Biological Macromolecules, Protein Structure, Lipids, and General Biology Review

Vocabulary practice flashcards covering proteins, amino acids, protein structure levels, lipids, cell membranes, and foundational chemistry principles from the lecture transcript.

Monosaccharide

A simple sugar that serves as the basic monomer unit for complex carbohydrates or polysaccharides.

Nucleotide

The monomer or single repeating unit that makes up nucleic acids such as DNA and RNA.

DNA Polymerase

An enzyme that assists in synthesizing multiple copy strands of DNA during laboratory processes like PCR.

Aquaporin

A channel protein located in the cell membrane that specifically allows water molecules to pass into the cell.

Actin and Myosin

Two muscle proteins that work in combination to generate mechanical movement and muscle contraction.

Transcription Factors

Regulatory proteins that bind to DNA strands to direct when, where, and how a gene is transcribed into RNA.

Hemoglobin

A protein in the body responsible for binding, holding, and storing iron ions.

Amino Acid

The monomer unit of proteins consisting of a central carbon atom bonded to an amine group, a carboxyl group, a hydrogen atom, and a variable R group.

Chiral Carbon

An asymmetric carbon atom attached to four completely distinct atoms or chemical functional groups.

Glycine

The simplest of the $20$ amino acids, in which the variable R group is a single hydrogen atom, making its central carbon non-chiral.

Peptide Bond

A covalent $\text{CONH}$ amide bond formed between the carboxyl group of one amino acid and the amine group of another via a dehydration reaction.

Polypeptide

A continuous, linear chain of multiple amino acids linked together by peptide bonds.

Primary Structure

The specific linear sequence of amino acids linked sequentially by peptide bonds in a polypeptide chain.

Secondary Structure

Local spatial arrangements in a polypeptide chain stabilized by backbone hydrogen bonds, occurring primarily as alpha helices or beta sheets.

Alpha Helix

A coiled, spiral secondary protein structure formed through regular hydrogen bonding along the polypeptide backbone.

Beta Sheet

A planar, accordion-folded secondary protein structure formed by hydrogen bonds between adjacent segments of a polypeptide chain.

Disulfide Bridge

A strong covalent bond formed between the sulfur atoms of cysteine or methionine amino acids that stabilizes tertiary protein folding.

Tertiary Structure

The overall three-dimensional shape of a single folded polypeptide, stabilized by hydrogen bonds, ionic bonds, hydrophobic interactions, van der Waals forces, and disulfide bridges.

Quaternary Structure

A macromolecular protein complex composed of two or more individual polypeptide chains or tertiary subunits folded together.

Protein Motif

A recognized arrangement or pattern of secondary structural elements, such as a helix-turn-helix or two beta sheets connected by an alpha helix, common across protein families.

Protein Domain

A distinct, stable, and independently functional structural unit within a folded protein or quaternary complex.

Chaperone Protein

A specialized protein, such as chaperonin, that consumes ATP energy to assist misfolded or unfolded proteins in attaining their correct native structure.

Denaturation

The process in which a protein loses its functional three-dimensional tertiary or secondary structure due to extreme shifts in temperature, pH, or ionic strength.

Ribonuclease

An enzyme used in experiments demonstrating that a denatured protein stripped of its disulfide bonds can spontaneously refold into its functional native structure under optimal conditions.

Lipid

A broad category of water-insoluble, hydrophobic macromolecules composed mainly of nonpolar carbon-hydrogen bonds, including fats, oils, waxes, steroids, and vitamins.

Triglyceride

A lipid molecule composed of a three-carbon glycerol backbone covalently attached to three fatty acid chains.

Saturated Fatty Acid

A fatty acid chain containing exclusively single bonds between carbon atoms, allowing tight packing and resulting in higher melting temperatures.

Unsaturated Fatty Acid

A fatty acid chain containing one or more carbon-carbon double bonds, which introduces kinks in the chain and lowers its melting point.

Trans Fat

An unsaturated fat containing trans double bonds that alter the spatial orientation of the fatty acid chain, making it unhealthy by increasing bad cholesterol.

Phospholipid

A membrane lipid consisting of a glycerol backbone linked to two hydrophobic fatty acid tails and one hydrophilic phosphate head group.

Micelle

A spherical droplet formed by phospholipids or detergent molecules in water, where hydrophilic heads face outward toward water and hydrophobic tails cluster inward.

Phospholipid Bilayer

A double-layered sheet of phospholipids with hydrophilic phosphate heads exposed to aqueous environments on both sides and hydrophobic tails hidden in the interior.

Nucleoid

The non-membrane-bound region within a prokaryotic cell where the circular chromosome is located.

Atomic Number

The total number of protons found in the nucleus of an atom, defining its chemical identity.

Atomic Mass

The sum of the protons and neutrons inside the nucleus of an atom.

Isotope

Atoms of the same element that share the same atomic number of protons but differ in atomic mass due to a different number of neutrons.

Valence Electrons

The electrons residing in the outermost shell of an atom that govern its chemical reactivity and bond formation.

Empirical Formula

The simplest whole-number ratio formula representing the elemental composition of a chemical compound, such as $\text{CH}_2\text{O}$ for carbohydrates.

Avogadro's Number

The universal constant $6.022 \times 10^{23}$, representing the exact number of atoms or molecules contained in one mole of any substance.

Ionic Bond

A chemical bond formed by electrostatic attraction between oppositely charged ions, which remains strong when dry but weakens significantly in water.

Covalent Bond

A strong, stable chemical bond created when pairs of valence electrons are shared between atoms.