[Slavivlad]

(Original post by freddy)
is it ok to say different populations in different countries hence allows comparison???

Yes.

[Emma~]

For the bull/milk one (9e?) I put something about genetic fingerprinting - search for gene which codes for milk production???

[Slavivlad]

(Original post by freddy)
i though the iaa queston was about gravity causing iaa to redistribute to the bottom half??? is that right?:/

IAA moves to the bottom due to gravity, yes.

[JimmyK]

(Original post by Picture~Perfect)
Thanks I'll work forwards as best as I can

I did Q5-9 so you can copy them across to your post

[JimmyK]

(Original post by Slavivlad)
IAA moves to the bottom due to gravity, yes.

Huh? IAA causes elongation of cells so to cause the root to curve downwards towards gravity IAA must have moved to the upper side against gravity?

[Slavivlad]

(Original post by JimmyK)
Huh? IAA causes elongation of cells so to cause the root to curve downwards towards gravity IAA must have moved to the upper side against gravity?

No, elongation of the cells is caused ONLY in the shoots, but in the roots it's the opposite.

IAA moves down due to gravity which INHIBITS cell growth/elongation and so it bends down.

[asaaal]

(Original post by Picture~Perfect)
I'm going to attempt an unofficial mark scheme, but I'll need your help


(ii) Error bars don't overlap so the results are not due to change (less than 0.05)
All the results of the change in mean heart rate are negative numbers.
Positive Correlation
Quantitative analysis (numbers mentioned?)

you sure its positive?

[Picture~Perfect]

(Original post by asaaal)
you sure its positive?

I didn't answer that question, I'm not sure which it is, that graphs really confused me.

[asaaal]

(Original post by Picture~Perfect)
I didn't answer that question, I'm not sure which it is, that graphs really confused me.

im sure it was positive :/

[Picture~Perfect]

(Original post by Picture~Perfect)
I'm going to attempt an unofficial mark scheme, but I'll need your help

Why would give me negative reputation? o.O
If you don't agree with come of my answers then say so or make your own mark scheme.

[Picture~Perfect]

(Original post by JimmyK)
I did Q5-9 so you can copy them across to your post

Thank you for your help

[JimmyK]

(Original post by Slavivlad)
No, elongation of the cells is caused ONLY in the shoots, but in the roots it's the opposite.

IAA moves down due to gravity which INHIBITS cell growth/elongation and so it bends down.

Uh-oh :P. I just assumed it must be the same in the roots even if it's counter-intuitive.

[asaaal]

Here are some suggestions ive added




5bi) It is a fluorescent gene marker. We will be able to see if the insertion/transformation is successful because a fluorescent protein will be produced as well, therefore we can identify which are successful.
fluorescent protein will not fluorescent if the insertion is successful


5ci) not sure Important genes are disrupted by the insertion of new DNA and therefore the embyro cannot develop? i wrote about only 1% of the vectors are actually taken up by the host cell? :/



7ci) IAA produced in tip diffuses down shoot but moves to the upper side, showing negetive geotaxis. IAA causes cells to elongate, so cells on the upper side elongate causing the root to curve downwards towards gravity. positive geotropism - tropism is for plants NOT taxis - and i thought we spoke about the growth movemenet not chemical movement. IAA inhibits cell elongation in the roots as it moves to the lower side (only say causes elongation in the shoot)-bends down.


8ai) Not sure if enough points Yes there is positive correlation, the more CAG repeats the younger the person is when symptoms appear. However there is too large a range particularly with lower repeats. For example with 39 repeats the age could be between 25 and 70. Above 50 repeats there is not enough data to be conclusive. -

8aii) Often symptoms don't appear until after the sufferer has had children and passed on the genes. In the graph it can be seen that it often doesn't present symptoms until after 50 years, and presumably some people wouldn't have genetic screening. The CAG repeats of 36-40 is what causes huntingtons-This number of repeats is found in older people-theve survived while having the allele as theyve only just developed their first symptoms where huntingtons beings to become fatal-by this age theyve probably had children and passed on the allele.


8biii) It may have travelled further than the others and dropped off the end of the gel. Or maybe it's the same size as the other one so appears as one band? -No probe attached to this fragment-although it is there it cannot be seen.




9c) Milk production decreases because metabolic rate/respiration decreases so less ATP is available for secreting milk or synthesising milk proteins. -milk is a source of protein-enzymes used in protein synthesis e.g. rna polymerase being to denature-less milk produced




9f) not sure Countries have different numbers of people so using percentages allows for comparison between countries. what you said and allows us to see the significance of people who are lactose intolerant in a country e.g 5 of 500 is more significant than 5 in 5000000 hence work out a %

9g) Sorry to any lactose intolerant people :P In past dairy was very small part of diet so not producing much lactase wasn't an issue. Today due to transportation and refridgeration lactase makes up a much larger proportion of our diet. Therefore people who are lactose intolerant are at an evolutionary disadvantage because if they eat dairy products they become ill. Perhaps they do not have as many children or may be more likely to die as a child, so over time a larger proportion of genes passed on will be from lactose tolerant people and more of the population will become so. This is directional selection. This will happen faster in a country that eats more dairy products because lactose intolerant people will be at more of a disadvantage. before not a lot of dairy/milk eater/drank--> nobody would die as it wasnt an issue. today they do --> more people die from it. These individuals are selected against as they do not survive long enough to get to reproductive age and pass on their alleles --> they are selected against and this changed allele frequency as the more advantageous allele increases while the disadvantage allele decreses over generations. oh and talk about mutations over many years giving a massive gene pool

[JJMick]

(Original post by JimmyK)
Huh? IAA causes elongation of cells so to cause the root to curve downwards towards gravity IAA must have moved to the upper side against gravity?

IAA inhibits cell growth in roots so it would diffuse to the bottom half causing it to bend downwards.

[Arusa01]

Just seen this thread now, I didn't do that bad afterall

[alan-93]

(Original post by freddy)
is it ok to say different populations in different countries hence allows comparison???

and yh if you say i's easier to compare figures, i think you'll get the marks. coz i seen this type of question in the past paper!

[hcd22]

What sort of things should've been included in the essay on shapes?

[Apa]

(Original post by hcd22)
What sort of things should've been included in the essay on shapes?

I put transport proteins, enzymes, haemoglobin, DNA binding (?), protein channel in the axon and neuron, receptors on the neuromuscular junctions and possibly something else, I can't remember.

OP - thank you for this! Feeling so much more confident now, I only need to get like 42% in this exam to get my grades so hopefully I should be alright

[sydney07]

(Original post by Picture~Perfect)
I didn't answer that question, I'm not sure which it is, that graphs really confused me.

hehe at least I'm not the only one... I still don't understand it hahaa, I had no chance with those questions in the exam haha

[Kidneyjean]

(Original post by Picture~Perfect)
Question 8:
(a)
(i) Not sure if enough points Yes there is correlation, the more CAG repeats the younger the person is when symptoms appear. However there is too large a range particularly with lower repeats. For example with 39 repeats the age could be between 25 and 70. Above 50 repeats there is not enough data to be conclusive.
(ii) Often symptoms don't appear until after the sufferer has had children and passed on the genes. In the graph it can be seen that it often doesn't present symptoms until after 50 years, and presumably some people wouldn't have genetic screening.
(b)
(i) K. Because it has travelled the shortest distance so is the longest fragment and contains the highest number of CAG repeats.
(ii) Compared them to fragments of known length (DNA ladder).
(iii) It may have travelled further than the others and dropped off the end of the gel. Or maybe it's the same size as the other one so appears as one band?

For 8bii) I put L, because the smaller of L's two fragments had moved the shortest distance, so it was the heaviest, as it contained the most CAG repeats (it was stated that J, K, and L all had two fragments). As far as I know, fragments can't just fall off the end of the electrophoresis gel...

For 8biii) I put that the larger of L's two fragments hadn't left the well; it contained so many CAG repeats that it was too heavy to be moved by the electrical current.

I asked my teacher about this question after the exam, and they were pretty sure that this was the correct reasoning! Sorry if this sounds patronising