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There are four chromosomes visible at the beginning of mitosis. Mitosis is the phase for cellular growth and preparation. The cell does not divide until the end of mitosis.
Two chromatids at the beginning of mitosis makes up one chromosome.
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Down syndromeis caused by errors in what?
Downs syndrome is caused by a genetic mutation called trisomy. Trisomy is when an extra chromosome is present on one set of chromosomes, so instead of the 46 chromosomes of a normal human there are 47. Trisomy can often result in miscarriage as the body cannot cope well with extra chromosomes. Downs syndrome is when there is an extra chromosome 21. Other genetic defects which are caused by trisomy are Edwards syndrome and Patau syndrome.
Why are male mutation rates higher than female?
This is because mutations occur in x chromosomes. The male, who has "xy" sex chromosomes, will have the mutation if it is present in the x chromosome. Females, there is a smaller chance because there are two "xx" chromosomes, which reduces the chance that the mutation will be present.
How many chromosomes are present in a sperm cell before fertilization and in the zygote after fertilization?
There are 22 in each, along with an X sex chromosome for the female form and a Y sex chromosome for the male form.
When does the nucleus reappear?
False, No it is the only phase where it disappears. It directly says it comes back in telophase but may be present during all other phases EXEPT prophase.
What are the 3 phases of interphase?
The three stages are G1 phase - the cell is functionally normally and begins to grow in size. The nuclear envelope begins to break down. S (Synthesis) phase - the cells DNA replicates G2 phase - The mitotic spindle, made from cytokinetic fibres, begins to form. The cell ensures that the correct number of chromosomes and organelles are present. If so, Interphase ends and cell division continues.
How many chromotids are present in a chromosome at the beginning of mitosis?
2
How many sister chromatids present during anaphase of mitosis?
There are a total of four sister chromatids present during anaphase of mitosis. Each replicated chromosome consists of two sister chromatids that are held together by a centromere. During anaphase, these sister chromatids separate and are pulled to opposite poles of the cell by the spindle fibers.
In a human nucleus just before cell division how many chromatids are present?
In a human nucleus just before cell division, each chromosome is composed of two identical sister chromatids, so there are typically 46 chromatids present (in a diploid cell with 46 chromosomes).
If you have 24 chromosomes during prophase in mitosis how many chromatids does it have?
If you have 24 chromosomes during prophase in mitosis, each chromosome consists of 2 sister chromatids connected at the centromere. Therefore, there would be a total of 48 chromatids present.
Does metaphase of mitosis meiosis 1or meiosis2 have the haploid number of chromosomes at the equator of the spindle?
In metaphase of meiosis 1, the haploid number of chromosomes is present at the equator of the spindle. Each chromosome is made up of two chromatids.
What will happen to an unfertilized egg that undergoes mitosis but not cytokinesis?
If an unfertilized egg undergoes mitosis without cytokinesis, it will result in multinucleation, where multiple nuclei will be present within a single cell. This condition is known as syncytium. It can affect the cellular functions and potentially lead to developmental abnormalities.
Are sister chromatids present in G1 phase of the cell cycle?
Sister chromatids are present in G1 phase of the cell cycle following DNA replication in S phase. Sister chromatids are two identical copies of a chromosome joined together at the centromere. During G1 phase, the cell prepares for DNA replication in the subsequent S phase.
What is difference between a chromosome and a chromatid?
Chromatin is DNA wrapped around a sequence of histone proteins (nucleosomes) to allow full strands of DNA to fit inside the nucleus. At the beginning of cell division the histone proteins condense and join together to form a chromatid, a copy package of DNA also known as a 30 nm fiber.Sometimes one chromatid is present in a chromosone however prior to cell division this copy of DNA is duplicated to create a chromosone with two chromatids.Hi,Basically, a chromosome is two chromatids joined together at the centromere, and the two chromatids on a chromosome are identical. Normally, the cell only needs one copy of each set of genetic material so chromatids are enough, but because the genetic information of the cell will be distributed to two daughter cells during mitosis/meiosis the chromatids must be doubled. This is achieved in the S-Phase of a cell cycle. With two copies of each allele, the genetic information will be evenly distributed and will be the same between the two sister cells.Hope this helps
What are the differences between chromatin and chromosomes?
Chromatin and chromosomes are basically the same thing. The difference is that chromatin is unfolded, uncondensed, extended DNA while chromosomes are condensed DNA. Chromosomes are condensed chromatin and chromatin is unfolded chromosomes. The only difference I know is that chromatin are present normally in a cell, while chromosomes are there only when the cell is about to divide. When the cell is about to divide, the chromatin threads get organised into chromosomes. Utilizing their histone proteins to accomplish this, DNA first condenses into 10 nm strands and then into 30 nm strands, ready for Condensation and then Cytokinesis.
Are sister chromatids present in all or part of the s and g2 phase?
1. Are sister chromatids present in all or part of this phase?answer: G1 no, S yes, G2 yes, Beginning of M yes, End of M no2. Is the DNA condensed in all part of this phase?answer: G1 no, S no, G2 no, Beginning of M yes, End of M yes3. Does the cell contain Twice as much DNA in this phase as it did in the G1 phase?answer: G1 no, S yes, G2 yes, Beginning of M yes, End of M yes.
If an organism has 16 chromosomes in each of its egg cells what is the diploid number?
The diploid number of chromosomes in the organism would be 32 because the egg cell carries half of the total chromosomes, which in this case is 16. Therefore, the full set of chromosomes in the organism would be twice the number in the egg cell, resulting in 32 chromosomes.
How many chromosomes were present in the nucleus when mitosis began?
Before mitosis begins, a cell has a diploid number of chromosomes, which means there are two sets of chromosomes. This is because during interphase, before mitosis begins, the DNA has already replicated, so the cell contains identical copies of each chromosome.
