topic 2.1- molecules to metabolism Flashcards
what does molecular biology do?
explains living processes in terms of the chemical substances involved
describe the approach of molecular biologists.
reductionist- considers the various biochemical processes of a living organism, and breaks it down into its component parts
how many elements are found in living systems? which are the most prevalent?
16
carbon, oxygen, hydrogen, nitrogen
why is CHON so prevalent?
these elements make covalent bonds that are very stable.
give an example of a compound that is produced by living organisms but can also be artificially synthesised.
urea
when and where is urea produced in the body?
when there is an excess of amino acids in the body; this happens in the liver
give the word equation for the artificial synthesis of urea.
ammonia + carbon dioxide -> ammonium carbamate -> urea + water
why is urea synthesised artificially?
it is useful as nitrogen fertiliser on crops.
in what ways does the artificial synthesis of urea differ from the natural one?
chemical reactions are different from those in the liver; enzymes are not involved.
explain the occurrence of a wide range of carbon compounds in biological systems
- can form up to four bonds with other atoms
- can form double and single covalent bonds (strongest, most stable bonds)
- can form chain and ring structures to which other groups can attach
what 4 types of carbon compounds is life based on?
carbohydrates, lipids, proteins, nucleic acids.
carbohydrates
- carbon, hydrogen, oxygen
- ratio of two hydrogen atoms to one oxygen
lipids
- broad class of molecules that are insoluble in water
- including steroids, waxes, fatty acids, triglycerides
proteins
- composed of one or more chains of amino acids
- all chains contain carbon, hydrogen, oxygen, nitrogen
- two of the twenty also contain sulphur
nucleic acids
- chains of subunits called nucleotides
- carbon, hydrogen, oxygen, nitrogen, phosphorous
- either ribonucleic acid (RNA) or deoxyribonucleic acid (DNA)
define metabolism
the web/sum total of all the enzyme catalysed reactions+ processes in a cell or organism
where do metabolic reactions take place?
most happen in the cytoplasm of cells but some are extracellular (eg reactions to digest food in small intestine)
give 3 examples of metabolism
respiration, translation, photosynthesis
where is potential energy found in molecules?
within the bond of ONE molecule or within the bonds holding 2 molecules together
describe how changes in potential energy can be achieved?
- PE is released by breaking molecules apart
- PE is gained/increased by fusing more molecules together and creating more bonds
define anabolism
the synthesis of complex molecules from simpler molecules
give a wide example of anabolism
including the formation of macromolecules from monomers by condensation reactions
describe anabolic reactions in terms of energy
- energy is required because you are forming bonds
- energy is stored in the bonds of the synthesised molecules
give 4 examples of anabolic reactions
- protein synthesis using ribosomes
- DNA synthesis during replication
- photosynthesis
- synthesis of complex carbs (eg starch, cellulose, glycogen)
