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 5 years agoPosted 5 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
FAQs
What is the difference between mitosis and meiosis Khan Academy? ›
Mitosis occurs in somatic cells and results in two identical daughter cells with a diploid (2n) number of chromosomes. This process is essential for growth and repair in the body. On the other hand, meiosis occurs in germ cells and produces four non-identical gametes with a haploid (n) number of chromosomes.
What is meiosis answers? ›Meiosis is a process where a single cell divides twice to produce four cells containing half the original amount of genetic information. During meiosis one cell divides twice to form four daughter cells. These four daughter cells only have half the number of chromosomes of the parent cell – they are haploid.
How many copies does meiosis make? ›Meiosis is a type of cell division by which gametes – eggs and sperm – are formed. It includes two rounds of cell division to produce four haploid cells from a single diploid cell.
How many hours does meiosis take? ›The complete meiosis process in human males takes about 74 hours. Spermatogenesis usually begins at 12-13 years of age and continues throughout life. Several hundred million sperm cells are produced daily by healthy young adult males.
What is the best thing to study meiosis? ›Meiosis takes place in reproductive organs. It results in formation of gametes with half the normal chromosome number. Young anthers are the best materials to study meiosis. So, the correct is 'Young anther'.
Is meiosis asexual? ›Meiosis does not occur during asexual reproduction. Meiosis is the process of producing gametes (eggs and sperm).
Is mitosis asexual? ›Mitosis is a phase of the cell cycle in which a cell's nucleus is divided into two nuclei, each with an equal quantity of genetic material. It is an asexual reproductive process that occurs in unicellular organisms. Thus, mitosis is a type of cell division that occurs during the asexual reproduction process.
Which cell cannot show meiosis? ›Meiosis is the cell division process in which a diploid cell (2n) produces two haploids (n) cells. So, the haploid cell cannot undergo further division. 'n' means the chromosome number. So, a haploid cell cannot undergo meiosis as the chromosome number gets half in meiosis.
What is meiosis summary easy? ›Meiosis functions to reduce the number of chromosomes to one half. Each daughter cell that is produced will have one half as many chromosomes as the parent cell. Meiosis is part of the sexual process because gametes (sperm, eggs) have one half the chromosomes as diploid (2N) individuals.
What is meiosis easy? ›Meiosis is a type of cell division during which a single cell divides twice and produces four daughter cells. These four daughter cells contain half the amount of genetic material and are known as our sex cells (gametes).
What is meiosis pdf? ›
Meiosis is a specialised type of cell division, the principal function of which is to produce spores/gametes (sperm and eggs in mammals) that have the haploid number of chromosomes. In humans, this represents a reduction from 46 (23 pairs) to 23 chromosomes (one complete set) in sperm and eggs.
Does meiosis copy DNA? ›DNA replication occurs in both mitosis and meiosis. In meiosis, the cell undergoes two divisions, i.e. meiosis I and II. Meiosis I is reduction division and meiosis II is similar to mitosis but DNA replicates only once during meiosis, i.e. before meiosis I in S phase.
Do human cells have 46 chromosomes? ›Normally, each cell in the human body has 23 pairs of chromosomes (46 total chromosomes). Half come from the mother; the other half come from the father. Two of the chromosomes (the X and the Y chromosome) are called sex chromosomes, and in almost all people: Females have 2 X chromosomes.
Does each egg have different DNA? ›Women are born with all the eggs they will ever have*. To become eggs (or sperm), the germ cells must undergo another kind of division, called meiotic division. Instead of giving each daughter cell a copy of all the mother cell's DNA, meiotic division gives each daughter cell a copy of only half the mother cell's DNA.
How can I understand meiosis better? ›Meiosis has similar steps to mitosis but with two sets of divisions. The first division results in two cells that each have two sets of chromosomes, like in mitosis. The second division creates four cells that each contain one set of chromosomes, because the genetic information isn't copied a second time.
What is the trick to remember the difference between mitosis and meiosis? ›An easy way to remember the difference between Mitosis and Meiosis is Mi'T'osis and Me'I'osis, where the 'T' in 'Mitosis' stands for 'tall,' and hence, growth, whilst the 'I' in 'Meiosis' stands for 'intercourse,' and hence, sexual reproduction.