Chapter 1 WS Flashcards
What is ionizing radiation?
Radiation consisting of particles, X-rays or gamma rays, with sufficient energy to cause ionization (removes electrons from the atomic shells of the target which can lead to breaking of chemical bonds and other damages leading to cell death) in the medium through which it passes.
In 1600 BC, what was believed to be the cause of cancer
black bile
define cellular differentiation
A stem cell that undergoes mitosis and divides into daughter cells. It is the degree to which a cell resembles its cell of origin in morphology and function
cancer is a disease of the
genes
what are somatic cells
Any cell of a living organism other than reproductive cells.
define proto-oncogenes
Normal genes that play a role in normal growth and differentiation. They are precursors of oncogenes.
define oncogenes
genes that regulate the development and growth of cancerous tissue
define antionocogenes
? Also called tumor-suppressor genes. Genes that tell cells to stop multiplying. Inactivation of antioncogenes allows the malignant process to flourish
what is a DNA point mutation
A change within a gene in which one base pair in the DNA sequence is altered. Point mutations are frequently the result of mistakes made during DNA replication, although modification of DNA, such as through exposure to X-rays or to ultraviolet radiation, also can induce point mutations.
Can transform a pro-oncogene into an oncogene, resulting in unrestricted cellular growth. P. 3
Example of a DNA point mutation is sickle cell anemia. This single small change causes a normally round red blood cell to instead be sickle-shaped.
what is a DNA amplification
An increase in the number of copies of a gene. There may also be an increase in the RNA and protein made from that gene. Gene amplification is common in cancer cells, and some amplified genes may cause cancer cells to grow or become resistant to anticancer drugs.
what are DNA translocations
? In a translocation, a segment from one chromosome is transferred to a nonhomologous chromosome or to a new site on the same chromosome. Translocations place genes in new linkage relationships and generate chromosomes without normal pairing partners
- What is the relationship between cancer and point mutation, amplification, and translocations?
These mutations transform a proto-oncogene into an oncogene, resulting in unrestricted cellular grown
what are mammalian cells
Cells that belong to any warm blooded vertebrate having the skin more or less covered with hair;young are born alive and are nourished with milk
located outside the cell cycle continuum because these cells are fully functioning, not preparing for DNA replication.
G0 phase
(first growth phase)-characterized by rapid growth and active metabolism. The length of time a cell remains here is variable.
The cells synthesizes the necessary RNA and proteins to carry out the function of the cell.
G1 phase
the period in which the cell prepare for actual division. Enzymes and proteins are synthesized and the cell continues to grow and moves relatively quickly into the M phase
G2 phase
cells divides
M (mitosis)
during which phase of the cell cycle are cells most sensitive to radiation
G2 and M; but if you only option is to pick one, choose M this is when the cell is actually dividing
define necrosis
dead tissue
why does necrosis occur when malignant tumors grow larger
Because the tumor outgrows the blood, oxygen and nutrient supply
what does the gompertzian growth curve demonstrate
Demonstrates that with cancer: there is rapid cellular proliferation followed by continuous but slowed proliferation.
define cell morphology
identifying the shape, structure, form, and size of cells.
define pleomorphic cells
cells vary in size and shape
define cell doubling time
the amount of time it takes for one cell to divide or for a group of tumo cells to double in size
