Chromosomes condense and become visible by light microscopy as eukaryotic cells enter mitosis or meiosis. During interphase (G1 + S + G2), chromosomes are fully or partially decondensed, in the form of chromatin, which consists of DNA wound around histone proteins (nucleosomes).
The chromosome number is reduced from 2N to 1N in the first meiotic division, and stays at 1N in the second meiotic division. Because homologous chromosomes separate in the first division, the daughter cells no longer have copies of each chromosome from both parents, so they have haploid genetic information, and a 1N chromosome number. The second meiotic division, where sister chromatids separate, is like mitosis. Chromosome number stays the same when sister chromatids separate.
DNA/RNA, Mitosis/Meiosis Protein Synthesis 1.
produces two daughter cells that are genetically identical to each other, and to the parental cell. A diploid cell starts with 2N chromosomes and 2X DNA content. After DNA replication, the cells is still genetically diploid (2N chromosome number), but has 4X DNA content because each chromosome has replicated its DNA. Each chromosome now consists of a joined pair of identical sister chromatids. During mitosis the sister chromatids separate and go to opposite ends of the dividing cell. Mitosis ends with 2 identical cells, each with 2N chromosomes and 2X DNA content. All eukaryotic cells replicate via mitosis, except germline cells that undergo meiosis (see below) to produce gametes (eggs and sperm).
p53 inhibits entry into mitosis when DNA synthesis is …
There are four different nitrogen bases, adenine, thymine, cytosine and guanine. The synthesis of a particular protein such as insulin is determined by the sequence in which these bases are repeated (see fig.
DNA Replication and Protein Synthesis - Biology Is Fun
DNA replication occurs during the S (synthesis) phase of of the cell cycle.S phase: The period during which DNA is G2 phase: The period after DNA synthesis has occurred Cytokinesis occurs after nuclear division (mitosis).DNA replication occurs during this phase.
DNA Replication and Protein Synthesis
The cell cycle includes the S phase (during which DNA synthesis occurs), the M phase (during which mitosis occurs).The cell cycle consists of interphase and the mitotic phase.
DNA Replication, Mitosis, Meiosis, and Cell Cycle
This chromosome number stays the same after chromosome replication during S phase: each chromosome entering cell division now consists of a pair of sister chromatids joined together at the centromere. Then in mitosis, the sister chromatids of each chromosome separate, so each daughter cell receives one chromatid from each chromosome. The result of mitosis is two identical daughter cells, genetically identical to the original cell, all having 2N chromosomes. So during a mitotic cell cycle, the DNA content per chromosome doubles during S phase (each chromosome starts as one chromatid, then becomes a pair of identical sister chromatids during S phase), but the chromosome number stays the same.
Synthesis of DNA during Mitosis - ResearchGate
This Review is intended for veterinary students studying embryology (developmental anatomy). Its purpose is to remind students how mitosis and meiosis differ and the role that plays enabling DNA transfer across generations.