CIE IGCSE Biology Alternative to Practical

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In all the catalase decomposition questions I've done the control was boil potato to denature enzyme it even said this on the sample paper but I suppose there could've been many controls

I second this

Reply 61

123Master321

Original post by examhater44

Guys, listen for the control experiment the answer could have been to substitute a test tube of hydrogen peroxide for a test tube of water. In fact it is the preferred answer!!!

Ive never seen this on a mark scheme I could be wrong though

Reply 62

examhater44

Gguys what did u put for a safety precaution when handling ethanol??

Reply 63

Zx12r1

Original post by examhater44

Gguys what did u put for a safety precaution when handling ethanol??

I put 2 things down firstly that wear safety goggles since it is an irritant and then since ethanol is organic never heat with bunsen burner since it is flammable

What did everyone else put?

Reply 64

juannypacquiao

Original post by Zx12r1

I put 2 things down firstly that wear safety goggles since it is an irritant and then since ethanol is organic never heat with bunsen burner since it is flammable

What did everyone else put?

Put the exact same thing except I said safety google and lab coat not just safety googles.

Reply 65

CIEBioloysifh

Original post by examhater44

Yea thats the point xD
Biology teacher said water is right

Fair enough, might be right then.

Reply 66

Kailum ni1gga

I put those at first but i dont think they link at all u melt. Because number of bubbles dont link to volume in gas syringe

Reply 67

c0mmodity

Original post by Kailum ni1gga

I put those at first but i dont think they link at all u melt. Because number of bubbles dont link to volume in gas syringe

There would be some correlation to the volume of gas though, just not an accurate one.

Reply 68

XCharlotteDoyleX

So if i drew the diagram exactly how it looked on the paper will i get any marks at all? :frown:

Reply 69

123Master321

Original post by lin-e

There would be some correlation to the volume of gas though, just not an accurate one.

This has appeared in previous mark schemes, gas syringe is fine

Reply 70

123Master321

Original post by XCharlotteDoyleX

So if i drew the diagram exactly how it looked on the paper will i get any marks at all? :frown:

I think you might lose one or two, its not like you lose all the marks, some marks you get if you drew some random circle

Reply 71

123Master321

Original post by juannypacquiao

Put the exact same thing except I said safety google and lab coat not just safety googles.

It asked for one in bold

Reply 72

Zx12r1

Original post by XCharlotteDoyleX

So if i drew the diagram exactly how it looked on the paper will i get any marks at all? :frown:

It was worded very badly dont worry i did the exact same thing we will only lose 1-2 marks MAX since most of the marks come from size, label, overall shape etc.

Reply 73

Zx12r1

Original post by 123Master321

It asked for one in bold

You can't get penalised for putting 2 things that are correct down however they will only mark the first thing you put.

Reply 74

examhater44

For the safety one, I put wear safety googles and gloves

Reply 75

XCharlotteDoyleX

Original post by 123Master321

I think you might lose one or two, its not like you lose all the marks, some marks you get if you drew some random circle

ah I really hope so, five marks is such a large chunk!
I know it wont be accurate, but what would you guys think the garde boundary would be for an A?
would you say it was a hard paper?

Reply 76

XCharlotteDoyleX

Original post by Zx12r1

It was worded very badly dont worry i did the exact same thing we will only lose 1-2 marks MAX since most of the marks come from size, label, overall shape etc.

thankyou so much :smile:

so worried, i absolutely have to get at least a B overall and i really panic in exams :frown:

Reply 77

IWriteNovels

Yeah, I got stuck on the table tbh :colondollar:

I know it was easy looking back, but hey :/
The phloem and xylem thingy was easy I thought? Just the xylem + phloem cells were the holes.
For the last question I just put it clear and simple, something like: "The lignin will take up the red dye through the xylem, so place the shoot in a beaker of water, leave for a few hours, come back, cut the stem with a scalpel, and look for a stain. The stained areas are the xylem vessels." Tbh, I didn't really know - I took a while on the table thing. But it was easier than I thought :smile:

Reply 78

IWriteNovels

Original post by XCharlotteDoyleX

So if i drew the diagram exactly how it looked on the paper will i get any marks at all? :frown:

Yeah, you'd get marks for showing the different segments of the vascular tissue. But it did say not to draw in individual cells...

Reply 79

Zx12r1

Original post by IWriteNovels

Yeah, you'd get marks for showing the different segments of the vascular tissue. But it did say not to draw in individual cells...

Tbh it was open to interpretation. Individual cell could mean dont draw one xylem cell and one phloem cell and then start labelling all the internal features of that...