Recall that there are two divisions during meiosis: meiosis I and meiosis II. The genetic material of the cell is duplicated during S phase of interphase just as it was with mitosis resulting in 46 chromosomes and 92 chromatids during Prophase I and Metaphase I.
How many chrosomeare there in prophase?
How many replicated chromosomes does the cell contain during prophase? For humans, this means that during prophase and metaphase of mitosis, a human will have 46 chromosomes, but 92 chromatids (again, remember that there are 92 chromatids because the original 46 chromosomes were duplicated during S phase of interphase). Click to see full answer.
How many centromeres are visible in prophase?
In a human cell, in late prophase, there would be 46 centromeres visible if the magnification is high enough. Each of the 46 pairs of sister chromatids is held together by a centromere. How many chromosomes does a human cell have at the start of mitosis?
How many chromatids can be seen during prophase mitosis?
Prophase. Each chromosome is made of two genetically identical chromatids, joined by a centromere. During DNA replication, genetic material is loosely packed as chromatin. However, during mitosis DNA needs to be more tightly packed to allow for easier separation in anaphase. At the start of prophase, chromatin begins condensing into chromosomes.
How many chromosomes are existent during prophase 2?
Prophase II: Since the mother cell split in the previous phase, the ploidy of the daughter cells are cut in half. In the daughter cell, a new spindle (used to separate chromosomes) forms around the bunch of sister chromatids waiting to be separated. No. of chromosomes: 9. No. of DNA molecules: 18.
How many replicated chromosomes are in each of these cells?
How many replicated chromosomes are in each of these cells? 8. Cell with a full set of chromosomes are referred to as diploid or 2n, whereas cells with half the chromosomes are haploid or n.
Does chromosome replication occur in prophase?
The chromosomes at prophase will consist of two identical parts called sister chromatids that stay connected at the centromere. It is now clear that the chromosomes have been replicated.
How many chromosomes are replicated in mitosis?
46 chromosomesOnce mitosis is complete, the cell has two groups of 46 chromosomes, each enclosed with their own nuclear membrane. The cell then splits in two by a process called cytokinesis, creating two clones of the original cell, each with 46 monovalent chromosomes.
How many chromosomes are found in each of the cells during prophase two?
The absence of homologous pairs in haploid cells is the reason why no further crossing over occurs during prophase II. After crossing over, the tetrads (recombinant chromosome pairs) can be separated. Tetrads contain 23 chromosome pairs composed of 92 chromatids.
Where are the chromosomes in prophase?
During prophase, the complex of DNA and proteins contained in the nucleus, known as chromatin, condenses. The chromatin coils and becomes increasingly compact, resulting in the formation of visible chromosomes. Chromosomes are made of a single piece of DNA that is highly organized.
What is a replicated chromosome?
A replicated chromosome contains two identical double strand -DNA- molecules, the chromatids, that are joined at their centromere. Two single sets of pairs (daughter) chromosomes are formed by separation of the pair of chromatids during cell division (from anaphase on in mitosis and anaphase II in meiosis)
What phase is 92 chromatids?
Answer and Explanation: The S phase is where DNA is duplicated and there become 92 chromatids.
What is the number of replications in meiosis?
Note: The DNA replication occurs only once in both meiosis and mitosis although the number of cell divisions is two in meiosis and one in mitosis which results in the production of different numbers of haploid cells in both the process.
How many times are chromosome replicated during meiosis?
Answer : (a)Meiosis consists of two divisiob:meiosis-I and meiosis-II. These occur in rapid succession. the chromosomes replicate only once.
Are there 92 chromosomes in meiosis?
Meiosis differs in that; during metaphase the chromosomes lie side by side. Then in the anaphase there is no division of the chromatid. The whole chromosome is pulled to the one pole of the cell. The parent cells have 4N (92 chromosomes) and the daughter cells have 2N (46 chromosomes).
How many chromosomes are there during metaphase?
During metaphase, there are 46 chromosomes composed of two sister chromatids each that align at the metaphase plate. Then, during anaphase, these chromatids are separated and pulled to opposite poles of the cell. This separation results in 92 separate chromatids in the cell, which are considered 92 chromosomes.
What does 2N 6 mean in mitosis?
The karyotype is described as 2N=6, XY. At this stage, the number of chromosomes equals the number of chromatids, and these are the same between males and females.
What events occur during prophase?
The main events of prophase are: the condensation of chromosomes, the movement of the centrosomes, the formation of the mitotic spindle, and the beginning of nucleoli break down.
Does DNA replication occur in prophase 1?
During prophase I, the chromosomes condense and become visible inside the nucleus. Because each chromosome was duplicated during the S phase that occurred just before prophase I, each now consists of two sister chromatids joined at the centromere. This arrangement means that each chromosome has the shape of an X.
What stage of prophase does the DNA replicate?
In the synthesis (S) phase the DNA is replicated resulting in two copies of each of the chromosomes. Upon entering the G2 phase the cell continue to grow and assess whether the DNA has been properly replicated to prepare for the mitosis (M) phase.
Which of the following events does not occur during prophase?
So, the correct option is 'Chromosomes replicate'.
How many pairs of chromosomes are available in each cell for division in the prophase?
In meiosis since one from the homologous chromosomes have gone to each daughter cell after meiosis 1, only 23 pairs of chromosomes are available in each cell for division in the prophase.
How many chromosomes are in a cell in the synthesis phase?
In the synthesis phasethe cell 46 chromosomes or 23 homologous chromosome pairs are replicated to double the amount which will de given to 2 daughter cells of same genetic composition. Prophase is the phase where the chromatin is condensed to form chromosomes, nuclear membrain disappeared and the centrioles are moved to the two poles of the cell. It’s the beginning of the mitosis.
What is the name of the process where chromosomes exchange genetic information?
In meiosis , the chromosome or chromosomes duplicate (during interphase) and homologous chromosomes exchange genetic information (chromosomal crossover) during the first division, called meiosis I. The daughter cells divide again in meiosis II, splitting up sister chromatids to form haploid gametes. Two gametes fuse during fertilization, creating a diploid cell with a complete set of paired chromosomes.
What happens in the first division of meiosis?
In the first division of meiosis, the homologous chromosomes are split apart and the chromosome number is halved from the 2n state to the n state.
How many chromosomes are in a mother cell during mitosis?
Mitosis generates identical cells, except for the rare unrepaired mutation. So if the mother cell had 10 (5 pair) chromosomes then the 2 daughter cells will have 10 as well. This is because there was a stage prior to mitosis called “S phase” in which the chromosomes were duplicated. This duplication allows identical copies of the chromosomes to be delivered into daughter nuclei during mitosis.
How many chromosomes are in a somatic cell?
A human somatic cell has 23 pairs of chromosomes. How many chromosomes are in each daughter cell after mitosis (would it be 23?)
What is the resulting product of a haploid cell?
The resulting product is the haploid cell or the gamete. This will go on to be fertilized by another gamete in order to make a zygote with the full set of chromosomes.
When homologous chromosome pairs align on the spindle during metaphase I, the orientation of one?
When homologous chromosome pairs align on the spindle during metaphase I the orientation of one pair is independent of the orientation of any other pair. This is known as independent assortment. Humans have 46 chromosomes, arranged as 23 pairs. During metaphase I each pair lines up independently, which results in 2 (23) possible combinations.
How many chromosomes does a zygote have?
If the sperm and egg were to be produced by mitosis, they would both be diploid and the zygote would have four sets of chromosomes. If the zygote produced sperm and egg with four sets of chromosomes then that next generation would have eight sets, and so on.
What is the difference between a diploid and a haploid?
Cells with a full set of chromosomes are referred to as diploid o 2n, where as cells with half the chromosomes are haploid or n. At which stage (s) of meiosis I are the cells diploid and at which stages are they haploid?
Which organelle is smaller during meiosis II?
Be specific in your answer. During meiosis II, the secondary oocyte divides unevenly, with one cell (the ovum) receiving half of the chromosomes and nearly all the cytoplasm and organelles, while the other cell, the polar body, is much smaller and eventually degenerates.
What causes a mixing/scrambling of homologous pairs?
1) Independent assortment causes a mixing/scrambling of the homologous pairs. 2) Crossing over causes exchanges of alleles on the homologous pairs. 3) Random fertilization unites different combinations of maternal and paternal chromosomes. Upgrade to remove ads.
Where do homologous pairs come from?
Half of the homologous pairs come from one parent and the other pair comes from another parent.
Can chromosomes pair up?
Yes - it just depends on how the chrom osomes pair up.
What is the term for the chromosomes that have formed a pair at the end of meio?
late prophase 1. once the chromosomes have formed a pair, what are they called. tetrad. at the end of meiosis 1, two cells have been produced. How many replicated chromosomes are in each of these cells. 2. at which stage of meiosis 1 are the cells diploid and at which stage are they haploid.
How many daughter cells are there at the end of meiosis 2?
at the end of meiosis 2 are four daughter cells. Are they haploid to diploid? Explain your answer in complete sentence
Which stage of meiosis is haploid?
diploid are in the stage of early telophase. and haploid is in the stage of late telophase. considering the genetic makeup of homologous pairs, will the cells at the end of telophase 1 be genetically identical to each other.
Does mitosis reduce the number of chromosomes by half?
the ploidy of zygote would be genetically identical to the parent cells. Since mitosis doesn't reduce the number of chromosomes by half. with your group rent a statement to explain the origin of the chromosomes found in the zygote. Your statement must include the term homologous pair.
