Log in jennifer komen 6 years agoPosted 6 years ago. Direct link to jennifer komen's post “In telophase 1 and teloph...” In telophase 1 and telophase 2, I am confused about the use of the word "haploid." They are both labeled "haploid," but they do not look the same. • (22 votes) Scout Finch 6 years agoPosted 6 years ago. Direct link to Scout Finch's post “That is because in Teloph...” That is because in Telophase 1, the sister chromatids are still attached. Telophase 2 is basically splitting the 2 sisters apart, but, as each contains the same genetic info, it is still haploid. Hope that answers your query! (29 votes) Hoi Ki Cheng 6 years agoPosted 6 years ago. Direct link to Hoi Ki Cheng's post “I am confused about the n...” I am confused about the number of sister chromatids between mitosis and meiosis. For example, human. After replication, there are 46 chromosomes (92 sister chromatids in total) in a cell, right? During mitosis, they are split into 2 cells, each of which has 46 chromosomes (46 sister chromatids in total). On the other side, during meiosis I, same as mitosis, they are split into 2 cells, each of which has 46 chromosomes (46 sister chromatids in total). So, during meiosis II, these 2 cells was split again into 4 cells, each of which has 23 chromosomes (23 sister chromatids in total). Am I right? • (6 votes) Kim Kelly 6 years agoPosted 6 years ago. Direct link to Kim Kelly's post “Your thought is correct b...” Your thought is correct but plz notice, after splitting 2 sister chromosomes in mitosis, each single one is no longer a sister chromatid but a chromosome. So you cannot say 46 chromatids in total in your second graph, it is only 46 chromosomes or 23 pairs of hom*ologous chromosomes:) (9 votes) amaan_zafar 6 years agoPosted 6 years ago. Direct link to amaan_zafar's post “what is the difference be...” what is the difference between crossing over and synapsis? • (4 votes) Anagha Tiwari 5 years agoPosted 5 years ago. Direct link to Anagha Tiwari's post “Synapsis is when the hom*o...” Synapsis is when the hom*ologous chromosomes of the same size and length pair up. Crossing over is when bits of DNA are exchanged from each chromosome to produce genetically unique chromosomes. Though both happen in Prophase I, synapsis happens before the chromosomes can cross over. Hope that helps! (7 votes) Lia Naqi 6 years agoPosted 6 years ago. Direct link to Lia Naqi's post “What does hom*ologous mean...” What does hom*ologous mean? • (4 votes) James Best 6 years agoPosted 6 years ago. Direct link to James Best's post “In biology it means simil...” In biology it means similar in position, structure, and evolutionary origin but not necessarily in function for organs, but for chromosomes it means similar in position, structure, and evolutionary origin but not necessarily in function. hope this helps:) (7 votes) nddaksh23 6 years agoPosted 6 years ago. Direct link to nddaksh23's post “How can n divide to give ...” How can n divide to give 2n • (6 votes) val.yumyum 4 years agoPosted 4 years ago. Direct link to val.yumyum's post “it's because the germ cel...” it's because the germ cell goes through interphase another time before meiosis 2, so the chromosomes duplicate again. (1 vote) Daniyal Bilal 4 years agoPosted 4 years ago. Direct link to Daniyal Bilal's post “what happens to cells ( w...” what happens to cells ( what is their fate or role) that have completed the mitosis cycle and the meiosis process?? • (3 votes) Manan Upadhyaya 2 years agoPosted 2 years ago. Direct link to Manan Upadhyaya's post “after mitosis, cells go b...” after mitosis, cells go back to the interphase stage of the cell cycle and carry on the cell cycle. for human somatic cells, mitosis can only occur about 20-50 times before it undergoes apoptosis, a number known as the Hayflick limit. scientifically, this is beneficial because of the accumulation of mutations that may potentially be dangerous. an exception is cancerous cells such as with the TP53 mutation, where mitosis keeps going on continuously even if there is insufficient energy/organelles available, often resulting in tumours. note that some cells are stuck in a phase of the cell cycle known as G_0, where they do not go through mitosis till reverted back to the G_1 stage. (5 votes) doraozioma a year agoPosted a year ago. Direct link to doraozioma's post “There is something confus...” There is something confusing in meosis 1. A cell with 46 chromosomes duplicates and just like in Mitosis divides... But the sister chromatids didn't split but remained together and went to opposite poles. Yet we say the end product of meosis 1 are haploid cells. Where did the duplicated chromosomes go? But in mitosis we say the end products are diploid...yet they divided and even splitted. Is this maths not wrong? • (3 votes) Leia 10 months agoPosted 10 months ago. Direct link to Leia's post “This confuses me too, but...” This confuses me too, but maybe I can offer some help. So I think it is not until Meiosis 2 that cells become haploid. Because first, the cell goes through interphase where it duplicates its 46 chromosomes into 92 chromosomes. At this stage there are now 92 Xs. However, each X is hom*ologous to another, and so is in a hom*ologous pair. That means that there are 46 pairs. (23 pairs duplicated is 46 pairs). You were right that in Meiosis 1 that it is only the pairs that separate. Therefore it is not yet haploid. I like my biology book’s definition of Haploid and Diploid. (5 votes) Deontae Baker 5 years agoPosted 5 years ago. Direct link to Deontae Baker's post “Is Meiosis a continues pr...” Is Meiosis a continues process or does it stop and begin whenever the body wants it to? • (4 votes) amina.mcdiarmid 4 years agoPosted 4 years ago. Direct link to amina.mcdiarmid's post “Meiosis occurs in the tes...” Meiosis occurs in the testes in males and in the ovaries in females. In males, sperm production occurs in the testes almost continuously to replenish the supply. In females, egg cells are made from oocytes which are produce when the female is a fetus. Oocytes are cells arrested in meiosis I. Meiosis resumes when the oocyte is activated ready for ovulation and then arrests again in metaphase II. It is during fertilisation that the cell undergoes anaphase II so that the sister chromatids are finally separated (2 votes) Ammar Hasan 4 years agoPosted 4 years ago. Direct link to Ammar Hasan's post “so are the sister chromat...” so are the sister chromatids diploids? • (3 votes) JHuang 4 years agoPosted 4 years ago. Direct link to JHuang's post “We say a cell is diploid ...” We say a cell is diploid or haploid or more, (4 votes) shellyjpix 6 years agoPosted 6 years ago. Direct link to shellyjpix's post “In the Starting Cell of M...” In the Starting Cell of Meiosis I, you say that it is the hom*ologous chromosomes from mother and father that cross over... but how can this be if the cell has not been fertilized yet and Meiosis describes how a gamete cell is produced. Therefore, an egg would only have the chromosomes from the mother and a sperm would have only the chromosomes from the father. • (3 votes) Mary 6 years agoPosted 6 years ago. Direct link to Mary's post “You received hom*ologous c...” You received hom*ologous chromosomes from your mother and some from your father, that is your genetic make up. I think the process of meiosis separates them so that the traits you pass on to your children can seem as if they are coming from grandparents or from you. I think it why I have blue like my dad and not brown ones like my mom. My maternal grandmother had blue eyes so she gave my mom the blue eyed chromosome. I was the one child of 4 with blue eyes. My eye color chromosomes from both my parents were different than for my siblings. I think meiosis has a role in that. (4 votes)Want to join the conversation?
Meanwhile, in meiosis1, after splitting into two cells, each one contains 46 sister chromatids but only 23 chromosomes (notice that two sister chromatids is a chromosome).
Telophase 1 has 2 chromosomes each and they are n and Telophase 2 has 1 chromosomes in 1 cell and is also n how??
as for meiosis, cells are usually nourished so that they grow. in humans, the sperm is nourished by the sertoli cells in the testes to ensure that they grow and mature. the ova are developed inside the follicles of the ovary and typically the one ovum that matures the most is released from its follicle during ovulation. their fate is either fertilization, in which case the sperm and ovum form an embryo that develops in the fallopian tubes and then in the uterus. in case that this does not occur, the ovum is shed off with the uterine lining in a process known as menstruation. as for the sperm, they are usually just left in the testes, and if not released through a process such as ejacul*tion they may start to die in the testes.
How man chromosomes are present after meosis 1? That's quite confusing in my opinion
Diploid Cell - “A cell with chromosomes that come in hom*ologous pairs or two sets of chromosomes”
Haploid Cell - “A cell that has only one representative of each chromosome pair or half the total number of chromosomes.”
This seems like it would be haploid at the end of Meiosis 1, but since it duplicated beforehand, it is only back to the original number of 46 chromosomes. Then in Meiosis 2 it cuts the actual chromosomes into chromatids and makes 23. It seems though that since the pairs are separated in Meiosis 1 then it would be haploid, but I think it has to do with the total number of chromosomes. A single chromatid can be called a chromosome, and a duplicated 2 sister chromatids joined together can also be a chromosome. So, in Mitosis the cell has 46 individual chromosomes, duplicates to have 92 chromosomes making Xs, and back to having 46 single chromosomes again. This means that the original number was never cut in half despite the X pairs being cut in half. In meiosis 1 they go from 46 to 92 and back to 46, while in meiosis 2 it does not duplicate in between and goes from 46 to 23. Idk. This is honestly the best I can think of. Every definition I find is slightly different than another and I remain confused. But I think that is how it is not yet haploid in meiosis 1. If it were haploid in meiosis 1(going from 46 to 92 to 46) then you could consider mitosis to make haploid as well (also going from 46 to 92 to 46) since it cuts in half the number and splits the chromosomes. But mitosis makes diploid cells from diploid cells. I may have this wrong and maybe I just made things more confusing. But I think the key is the total number that determines if it is haploid or not.
Oh and also, the definition for haploid states, “A cell that has only one representative of each chromosome pair…”. If you think about it, even though the pairs are separated in meiosis 1, it has the pairs still together in each cell. Kind of.
} } -> }{ }{-> }{ | }{
/ /-> X X -> X | X
Ok, so you go from 4 hom*ologous chromosomes not yet duplicated in chromatin form, and so you have 2 pairs. 1 pair: } } and 2nd pair / /. Then you duplicate them and have 2 pairs, but 4 chromosomes counting the whole Xs and 8 chromosomes counting the individual chromosomes. Each X is made of 2 sister chromatids, so count each one. (So I can say that there are 4 chromosomes for counting whole Xs or 8 chromosomes counting the chromosomes individually. You can see that they were doubled though.). Then you split it in half and actually still have the } } and / /. They will have been mixed, but you should have directly returned back to the original because the original pair was between the individual chromosomes. We just don’t show them outside Xs because you can’t see chromatin well in a microscope. I Believe this might also help to explain and show that the cells are not made haploid until meiosis 2. In meiosis 2 there are only one representative of each chromosome pair. Remember, Xs are the duplicated form of the single chromosomes before synthesis. And also that it becomes haploid when the cell has just } and / by themselves.
And for the amount of chromosomes present after meiosis 1, there are (using the example of an organism with just 2 chromosomes) 2 chromosomes. It duplicated first: 2 chromosomes (1 pair) -> 4 chromosomes (2 pairs) -> 2 chromosomes. This means that there are 2 chromosomes present in each cell (two Xs but the same number of individual chromosomes) after meiosis 1. I hope this wasn’t all a mess of an answer and made at least some sense…
Sister chromatids are just 'one-half' of the chromosome
