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Ketone bodies are produced mainly in the mitochondria of liver cells, and synthesis can occur in response to an unavailability of blood glucose, such as during fasting. [4] Other cells, e.g. human astrocytes, are capable of carrying out ketogenesis, but they are not as effective at doing so. [6] Ketogenesis occurs constantly in a healthy ...
The eukaryotic cell cycle consists of four distinct phases: G 1 phase, S phase (synthesis), G 2 phase (collectively known as interphase) and M phase (mitosis and cytokinesis). M phase is itself composed of two tightly coupled processes: mitosis, in which the cell's nucleus divides, and cytokinesis, in which the cell's cytoplasm and cell membrane divides forming two daughter cells.
Mitosis occurs in the following circumstances: Development and growth: The number of cells within an organism increases by mitosis. This is the basis of the development of a multicellular body from a single cell, i.e., zygote and also the basis of the growth of a multicellular body.
Steps of the cell cycle. The G 2-M checkpoint occurs between the G 2 and M phases. G2-M arrest. The G 2-M DNA damage checkpoint is an important cell cycle checkpoint in eukaryotic organisms that ensures that cells don't initiate mitosis until damaged or incompletely replicated DNA is sufficiently repaired.
During the phase of meiosis labeled “interphase s” in the meiosis diagram there is a round of DNA replication, so that each of the chromosomes initially present is now composed of two copies called chromatids. These chromosomes (paired chromatids) then pair with the homologous chromosome (also paired chromatids) present in the same nucleus ...
Mitotic exit is an important transition point that signifies the end of mitosis and the onset of new G1 phase for a cell, and the cell needs to rely on specific control mechanisms to ensure that once it exits mitosis, it never returns to mitosis until it has gone through G1, S, and G2 phases and passed all the necessary checkpoints.
Chk1/2 phosphorylate cdc25 which, in addition to being inhibited, is also sequestered in the cytoplasm by the 14-3-3 proteins. 14-3-3 are upregulated by p53, which, as previously mentioned, is activated by Chk1 and ATM/ATR. p53 also transactivates p21, and both p21 and the 14-3-3 in turn inhibit cyclin B-cdc2 complexes through the ...
Interphase is the process through which a cell must go before mitosis, meiosis, and cytokinesis. [15] Interphase consists of three main phases: G 1, S, and G 2. G 1 is a time of growth for the cell where specialized cellular functions occur in order to prepare the cell for DNA replication. [16]