Biology 33, how was it?

[dman7000]

Umm, let's see:
Benedict's solution was supposed to be kept anywhere between 80 and 100 degrees (anything written in between would be acceptable)
You're supposed to take 2 cm3 from each solution and 2cm3 (or more) from benedict's
Table:
Headings: concentrations of R, volume of solution, volume of water
0.4---10---0.0
0.3---7.5---2.5
0.2---5.0---5.0
o.1---2.5---7.5
0.0---0.0---10

Describing trend of change in pH for leaves: sharply increases until pH of 5.3 then sharply decreases (although decrease is less steep than increase)
Explaining trend in activity between pH between 5.3 and 6.4: the relatively higher concentrations of OH- ions could interact with the protein structure (by forming hydrogen bonds with the polypeptides) and denature the enzymes. So activity decreases.

And I think that's all. Good luck to everyone on paper 1 this Monday. How are you guys preparing? I've killed the book already (more than 10 times) studying for paper 2, and right now I'm solving all past papers from 2007 - 2012, starting from the most recent. I'll try to be on the paper 1 thread as much as possible

what was your estimation on the concentration of sucrose solution??

 

[♥Яαηõõşḧ♥]

0.4%

 

[Nishii]

it was between 0.1% and 0.2% for me!

 

[Irfan1995]

It's literally impossible for every single students to get identical seeds. So we're definitely going to get different very different answers estimating the concentration of reducing sugars. Mine, for example, was around 0.44%, other students in my class got between 0.2% to 0.5%. It really depends on what you got as a result. If you found out that it took too long for "S" to change colour, then you could put anything below 0.2% (as long as your results are consistent with the timings of the known concentrations).

 

[dman7000]

i got 0.4

 

[Nishii]

i got 0.4

different centres and different countries will get different results i guess, btw ,from which country are you?

 

[Irfan1995]

It's not about the centre or the country, people in my class for answers between 0.2 and 0.5. And maybe you're right, some people might get different types of seeds!
I'm from Jordan.

 

[Nishii]

yeahh..at my centre, all of us got between 0.1 to 0.2 %!

 

[xtremeforums]

What was the variable that you had to keep constant while selecting the seeds? (this question was the first question i think...)

 

[Nishii]

What was the variable that you had to keep constant while selecting the seeds? (this question was the first question i think...)

i wrote size! hey btw, the phloem tissue of slide K1 was very very thin right?