Some biology practical doubts

[lionkill3r]

Hello people. As you can see in the topic i have some bio practical doubts...

1. During Reducing sugar test do we put the solution with benedicts reagent in aWater bath already at 100 degree celsius or do we add it in a water bath and then start to heat.
2.During Reducing sugar test what is the optimum time to keep the solution in the water bath.
3.For biuret and emulsion test should we measure and add biurets reagent/ethanol or de we just add an excess.
4.Whats the diffference between High power drawing and low power drawing ?

 

[blabla]

1. As far as I know, we put the solution with the bendicts reagent in a water bath already at 100 degrees.

2. I usually keep it around 4-5 minutes. Sometimes it takes even less time. In general, if no color change appears after 5-6 mins, it probably has no sugar.

3. 5drops of CuSo4, 10 drops of KOH for biuret test. Source: http://faculty.clintoncc.suny.edu/f...on of cells/chemical composition of cells.htm
but if i'm given the biuret reagent itself without having to prepare it, i usually add around 5-6 drops. Not sure about ethanol though.

4. In low power drawings, we draw tissues as layers, rather than drawing individual cells. In high power diagram, we are asked to draw cells individually, with certain visible components, like the vacoule or starch grains and stuff.

Hope this helps! and I might be wrong too so i'd cross check if i were you

 

[Saad (سعد)]

Hello people. As you can see in the topic i have some bio practical doubts...

1. During Reducing sugar test do we put the solution with benedicts reagent in aWater bath already at 100 degree celsius or do we add it in a water bath and then start to heat.
2.During Reducing sugar test what is the optimum time to keep the solution in the water bath.
3.For biuret and emulsion test should we measure and add biurets reagent/ethanol or de we just add an excess.
4.Whats the diffference between High power drawing and low power drawing ?

1. I think the water-bath is already set at 80/90 degrees (if its electronic). That's enough; I don't think its ever at 100, because if it were, there would be no water there after a few minutes. o_o
2. 5 minutes.
3. Measure; the volume of biuret solution (or 5% potassium hydroxide) should be equal to the volume of the protein solution. If you use 5% potassium hydroxide, take equal volume as that of protein solution, then add one drop of 1% copper sulfate.
4. High power drawing is a drawing of what you see when you view a specimen via the microscope at high power, i.e., the objective lens is 40x. Low power is what you see when you view the specimen through 4x or 10x objective lens.

I hope that helped insha'Allah!

 

[lionkill3r]

thanks you
what about emulsion test ??? the volume of absolute ethanol to be used (if i dont drink it )

Oh yeah btw our BIO LAB we dont use electronic heaters or whaever you said about electronic

 

[Saad (سعد)]

thanks you
what about emulsion test ??? the volume of absolute ethanol to be used (if i dont drink it )

Oh yeah btw our BIO LAB we dont use electronic heaters or whaever you said about electronic

I think the water-bath in Centers is electricity-powered (electronic). I mean, my college became a Center of my city and the water-bath here is electronic. And I don't think we use a regular 'water-bath-in-a-beaker' thing in AS Levels, unless that's specifically the question.

Anyways, for emulsion test, you also have to measure. Normally, to about 2 cm3 of the sample, add an equal volume of absolute ethanol (100% ethanol, and don't drink it; 15% ethanol is haraam, 100% would kill you in two minutes), then keep shaking it for about 30 seconds. Then add an equal volume of cold water, mix well, allow to stand.

And as you know, a milky white emulsion means you have a fat.

Don't eat it, it'll make you obese.

 

[lionkill3r]

thanks
Any tips for getting really good clear magnifications by microscopes ?

 

[Saad (سعد)]

thanks
Any tips for getting really good clear magnifications by microscopes ?

Hmm... do not set a microscope at high power immediately, even if they ask for you to look at high power. Set it up at low power first, find a clear image in sharp focus, then change it to high power. If the image loses clarity again, use the fine adjustment knob to find the clear image in sharp focus; do not use the bigger one (coarse adjustment knob) - unless absolutely necessary (I don't think it will be). All these things ensure you don't break either the microscope lens or the slide.

If you wear glasses, remove them, as the microscope adjustment will take care of most eyesight deficiencies, except astigmatism.

Other than that... I dunno. Are we the only Bio students here giving 34? Where is everyone? I need some tips and stuff too.

 

[lionkill3r]

Ask me dude im not that bad in bio i am just scared of practicals since this is my first practical ( we only had about 4 practical lessons in skul -_- )

 

[Saad (سعد)]

Ask me dude im not that bad in bio i am just scared of practicals since this is my first practical ( we only had about 4 practical lessons in skul -_- )

I've done lots of practicals but I'm still scared. I can't observe very well, and its hard to judge what something is in the microscope to label it. I mean, sure, everyone can find the plasma membranes, cell walls, nucleus, cytoplasms etc. but there are times when an Examiner requires more than that.

Can you tell me the differences between Dicot and Monocot stems? And how to judge between Xylem and Phloem? I suck at Transport in Plants. o_o

 

[lionkill3r]

There you go i found this pic on this site and forgot the thread where i found it :S
Anyway credit goes to the real uploader of this.
Everything you want is in the pic ...

 

[Amaryllis]

hi everyone ..how to do labeling for a xylem or vascular bundle ,by drawing circles?

 

[Saad (سعد)]

hi everyone ..how to do labeling for a xylem or vascular bundle ,by drawing circles?

What do you mean 'by drawing circles'?

 

[lionkill3r]

i think he means plan diagrams

 

[Saad (سعد)]

hi everyone ..how to do labeling for a xylem or vascular bundle ,by drawing circles?

If you meant how to label Xylem and Phloem, then only a straight line. No circles. Straight line leading out from the Xylem or Phloem to the side of your drawing, and then write down the label there.

Keep in mind, while drawing a plan diagram, that there should be ample space on the sides for labeling.

 

[blabla]

I've done lots of practicals but I'm still scared. I can't observe very well, and its hard to judge what something is in the microscope to label it. I mean, sure, everyone can find the plasma membranes, cell walls, nucleus, cytoplasms etc. but there are times when an Examiner requires more than that.

Can you tell me the differences between Dicot and Monocot stems? And how to judge between Xylem and Phloem? I suck at Transport in Plants. o_o

I'm worried about the labeling bit as well, especially when we have to label xylem and phloem and cortex and pith and what not These sites have really good labelled slides, you could check them out. Theres some extra stuff here though, just look at the ones with xylem and phloem in them!

http://www.biog1105-1106.org/images/105slides/Unit04/index4.html, http://www.northlakebiology.com/1411/lab/exam_1/tissue_lab.htm

 

[lionkill3r]

I'm worried about the labeling bit as well, especially when we have to label xylem and phloem and cortex and pith and what not These sites have really good labelled slides, you could check them out. Theres some extra stuff here though, just look at the ones with xylem and phloem in them!

http://www.biog1105-1106.org/images/105slides/Unit04/index4.html, http://www.northlakebiology.com/1411/lab/exam_1/tissue_lab.htm

THANK YOU A LOT SISTER

 

[Saad (سعد)]

I'm worried about the labeling bit as well, especially when we have to label xylem and phloem and cortex and pith and what not These sites have really good labelled slides, you could check them out. Theres some extra stuff here though, just look at the ones with xylem and phloem in them!

http://www.biog1105-1106.org/images/105slides/Unit04/index4.html, http://www.northlakebiology.com/1411/lab/exam_1/tissue_lab.htm

Yeah, Jazak Allah Khayr.

 

[Amaryllis]

If you meant how to label Xylem and Phloem, then only a straight line. No circles. Straight line leading out from the Xylem or Phloem to the side of your drawing, and then write down the label there.

Keep in mind, while drawing a plan diagram, that there should be ample space on the sides for labeling.

yeah this is what i meant thank you....so we can leave the vascular bundle position and identify it by label only?

 

[The Munchkin]

Hi!
Could anyone please tell me some sources of errors and improvements of experiment relating to enzymes and rate of reaction ??

Pretty Pretty Pleeeease....

 

[narutogirl]

You said..

. 5drops of CuSo4, 10 drops of KOH for biuret test

while you said

If you use 5% potassium hydroxide, take equal volume as that of protein solution, then add one drop of 1% copper sulfate.

isn't that quite different?