Carbon and molecular diversity of life Flashcards
Why is carbon the backbone of life?
70-95% water, but the rest consists mostly of carbon-based compounds
- carbon enters the biosphere through the action of plants
- has ability to form large, complex and diverse molecules (proteins, DNA, carbohydrates and others are all composed of carbon compounds)
Who is Stanley Miller?
provided evidence that organic compounds might have been the first step in the origin of life, in 1953
What is the Miller’s Experiment?
closed system to simulate the conditions of early earth
- water mixture in flask was heated -> vapor entered the atmosphere
- the atmosphere contained a mixture of Hydrogen gas, methane, ammonia and water vapor
- sparks were discharged to mimic lightning
- a condenser cooled the atmosphere, raining water and any dissolved molecules down the flask
- as materail cycled through the apparatus, miller periodically collected samples for analysis
What were the results of miller’s experiment?
- variety of organic compounds that play key roles in living cells were synthesised in miller’s apparatus
- simple compounds like formaldehyde CH2O, hydrogen cyanide HCN
- complex molecules like amino acids and hydrocarbons
What was the conclusion to miller’s experiment?
organic compounds may have been synthesised abiotically on the early Earth, setting the stage for the origin on life
Miller’s experiment helped bring the abiotic synthesis of organic compounds into the context of evolution
Whats the principle of the formation of bonds with carbon?
electron configuration is the key to an atom’s characteristics -> determines the kinds and number of bonds an atom will form with others
- Carbon can bond covalently to four other atoms -> has 4 valence electrons
- its bonding versatility allows it to form many diverse molecules, incl carbon skeletons
What enables carbon to form complex molecules?
its electron configuration -> gives covalent compatibility with many different elements
What are the most frequent partners of carbon?
- hydrogen
- oxygen
- nitrogen
What are carbon chains?
the linking of covalent bonds of two or more carbon atoms to form a chain
- form the skeletons of most organic molecules
- vary in length and shape (straight, branched, rings)
- vary in number and location of double bonds
What are hydrocarbons?
=organic molecules consisting only of carbon and hydrogen
- found in many of a cell’s organic molecules, but are not prevalent
- can undergo reactions that release a large amount of energy (petroleum, fats)
What is petroleum made of?
partially made of decomposed remains of organisms that lived millions years ago
Why are petroleum and fats hydrophobic?
a great majority of their bonds are non-polar carbon-hydrogen linkages
What are isomers?
molecules with the same molecular formula, but differ in structure amd properties
- the greater the size of carbon skeleton, the greater the possibility of isomers
What are structural isomers?
different covalent arrangement of atoms, number of double bonds
What are geometric isomers?
carbons have covalent bonds at the same atoms, but these atoms differ in their spatial arrangement due to the inflexibility of double bonds
- cis and trans isomers
