Cells: Altering Metabolism

Question 1

Altering Cell Metabolism

Answer 1

chemicals can interfere with cell metabolism

Question 2

Chemicals & Effects

Answer 2

carbon monoxide: binds to haemoglobin, can’t carry oxygen
carbon monoxide & cyanide: disables enzyme in metabolic pathway (cellular respiration)
hydrogen sulfide: enzyme cytochrome oxidase
barbiturates: block another respiratory enzyme
some antibiotics: affect respiration, bind to enzymes, alter membrane of mitochondria

Question 3

Chemical that inhibit protein synthesis

Answer 3

in prokaryotes (antibiotics)
eg. tetracycline inhibits tRNA binding to ribosomes
in eukaryotes
eg. amanitin stops mRNA synthesis
in both
eg. actinomycin prevents RNA synthesis

Question 4

Dangers & Benefits of Radium

Answer 4

benefits: numerous medical applications, luminous paint (watch faces and compasses)
danger: carcinogen (causes mutations in cells)

Question 5

Dangers & Benefits of Mercury

Answer 5

benefits: many uses, only metal liquid at room temp.
dangers: reasonably toxic as element, more dangerous when escape into environment, converted to very poisonous methyl mercury - biaccumulation

Question 6

Dangers & Benefits of chemicals in agriculture

Answer 6

benefits:
- no crop competition
- eliminate weeds
- protect from pests
- thin crops
- produce desirable growth characteristics (industrial)
dangers:
- DDT (prevents malaria) - damages the environment

Question 7

Dangers & Benefits of Preservatives

Answer 7

benefits: keeps food in good condition for long period of time
dangers: can cause allergic reactions

Question 8

Dangers & Benefits of Medical Drugs

Answer 8

eg. thalidomide
benefits: nausea suppressor
danger: caused mutations, missing limbs

Question 9

Dangers & Benefits of Antibiotics

Answer 9

benefits: save many lives
danger: due to widespread use, ‘superbugs’ evolving

Question 10

Recent Developments

Answer 10

• trouble-free chemicals for use in living organisms (highly specific compounds, small stretches of RNA matching region of DNA in pathogen; RNA sits on target DNA, renders inoperative - virus/plasmid vectors)