dry mass u need to kill the organism.

I'll put down exactly what the book says..take a look

Dry mass is often used as a measure of growth, because wet mass varies from day to day. The value for dry mass is obtained by drying out the organism in an oven, but this involves killing it.

yea nid i wrote the same i wrote dry it in an oven n den weighit using a measurin balance am i correct

[girl_92]

Liver cells - Nucleus, Cytoplasm, and cell membrane. I hope.
Yeah, hepatic portal vein and ileum
dry mass, i put measure the amount of solution uptaken by the plants., and then subtract from original. I think its wrong.

yea thats wrond dude.... uve gotta bake the radish plant to find the dry mass..!

But the same radish has to be used for 6 weeks. How would you "bake" it without killing it? Thats what the
experiment says nid. They measure the growth of the plant for 6 weeks. They wont use different plants.

it says in the Hodder Murray revision guide, By the way, so it s gotta be rite. theres no 2 ways about it, to find the dry mass uve gotta bake the organism, even if cells denature etc etc

As the plant can't make WATER, they have to absorb it from the solution. So if U subtract the mass of water absorb from the mass of radish u get the dry mass.

hey not necesarrily the cells have water frm b4 as well dey need more water to promote further growth so for the dry mass u need to completely dry it out

[aquarian93]

lemme think
i got the dry mass thing rong cuz i jus sed withdraw the water from the plant.
and the enzyme bacteria thing i rote use a fermenter, starch soln is the source, and a water jacket to make the temp constant, dunno if ill get all 3 marks tho  
and u noe da 3 reasons why the energy  decreases from the plants to animal quesiton i think ill lose 1 mark.

[examsaresoon]

Birds have external ears...

[ghostt]

i made so stupid mistakes i m losing aprox. 10 marks so is there any chance that i get an A* as il get above 35 in p3 n p6 inshAllah!!

[hdbkiwi]

If you're getting confused between the variant 1 and 2, there's a new poll+thread for variant 1 

[cool_dude]

Birds have external ears...

they do not have external ears..
but they do have middle ear...

[examsaresoon]

They do have external ears! I have pet birds myself!

"Birds have external ears but they can't be seen. Most birds have their ear holes covered with tiny feathers specially designed to cut down on wind noise while permitting sound waves to pass through."


*i hope i don't sound arrogant*