Biochem Lecture Sept. 4th

Flashcards covering fundamental concepts of biochemistry, biological molecules, polymers, thermodynamics, and the central dogma of molecular biology, based on lecture notes from UNIT A: Proteins.

Four major classes of biological molecules

Amino acids, Carbohydrates (also called monosaccharides), Nucleotides, Lipids.

Three major types of biological polymers

Proteins (polymers of amino acids), Nucleic acids (polymers of nucleotides), Polysaccharides (polymers of carbohydrates).

What is Biochemistry?

The scientific discipline that seeks to explain life at the molecular level by understanding molecules' physical structure, chemical reactivity, and cooperation to form functional units and organisms.

What are amino acids made of?

A major type of biomolecule containing an amino group, a carboxylate group, and a side chain (R group) which determines its identity.

What is the R group (Side Chain)

The unique identifying component of an amino acid.

What is a Monomer?

Individual smaller units that link sequentially to form a larger polymer.

What is a Polymer?

A large molecule composed of repeating monomer units linked together.

What is a Residue?

A term for a monomer unit once it has been incorporated into a polymer.

What are Proteins?

Biological polymers formed from amino acid monomers.

What are Nucleic acids?

Biological polymers formed from nucleotide monomers.

What are Polysaccharides?

Biological polymers formed from carbohydrate (monosaccharide) monomers.

Enthalpy (H)

The heat content of a system, measured in J mol-1.

Entropy (S)

A measure of the system’s disorder or randomness, measured in J K-1 mol-1.

Gibbs free energy (G)

The free energy of a system based on its enthalpy (H) and entropy (S), defined by G = H - TS and measured in J mol-1.

Gibbs free energy change (ΔG)

The change in free energy of a system, calculated as ΔH – TΔS.

Exergonic reaction

A spontaneous process where ΔG < 0, indicating the release of energy.

Endergonic reaction

A non-spontaneous process where ΔG > 0, requiring energy input to proceed.

Coupled Chemical Reactions

A cellular mechanism where energy-releasing reactions are linked with energy-requiring ones to ensure a net negative change in Gibbs free energy.

Central Dogma of Molecular Biology

The fundamental concept describing the flow of genetic information: DNA makes RNA makes protein (storage of genetic information, RNA synthesis, protein synthesis).

Transcription

The process of synthesizing RNA from a DNA template.

Translation

The process of synthesizing protein from an RNA template.

What does high entropy mean?

more disorder (e.g. gas molecules spread out)

What does low entropy mean?

more order (e.g. solid crystals with fixed positions)

∆G<0

spontaneous (exergonic) process

∆G>0

Non-spontaneous (endergonic) process. requires energy input.

∆G=0

at equilibrium