BIOL354 Lecture 13: Lecture 13 Summary.docx
25 Dec 2012
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Lecture 13 biochemical and physiological effects of chemicals part i inorganic pollutants. Toxic effects begins during interactions between toxicants & biomolecules. Negative effects: narcosis: membrane damage, biochemical toxicity: enzyme inhibition (ribosome no protein; dnap no dna synthesis, ros: oxidative stress through radical production, endocrine toxicity: mimic hormones, genotoxicity: mutation (initiate/stop replication) cancerogenic. Protective/positive effects ( toxicity through adaptation: detoxification (defense against chemical): degradation & excretion (multicellular organisms, acclimation (defense against effects of chemical): defense responses. Variable effects : depending on the organism, chemical, []/dose, & modifying factors. Negative and positive effects of contaminants on a chemical class basis. Negative impacts of metals: dose dependent: all metals are toxic in excess, metal dependent: metabolic vs. non-metabolic; valencies (mono m+, di m++); mechanisms of action; & different toxicity levels (class a vs. class b: environment dependent (chelation): soil ( bioavailability) vs. Essential: fe, ca, zn, se, cu, co, mg, mn. Non-essential: pb, cd, ti, hg, ni (& silver films: biologically relevant.
