Immunity
Chp. 16 (pp. 323-350)
~20,000 genes affect immunity, usually polygenic or multifactorial traits
I.
II.
Cell Surfaces
a. Cell surfaces used to recognize “foreign” or “nonself” surfaces
b. initiate immune response
c. Autoimmune- immune system attacks individuals own tissues or organs
d. Genes encode for
i. antibodies are proteins which attack foreign molecules
ii. cytokines are biochemicals which attack foreign molecules
e. antigens molecules that cause an immune response
Human Immunity- The Immune (Lymphatic) System – SEE PPT
Cancer
Chp. 17 (pp. 351-370
Tumor- a cell that escapes normal division
Benign- grows in place but does not extend into surrounding healthy tissue
Cancerous or malignant- extend into surrounding tissue
Cancer- Latin for “crab” – the shape that cancer growths extend into other tissues
- arise from alteration in genes (90% are environmentally introduced)
- genetic at cellular level- Heritable, NOT WHOLE BODY level
Carcinogen- substances known to cause cancer
- also found to be mutagens (damage DNA)
I.
Cancer as a Genetic Disorder
a. Studied families where cancer appeared to be genetic
b. found 100 oncogenes – cause cancer when inappropriately activated (“onco”-cancer)
c. found 30 tumor suppressor genes – deletion or inactivation or these genes causes cancer
d. cells loose control of the cell cycle
i. check points have a problem
ii. telomeres not functioning properly
II.
Characteristics of Cancer Cells
a. can complete mitosis quickly (table 17.1)
b. transplantable- can be injected into a health animal of the same species and persist
c. dedifferentiated- less specialized than the normal cell type
d. Lack contact inhibition- stop dividing when crowded
e. Invasiveness- ability for cells to squeeze into small spaces
f. Create angiogenesis-growth of new capillaries toward tumor
III.
Genes that Cause Cancer (Oncogenes)
a. proto-oncogenes- trigger normal cell division
i. act as oncogenes when they are faulty
b. Fusion Proteins- caused by more than one gene being transcribed as one gene
c. p53- gene that codes for a protein that causes more than half of human cancers
i. usually an environmental trigger causes a mutation at p53
d. BRCA1- gene that shows a predisposition to breast cancer
IV.
Cancer Prevention, Diagnosis, and Treatment
a. population study-compares populations (Table 17.7)
b. Case-control study- compare people with different types of cancer
c. Prospective study- two or more groups of people follow a specified dietary regimen and are
checked periodically for cancer (Reading 17.2)