2-Nucleic Acids Flashcards
DNA
Deoxyribonucleic acid
Double helix structure
Complementary base pairs of Adenine&Thymine and Cytosine&Guanine.
Each nucleotide consists of a pentode sugar, a phosphate group and an organic nitrogenous base (A,T,C,G)
Phosphodiester bond
Formed by condensation reaction.
The bond between the deoxyribose sugar of one nucleotide and the phosphate group of another.
RNA
Ribonucleic acid
Single short straight polynucleotide chain
Has the same bases as DNA but has Uracil instead of Thymine.
Involved in protein synthesis.
Stability of DNA
Phosphodiester backbone protects the chemically reactive bases inside the double helix.
3 H-bonds between C&G, 2 H-bonds between A&T. The more C-G pairings, the more stable the molecule.
Properties of DNA that let it carry out its function
Stable structure passes down from generation to generation.
2 strands can separate during DNA replication and protein synthesis.
Very big so carries a lot of genetic information.
Semi-conservative Replication
1) DNA helical separates strands by breaking H-bonds.
2) Each strand acts as a template for complementary free nucleotides to bind to specific base pairing.
3) DNA polymerase joins 2 strands together in a condensation reaction.
4) Each new strand consists of an original template strand and a complementary strand.
ATP
Adenosine Triphosphate is a phosphorylated macromolecule that supplies energy.
ATP + H2O ——> ADP +Pi + E
ATP= Adenosine Triphosphate H2O= Water ADP= Adenosine Diphosphate Pi= Inorganic Phosphate E= Energy
Roles of ATP
Provides energy for metabolic processes.
Provides energy for movement/muscle contraction.
Provides energy to change shape of carrier proteins in plasma membranes for active transport.
Necessary to form lysosomes for secretion of cell products.
The dipolar water molecule
O has a slightly negative charge and both H have a slightly positive charge. This makes it so the water molecule has a permanent dipole.
Water and Hydrogen bonding
Positive pole of one water molecule is attracted the negative of the other.
Specific Heat Capacity of Water
High specific heat capacity because more energy is needed to separate water molecules that stick to each other.
Latent Heat of Vaporisation of Water
Hydrogen bonding means that a lot of energy is required to evaporate 1 gram of water so it has a large latent heat capacity.
Cohesion
The tendency of molecules to stick together, apparent in water.
Cohesive forces of Water
Very large
Allow it to be pulled up xylem vessels in plants.
Allows it to be pulled back into the body of water rather than escaping from it (surface tension). This is strong enough to support small organisms like pond skaters.
Water in Metabolism
Breaks down complex molecules by hydrolysis and is produced in condensation reactions.
Chemical reactions take place in an aqueous medium.
A major raw material in photosynthesis.
