ozmo19
Badges: 16
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#1
Report Thread starter 6 years ago
#1
This may be a stupid question.

So, seeing as mitosis produces diploid cells, the DNA must be duplicated which happens in the S phase of interphase. This means 92 chromosomes, thus 92 chromatids going to each new cell, which will mean 46 chromosomes. This is fine, however, when it comes to meiosis, after meiosis I, there are two daughter cells with a haploid number of chromosomes. If these are to split and chromatids go to separate cells, 23 chromatids will go to each of the four cells. Is this right or am i missing something that my textbook isn't stating because this doesn't product 4 haploid cells?
0
reply
username2284409
Badges: 3
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#2
Report 6 years ago
#2
NOTE: Mitosis produces diploid cells in species with a diploid life cycle (or part in haplo-diploid).

Yes, you are right.

You have 92 chromatids which suffer the first division, 46, second division, 23.
You'll have 4 cells with 23 chromatids each: 23 + 23 + 23 + 23 = 92

What happens is that is in meiosis I, the homologous chromossomes will separate. In the beginning of meiosis II there is 23 chromossomes. Saying this, in meiosis I the chromatids aren't separated only the homologous chromossomes. The meiosis II is basically mitosis but with half of the chromossomes (23) where the chromatids are separated from the chromossomes.

Sorry about the poor explanation, my science related english is bad. Hope it helped

ozmo19
1
reply
ozmo19
Badges: 16
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#3
Report Thread starter 6 years ago
#3
Yes, you are right.

You have 92 chromatids which suffer the first division, 46, second division, 23.
You'll have 4 cells with 23 chromatids each: 23 + 23 + 23 + 23 = 92

What happens is that is in meiosis I, the homologous chromossomes will separate. In the beginning of meiosis II there is 23 chromossomes. Saying this, in meiosis I the chromatids aren't separated only the homologous chromosomes. The meiosis II is basically mitosis but with half of the chromossomes (23) where the chromatids are separated from the chromosomes.
But how can say a haploid cell produced from meiosis (that has 23 chromatids) join with another to form 46 chromosomes that have 92 chromatids?

(23+23=46 chromatids which is only sufficient to produce 23 chromosome, therefore not restoring the diploid number like in fertilisation.)
Last edited by RK; 3 years ago
0
reply
username2284409
Badges: 3
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#4
Report 6 years ago
#4
(Original post by ozmo19)
But how can say a haploid cell produced from meiosis (that has 23 chromatids) join with another to form 46 chromosomes that have 92 chromatids?

(23+23=46 chromatids which is only sufficient to produce 23 chromosome, therefore not restoring the diploid number like in fertilisation.)
A "full" chromosome has 2 chromatids, in the beginning of meiosis II you have 23 chromosomes and 46 chromatids. In the end of meiosis II there is 23 chromosomes and 23 chromatids.

When karyogamy occurs you have, in result, a cell with 46 chromosomes and 46 chromatids. I think you forgot that, before mitosis or meiosis can happen the cell has to double all it's genetic material, basically, this means that the only chromatid from 1 chromosome will duplicate and form a 2 chromatid chromosome.

(Sorry about the chromoSSome one, in Portugal we say cromossoma :-) )

Hope it helped ^_^
0
reply
rileystringer1
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#5
Report 6 years ago
#5
(Sorry about the chromoSSome one, in Portugal we say cromossoma :-) )

Hope it helped ^_^
oi
Last edited by RK; 3 years ago
0
reply
username2284409
Badges: 3
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#6
Report 6 years ago
#6
(Original post by rileystringer1)
oi
oi :-)
0
reply
rileystringer1
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#7
Report 6 years ago
#7
oi :-)
tudo bem?
Last edited by RK; 3 years ago
0
reply
username2284409
Badges: 3
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#8
Report 6 years ago
#8
(Original post by rileystringer1)
tudo bem?
Sim! e tu?
0
reply
rileystringer1
Badges: 11
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#9
Report 6 years ago
#9
Sim! e tu?
tudo obrigado
Last edited by RK; 3 years ago
0
reply
username2284409
Badges: 3
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#10
Report 6 years ago
#10
(Original post by rileystringer1)
tudo obrigado
1
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

How did your AQA A-level Psychology Paper 1 go?

Loved the paper - Feeling positive (270)
42.19%
The paper was reasonable (265)
41.41%
Not feeling great about that exam... (58)
9.06%
It was TERRIBLE (47)
7.34%

Watched Threads

View All