Edexcel 6BIO2 ~ 3rd June 2013 ~ AS Biology

Well during interphase... the cell is growing up and performing its own functions...? Or because it needs to go through a lot of processes for the cell cycle. Like condensing the chromosomes, synthesising proteins and etc.

Not finished yet - maybe Monday now.

Does anyone know what xerophytes are?

I have a few doubts about translocation in plants,
- mineral ions enter the roots dissolved in water right?
- so does some water also enter the phloem along with the nutrients?
- or is the water kind of 'filtered' by the casparian strip and directed into the xylem instead?

- what is the function of companion cells in the phloem?
- do they only store nutrients for later use by the plant?

is this stuff in the syllabus? :O casparian strip? companion cell?

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I have a few doubts about translocation in plants,
- mineral ions enter the roots dissolved in water right?
- so does some water also enter the phloem along with the nutrients?
- or is the water kind of 'filtered' by the casparian strip and directed into the xylem instead?

- what is the function of companion cells in the phloem?
- do they only store nutrients for later use by the plant?

is this stuff in the syllabus? :O casparian strip? companion cell?

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old spec. we don't need to know about it yet

Mineral ions do enter the roots in an aqueous solution (may not necesarily be water)
water or minreal ions aren't transported by the phloem.. the phloem transports products of photosynthesis

Oh? There's stuff about the casparian strip in the Edexcel student book (green one - pg 213), but yeah, I can't find any of them in the spec.

Ok, so water is transported in xylem, products of photosynthesis (glucose/sucrose) in the phloem, what about minerals? Are they transported in the xylem?

Haha, the textbook has found yet another victim! the textbook is for leisure reading BTW

The Xylem transports inorganic substances, the substances that the plant does not manufactures. It transports water and mineral ions dissolved in water.
The phloem transport organic substances, substances that the plant manufactures. It transports the sucrose (not glucose!) and amino acids as well as plant hormones. The phloem does contain water also! sucrose is dissolved in water

So the two main differences between the phloem and Xylem tissues are
1.Xylem transports water and mineral ions while phloem transports sucrose,amino acids,plant hormones.
2. The movement of substances through the xylem is from the root UPWARDS to the rest of the plant but in the phloem it is from the leaves to the storage organs etc upwards or downwards.

With regards to the plant stem we should know:
1. The functions and the cross section diagram of the dicot stem.
2. The differences between xylem and phloem, sclerenchyma and xylem, and sclerenchyma and collenchyma.
3.The adaptations of the xylem vessels to its two functions.
4. Mineral deficiency symptoms of plants
5. The core practical to demonstrate them.

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the january 2013 paper http://www.freeexampapers.com/#A Level/Biology/Edexcel/2013 Jan

Haha, the textbook has found yet another victim! the textbook is for leisure reading BTW

The Xylem transports inorganic substances, the substances that the plant does not manufactures. It transports water and mineral ions dissolved in water.
The phloem transport organic substances, substances that the plant manufactures. It transports the sucrose (not glucose!) and amino acids as well as plant hormones. The phloem does contain water also! sucrose is dissolved in water

So the two main differences between the phloem and Xylem tissues are
1.Xylem transports water and mineral ions while phloem transports sucrose,amino acids,plant hormones.
2. The movement of substances through the xylem is from the root UPWARDS to the rest of the plant but in the phloem it is from the leaves to the storage organs etc upwards or downwards.

With regards to the plant stem we should know:
1. The functions and the cross section diagram of the dicot stem.
2. The differences between xylem and phloem, sclerenchyma and xylem, and sclerenchyma and collenchyma.
3.The adaptations of the xylem vessels to its two functions.
4. Mineral deficiency symptoms of plants
5. The core practical to demonstrate them.

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hi in jan 2009 Q 5 a iii , the mark scheme quite confuses me can anyone put it linked in a better easy way?

Someone please explain to me how red blood cells produce new cells when they have no nucleus

They are plants adapted to surviving in environments that have a severe lack of water. (i.e, deserts)
They have various features that help prevent water loss, like
- hairs on the epidermis, to reduce the layer of air, hence reducing transpiration.
- waxy layers on the epidermis also prevent water loss by evaporation
- most xerophytes have small leaves, and fewer branches, again, to reduce water loss by evaporation.

Haha, can they ask about plant adaptations in this paper??

This asks for changes, so what happens to the sperm cell and egg cell. so you just describe the steps during fertilisation. Its 3 marks so three points are required:

I would write (well, i haven't looked in the markscheme) something along the lines on:

1) The sperm cell penetrates through the zona pellucida layer and is hydrolysed by the digestive enzymes secreted from the sperm head.
2) After penetration, the zona pellucida then reforms/hardens after a sperm has entered to prevent polyspermy (multiple sperms)
3) Therefore, the process of meiosis is completed.



The nucleus of a cell is responsible for cellular activity including cell division. Blood cells don't divide, they are produced by other cells within bone marrow.

Oh? There's stuff about the casparian strip in the Edexcel student book (green one - pg 213), but yeah, I can't find any of them in the spec.

Ok, so water is transported in xylem, products of photosynthesis (glucose/sucrose) in the phloem, what about minerals? Are they transported in the xylem?