Cell division is necessary for many life roles. It is needed for prokaryotes and single-celled eukaryotes to reproduce. Multicellular eukaryotes require cell division to develop from embryos into full-grown organisms. Those organisms then need further cell division for processes like growth, cell renewal, and damage repair. Describe the phases of the cell cycle, including the mitotic phases. Provide at least one major characteristic of each phase.

The mitotic phases alternate with interphase in the cell cycle. In interphase, the G1 phase occurs first where the cell grows while carrying out cell functions unique to its cell type. Then the S phase takes place where the cell duplicates its chromosomes. Next is the G2 phase, just before mitosis where the cell continues to grow and carry out its functions. After interphase, mitosis occurs, the first phase in mitosis is prophase where the chromatin becomes tightly coiled and the nucleoli disappear. Next is prometaphase where the nuclear envelope begins to fragment, and the two chromatids of each chromosome are held together by the centromere. After prometaphase is metaphase during which the microtubules and move the chromosomes to the metaphase plate at the equator of the cell. Next is anaphase where the sister chromatids separate. After anaphase, telophase occurs where the nuclear envelopes reform around the set of chromosomes located at opposite ends of the cell. Cytokinesis also occurs which is the division of the cytoplasm.

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products