Cyto - Cell Cycle (Stages of Mitosis)

Cell Cycle

Refers to the regular and repetitive physical and chemical process taking place within the cell which means there is no fixed starting point

Interphase

first major phase of the cell

M phase

second major phase of the cell

G1 phase

involves rapid growth of cells during interphase

S phase

cells are preparing for division by duplicating their chromosome and by the end of this phase, chromosomes are duplicated

G2 Phase

- Third stage of the interphase
- Increase in synthesis of structural proteins and regulatory factor which promotes proofreading
- Mitotic spindle formed from cytokinetic fibers

G0

- The quiescent phase
- Cells are not divided and maintained
- Still diploid (2n) chromosome

G1

- point of entry for division, mRNA transcription and involvement of proteins necessary for DNA replication occurs
- protein synthesis and RNA synthesis, resumes cells that was interrupted during the process of mitosis
- Growth of young cell maturation occurs
- Follows mitosis (16-24 hours)

S Phase

- DNA synthesis phase
- Semi-conservative synthesis of DNA
- Replication of cellular DNA begins
- After DNA replication, moves into the G2 phase

Synthesis

"S" in S Phase stands for?

Stages of Mitosis

- Only occurs among somatic cells and body cells
- Form of eukaryotic cell division that produces two daughter cells with the same genetic component as the parent cell
- Important for the maintenance of chromosomal set

Mitosis Promoting Factor (MPF)

protein complex which initiates the mitotic phase of the cells cycle

Cyclin B

one that oscillates in quantity during cell cycle

CDC2

one whose quantity is constant during cell cycle

CDC2 Kinase

only functional when combined with cyclin

Anaphase-promoting complex

APC stands for?

G1/S Phase

In this checkpoint, the cell detects for damage, the p53 protein targets the cells for regulated death

p53 protein

responsible for regulated cell death during G1/S Phase

Spindle attachment

In this checkpoint: before the sister chromatids separate, this ensures that the spindle fibers are attached

Prophase
Prometaphase
Metaphase
Anaphase
Telophase

5 Stages of Mitosis

Prophase

- Chromatin condensed
- Nucleolus disappears
- Centrioles move to the opposite sides of the cells and fibers extended from the centromere to form mitotic spindle
- Initial stage in mitosis where chromosomes can be identified by the condensation of chromatin due to phosphorylation of histones.

Prometaphase

- Nuclear membrane dissolves
- Proteins attach to the centromere, creating the kinetochores
- Chromosomes begin to move

Metaphase

- Spindle fibers attached to centromeres align to the chromosome (metaphase plate)
- Most visualized stage of mitosis

Anaphase

- Paired chromosomes separate, moves to the opposite sides of the cell
- Sister chromatids separate
- Important for segregation of genetic material

Telophase

- Chromatids arrive at opposite poles of the cell where a new membrane forms around the daughter nuclei
- Chromosome and spindle fibers disperse
- decondensation of chromatin

Cytokinesis

- Cleavage furrow forms
- Final step of Telophase
- Contraction and pinching of cells into two daughter cells
- Actin helps to divide the cell by means of pinching, creating a cleavage formation
- In order to produce two daughter cells, there will be division from mitotic nuclear followed by the separation of the cell cytoplasm