General Terms

• Mitosis is a type of cell division that results in two daughter cells each identical to the parent cell, happens in the body cells
• The stages of mitosis are prophase, metaphase, anaphase, telophase
• Interphase is the stage of cell cycle that occurs before mitosis and prepares the cell for division, the cell grows and DNA replicates
• There are four parts of interphase: G1, S, G2, and M
• In G1 phase, the cell grows physically and increases the volume of both protein and organelles and prepares for DNA replication
• In S phase, the cell synthesizes a complete copy of the DNA molecule. This is when DNA replication occurs in the cell
• In G2 phase, the cell grows more and prepares for mitosis. It is where the spindle forms and proteins are being synthesize
• Apoptosis is the suicidal death of cells which occurs as a normal and controlled part of an organism's growth or development. It ensures that irreparable cells will not divide
• In G0 phase, the cell is still performing cell function, but are not preparing to divide. Cells may stay here temporarily or permanently
• Cell cycle is a series of stages that a cell goes through in order to copy all of its genetic material and divide into two new daughter cells. This is also how cells in our body produce new cells to replace the old ones
• chromosomes are made of DNA and proteins and are found in the nucleus of a cell
• DNA replication is the process of making two identical copies of DNA in a cell.
• chromatid is one copy of a newly copied chromosomes, which is still joined to the original chromosome by a single centromere
• Somatic cells are all the cells in our body except the sex cells
• two sister chromatids make up chromosomes
• histones are proteins that make up the core of the chromosome and are wrapped around in DNA
• nucleosomes is the basic structural unit of chromatin. It is made up of coil of DNA wrapped around a histone protein
• centromere are the centers of the chromosomes, where the chromatids are attached
• restriction point is checkpoint in G1 phase that gets the signal if the cell should continue to S phase or enter G0 phase
• The phases of mitosis are prophase, prometaphase, metaphase, anaphase, telophase
• In prophase, firstly, there are pair of centrosomes (containing two centriole each) and chromosomes with sister chromatids linked by a centromere
• centrosomes contains two centrioles and are duplicated in G2 phase before cell division
• mitotic spindle is made up of two centrosomes and a number of microtubules that begin to form between them, happens in prophase during mitosis
• Each centrosomes will begin to have radial array of microtubules surrounding it called aster, happens in prophase during mitosis
• After aster is formed, the microtubules grow and push the centrosomes further apart, last happening in the prophase in mitosis
• In prometaphase, first the nucleus breaks apart, then the growing microtubules cover the area where the nucleus used to be so that they can attach to kinetochore (proteins that are assembled on the chromosomes at their centromere). Afterwards, microtubules push the centrosomes farther apart as they grow.
• In metaphase, the centrosomes have settled at the poles of the cell with the astral microtubules attached to the plasma membrane. Afterwards, all of the chromosomes have been arranged nicely along a plane line in the middle of the cell. These imaginary plane is called the metaphase plate. Next, there is a checkpoint to ensure that each pair of sister chromatids is firmly attached to opposite ends of the mitotic spindle. Once the kinetochores attach to the spindle and every thing is lined up nicely, the cell can pass through this checkpoint, which means it is ready for the next phase
• In anaphase, firstly, the enzyme separase cleaves the cohesins that keeps the sister chromatids together, and the kinetochores attached to them, pull the chromatids apart on each chromosomes. Thus, generating the two separate sets of the entire genome. These chromosomes are then pulled by motor protein that are attached to the kinetochore, which reel them in by their centromeres to opposite ends of the cell, with the microtubules they are attached to coming apart as they go. The cell also elongates during this phase, until the two sets of chromosomes are far apart.
• In the Telophase, two new nuclei form, rebuilt from the fragments of the original nucleus that came apart in the prometaphase. Then, the chromosomes unwind into chromatin, the microtubules in the spindle come apart
• Lastly, cytokinesis will occur, which is where the cytoplasm, which has already begun dividing the cell into two smaller ones, will continue until the cells are distinct and separate. Actin microfilaments pull the cell inwards, which eventually pinches the cell in two, happens only to animal cells
• In M phase, the cell divides and it is divided into two stages: mitosis and cytokinesis
• In plant cell, cytokinesis occurs by the addition of cell plate between the two nuclei that will eventually split the two cells by forming cell walls