What must happen before meiosis can begin apex?
What must happen before meiosis can begin? (APEX)Answer: The chromosomes must replicate.
Before meiosis begins, the DNA in each chromosome is replicated. The two identical copies that result from this DNA replication are referred to as 'sister chromatids', and are joined to each other by a region of the chromosome called the centromere (as shown in figure 1).
What must happen before a cell can begin mitosis? The chromosomes must be duplicated. Before mitosis can begin, the chromosomes, or genetic material, must be copied, which occurs during interphase.
Before meiosis starts, the hom*ologous chromosomes must duplicate. After the chromosomes duplicate, each part of the 'X' is called a sister chromatid. These sister chromatids line up to form a tetrad during prophase I.
Before germ cells enter meiosis, they are generally diploid, meaning that they have two hom*ologous copies of each chromosome. Then, just before a germ cell enters meiosis, it duplicates its DNA so that the cell contains four DNA copies distributed between two pairs of hom*ologous chromosomes.
Before the cell undergoes mitosis, the cell must make two copies of its DNA so that each daughter cell has a complete copy of the genetic material. At the onset of mitosis the nuclear envelope dissolves, and each chromosome lines up with its copy.
Interphase must occur once before meiosis can happen.
Before cells can divide, either through mitosis or meiosis, they must go through interphase. In interphase, the contents of the cell double. All of the chromosomes are copied, and the organelles are doubled as well.
Meiosis I, the first meiotic division, begins with prophase I. During prophase I, the complex of DNA and protein known as chromatin condenses to form chromosomes. The pairs of replicated chromosomes are known as sister chromatids, and they remain joined at a central point called the centromere.
Both meiosis and mitosis initiate after DNA replication, so each chromosome consists of two sister chromatids. In meiosis I, hom*ologous chromosomes pair and then segregate to different cells.
What must happen during interphase before meiosis can begin?
For example, prior to undergoing meiosis, a cell goes through an interphase period in which it grows, replicates its chromosomes, and checks all of its systems to ensure that it is ready to divide. Like mitosis, meiosis also has distinct stages called prophase, metaphase, anaphase, and telophase.
DNA replication takes place in S-phase of the Interphase before Meiosis I begins.
In this process, we begin with a cell with double the normal amount of DNA, and end up with 4 non-identical haploid daughter gametes after two divisions. There are six stages within each of the divisions, namely prophase, prometaphase, metaphase, anaphase, telophase and cytokinesis.
Cells must replicate their DNA before they can divide. This ensures that each daughter cell gets a copy of the genome, and therefore, successful inheritance of genetic traits.
Before a cell divides, its entire genetic information is replicated: An identical copy of each chromosome is made. The strands of DNA become more tightly packed into a condensed form and can be seen under a microscope. Each original DNA strand and its copy remain attached to each other in one place.
Entry into mitosis is triggered by the activation of cyclin-dependent kinase 1 (Cdk1). This simple reaction rapidly and irreversibly sets the cell up for division.
Meiosis starts with a diploid (2n) parent cell that divides to make 4 haploid (n) cells. In sexual reproduction, haploid gametes from two different individuals combine to produce a diploid zygote. The resulting offspring is genetically different from both parents.
Prophase I is the first step in meiosis I. During prophase I, the chromatin condenses, centrosomes move to opposite poles, and a spindle apparatus forms as in mitosis.
The correct answer is (c) synapsis and crossing over. 1. During prophase I of meiosis, synapsis and crossing over take place.
Before cells can divide, either through mitosis or meiosis, they must go through interphase. In interphase, the contents of the cell double. All of the chromosomes are copied, and the organelles are doubled as well.
What causes meiosis to start?
Hormonal stimulation of diplotene-arrested oocytes initially triggers the resumption of meiosis by activating MPF, as at the G2 to M transition of somatic cells. As in mitosis, MPF then induces chromosome condensation, nuclear envelope breakdown, and formation of the spindle.
During meiosis, each diploid cell undergoes two rounds of division to yield four haploid daughter cells — the gametes.
