The first division will form two intermediate haploid cells in which both of them will contain 23chromosomes, with each chromosome having 2 chromatids and so a total of 46chromatids in each of these 2 cells.
Now the second division occurs, in this the 23 chromosomes with 2 chromatids split to form 2 separate chromatids. These chromatids are now referred to as chromosomes hence forming 4 cells each containing 23 chromosomes.
Main Point: When Chromatids split from the chromosome they become 2 separate chromosomes.
I hope you understand now.
Thanks so much, that really helps! I understand it now.
And to everyone who says it won't come up, it probably won't, I was just interested in the subject I'm studying and want to understand it fully!
In metaphase chromosomes do not line up at the centromere of the cell they line up at the equator of the cell. Then the centromere of the chromosome is attached to a spindle fibre.
In anaphase the spindle fibres contract and not shorten, you could have lost marks for incorrect terminology.
Its just that, that made me think alot, you were quite right after all.
no, it is correct in aqa mark schemes to refer to the spindles as shortening.
not fully prepared on these topics :- variation, antibiotic resistance and biodiversity.i have read and understand but i feel am not confident to answer HSW que. do you have any exam questions related to this topics to help me out...
Yehh av ucheked out the bio unit 2011 paper its on biodiversity its goes on the lines of: what effect does agriculture have on biodiversity of animals then u talk about the three factors: genetid diversity reduce obviosly but alwais talk about the use of pesticides fewer food sources fewer habitats
yh so remember that so far interspecif ad intraspecific variation hasnt kum up so make sure u knw that jus mak esure u knw unit2 jan 11 paper! let me knw if u need any help on it
Could someone explain answer of question 5dii in the June 2010 paper please?
Also what does the term degenerate mean for DNA base sequences?
degenerate means that more that one codon (triplet of bases that codes for a single amino acid) codes for the same amino acid.
So, say the amino acid is Methionine, the code is degenerate because AAG & ATT & ACT each code for methionine. (fictional btw, but the principle is the same)
degenerate means that more that one codon (triplet of bases that codes for a single amino acid) codes for the same amino acid.
So, say the amino acid is Methionine, the code is degenerate because AAG & ATT & ACT each code for methionine. (fictional btw, but the principle is the same)
Could someone explain answer of question 5dii in the June 2010 paper please?
Also what does the term degenerate mean for DNA base sequences?
Well i just read the exam report on 5dii , and it seemed that less than 10% of candidates actually got that mark, indicating that in true aqa style it was a stupid question.
Yehh av ucheked out the bio unit 2011 paper its on biodiversity its goes on the lines of: what effect does agriculture have on biodiversity of animals then u talk about the three factors: genetid diversity reduce obviosly but alwais talk about the use of pesticides fewer food sources fewer habitats
yh so remember that so far interspecif ad intraspecific variation hasnt kum up so make sure u knw that jus mak esure u knw unit2 jan 11 paper! let me knw if u need any help on it
thanx for that, i'll do the paper tomorrow and i'll let you knw any problems that will crop up.have you finished ol bio Past papers..
Well i just read the exam report on 5dii , and it seemed that less than 10% of candidates actually got that mark, indicating that in true aqa style it was a stupid question.
You just have to do 2 to the power 3. 2 being a constant number and 3 being the number of chromosomes. Look at page 141 on the nelson thornes book at the hint box
Could someone explain answer of question 5dii in the June 2010 paper please?
Also what does the term degenerate mean for DNA base sequences?
You just have to do 2 to the power 3. 2 being a constant number and 3 being the number of chromosomes. Look at page 141 on the nelson thornes book at the hint box.
Can someone please explain how water is transferred up from the xylem? I believe there are two ways. Can you also make your answer specific to what the markscheme answer for such a question would be.