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Official AQA GCSE Biology Unit 2 22nd Janurary NEW SPEC

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Reply 120

Ammy97

What is iodine used for? I can't remember :frown:

Good luck guys! Just be calm and think positive x

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Reply 121

ali_d123

Original post by Ammy97

What is iodine used for? I can't remember :frown:

Good luck guys! Just be calm and think positive x

This was posted from The Student Room's iPhone/iPad App

used to find the presence of starch in leaves and variegated leaves

Reply 122

Ammy97

Original post by ali_d123

used to find the presence of starch in leaves and variegated leaves

Ok thank you, what colour does it turn? Purple? Also "variegated" is that leaves that aren't all green?

Sorry haha

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Reply 123

issie1234

Original post by Ammy97

What is iodine used for? I can't remember :frown:

Testing for starch in leaves i think

Reply 124

ali_d123

Original post by Ammy97

Ok thank you, what colour does it turn? Purple? Also "variegated" is that leaves that aren't all green?

Sorry haha

This was posted from The Student Room's iPhone/iPad App

dont be sorry im happy to help :smile:

the leave will turn black if starch is present, and yes variegated leaves is where there is not chloroplasts in the whole leaf which leads to why only part of it is green.

Reply 125

Arshii

Can anyone give me 3 reasons why Gregor Mendel's ideas weren't accepted? :smile:

Thanks

Reply 126

Ammy97

Original post by ali_d123

dont be sorry im happy to help :smile:

the leave will turn black if starch is present, and yes variegated leaves is where there is not chloroplasts in the whole leaf which leads to why only part of it is green.

OK thank-you very much! :biggrin:

So if the leaf covered in iodine? (Or dipped in..)

Reply 127

Mrkingpenguin

Original post by Arshii

Can anyone give me 3 reasons why Gregor Mendel's ideas weren't accepted? :smile:

Thanks

3>? There are only 2 in the textbook:

1. No knowledge of DNA at the time
2. his findings published in an obscure journal no one had seen

Reply 128

issie1234

Original post by Arshii

Can anyone give me 3 reasons why Gregor Mendel's ideas weren't accepted? :smile:

Thanks

I can give you one? They didn't know about genes and chromosomes

Reply 129

Arshii

Original post by Mrkingpenguin

3>? There are only 2 in the textbook:

1. No knowledge of DNA at the time
2. his findings published in an obscure journal no one had seen

Ohh yeah! that was the one he didn't publish he findings widely enough and he was a monk...
Thankss! :smile:

Reply 130

Chlorophile

Original post by Arshii

Can anyone give me 3 reasons why Gregor Mendel's ideas weren't accepted? :smile:

Thanks

People hadn't actually discovered genes yet, so he couldn't properly explain his observations. Since he was a monk, many people did not accept that he was a scientist and rejected his work. Because Mendel experimented on pea plants, a lot of people were not convinced that the conclusions would be applicable to people. I'm also pretty sure that another reason was because he had made some serious mistakes before which had infringed his reputation (but I'm not 100% sure).

Reply 131

Ammy97

Does anyone want to test each other? :tongue:

Reply 132

ali_d123

Original post by Ammy97

Does anyone want to test each other? :tongue:

yes! :P

Reply 133

lildchic

I think it could be on the digestive system (i don't know why I just have a feeling) enzymes didn't come up in the specimen paper or the June 2012 one so I think it might tomorrow... :/

Reply 134

Ammy97

Original post by ali_d123

yes! :P

Okay, your question is:

What did Mendel mean by "hereditary unit"? (probs a 1 marker)

Reply 135

shezz4

What would the 6 mark question on enzymes be on though? Like the uses?

Reply 136

lildchic

Original post by sakbo

Is it just me or are specimen mark schemes just ridiculous?

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They are RIDICULOUS I did one today and I was answering the questions correctly but the specific answers weren't in the mark scheme so they were wrong...

Like question 4a) "Give three differences between aerobic and anaerobic respiration."

What I put was correct from the specification but the mark scheme didn't credit it.

Reply 137

lildchic

Original post by shezz4

What would the 6 mark question on enzymes be on though? Like the uses?

Yeah like describe how an enzyme breaks down protein and then you would have to do through each organ in the digestive system and what it does? :/

Reply 138

Chlorophile

Original post by lildchic

e differences between aerobic and anaerobic respiration."

What I put was correct from the specification but the mark scheme didn't credit it.

Similar issue with question 8.b.ii. The only answer accepted in the mark scheme is bile provides the optimum pH, but another acceptable answer should be bile acts an emulsifier which increases the surface area thus rate of reaction. I wouldn't take the specimen too seriously.