Biology P5

[MukeshG93]

THANKU....
I REALLY APPRECIATE...

HAS ANY1 DONE N/09/51??
THERE'S A QS ASKING TO MAKE A GRAPH OF TEMP V/S LIGHT DEPENDENT STAGE...
I CAN NOT UNDERSTAND WHY IS THERE A HORIZONTAL LINE N THEN DECREASING....???
ISNT IT SUPPOSE TO B INCREASING INITIALLY...???

M REALLY CONFUSED...

ANYONE WHO HAS THE QS TO THIS QS??? :Search:

well we know that light dependent reactions are light dependent not temperature dependent... so the rate remains constant initially ...but as the temperature increases and exceeds the optimum level, the membrane systems within the chloroplasts are damaged, hence, decreasing rate of light dependent reactions...
hope that helps

Actually, the pigments have bonds in them that are broken at high temperatures as well so the light-dependent stage is also sort of temperature-dependent

 

[MukeshG93]

YOU R RITE...
BUT DO V HAVE TO COMPLETELY IGNORE THE TWO TYPES OF LEAVES USED....
IT WILL MAKE A DIFFERENCE...

Of course it will make a difference, that's why we are comparing them and the effects that different light intensities have on them. We are not just observing the effect of light intensity of leaves, we are investigating the difference in the effects in two different types of leaves.

 

[beacon_of_light]

THANKU....
I REALLY APPRECIATE...

HAS ANY1 DONE N/09/51??
THERE'S A QS ASKING TO MAKE A GRAPH OF TEMP V/S LIGHT DEPENDENT STAGE...
I CAN NOT UNDERSTAND WHY IS THERE A HORIZONTAL LINE N THEN DECREASING....???
ISNT IT SUPPOSE TO B INCREASING INITIALLY...???

M REALLY CONFUSED...

ANYONE WHO HAS THE QS TO THIS QS??? :Search:

well we know that light dependent reactions are light dependent not temperature dependent... so the rate remains constant initially ...but as the temperature increases and exceeds the optimum level, the membrane systems within the chloroplasts are damaged, hence, decreasing rate of light dependent reactions...
hope that helps

Actually, the pigments have bonds in them that are broken at high temperatures as well so the light-dependent stage is also sort of temperature-dependent

Yeah it is so the conclusion is that light dependent reactions will only be effected at very high temperatures... otherwise normally light effects the rate of Light dependent reactions...

 

[Sweet_angel]

can any one plzzz explain me about null hypothesis and both types of variables.....plzzzz.z.....m really getting confused.....

 

[MukeshG93]

Okay people, keep it coming, what else do we have? Potometer, Respirometer, Alginate beads, what else do we have?

 

[MukeshG93]

can any one plzzz explain me about null hypothesis and both types of variables.....plzzzz.z.....m really getting confused.....

A null hypothesis is a supposed opposite of the hypothesis that we are actually testing. So, if we are testing the difference between two results, the null hypothesis would state that they are not same, not different.

Types of variables:
- Independent variable: the variable that does not depend on other variables, the thing we control
- dependent variable: the variable that depends on the independent variable, the thing that cannot be controlled and can depend on the changes in the independent variable

 

[beacon_of_light]

can any one plzzz explain me about null hypothesis and both types of variables.....plzzzz.z.....m really getting confused.....

Okey I'll try to explain with an example...
Suppose you have two sets of data... you calculated their means...now you have to perform a test to see whether the means differ significantly or not...so initially you make a statement that " there is no significant difference b/w the means of the two sets of data" and this is your null hypothesis... now you'll be performing the test to check whether it's right or wrong...

And for the variables, independent ones are those which you vary while the dependent ones are to be calculated or determined and effected as a result of independent variables... independent variables are the ones which you control while the independent variables control the dependent ones...
Hope you get that

 

[Sweet_angel]

 

[Xam]

Yar may june 09 Q3b part 4, how is degrees of freedom 38?
yar plz help

 

[MukeshG93]

Yar may june 09 Q3b part 4, how is degrees of freedom 38?
yar plz help

I have had at least 3 people ask me this in my personal life already. It is quite tricky and CIE really shouldn't expect us to waste a lot of time figuring this out because there is already so much pressure. Alright, so here you are comparing two pHs which were tested for 20 hours each. So, for each, the respective degrees of freedom would be 19. Now, in a case like this, the degrees of freedom ADD UP!! giving 38. Do not forget this!

 

[Xam]

thanks a lot man!!!!
n oh plz 1 more
oct nov 08 q2 part b.ii n iii
where did ths n cme frm? n d.f?

 

[MukeshG93]

thanks a lot man!!!!
n oh plz 1 more
oct nov 08 q2 part b.ii n iii
where did ths n cme frm? n d.f?

There are 4 strips for each 5 leaves so the total number of data = 4x5 = 20 and root(20) = 4.47

degrees of freedom = n - 1 = 20 - 1 =19

 

[Xam]

@mukesh

see when t is greater than critical value than it is not significant difference rite?
or when t is less thn crtical value? Thanks

 

[AN10]

when drawing error bars on bar graphs is it suppose to be +/- Sm or +/- 2Sm?

 

[MukeshG93]

@mukesh

see when t is greater than critical value than it is not significant difference rite?
or when t is less thn crtical value? Thanks

It is significant when t is greater than the critical value and you can reject the null hypothesis.

 

[Xam]

thnx man u made my day
i thnk thn chi square gr8r thn 0.05 is not significant n we reject null hypothesis

 

[fusionistics]

when drawing error bars on bar graphs is it suppose to be +/- Sm or +/- 2Sm?

I also wanted to ask this! I'm really confused about which one to use. The books say 2Sm but some of the mark schemes say Sm. Can someone clarify???

 

[zeebujha]

when drawing error bars on bar graphs is it suppose to be +/- Sm or +/- 2Sm?

I also wanted to ask this! I'm really confused about which one to use. The books say 2Sm but some of the mark schemes say Sm. Can someone clarify???

Use the 2Sm. It covers the 95% range and hence is more appropriate than 1 Sm which I think only covers 67% range

 

[ijat91]

Why M/J 07 no 1 iv) the mark scheme write plus minus 1Sm not 2Sm???

 

[MukeshG93]

when drawing error bars on bar graphs is it suppose to be +/- Sm or +/- 2Sm?

I also wanted to ask this! I'm really confused about which one to use. The books say 2Sm but some of the mark schemes say Sm. Can someone clarify???

Use the 2Sm. It covers the 95% range and hence is more appropriate than 1 Sm which I think only covers 67% range

The point is that the error ranges from the bottom ( - Sm) to the top (+ Sm) so the difference (the range of plot) would be + Sm - ( - Sm) = 2Sm