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AQA Biology B2 - Unofficial Mark Scheme

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The pictograms thing said that A is a cell then B is double its size then it spilits (C) so back to same size as A then that splits again

And D,E,F,G are sperm cells

So A = 6.6
B = 13.2
C = 6.6
And D onwards are 3.3 I think???

I got all that, and also the fertilised egg one which I think was 6.6?

Reply 21

mrpaper

for the 6 marker I said to put soil in the beaker with a constant amount of water and then put the bulb a certain distance away from the plant then measure the plant and move the light back 5cm and measure again next week
control variables - amount of water and amount of soil
changing the light intensity
is this still right or?

Reply 22

Naco88

Original post by Adamtoo

Was there a question after the speciation one (the 5 marker)? I think I missed it -_-

Yeah, I only saw it when going through. It was on its own between the two last pages.

Reply 23

AK45HSR

Original post by Naco88

That's what I got :smile:

Thank God!

Was I the only one who worked out half of 13.2 was 6.6 but then did it again with a calculator to be sure?

Reply 24

Adamtoo

Original post by Naco88

Yeah, I only saw it when going through. It was on its own between the two last pages.

How many marks?

Reply 25

Naco88

Original post by Adamtoo

How many marks?

I believe it was 2.

Reply 26

AK45HSR

Original post by Naco88

We were seeing how the light intensity affects the amount a plant photosynthesizes. Plants produce oxygen in photosynthesis so measuring the bubbles or oxygen produced in a certain amount of time should be a symbol of how much is is photosynthesizing.

But you said measure diff in water? You're probably right but I'm completely confused

Reply 27

Certified

Stem cells are undifferentiated - could become any type of cell (in theory).

Stem cells from umbilical cords are more ethical because the embryo cannot consent to having cells taken (breach of human rights) or 'sanctity of life'.

Stem cells are better if they are from the person affected and not a donor - less chance of rejection.

Stem cells will carry the faulty gene so they cannot cure a genetic disorder in a person if you use their own cells.

Improvements : Bigger sample size, Place quadrats randomly, Try different areas to see how plantain grow compared to grassy areas

Genetic hair:

Bb Bb
25 percent red 75 percent brown

Values were 3.3 , 6.6 and 13.2 (not in order)

Bottom answer was Mitosis

Reply 28

mellowjoker

What did everyone get for the genotype, phenotype and gametes question for the mother, father and then children? I couldn't remember what a phenotype was and so I'm pretty sure I completely messed up that page :frown:

I put as the phenotype Bb and Bb and then the Genotype I put heterozygous and gametes I put XY and XX - I'm certain I've got this entire page wrong as it was something I only briefly revised and now wish I had spent more time on!

Posted from TSR Mobile

(edited 7 years ago)

Reply 29

danniconda

For question 4 (the one about quadrats) I can't remember the answers but I can remember the question so if anyone wants to try and work it out.
The area of the field was 100mx50m(So 5000m^2) and the area of a single quadtrat was 25mx25m(so 625m^2?).There were 10 different quadrats placed with a total of 20 plants and the questions asked for:
1)Total number of plantains
2)Total area of 10 quadrats (in m^2)
3)Mean number of plantains per m^2
4)Total area of the field
5)Estimated number of plantains in field

Reply 30

ozziess

For the quadrat question I got 20 flies, then 62.5metres in total, so I got 0.32metres per metres squared, leaving me with answer or 1,300

Reply 31

AK45HSR

Original post by lily628

I got all that, and also the fertilised egg one which I think was 6.6?

I think I put 6.6 as a guess but how are we supposed to know that?

Reply 32

Holly Gorton

Original post by Naco88

No it will get you some marks because you have shown testing it with different light intensities. Also as long as you showed how you used the equipment and the control variables then you should be okay :smile:

Thank god cause that's what I wrote too

Reply 33

Adilpatel

Any predictions for the grade boundaries?

Reply 34

Adamtoo

Original post by Holly Gorton

Thank god cause that's what I wrote too

I mentioned how the beaker can be used as a water bath so that the heat released from the light doesn't affect the rate of photosynthesis. Then mentioned how the ruler can be used to measure the starting height of the plant and the distance of the lamp to the plant. For a fair test, I said measure in 10cm intervals each time the lamp is moved away and do this every 5 minutes. Idk if this is right LOL

Reply 35

blessup

There wasnt another question after the speciation five marker?

Reply 36

AK45HSR

Original post by Adamtoo

I used LED lamp to stop halogen bulb increasing the temp.
Measure 5cm away from lamp in increments and use like 20ml of de ionised water and 5ml of plant food put pondweed in and count bubbles for 3 mins and then move another 5cm away and record and repeat as you do.

Reply 37

danniconda

Original post by blessup

There wasnt another question after the speciation five marker?

Yeah there was, it was only a 1 marker though on why the island foxes didn't become a new species like the grey(?) foxes

Reply 38

AK45HSR

Original post by Adilpatel

Any predictions for the grade boundaries?

46 A*
41 A
32 B
28 C

These are complete guess but as the paper was easier than last year (general consensus) it is very likely that the grade boundaries are set higher to compensate.