Protein Structure, Nucleic Acids, and Biological Molecules

Vocabulary flashcards covering protein structures, amino acid types, misfolding diseases, nucleic acid properties, central dogma, and general biological macromolecules.

Amino Acid Basic Structure

A central carbon atom bound to an amino group, a carboxyl group, a hydrogen atom, and a variable R group side chain.

Glycine

An amino acid whose R group side chain consists of a single hydrogen atom.

Alanine

An amino acid whose R group side chain consists of a methyl group.

Nonpolar Side Chains

Hydrophobic amino acid side chains composed mostly of carbon and hydrogen atoms that avoid water.

Polar Side Chains

Hydrophilic amino acid side chains that interact favorably with water.

Tertiary Structure

The overall 3D shape of a single polypeptide formed by interactions among R side chains, such as folding of alpha helixes and beta sheets.

Disulfide Bridge

A strong covalent bond formed between two sulfur/sulfate atoms within a protein's tertiary structure.

Ionic Bond (in proteins)

A bond in a protein structure formed when one atom completely transfers an electron to another, resulting in full positive and negative charges.

Quaternary Structure

The overall 3D shape resulting from the interaction, folding, and bonding of two or more polypeptide chains.

Collagen

A quaternary protein formed by three helical polypeptides that makes up connective tissues such as skin and tendons.

Hemoglobin

A globular quaternary protein composed of four polypeptide subunits responsible for binding and transporting oxygen throughout the body.

Sickle Cell Anemia

A condition caused by a single DNA point mutation that alters a hemoglobin amino acid, causing proteins to misfold into a sickle shape.

Glutamic Acid

The normal, polar (hydrophilic) amino acid found in functional hemoglobin.

Valine

The abnormal, nonpolar (hydrophobic) amino acid substituted in sickle cell hemoglobin that leads to misfolding.

Denaturation

The process where environmental changes in temperature or pH cause a protein to unravel, lose its shape, and cease functioning.

Prions

Infectious, misshapen proteins that interact with healthy proteins and induce them to misfold, leading to diseases such as Mad Cow Disease.

Nucleotide

The monomer unit of nucleic acids, consisting of a phosphate group, a sugar, and a nitrogenous base.

DNA (Deoxyribonucleic Acid)

A double-stranded helical nucleic acid containing deoxyribose sugar and bases $C$, $T$, $A$, and $G$ that stores genetic information in the nucleus.

RNA (Ribonucleic Acid)

A single-stranded helical nucleic acid containing ribose sugar and bases $C$, $U$, $A$, and $G$ that transfers genetic information outside the nucleus.

Central Dogma of Biology

The principle stating that DNA encodes RNA, which then synthesizes protein to execute gene expression.

Pyrimidine

A class of nitrogenous bases composed of a single six-member ring, including cytosine ($C$), thymine ($T$), and uracil ($U$).

Purine

A class of nitrogenous bases composed of a six-member ring connected to a five-member ring, including adenine ($A$) and guanine ($G$).

Base Pairing Rules (DNA)

The specific hydrogen-bonding rule where adenine ($A$) always pairs with thymine ($T$) via two hydrogen bonds, and guanine ($G$) always pairs with cytosine ($C$).

Polymer

A large molecule composed of repeating monomer units bonded together, including carbohydrates, proteins, and nucleic acids.

Lipids

A group of hydrophobic biological molecules including fats, oils, waxes, cholesterol, and fatty acids that do not form polymers.

Glycogen

A carbohydrate polymer used for glucose storage in animals.

Starch

A carbohydrate polymer used for glucose storage in plants.

Enzymes

A type of protein that acts as a catalyst to speed up chemical reactions.