The Cell Cycle

Cell Cycle - an orderly set of stages that takes place between the time a eukaryotic cell divides and the time the resulting daughter cells also divide. 

Interphase - The period of time between cell divisions

G0 stage - After a division the cell has the option to continue dividing or it can stop. If this cell decides to stop dividing it goes into the G0 stage where it continues to perform normal everyday processes but does not make any preparations for cell division. it is a substage for G1. 

G1 stage - Growth. In this stage the cell recovers from the previous division. Then it increases in size, doubles its organelles (such as mitochondria and ribosomes), and accumalates molecules that will be used for DNA synthesis. 

S stage - Synthesis. In this stage DNA replicates or makes a copy of itself. 

G2 stage - Growth and final preparations for division.Organelle replication continues during the S stage and the cell synthesizes proteins that will assist cell division. It makes proteins such as tubulin which forms microtubules. Microtubules are used during the mitotic stage to form a spindle apparatus that helps nuclear division occur. 

M Stage - Mitosis also known as a Nuclear Division. In mitosis the daughter cell maintains the same number of chromosomes as the parent cell had. This is because of DNA replication which happened in the S stage. 

Adult Stem cells - relatively nonspecialized cells whose job is to divide and produce cells that will become mature. In red bone marrow, the division of stem cells gives rise to all the types of blood cells in the body.

Chromosomes - DNA and Associated proteins that are packed, which create a set of chromosomes

Sister Chromatids - two identical halves in a duplicated chromosome, they occur in DNA replication. Sister chromatids in other words are a suplicated chromosome. Referred to together as both halves are sister chromatids.

Centromere - The middle part which holds together both chromatids at a constricted area. This centromere splits and a daughter nucleus recieves a copy of every chromosome the parent cell had. 

Cytokinesis - happens during the end of Mitosis. It is the division of the cytoplasm. 

Daughter Cells - The nuclei of two new cells 

Parent Cell - The cell that divides 

Diploid - cells whose chromosomes occur in pairs. (2n)

Haploid - Cells whose chromosomes are not in pairs (n)

Centrosome - is the microtubule organizing center of the cell, which devides at the start of nuclear division. 

Spindle Apparatus - assists the separation of the chromatids as they move toward the opposite poles of the spindle. The daughter centrosomes produce the spindle fibers of a spindle apparatus. 

Aster - short spindle fibers, which radiate from pair of centrioles located withim each centrosome.

Proprohase : Centrosomes have divided; Chromatin is condensing into chromosomes, and the nuclear envelope is fragmenting.

Prophase : The nucleolus has dissapeared, abd the duplicated chromosomes are visible. Centrosomes begin moving apart, and spindle is in process of forming. 

Prometaphase : Each duplicated chromosome is attached to the spindle apparatus. Polar spindle fibers stretch over each pole and overlap.

Metaphase : Centromeres pf duplicated chromosomes are aligned at the equator (center of fully formed spindle). Sister chromatids are attached to spindle fibers that come from opposite poles.

Anaphase : Sister chromatis part and become daughter chromosomes that are pulled toward the poles. In this way, each pole recieves the same number and kinds of chromosomes as the parent cell. 

Telophase : Daughter cells are forming as nuclear envolopes and nucleoli reappear. Chromosomes will becomes indistict chromatin. 

Cleavage Furrow - an indentation of the membrane between the two daughter nuclei, begins at the start of telophase.

Cell Plate - newly formed plasma membrane that expands outward until it reaches the old plasma membrane and fuses with it. 

P53 - an interning signal protein which can stop the cycle at this checkpoint. In the G1 checkpoint if the DNA is damaged beyond repair, the interning signal protein P53 first attempts to innitiate DNA repair, but if that is not possible, it brings about the death of the cell by apoptosis. 

Apoptosis - programmed cell death

Mutations - permanent DNA changes due to different environmental assaults can result in abnormal growth of cells and eventually cancer. 

Carcinogenesis - the development of Cancer 

Cancer Classifications

Carcnomas - cancers of the tissue type that ines organs

Sarcomas - cancers arising in muscle or bone and cartilage

leukemias - cancers of the blood 

Tumor - when cancer cells are present and have lost all restraint so they pile on top of each other and grow in multiple layers, forming a tumor. 

Angiogenesis - the formation of new blood vessels

Metastasis - When invasive cells begins to create new tumors far away from the primary tumors. Ony 1 in 10,000 can successfully metastasize cancer through the body. 

Oncogenes - a gene that has the potential to cause cancer. In tumor cells, these genes are often mutated, or expressed at high levels.

Tumor suppressor genes - A type of gene that makes a protein called a tumor suppressor protein that helps control cell growth. Mutations (changes in DNA) in tumor suppressor genes may lead to cancer. Also called antioncogene.

Inhibiting Proteins - The inhibitor protein (IP) is situated in the mitochondrial matrix and protects the cell against rapid ATP hydrolysis during momentary ischaemia.