Biology; Chemistry; Physics: Post your doubts here!

[screamingskull]

http://www.xtremepapers.com/papers/...onal O Level/Biology (5090)/5090_w07_qp_6.pdf

Please solve question 2b
Answer needed urgently!!

 

[Anam Noor]

help!!!
can someone please tell me
how to find the energy content of foods?
and how to demonstrate the presence of stomata in a leaf?
also what is lymph and lymphatic system?

 

[ayeshaK]

http://www.xtremepapers.com/papers/...onal O Level/Biology (5090)/5090_w07_qp_6.pdf

Please solve question 2b
Answer needed urgently!!

Holes,smearsorfilterpaperdiscsonculturedishes; [or a group of separate dishes]
dilutions mentioned ; R: volumes
clear areas measured/observed ;
how results assessed ;
replication ;
control qualified ;
constant environment/temp/volume/
As specified in mark scheme

 

[screamingskull]

Holes,smearsorfilterpaperdiscsonculturedishes; [or a group of separate dishes]
dilutions mentioned ; R: volumes
clear areas measured/observed ;
how results assessed ;
replication ;
control qualified ;
constant environment/temp/volume/
As specified in mark scheme

haha i have already read the marking scheme but i want a proper constructed answer...anyone??

 

[scouserlfc]

http://www.xtremepapers.com/papers/CIE/Cambridge International O Level/Biology (5090)/5090_w07_qp_6.pdf

Please solve question 2b
Answer needed urgently!!

Just give an experiment or make a diagram and explain use six or seven petri dishes in one dont add any penicillin and make it a control in the rest add increasing conc of penicillin using a dropper or a suitable apparatus and then keep all in the same temp.,same conditions as well ,make sure dishes are sterile and equal bacteria was grown on them when u add the penicillin strain,keep the dishes and then at a particular time like one day compare with control and make sure u give all dishes equal time period ! The dish which has killed bacteria only slightly and bacteria still is there but has been removed from some regions is the conc u are looking for record the results
Replication might help as well !

 

[asd]

help!!!
can someone please tell me
how to find the energy content of foods?
and how to demonstrate the presence of stomata in a leaf?
also what is lymph and lymphatic system?

1) Use different samples of food and ignite them under a test tube containing water with a thermometer(at least 1/3rd immered). use the method for each food sample, like separately for carbohydrate, fat, and protein. Record the temperature increase in each test tube by burning the food sample. The highest temperature difference indicates highest energy content. This will be of fats.
2) stomata are minute openings (pores) on the underside of the leaf. Their presence can be demonstrated simply by immersing a leaf in water. Bubbles will come out of the lower surface of the leaf showing that there are pores.
3) Tissue fluid forms at the arterial (coming from the heart) end of capillaries because of the higher pressure of blood compared to veins, and most of it returns to its venous ends and venules; the rest (1%) enters the lymph capillaries as lymph. Thus, lymph when formed is a watery clear liquid with the same composition as the tissue fluid. However, as it flows through the lymph nodes it comes in contact with blood, and tends to accumulate more cells (particularly, lymphocytes) and proteins. Lymphatic system is just that it is in continuous circulation as it takes in tissue fluid and returns it to the blood.

 

[Meg]

Please solve my doubt. May-June 2004 q. 3.a.i.) Need to know the position of the seed. Also all the bio p6 q, need to know the labeling for the diagrams as it aint mentioned in the markscheme. please reply asap. thank u

 

[screamingskull]

Please solve my doubt. May-June 2004 q. 3.a.i.) Need to know the position of the seed. Also all the bio p6 q, need to know the labeling for the diagrams as it aint mentioned in the markscheme. please reply asap. thank u

I can't find any question in paper 6 and 2 regarding a seed
Please specify exactly which paper and question

 

[Meg]

its may-june 2005, q2aii./0610/06.
next doubt is june 2004 q3ai. /0610/06

 

[screamingskull]

its may-june 2005, q2aii./0610/06.
next doubt is june 2004 q3ai. /0610/06

X is the anther
Y is the stigma (only one stigma is present surrounded by three-four pistils which have X on top of them)
Z is the long tube in the carpel-i.e the style.

 

[Meg]

I know that
I just dont know its location :/
can you label and upload the pic please?

 

[asd]

I know that
I just dont know its location :/
can you label and upload the pic please?

You might be confused in stigma and anther, actually the 2 in between are the stigmas, and the other 3 are stamens.

 

[Anam Noor]

1) Use different samples of food and ignite them under a test tube containing water with a thermometer(at least 1/3rd immered). use the method for each food sample, like separately for carbohydrate, fat, and protein. Record the temperature increase in each test tube by burning the food sample. The highest temperature difference indicates highest energy content. This will be of fats.
2) stomata are minute openings (pores) on the underside of the leaf. Their presence can be demonstrated simply by immersing a leaf in water. Bubbles will come out of the lower surface of the leaf showing that there are pores.
3) Tissue fluid forms at the arterial (coming from the heart) end of capillaries because of the higher pressure of blood compared to veins, and most of it returns to its venous ends and venules; the rest (1%) enters the lymph capillaries as lymph. Thus, lymph when formed is a watery clear liquid with the same composition as the tissue fluid. However, as it flows through the lymph nodes it comes in contact with blood, and tends to accumulate more cells (particularly, lymphocytes) and proteins. Lymphatic system is just that it is in continuous circulation as it takes in tissue fluid and returns it to the blood.

thank you
for solving m problem

 

[diana barnieh]

Can someone please send me 2007-2010 igcse biology edexcel exams? I can't seem to find any on the internet!

 

[Spidey21]

Can someone please send me 2007-2010 igcse biology edexcel exams? I can't seem to find any on the internet!

sorry but its hard to say that one might help you here..most probably if you go into the IGCSE section then you might find someone to help you with that part..

 

[Meg]

alright
thanks

 

[Vogue]

does yeast respires aerobically or anaerobically? especially in bread, cheese nd yogurt making

 

[scouserlfc]

does yeast respires aerobically or anaerobically? especially in bread, cheese nd yogurt making

It depends what conditions are provided to it it can respire both ways if conditions allow it to but preferably it respires Aerobically in oxygens presence !
In bread making it respires anaerobically because u make it do it and in yoghurt and bread when it feeds if it does it depends on the conditions

 

[Meg]

does yeast respires aerobically or anaerobically? especially in bread, cheese nd yogurt making

It respires anaerobically

 

[Tharindu]

What's the purpose of slip rings and split rings