Bio question... (1 Viewer)

[Chocolat]

Hey guys...(by the way, I'm sorry if I posted this in the wrong location )
I was doing some revision notes for Bio and I was writing my notes according to the syllabus dot points. One of the points stated something like 'perform and plan an investigation which determines the presence of protein, glucose, starch, lipids, chloride ions and lignin in tissues.' In my notes from class, I found all the tests except for that of lignin...and I can't seem to find it anywhere! So if anyone knows...I'd be really appreciative!

 

[yoakim]

mmm i remember that tissue prac.... mmm
protein = i fogot
chloride ions = i forgot
lignin = i fogot also
glucose = bendict solution
starch = iodine /potassium solution
lipid = brown paper

haha sorry i can't help you there, but you can help me

 

[Chocolat]

mmm i remember that tissue prac.... mmm
protein = i fogot
chloride ions = i forgot
lignin = i fogot also
glucose = bendict solution
starch = iodine /potassium solution
lipid = brown paper

haha sorry i can't help you there, but you can help me

Geez...some help you are! Haha...jokes!
Well, this is what I've got so far:
Protein = Biuret's Solution = If protein is present, the solution will turn purple.
Glucose = Benedict's Solution = If glucose is present, the solution will turn red.
Starch = Iodine = If starch is present, the solution will turn blue/black.
Lipid = Brown paper = If a lipid is present, then the paper will become translucent.
Chloride Ions = Silver Nitrate = If chloride ions are present, a white precipitate will form.
Lignin = *silence* :mad1:

 

[kathrynso]

ahhhh i remember doing those notes.... let me have a looky

lignin... ahh found it

to test for lignin, place a piece of tooth pick into water. soak for5 mins. mash up the toothpick then add Toluidine Blue. if it changes to greenish blue - lignin is present. See if the actual test material changes colour and not the soloution

on my sheet there is also Phloroglucinol-HCl - and it should turn red in presence of lignin.

Hope that helps.

 

[Chocolat]

ahhhh i remember doing those notes.... let me have a looky

lignin... ahh found it

to test for lignin, place a piece of tooth pick into water. soak for5 mins. mash up the toothpick then add Toluidine Blue. if it changes to greenish blue - lignin is present. See if the actual test material changes colour and not the soloution

on my sheet there is also Phloroglucinol-HCl - and it should turn red in presence of lignin.

Hope that helps.

OMG! Thank you so much! Don't remember that at all but anyway...thank you!
Well...um...since you're having a lookie at your notes ...you don't happen to recall the experiment that demonstrated the difference between osmosis and diffusion? I know theorically what the difference is...but practical wise = HUH?!

 

[kloudsurfer]

Oooooh me! I know this one! Your lucky Ive got my bio folder out because Im supposed to be doing my bio homework but im having a 'break' lol

For diffusion we did an experiment with potassium permanganate crystals dropped into 2 seperate hot and cold beakers. The porassium permanganate is soluble so it dissolves (or diffuses) through the water, faster through the hot water because heat is a catalyst and generally makes everything go faster.

The osmosis experiment was with a dialysis bag filled with starch solution suspended in a container of iodine solution. The dialysis bag acts as the differentially permeable membrane as it allows the starch solution out as indicated by the colour change in the iodine solution outside the bag. So the bag full of starch solution represents a cell, and the water (starch solution) from inside the cell osmosises (i know, its not a word) out of the cell through the semi-permeable cell membrane (dialysis bag) into the surrounding environment of the cell (iodine solution).

Hope that made sense, i should be asleep right now.

 

[yoakim]

haha i remember that yes.

 

[Chocolat]

Thank you guys so much! I really appreciate it! I think that I should keep this thread up here cause no doubt I'll have more questions...haha