Biochemistry

Chemistry Overview

Hydrogen Bonding: A weak bond between a hydrogen atom in one molecule and an electronegative atom (like oxygen or nitrogen) in another molecule.

Electronegativity: The ability of an atom to attract shared electrons in a covalent bond.

Polar Molecule: A molecule with an uneven distribution of charge, resulting in partially positive and negative ends.

Solubility: The ability of a substance to dissolve in a solvent, like water.

Hydrophilic: Substances that are attracted to water and dissolve easily.

Hydrophobic: Substances that repel water and do not dissolve easily.

Functional Group: Specific groups of atoms within molecules that determine their chemical properties.

Hydroxyl: (-OH) Functional group found in alcohols and sugars.

Carbonyl: (C=O) Functional group found in ketones and aldehydes.

Aldehyde: A carbonyl group at the end of a carbon chain (R-CHO).

Carboxyl: (-COOH) Functional group found in acids, like amino acids and fatty acids.

Amine/Amino: (-NH2) Functional group found in amino acids and proteins.

Phosphate: (-PO4) Functional group important in energy transfer (e.g., ATP).

Condensation/Dehydration Reaction: A chemical reaction where two molecules join to form one, releasing water.

Hydrolysis Reaction: A chemical reaction where water breaks a bond, splitting a molecule.

Macromolecules

Monomer: A small molecule that can join others to form polymers.

Polymer: A large molecule made of repeating monomers.

Carbohydrates: Organic compounds made of carbon, hydrogen, and oxygen; provide energy.

Monosaccharide: Simple sugar (e.g., glucose, fructose).

Disaccharide: Two monosaccharides linked (e.g., sucrose, lactose).

Polysaccharide: Long chains of monosaccharides (e.g., starch, glycogen).

Starch: A polysaccharide used by plants to store energy.

Amylose: Linear form of starch.

Amylopectin: Branched form of starch.

Glycogen: Energy storage polysaccharide in animals.

Cellulose: Polysaccharide in plant cell walls; provides structure.

Sucrose: Disaccharide made of glucose and fructose.

Glucose (alpha/beta): Simple sugar; alpha (OH down) or beta (OH up) form.

Glycosidic Bond (1-4, 1-6): Covalent bond between sugars; 1-4 for straight chains, 1-6 for branching.

Lipids

Triglycerides: Lipid made of glycerol and three fatty acids.

Phospholipids: Lipid with a glycerol, two fatty acids, and a phosphate group; forms cell membranes.

Steroids: Lipids with a four-ring structure (e.g., cholesterol).

Glycerol: A three-carbon molecule that forms the backbone of triglycerides.

Fatty Acids: Hydrocarbon chains that can be saturated or unsaturated.

Ester Linkage: Bond between glycerol and fatty acids in lipids.

Saturated Fatty Acid: Fatty acid with no double bonds; solid at room temperature.

Unsaturated Fatty Acid: Fatty acid with one or more double bonds; liquid at room temperature.

Proteins

Amino Acid: Building blocks of proteins; contains an amino group, carboxyl group, and R-group.

Peptide Bond: Covalent bond between amino acids.

R-group: Variable side chain in amino acids that determines properties.

Polypeptide: Chain of amino acids linked by peptide bonds.

Primary Structure: Sequence of amino acids.

Secondary Structure: Alpha-helices or beta-pleated sheets formed by hydrogen bonding.

Tertiary Structure: 3D folding of a protein due to interactions between R-groups.

Quaternary Structure: Protein structure made of multiple polypeptides.

Disulphide Bridge: Strong bond between sulfur atoms in cysteine residues.

Nucleic Acids

Nucleotides: Building blocks of DNA and RNA; made of a sugar, phosphate group, and nitrogenous base.

DNA vs. RNA: DNA has deoxyribose sugar and is double-stranded; RNA has ribose sugar and is single-stranded.

Phosphodiester Bonds: Bonds linking nucleotides in DNA or RNA.

Enzymes

Catalyst: Substance that speeds up a chemical reaction without being consumed.

Activation Energy: Energy needed to start a reaction.

Substrate: Molecule an enzyme acts on.

Active Site: Region on enzyme where substrate binds.

Enzyme-Substrate Complex: Temporary molecule formed when enzyme and substrate bind.

Lock and Key Model: Theory that enzymes fit substrates exactly.

Induced Fit Model: Theory that enzymes adjust shape to fit substrate.

Inhibitor: Molecule that decreases enzyme activity.

Competitive Inhibitor: Binds to active site, blocking substrate.

Non-competitive Inhibitor: Binds elsewhere on enzyme, altering its shape.

Allosteric Inhibition: Inhibitor binds to enzyme at a site other than the active site, changing its activity.

Cell Membranes and Transport

Cell Membrane: Phospholipid bilayer controlling what enters and exits the cell.

Glycoprotein: Protein with carbohydrate attached; involved in cell recognition.

Glycolipid: Lipid with carbohydrate attached; involved in cell recognition.

Integral Protein: Protein embedded in the cell membrane.

Peripheral Protein: Protein on the surface of the cell membrane.

Cholesterol: Lipid that stabilizes cell membranes.

Passive Transport: Movement of molecules without energy (e.g., diffusion).

Diffusion (simple vs. facilitated): Simple: direct through membrane; Facilitated: via channel or carrier proteins.

Osmosis: Diffusion of water through a semi-permeable membrane.

Semi-Permeable Membrane: Membrane that allows some substances to pass but not others.

Channel Protein: Protein that forms a pore for molecules to pass.

Iso/Hyper/Hypotonic: Isotonic: equal solute; Hypertonic: higher solute outside; Hypotonic: lower solute outside.

Active Transport: Movement of molecules using energy (ATP).

Endocytosis: Process of cell engulfing material.

Exocytosis: Process of cell expelling material.