Is my understanding of meiosis correct????

Question

the s*x cell (gamete) has 23 chromosomes

it replicates producing 46 chromosomes

it divides once producing 2 cells that have 23 chromosomes

it divides again producing 4 cells with 11.5 chromosomes in each cell???

it doesnt seem right,

please any help will do ive got a major exam coming and cant quite figure it out!!!!!

Future thanks

Answer 1

okay...this is gonna be a bit long.

meiosis is basically the splitting/reproduction of s*x cells. how it works is:

1. gamete (egg) joins up with another gamete (sperm) each gamete has 23 chromosomes. you got that right.

2.  when they join it now has 46 chromosomes. they then produce four daughter cells, by splitting and then copying each other.

3. Each daughter cell has 23 chromosomes. Why? so these daughter cells are gametes, and once again join with other gametes (i.e sperm) and reproduce once again.

Answer 2

n biology or life science, meiosis (pronounced my-oh-sis) is a process of reduction division in which the number of chromosomes per cell is cut in half. In animals, meiosis always results in the formation of gametes. The word "meiosis" comes from the Greek verb meioun, meaning "to make small," since it results in a reduction in chromosome number in the gamete cell.

Meiosis is essential for sexual reproduction and therefore occurs in all eukaryotes (including single-celled organisms) that reproduce sexually. A few eukaryotes, notably the Bdelloid rotifers, have lost the ability to carry out meiosis and have acquired the ability to reproduce by parthenogenesis. Meiosis does not occur in archaea or bacteria, which reproduce via asexual processes such as mitosis or binary fission. Each cell has half the number of chromosomes as the parent cell.

During meiosis, the genome of a diploid germ cell, which is composed of long segments of DNA packaged into chromosomes, undergoes DNA replication followed by two rounds of division, resulting in four haploid cells. Each of these cells contain one complete set of chromosomes, or half of the genetic content of the original cell. If meiosis produces gametes, these cells must fuse during fertilization to create a new diploid cell, or zygote before any new growth can occur. Thus, the division mechanism of meiosis is a reciprocal process to the joining of two genomes that occurs at fertilization. Because the chromosomes of each parent undergo genetic recombination during meiosis, each gamete, and thus each zygote, will have a unique genetic blueprint encoded in its DNA. Together, meiosis and fertilization constitute sexuality in the eukaryotes, and generate genetically distinct individuals in populations.

In all plants, and in many protists, meiosis results in the formation of haploid cells that can divide vegetatively without undergoing fertilization. In these groups, gametes are produced by mitosis.

Meiosis uses many of the same biochemical mechanisms employed during mitosis to accomplish the redistribution of chromosomes. There are several features unique to meiosis, most importantly the pairing and genetic recombination between homologous chromosomes.

Answer 3

Well yes, it does produce 4 haploid gamete cells in the end. But we don't say 11.5 chromosomes.

The number of chromosomes is halved :

From diploid (2n) ----> haploid (n)

So when you start out with 46, you end up with 23 chromosomes in each cell. You have to remember that the chromosomes are duplicated, that's why they are able to segregate without reducing the number of chromosomes during anaphase 2.

The gamete cell will then undergo fertilisation and will have 46 chromosome by means of mitosis.

Answer 4

you start with 46 chromatids (rod shaped). They replicate and form 46 chromosomes ( 2 sister chromatids - butterfly shape). first division you get 23 chromosomes in 2 cells. second division seperates the sister chromatids to 2 cells so now you have 4 cells wil 23 chramids (rods) each. check out this image to further understand what i am talking about: http://www.harlem-school.com/10TH/sci_pd...

Notice for the two answers above: sister chromatiDs make up a chromosome not chromatiNs. Chromatin is the complex of DNA and protein that makes up chromosomes.

Answer 5

Hello, well you somewhat understand the division process but it seems like you don't understand how it fits in.

Basically just know that every cell in the human body consists of 46 chromosomes. Each cell in the reproductive organs (for eg testis) undergo meiosis to produce 4 genetically different s*x cells (gametes) - which contain 23 chromosomes each.

When one gamete from the male and another from the female undergo fertilization and results in a cell with the original number of chromosomes (ie. 46).

Hope this explanation works for you!

Answer 6

No!

The gametocyte (the cell that produces gametes) has 46 chromosomes. Its chromosomes come together and duplicate, forming tetrades  (a structure of 4 chromatins stuck together). The cell divides and forms 2 cells with 23 pairs of chromosomes (2 chromatins that are joined together). Each cell divides again and forms 2 gametes (total of 4 gametes from the starting gametocyte) each with 23 single chromosomes.

Answer 7

You are so close.

the s*x cell PROGENITOR (gametOCYTe) has 23 PAIRS OF chromosomes (46)

it replicates producing 23 TETRADS OF chromosomes (92)

it divides once producing 2 cells that have 23 PAIRS OF chromosomes (46)

it divides again producing 4 cells with 23 UNPAIRED chromosomes in each cell???  <--- GAMETES

Answer 8

no this is just a bit wrong, but you get the main idea.

a cell starts off with 46 chromosomes and then it divides twice.

the first division forms 2 cells with 23 chromosomes each.

Those 2 cells then divide again, but the DNA for the 4 new cells are in chromatin (all unwound) form. They don't exactly have "11.5 chromosomes". but that's the sense of it.

You may want to check with some other answers to verify this