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How about the first question? What did you guys pick
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A level Biology: Post your doubts here!
- Thread starter XPFMember
- Start date
I don't remember the question exactly, but I think the answer is C
i chose c , the question was repeated
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in IVF a woman is first injected with LH and FSH like hormones to stimulate super ovulation ie. several follicles will mature at the same time .. the oocytes are then harvested from follicles prior to ovulation using a microscopic needle then the semen is collected from the male partner and centrifuged immediately to prevent damage to the sperms .. each oocyte is then mixed with about 100000 sperms in a dish and left for some time to allow fertilization .. the fertilised embryos are then checked for their quality at the 6-8 cell stage based on the shape of the embryo and the rate of its mitosis and 2 of the best quality embryos are then chosen and implanted into the woman's uterus using a tube that passes through her cervix .. during this time the woman would have been given progesterone hormone for 2 weeks to prepare her uterus for implantation ...... alternatively 1 sperm could be injected directly to the oocyte during fertilisation in case the sperm count was low this is called intra cytoplasmic sperm injection(ICSI)...... ' anyways its better to outline the first method of fertilisation- in the ques'
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anyone did paper 5?
Yeah I did it, the one with the enzyme/ contact lense experiment and the pre-natal alcohol exposure in babies
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i did that as well
How did you dilute that solution and what was the control?
I wrote the control was the same conc and volume of denatured enzyme or water and the weighted out 50cm3 in a pan balance and then mixed it in a 100cm3 volumetric flask to get a 5% solution
what variables did you state in your method?
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five concentrations of subtilisin A ranging from 20um to 100 um
temp. constant at 60C
pH constant at 7.0
area of plastic sheet constant
equal volume of concentrations
time to equilibrate the solution in a water bath
length of strings (to suspend the sheets) constant
that's all i remember
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about the enzyme graph what was thecorrect ans i wrote B
the dissociation curve for adult uman and fish bla bla wht was the ans ?
and the collagen question ?
And how did you find the actual concentration using the graph?
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i got very confused about the conclusions in the 2nd ques
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i wrote that we have to check for the rate of reaction touch the graph and then check for the corresponding conc.
- Messages
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- Reaction score
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- 153
I don't know what the correct answer is cuz I was misinterpreting the question so I immediately chose A. However one or two people told me it was B.
The fish one was the most left one. Human in middle, the mammal on most right.
Collagen one was A. Has many glycine.
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repeat the same procedure for the actual solution to find the rate of the enzyme, and compare it to the values of the graph. The corresponding value on the x-axis is the concentration of the solution.
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what were the difficulties in judging when to stop the stopwatch?
I wrote that it is difficult to judge when gelatin is fully gone
and the dye may dissolve in the solution, so it is difficult to judge transperancy..
was out of my league.