2.1 METABOLIC MOLECULES Flashcards
organic compound
contains carbon and is found in living things. exceptions: carbides, carbonates, carbon oxides and cyanides
carbon
forms the basics of organic life because it can form large complex molecules via covalent bonding. carbon atoms form 4 covalent bonds.
classes of carbon compounds
carbohydrates
lipids
nucleic acids
proteins
carbohydrates
most abundant in nature
composed of C, H, and O atoms in common ratio
store of energy
recognition molecule and structural component of DNA and RNA
lipids
non-polar, hydrophobic molecules
main component of cell membranes
long term energy storage molecules
signaling molecules
nucleic acids
genetic material of all cells. determines the inherited features of an organism
DNA functions as a master code for protein assembly
RNA plays an active role in manufacturing proteins
proteins
over 50% of the dry weight of cells.
composed of C, H, O, and N atoms.
regulatory molecules involved in catalysis (enzymes)
structural molecules
cell signalling
complex macromolecules may be comprised of…
monomers: small, recurring subunits
carbohydrate monomers
monosaccharides
building blocks of disaccharides and polysaccharides
they form ring structures and can exist in different 3D configurations.
e.g. ribose and glucose
lipid monomers
no recurring monomer
fatty acid chains instead
these are long chains of hydrocarbons that may or may not contain double bonds
unsaturated has double bonds, saturated does not
nucleic acid monomers
nucleotides join to form polynucleotide chains
each contains a pentose sugar, a phosphate group and a nitrogenous base
the type of sugar and composition of bases differs between DNA and RNA
protein monomers
composed of amino acids, which form a polypeptide chain.
each consists of a central carbon connected to an amine group and an opposing carboxyl group
amino acids may be polar or non polar
carbohydrate polymers
polysaccharides differ according to the type of monosaccharide they possess and the way the subunits bond together
glucose monomers can be combined to form a variety of different polymers
lipid polymers
simple lipids - esters of fatty acids and alcohol (e.g. triglycerides and waxes)
compound lipids - esters of fatty acids, alcohol and additional groups
derived lipids - substances derived from simple and compound lipids
nucleic acid polymers
nucleotides form bonds between the pentose sugar and phosphate group to form long polynucleotide chains
in DNA, two complementary chains will pair up via hydrogen bonding between nitrogenous bases to form double strands
the double stranded molecule may twist to form a double helix arrangement
protein polymers
amino acids join by peptide bonds which form between amine and carboxyl groups of adjaced amino acids.
the fusion creates a dipeptide, with further additions resulting in a polypeptide chain
the folding of the chain depends on the order of amino acids in a sequence
vitalism
this theory dictated that organic molecules could only be synthesised by living systems. it was believed that all living things possessed a “vital force” needed to make organic molecules
how was vitalism falsified
in 1828, Frederick Woehler heated an inorganic salt and produced urea, a waste product of nitrogen metabolism which is eliminated by the kidneys in mammals. the artificial synthesis of urea demonstrates that organic molecules are not fundamentally different to inorganic molecules.
metabolism
describes the totality of chemical processes that occur within a living organism in order to maintain life. it is the web of all enzyme-catalyzed reactions that occur within a cell or organism
2 key functions of metabolism
- provide source of energy for cellular processes.
- enable the synthesis and assimilation of new materials for use within the cell
anabolic reactions
the set of metabolic reactions that build up complex molecules from simpler ones. occur via condensation reactions
condensation reactions
when monomers are covalently joined and water is produced as a by-product
monosaccharides condensation reaction
joined via glycosidic linkages to form disaccharides and polysaccharides.
amino acids condensation reactions
joined via peptide bonds to make polypeptide chains
glycerol and fatty acid condensation reaction
joined via an ester linkage to create triglycerides
nucleotides condensation reaction
joined by phosphodiester bonds to form polynucleotide chains
anabolism: purpose, energetics, and mechanism
purpose: synthesizing complex molecules from simpler ones
energetics: uses energy to construct new bonds
mechanism: typically involves reduction reactions
catabolic reactions
the set of metabolic reactions that break complex molecules down into simpler molecules. typically occurs via hydrolysis reactions.
catabolism: purpose, energetics, and mechanism
purpose: breaking down complex molecules into simpler ones
energetics: releases energy when bonds are broken
mechanism: typically involves oxidation reactions
