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Biochemistry Core Concepts Flashcards

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  • Four major elements in living organisms

    Oxygen, Hydrogen, Carbon, and Nitrogen are the primary elements that make up all living creatures at the molecular level.

  • Four major classes of biological macromolecules

    Proteins, Nucleic Acids, Carbohydrates, and Lipids are the main classes of biomolecules essential for life.

  • Functions of proteins

    Proteins serve as signaling molecules, structural components, and catalysts (enzymes) that speed up biochemical reactions.

  • Nucleic acids and their roles

    DNA stores genetic information, while RNA acts as an intermediary to implement DNA's instructions.

  • Characteristics of lipids

    Lipids are amphipathic molecules with hydrophobic tails and hydrophilic heads, forming membranes and storing energy.

  • Types of chemical bonds in biochemistry

    Covalent bonds involve electron sharing and are strong; noncovalent bonds include ionic, hydrogen bonds, and van der Waals interactions and are weaker but dynamic.

  • Role of water in biological systems

    Water's hydrogen bonding and polarity make it an excellent solvent, enabling molecular mobility and biochemical reactions.

  • Definition of acid and base in biochemistry

    Acids donate protons (H+) and bases accept protons, influencing pH and biochemical equilibria.

  • First law of thermodynamics

    Energy cannot be created or destroyed, only transferred; total energy of an isolated system is constant.

  • Second law of thermodynamics

    Entropy, or disorder, of an isolated system tends to increase; spontaneous processes increase the universe's entropy.

  • Gibbs free energy (∆G)

    ∆G < 0 means a process is spontaneous (exergonic); ∆G > 0 means it requires energy (endergonic).

  • Central dogma of molecular biology

    Genetic information flows from DNA to RNA to protein through replication, transcription, and translation.

  • Amino acid structure

    Each amino acid has an amino group, carboxyl group, hydrogen, and a unique side chain (R group) attached to the α-carbon.

  • Peptide bond formation

    A covalent amide bond formed between the carboxyl group of one amino acid and the amino group of another, releasing water.

  • Protein primary structure

    The linear sequence of amino acids in a polypeptide chain, written from N-terminus to C-terminus.

  • Protein secondary structures

    Common motifs include the α-helix and β-sheet, stabilized mainly by hydrogen bonds.

  • Tertiary protein structure

    The three-dimensional folding of a polypeptide, determined by interactions like hydrophobic effects and disulfide bonds.

  • Quaternary protein structure

    Assembly of multiple polypeptide subunits into a functional protein complex.

  • Enzyme function

    Enzymes lower activation energy and increase reaction rates without being consumed.

  • Michaelis-Menten kinetics

    Describes enzyme activity with parameters Km (substrate affinity) and Vmax (maximum rate).

  • Lipid bilayer structure

    Membranes are formed by phospholipids with hydrophilic heads outward and hydrophobic tails inward, creating a barrier.

  • Types of membrane transport

    Includes passive diffusion, facilitated transport, active transport, and ion channels for moving substances across membranes.

  • Carbohydrate monomers

    Monosaccharides like glucose are simple sugars that can form polymers such as starch and cellulose.

  • Glycosidic bond

    Covalent bond linking monosaccharides in oligosaccharides and polysaccharides.

  • Isomers in carbohydrates

    Includes enantiomers (D and L), diastereomers, anomers (α and β), and epimers, differing in spatial arrangement.

  • Functions of carbohydrates

    Provide energy storage, structural support, and cell signaling.

  • Hydrophobic effect

    Nonpolar molecules aggregate in water to minimize disruption of hydrogen bonding, driving protein folding and membrane formation.