L33

Question 1

define biomagnification, bioconversion, bioremediation, and biocontrol

Answer 1

• conversion of one chemical compound, or one form fo energy, into another by living organisms
• contorl of a pest by th eintroduction of a natural enemy or predator

Question 2

explain biomagnification

Answer 2

• process by whcih a compound (such as a pollutant or pesticide) increases its conc. in the tissues of organisms as it travels up the food chain
• some pollutants in the environment cause concern even though they are present at low concs.
• e.g. lipophilic pollutants
• concentrate in the lipds of both prokaryotes + eukaryotes (lipid levels 3x higher then in environment)
  -ingestion up the food chain concentrates the substance even more
  -levels can affect viabiltiy of organism ingestin it (e.g. humans)
  e.g. lakes contaminated with pollution, caused mercury toxicity from fish consumption in peru

Question 3

explain bioremediation

Answer 3

• use of either naturally occuring or deliberately introduced microrganisms to consume + break down environmental pollutants, in roder to clean a polluted site
• process in which biological agents used to remove toxic waste from environment
• in order to stimualte breakdown, conditions ened to be changed
  -xenobiotic materials, synthetic products not formed naturally, difficult to dispose of

Question 4

approaches to bioremediation

Answer 4

-modification of environment- biostimulation e.g. nutrient application or aeration

• addition of xenobiotic degraders- bioaugmentation
• intrinsic treatment- let microbes do task voer time without manipulation (may be msot practical)

-bioremedation fo toxic wastes generally leads to harmless end products, but bioconversion may gvie risk to toxic or mutagenic substances

• related to biodegradation- sensitive to environmental conditoons

Question 5

explain degradative plasmids

Answer 5

• carry genes that code for proteins that metabolise unusual molecules
  -abiltiy to degrad epotentially toxic chemicals, potentially useful in clearing up polluted sites
  -commerically available bacteria based bioremediation products

Question 6

limits of bioremediation

Answer 6

• environmental
  
  • unfavourable pH, O2, nutrients, temp.,

-biodegrader limitations
- establishment + maintainance of biodegrader homeostasis may not be assured (solution: inoculate site with special biodegraders where large spills of toxic materials occur)
-microbes do not bidn to metals well (metals remain environment (solution: engineer organisms which have metal binding genes from animals added, bacteria end up covered in a layer of bound metal)

-substrate limitations
-xenobiotic compounds may fail to support microbial growth (solution: provide a structural analogue which can be metabolised to allow co-metabolism of xenobiotic compound)