Biology of Cancer & AIDS – Flashcards
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| define disease |
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| an abnormal condition of an organism that impairs bodily functions |
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| broad categories of disease |
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| - infectious (caused by a pathogen) - genetic (caused by abnormality in DNA) - environmental (includes things done to self, mold, cigarettes, toxins, etc) **cancer can be caused by all** |
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| scientific theory |
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| all cells come from pre-existing cells |
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| meat maggot experiment |
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| - performed by Redi - thought that flies came from flies rather than spontaneous generation (flies came from the meat) - disproved Aristotle's spontaneous generation |
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| modern cell theory |
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| - all known things are made up of cells - cells are the structural and functional unit of all living things - all cells come from pre-existing cells by division (hereditary info is passed) - all cells have the same chemical composition - all energy flow occurs within cells |
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| germ theory of disease |
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| microorganisms are the cause of many diseases - swan neck trap experiments - Louis Pasteur |
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| koch's postulates |
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| - suspected pathogen must always be found is diseased individuals but absent in heathy individuals - pathogen must be isolated from the diseased individual and grown in pure culture - pathogen from pure culture must cause disease when put in a healthy host - same pathogen must be re-isolated from the host that was inoculated with the pure culture |
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| define cancer |
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| uncontrolled growing mass of cells that is capable of invading neighboring tissues |
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| tissue growth |
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| - hypertrophy: increase in cell size - hyperplasia: increase in cell quantity - dysplasia: disorganized growth (mild, moderate, severe) - neoplasia: disorganized growth, net increase in number of divided cells **CANCER** |
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| how cancer develops |
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| cancer cells develop based on DNA damage |
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| malignant tumor vs benign tumor |
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| - benign: slower growing, self-contained, localized - malignant: grow out of control, metastasize, tumor angiogenesis |
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| biopsy |
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| removing a sample tissue of the tumor |
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| tumor grade vs. tumor stage |
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| - stage: how large tumor has grown and how it has spread - grade: based on microscopic appearance of cancer cells |
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| most common cancer |
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| skin cancer: most detectable form of cancer and therefore the least fatal form of cancer |
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| most fatal cancer |
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| lung cancer |
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| five-year rate |
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| after five years without cancer, chances of survival increase |
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| majority of cancer is... |
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| carcinoma (85%) |
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| DNA bases / nucleotides |
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| A, T, C, G (A-T & C-G) |
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| mitosis |
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| regular cell division: division of nucleus in M phase |
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| meiosis |
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| gametes/sex cells replication |
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| during replication, DNA stays in... |
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| the nucleus |
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| DNA --> RNA |
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| gene transcription (copy DNA in nucleus), mRNA forms and carries message to cytoplasm, where translation (rewrite DNA) occurs and forms a protein |
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| 1 codon = ... |
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| 3 nucleotides (aka 90 nucleotides = 30 codons) |
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| 3 forms of DNA mutation |
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| - substitution - deletion - addition of one piece in the DNA sequence |
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| oncogenes |
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| arise from proto-oncogenes, cause uncontrolled cell proliferation (cancer cells would WANT oncogenes) |
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| tumor suppressor genes |
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| inactivation contributes to cell proliferation, losing these genes allows cells to divide continuously (cancer cells would NOT WANT tumor suppressor genes) |
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| DNA repair genes |
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| mutations can lead to lack of "mismatch" repair and progress to cancer |
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| cell growth cycle |
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| - first growth phase: adequate size, nutrients - synthesis phase - second growth phase: cell size right, growth factors - mitotic phase: M phase, cell is ready to separate, spindles slit |
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| cell cycle checkpoints |
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| regulated by proto-oncogenes, tumor suppressor genes, and DNA repair genes and occurs after each stage of cell cycle |
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| cancer begins with... |
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| DNA damage - doesn't start with a single mutation: multistep process |
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| how cancer cells protect themselves |
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| - surround themselves with tissues to protect themselves from immune attacks - form molecules which can destroy T-cells - stimulate sustained angiogenesis |
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| telomeres |
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| - tip of chromosome - protect the real part of the chromosome (shoe lace tip) - defective telomeres lead to aging - needed every time a cell replicates (each time they get shorter) |
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| telomerase |
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| enzyme, makes cancer cells immortal |
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| antigen vs antibody |
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| antigen: foreign substance antibody: protein produced in response to foreign substance |
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| T-cells |
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| helper cells, choose how to respond to foreign antigen |
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| B-cells |
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| produce antibodies to fight foreign antigen |
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| metastasis |
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| spread of tumor cells through the bloodstream |
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| secondary cancer |
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| 90% of cancer deaths occur not because of where the cancer began, but where it spread to |
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| hematologic cancer |
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| blood cancer, kills because components of blood don't fulfill their duties, red blood cells (oxygen) reduce, white blood cells increase (clog arteries) |
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| ecadherin and intagrin |
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| cell to cell adhesion proteins, without which, cancer cells can invade |
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| apoptosis |
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| cells commit suicide, part of normal cell aging or response to cell injury |
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| angiogenesis |
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| formation of new blood vessels from preexisting ones -- tumor angiogenesis: new blood vessels form with cancer cells, creating a blood supply to grow |
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| vasculogenesis |
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| formation of new blood vessels spontaneously (no preexisting ones) |
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| 3 ways a cancer spreads |
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| - local spread - blood circulation - lymphatic system |
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| neutrophil |
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| white blood cells which hunt and kill bacteria |
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| adaptive vs innate immune system |
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| adaptive: immune system with memory innate: immune system you're born with |
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| define epidemiology |
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| the study of how often diseases occur in different groups of people and why **can never prove CAUSATION** |
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| 3 types of epidemiology |
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| - experimental (human equivalent to animal testing) - descriptive (correlations) - observational (case control: retrospective, cohort: prospective) |
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| absolute risk vs relative risk |
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| absolute risk: actual numeric chance relative risk: gives ratio - 1 is the baseline (2 = 100% increase in risk) |
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| 40% of people that die from cancer die from _______ |
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| malnutrition |
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| incidence vs prevalence |
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| incidence: rate at which new cases occur in a population over a specified period of time prevalence: total number of old and new cases (per 100,000) |
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| clinical trial phases |
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| - phase I: test for safe dose - phase II: preliminary testing for effectiveness - phase III: randomized double blind trial - FDA review --> approved treatment - phase IV: further evaluation of side effects and other uses |
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| clinical trials |
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| - 50% of trials are for children ages 0-14 years - idea, test tube trial, animal trial, human trial - interventional trials: experimental to test for safety - observational trials: experiments to address current issues |
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| leading cause of death in the world... |
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| cardiovascular diseases |
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| what is the major increase seen in cancer incidence rates seen today? |
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| increase in life expectancy, due to vaccines and better healthcare |
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| what is the greatest threat to life expectancy |
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| obesity related diseases |
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| which type of clinical trial would be most effective in determining if someone has cancer before symptoms appear? |
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| screening trial |
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| the ames test |
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| - test determines what substances create mutagens - bacteria & growth medium and incubate of substance & liver homogenate from rats - liver homogenate because it converts pre-mutagens into mutagens |
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| in which of the following cells would you expect the greatest expression of telomerase? |
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| developing embryo and metastatic cancer cells |
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| antibodies stimulate cancer cells to produce immunotoxins-- true or false? |
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| false |
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| what chemicals stimulate angiogenesis in the presence of cancer cells? |
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| VEGF and EGF |
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| what do proto-oncogenes do? |
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| - regulate cell division - accelerate cell growth and division |
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| to metastasize, a cancer cell must... |
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| - migrate - extravasate - intravasate |
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| after what stage in the cell cycle are there check points to help prevent the accumulation of mutation that can lead to cancer? |
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| G1, G2, M |
