10
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What is the point of Meiosis II, considering Meiosis I already produced haploid cells?
After meiosis I, those n=23 chromosomes have two chromatides. Meiosis II just separates them into single chromatides.
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8
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No. of meiotic divisions to produce specific no. of seeds
Assuming that you have studied megasporogenesis and microsporogenesis. To produce a seed, you require the production of pollen(n) and egg(n) and their fusion.
Let's start with pollen grain(n):
4 ...
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8
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How do gene locations change during crossing over events?
It depends on the regions of sequence homology between the two chromosomes. Crossing over occurs through pairing of homologous regions. If there's a substantial stretch of chromosome without a ...
- 1,711
7
votes
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Could multiplexed CRISPR disable the mitotic and meiotic genes of cancerous cells?
As with all cancer therapeutics one of the biggest problems is how you get the therapeutic to kill cancer cells without also killing so many healthy cells that the therapy kills the patient.
For ...
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5
votes
Why isn't meiosis II called mitosis (as the chromosome number doesn't half)?
Well, in my opinion, the entirety of the meiosis is a process (reproduction of sex cell) in which two levels of division occur, it's all kind of one process. Though meiosis II may seem to have many ...
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4
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How do I identify the different stages of meiosis under microscope?
ID characteristics that can help you recognize diplotene better:
diplotene :
the only difference between this phase and Diakinesis is that The centrosomes reach the poles.
you can see the photos ...
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4
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How can a haploid plant be bisexual?
Meiosis does not determine sexual form. Eukaryotes use meiosis and fertilization to recombine genes to form new combinations. Meiosis does produce haploid cells from diploid cells, but that has ...
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4
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How are germ cells not reduced in number?
In case of gametogenesis (let us talk about spermatogenesis) gametes are formed from meiotic division of Primary spermatocytes.
In Primates Primary spermatocytes are cells that that are formed from ...
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4
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No. of meiotic divisions to produce specific no. of seeds
For producing $x$ number of seeds (or say zygote) $x$ number of egg cells must fuse with $x$ number of male gametes.
In angiosperms, 1 meiotic division of Megaspore mother cell leads to formation of ...
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4
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When in the cell cycle is the number of chromosomes normally reduced?
It is the other way around. Meiosis I (or reductional division) splits chromosome pairs so each cell gets half of the chromosomes of the parent. Meiosis II (or equational division) splits double-...
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Considering Two Genes, Are There Only Two Possible Outcomes for the Four Gametes Produced After Meiosis, Regardless of Independent Assortment?
A "single meiotic event" would include both meiosis I and meiosis II. So, if you start with an AaBb mother cell prior to any phase of meiosis, then observe one of the resulting final ...
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3
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How are germ cells not reduced in number?
"How are germ cells not reduced in number?"
It does happen. Germ cells do eventually run out. It is called menopause in women. And age related infertility in men.
As for your question of where do ...
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3
votes
During what phase is the cell polyploid?
I assume that you mean phase of cell division. First off all i will write down a definition of word polyploid. Polyploid is cell which has two or more pairs of homologus chromozoms. There are two ...
- 1,863
3
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Is there random assortment in metaphase II?
Metaphase I
Your understanding of the metaphase I is not entirely correct. In normal (human) metaphase I homologous chromosomes separate. Therefore, sister chromatides go together. More precisely ...
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How could a cell only have chromosomes from father or from mother?
That graphic is just confusing you.
The cell doesn't keep track of all the chromosomes from Mother versus all the chromosomes from Father so it can sort them out later. That I know of! [I don't ...
- 2,455
2
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Formula for number of divisions required to form x number of cells (Mitosis and Meiosis)
For a male, one primary spermatocyte produces two secondary spermatocytes through meiosis I, which in turn produce two spermatids each through meiosis II. So one primary spermatocyte produces four ...
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2
votes
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What are chiasmata?
We need to make a distinction between the genetic map of a chromosome, which is usually built up from meiotic recombination frequencies between linked genetic markers, the physical map of a chromosome,...
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2
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Mechanics of Chromosomal Crossover
How does the cell select where to to make the break on both chromosomes?
There are proteins that direct the selection of a site where a double strand break will be made on one chromatid.
...
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2
votes
Doesn't meiosis form two pairs of similar cells and two pairs of opposite cells?
Great question - I think there are two misconceptions in your question that are interfering with your understanding.
First, crossing-over occurring at just the "tips" is just for clarity in textbooks ...
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2
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Do Gametes contain mitochondria/chloroplasts from their parent cell?
Is this DNA found in the mitochondria and chloroplasts coded for in the host's (animal's or plant's) DNA.
No, the DNA contained in these organelles it not a subset of the nuclear genome. However, ...
- 1,145
2
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Does chromosome cross occur over male and female or vice versa?
The question is unclear to me but hopefully that will help a little bit.
My understanding is homologous chromosome pair, which means male and female chromosome
There is no male and female ...
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2
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Aneuploidy in meiosis
From Study.com >>
On the off chance that nondisjunction happens amid anaphase II of meiosis II, it implies that no less than one set of sister chromatids did not isolate.
In this situation, two ...
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Is this how female and male gametes look like in plants?
The comments are very unclear and your interpretation of the figure seems very wrong (no offense). You should have a look at an intro course (such as this one by Khan Academy) as asking such intro ...
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2
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Why do some organelle (like ER and Golgi complex) cannot be seen under microscope during cell division?
A cell when undergoes the process of cell division there are structures known as spindle fibres that are required to pull the chromosomes off to the poles of the cell so that it can be segregated into ...
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Where did the nondisjunction occur?
Think about what gametes the father could have given the child. If the mother contributed an "A", then the father gave two "C"s, if the mother contributed a "C" then the father contributed an "A" and ...
- 136
2
votes
Polyploidy, or why plants of different species can produce fertile offspring hybrids more frequently than animals?
While I do not know if there is a definitive answer to this question, I suspect that at least part of the answer can be found in the fact that animals typically have much more complex and delicate ...
- 6,977
2
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Human ancestor reproduction after chromosome fusion
Strangely enough we actually do have an answer for that.
There are a several examples of individuals who are born with two chromosomes fused together in all their cells.
We even have a few examples ...
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2
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Human ancestor reproduction after chromosome fusion
My question is this: for the first ancestor whose chromosomes fused to
have 23 chromosomes instead of 24, how did he reproduce?
He or she reproduced the same way people today with balanced ...
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How long does each of the stages in meiosis take?
If you take a look at the figure directly above the image you posted in the link you posted, you'll see a very different set of figures.
It turns out, time spent in different phases of the cell ...
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