IGCSE Biology Paper 3

[Friends]

Now stop the discussen of this question as nor do i will agree with U and nor do U will agree with me.

[guru007]

well....it actually depends on the examiners mind...

Was the punnet square Hn           Hs
                            Hn HnHn       HnHs
                            Hs HnHs        HsHs

Sickle cell - HsHs


Correct ??

[nid404]

Now stop the discussen of this question as nor do i will agree with U and nor do U will agree with me.

i'm just trying to help u so that u don't keep a wrong ans in ur mind and go ahead. just correct urself...if sum1 would correct me if i were wrong i would make sure i don't keep my wrong,half knowledge and disagree. But i u insist fine

[aquarian93]

The natural selection answer was because the sickle cell hetero ppl cant get malaria right? So the survive due to survival of fittest, and they pass the trait onto their children right?

yuP

[aquarian93]

well....it actually depends on the examiners mind...

Was the punnet square Hn           Hs
                            Hn HnHn       HnHs
                            Hs HnHs        HsHs

Sickle cell - HsHs


Correct ??

dats wat i did

[annie_angel]

we HAD to show the punnet square ryt???because i did

[aquarian93]

I totally messed up with the Natural selection question[5mks]
But the paper was little bit hard compared to 2008.
Threshold will be 50/80 for A

hw do u noe abt the threshold? thats quite comforting

guys how did u find the paper!??

if this threshold is wrong then it's lower haha because i have never seen something above that for a paper 3 soo RELAX

The Paper was Ok, kinda lengthy with some trickies but i managed 

and i think everyone did


what about you?

yea i found it lengthy as well, i finished like JUST on time, no time to look bak, haha
it was ok, nthng great nthng horrible.
well i hope its 50. i thoght it was 57 dats y

[annie_angel]

Now stop the discussen of this question as nor do i will agree with U and nor do U will agree with me.

i dnt understand y u wnt agree and thts ok...but i would rather advise u to go open ur txt bk if u dnt believe us...we r just trying to help...no offense....

[IG_ICE09]

if u remember the last question, first subquestion which had sumthin "Suggest three reasons why not all the energy in the wheat crop is available in animal feed" or sumthin like that i wrote:

1) not all the sunlight available to the wheat crop is used by it
2) animal may not eat all of the wheat crop , some of it is undigested
3) wheat crop may use some of its energy for respiration i.e. for growth or active transport

does that make sense?

overall i thot the questions had too many marks! all 3,4, 5 mark questions..loads of questions were overmarkd n were given like 4 or 5 marks..nyway for the table in the first question, i ticked "Scales/scaly skin" for birds, as all textbooks say birds have scales on their feet, but many ppl in my class sed u didnt hav 2 tick it!

[annie_angel]

if u remember the last question, first subquestion which had sumthin "Suggest three reasons why not all the energy in the wheat crop is available in animal feed" or sumthin like that i wrote:

1) not all the sunlight available to the wheat crop is used by it
2) animal may not eat all of the wheat crop , some of it is undigested
3) wheat crop may use some of its energy for respiration i.e. for growth or active transport

does that make sense?

overall i thot the questions had too many marks! all 3,4, 5 mark questions..loads of questions were overmarkd n were given like 4 or 5 marks..nyway for the table in the first question, i ticked "Scales/scaly skin" for birds, as all textbooks say birds have scales on their feet, but many ppl in my class sed u didnt hav 2 tick it!

i ticked birds DO hav scales on their feet...

[mr_scholes]

if u remember the last question, first subquestion which had sumthin "Suggest three reasons why not all the energy in the wheat crop is available in animal feed" or sumthin like that i wrote:

1) not all the sunlight available to the wheat crop is used by it
2) animal may not eat all of the wheat crop , some of it is undigested
3) wheat crop may use some of its energy for respiration i.e. for growth or active transport

does that make sense?

u had to write about
energy loss e.g. energy lost by movement-respiration-heat loss in urine+faeces-not all organism is digested/eaten etc..

[QuickSilver]

if u remember the last question, first subquestion which had sumthin "Suggest three reasons why not all the energy in the wheat crop is available in animal feed" or sumthin like that i wrote:

1) not all the sunlight available to the wheat crop is used by it
2) animal may not eat all of the wheat crop , some of it is undigested
3) wheat crop may use some of its energy for respiration i.e. for growth or active transport

does that make sense?

overall i thot the questions had too many marks! all 3,4, 5 mark questions..loads of questions were overmarkd n were given like 4 or 5 marks..nyway for the table in the first question, i ticked "Scales/scaly skin" for birds, as all textbooks say birds have scales on their feet, but many ppl in my class sed u didnt hav 2 tick it!

Hey

I cant jude really if what you wrote is correct or not, but it seems ok
This is what I wrote:
1-Some energy is used by the wheat for itself and the process carried out in the plant itself
  
2-Some Tiny unwanted animals or insects such as rats or cockoraches may be feeding on the wheat too thus                                                                                                            
         reducing the total energy available for the animals

3-Some energy is wasted when it is flowing through the food chain i.e from the plant to the animals in the form of                                            heat


And YEAh ur  right tooo many marks for even small quesations

and for the birds YOU HAVE TO TICK THE SCALES IT IS CORRECT SCALES FOR BIRDS ARE CORRECT


Hope I Helped

[abcdef]

For dry mass question, I wrote, take the plants from solution and measure it. (that's what I remember)
I missed the natural selection and glucose concentration.

What did you write for "trophic level question" ?

[QuickSilver]

can someone check if my reasons are correct?

Thanks,

[thukon]

SCALES FOR BIRDS IS WRONG.
They want to know which organisms are covered in whatever. So scales/scaly skin is only reptiles and fish.