Can someone please help with these questions here? :D

So I was doing my half term homework and then got stuck in this last question here.
Q8.(a) Figure 1 shows one pair of homologous chromosomes.

(ii) Describe the role of X in mitosis. ( X is centromere ) (2)

(iii) Homologous chromosomes carry the same genes but they are not genetically identical. Explain why.
(1)

(b) Figure 2 shows three pairs of homologous chromosomes in a cell at the end of cell division. ( The figure's got a cell with 3 white and 3 black chromosomes like strands, not X shaped)
(i)The appearance of each chromosome in Figure 2 is different from those shown in Figure 1( which had 2 X shaped chromosomes) . Explain why. (1)

(ii) Complete the diagram to show the chromosomes in one cell that could be produced from the cell in Figure 2 as a result of meiosis. (2)

(iii) Other than independent segregation, give one way in which meiosis allows the production of genetically different cells. (1) (Here, should I just mention crossing over?)

Thanks!

I can't answer all these questions for you, but if you let us know your thoughts, I'm happy to help/correct you.

Since you've tried 8biii, I think mentioning crossing over and briefly explaining how it produces genetically unique cells would be fine.

Ok for the first one, does the centromere have something to do with aligning at the equator of the cell and spindles attaching to it during metaphase.

For the second one, is it because they have divided by mitosis?

And the third one, I'm thinking a cell with just one chromatid lyk one strand (will it be like combination of two?)
And I get the last one.

Boom. This is the important bit. Centromeres have less to do with homologous pairing - that happens because chromosomes sort of "compare" their sequences and match up with ones that have the same sequences.
The centromere's main role in division is to provide a site of attachment for spindle fibres so they can separate properly during anaphase.



You'll have to be more specific about what question you're answering. Are you talking about 8aiii?



And the same here. I have no idea what question you're answering.

Sorry
For 8b(i), is it because the cell has divided by mitosis.

Then for 8 aiii, is it because there are different alleles for every trait.

And for 8 bii, will there be a single chromatid but a combination of two of them in the cell. Idk, this is a really confusing topic.

Yes, but I think you'd want to mention that during mitosis, the sister chromatids are pulled apart, leaving the subsequent daughter cell with only unduplicated chromosomes.



Yep, but this doesn't directly answer the question. You'd more want to mention that the same genes can show variation, due to random mutation, giving rise to genes having multiple alleles with varying DNA sequences.



So meiosis creates a haploid cell (a cell that only has half the amount of required genetic material), doesn't it? So it'd be the same as in figure 2, but only 1 version of each chromosome (can be any proportion of black or white - chromosomes get split up randomly, so you can just pick your favourite combination of the two colours. )