biology practical

[princessnoor]

it inhibits the reaction between iodine and starch.

i got it wrong
hey in the table i didnt ook first sample at 0 minute and so how much marks ill lose any idea?

 

[princessnoor]

it inhibits the reaction between iodine and starch.

what about question 2??
i draw the slide like this check here--(file:///C:/Users/prado/Desktop/Nimra/Untitled.png)

 

[redd]

Google says:
ascorbic acid + I2 --> 2 I- + dehydroascorbic acid
Due to this reaction, the iodine formed is immediately reduced to iodide as long as there is any ascorbic acid present. Once all the ascorbic acid has been oxidised, the excess iodine is free to react with the starch indicator, forming the blue-black starch-iodine complex.

 

[happyperson]

If i added the value of sample A in table too, so will my marks be cut. I took 5 values; A, 1, 2, 3 and 4. 1 2 3 4 were taken at o, 5, 10 and 15 mins. Is it fine in the table to gain marks. Please tell.

 

[happyperson]

i got it wrong
hey in the table i didnt ook first sample at 0 minute and so how much marks ill lose any idea?

I think 1 mark for not using that value. 1 mark is for drawing the table, one for column headings with units and i guess the rest are for values and trend in the table.

 

[princessnoor]

I think 1 mark for not using that value. 1 mark is for drawing the table, one for column headings with units and i guess the rest are for values and trend in the table.

yeh
plzz tell me about question 2 i draw the slide like this is tht correct?

 

[happyperson]

yeh
plzz tell me about question 2 i draw the slide like this is tht correct?View attachment 44102

I thought that those were RBCs near the the alveolar wall. However, i'm not sure whether it could be nucleus.

 

[princessnoor]

Google says:
ascorbic acid + I2 --> 2 I- + dehydroascorbic acid
Due to this reaction, the iodine formed is immediately reduced to iodide as long as there is any ascorbic acid present. Once all the ascorbic acid has been oxidised, the excess iodine is free to react with the starch indicator, forming the blue-black starch-iodine complex.

tht question was hard because we were not to supposed to hve beenn studied it and i think we didnt had to give this much informaion about the reaction
wht u think?

 

[princessnoor]

I thought that those were RBCs near the the alveolar wall. However, i'm not sure whether it could be nucleus.

i did another paper before exam and we had to draw alveoli and the surrounding were were not rbc but nucleus.
wht did u draw?

 

[happyperson]

i did another paper before exam and we had to draw alveoli and the surround were were not rbc but nucleus.
wht did u draw?

Yeah right, i checked it on google, those were nuclei and i drew the same and marked nucleus at one of the wall of alveolus as you marked but i thought later that it was wrong, but now it's confirmed that it's correct.

 

[zain ul abidin]

what was the value of volume of iodine that reacted with 100% starch (on graph)?
i came up with 6.3cm^3

 

[princessnoor]

Yeah right, i checked it on google, those were nuclei and i drew the same and marked nucleus at one of the wall of alveolus as you marked but i thought later that it was wrong, but now it's confirmed that it's correct.

thanks god =D
so i get full marks for that diagram?

 

[princessnoor]

what was the value of volume of iodine that reacted with 100% starch (on graph)?
i came up with 6.3cm^3

dont remember but it was according to everyones graph

 

[princessnoor]

what was the answer to last part of question 1 tht asked how do u confirm iodine reacted with 100% starch?

 

[Dukeofwin]

There has to be a mixed response for ascorbic acid question. Threshold for that question will be low so calm down!

Btw what magnification did you guys get?

 

[princessnoor]

There has to be a mixed response for ascorbic acid question. Threshold for that question will be low so calm down!

Btw what magnification did you guys get?

i got x407
nd yeh i hope gt is low

 

[princessnoor]

ANYONE plz check if this is correct question 2 bii the diagram of plant cells

 

[Snowysangel]

Yeah right, i checked it on google, those were nuclei and i drew the same and marked nucleus at one of the wall of alveolus as you marked but i thought later that it was wrong, but now it's confirmed that it's correct.

I drew the epithelial cells as well...they didn't look like squamous tho

 

[Snowysangel]

what was the value of volume of iodine that reacted with 100% starch (on graph)?
i came up with 6.3cm^3

I got 3.0 cm3...I just extended the line since it was already rightly linear and I extrapolated the value from the graph

 

[redd]

tht question was hard because we were not to supposed to hve beenn studied it and i think we didnt had to give this much informaion about the reaction
wht u think?

yes right, this is far beyond everyone's reach, but i did mention that ascorbic acid breaks the iodine sol and then the excess iodine reacts with starch and it changes to blue black