ai notecards unit 1 bio 111

Vocabulary flashcards covering carbohydrates, nucleic acids, and proteins, including structure, bonds, and the central dogma.

Carbohydrates

Class of biomolecules including monosaccharides, disaccharides, oligosaccharides, and polysaccharides; primary energy sources in cells.

Monosaccharides

Simple sugars with 5 or 6 carbons, usually in a ring form (pentoses, hexoses).

Pentoses

5-carbon monosaccharides.

Hexoses

6-carbon monosaccharides.

Disaccharides

Two monosaccharides linked by a glycosidic (covalent) bond.

Glycosidic bond

Covalent bond joining monosaccharides in disaccharides and polysaccharides.

Oligosaccharides

3 to 10 monosaccharides joined by glycosidic bonds; added functional groups give special properties; often bound to proteins/lipids on cell membranes as recognition signals.

Polysaccharides

Polymers of hundreds to thousands of monosaccharides; can be linear (cellulose) or branched (starch, glycogen).

Cellulose

Linear polysaccharide in plants; structural component.

Starch

Branched polysaccharide used by plants for energy storage.

Glycogen

Branched polysaccharide used by animals for energy storage.

Nucleic acids

Polymers that store, transmit, and express hereditary information (DNA and RNA).

DNA

Deoxyribonucleic acid; stores genetic information and guides replication and transcription.

RNA

Ribonucleic acid; involved in transcription and translation; usually single-stranded.

Nucleotides

Monomers of nucleic acids; consist of a sugar, a phosphate group(s), and a nitrogenous base.

Nucleoside

Sugar bound to a nitrogenous base (without a phosphate group).

Nucleotide (as defined in notes)

A nucleoside with one to three phosphate groups; building blocks of nucleic acids and important cofactors (e.g., ATP).

Base

Nitrogen-containing purine or pyrimidine attached to the sugar in a nucleoside.

Pyrimidine

Single-ring nitrogenous bases (C, T, U in DNA/RNA).

Purine

Double-ring nitrogenous bases (A and G).

Adenine

Purine base; pairs with thymine in DNA and with uracil in RNA.

Guanine

Purine base; pairs with cytosine in both DNA and RNA.

Cytosine

Pyrimidine base; pairs with guanine.

Thymine

Pyrimidine base in DNA; pairs with adenine.

Uracil

Pyrimidine base in RNA; pairs with adenine.

Complementary base pairing

Hydrogen bonding between purine-pyrimidine pairs (A–T/U and C–G) that holds DNA strands together.

A–T and C–G pairs (DNA)

DNA base pairs: adenine with thymine; cytosine with guanine.

A–U and C–G pairs (RNA)

RNA base pairs: adenine with uracil; cytosine with guanine.

5′ end

Fifth carbon on the sugar; designates one end of a nucleic acid strand.

3′ end

Third carbon on the sugar; designates the other end of a nucleic acid strand.

Nucleic acid synthesis

Condensation reactions join nucleotides to form covalent phosphodiester bonds.

Oligonucleotides

Short nucleic acid chains with up to about 20 monomers; mostly RNA.

Polynucleotides

Long nucleic acid chains containing more than 20 monomers; longest polymers.

DNA structure

Double-stranded, antiparallel, with a sugar–phosphate backbone and hydrogen-bonded base pairs; right-handed helix.

RNA structure

Single-stranded; can fold via antiparallel base pairing to form 3D shapes affecting interactions.

Central dogma

Genetic information flows as DNA → RNA → Protein via replication, transcription, and translation.

Replication

DNA is copied to produce two identical DNA molecules (DNA → DNA).

Transcription

DNA sequences are transcribed into RNA (DNA → RNA).

Translation

RNA is translated into a polypeptide (protein) (RNA → protein).

Genes

DNA sequences that encode specific proteins and are transcribed into RNA.

Genome

Complete set of DNA in a living organism.

Protein

Polymers made up of amino acids.

Amino acids

Monomers of proteins; contain an amino group, a carboxyl group, and a variable R group.

Amino group

–NH2 group in amino acids.

Carboxyl group

–COOH group in amino acids.

R group (side chain)

Variable side chain of an amino acid determining its properties.

Hydrophilic

Tends to form hydrogen bonds with water and polar or charged substances.

Hydrophobic

Tends to cluster in protein interiors or interact with lipids in membranes.

Peptide bond

Covalent bond between a carboxyl and an amino group with loss of water (condensation).

Polymerization

Reaction that forms polymers from monomers.

Oligopeptide

Short polymer of amino acids; up to 20 residues.

Polypeptide

Long polymer of amino acids (more than 20 residues).

Primary structure

Linear sequence of amino acids in a protein.

Secondary structure

Regular patterns of folding due to hydrogen bonding (beta sheets and alpha helices).

Beta sheet

Pleated sheet; stabilized by hydrogen bonds; can involve two or more polypeptide chains.

Alpha helix

Right-handed coil stabilized by hydrogen bonds between backbone N–H and C=O groups.

Tertiary structure

Three-dimensional folding of a single polypeptide driven by R-group interactions (covalent disulfide bridges, ionic, hydrogen, van der Waals) and surface interactions.

Disulfide bridge

Covalent bond between cysteine residues that helps stabilize tertiary structure.

Ionic bond

Electrostatic attraction between charged side chains in proteins.

Hydrogen bond (in proteins)

Noncovalent bond between polar side chains contributing to structure.

Van der Waals interactions

Weak attractions between hydrophobic side chains in close proximity.

Quaternary structure

Assembly of two or more polypeptide subunits; held by similar forces as tertiary structure.

Denaturation

Disruption of a protein’s weak interactions by heat or chemicals, destroying secondary/tertiary structure and function.

Renaturation

Return of a denatured protein to its original structure when conditions are restored.

Protein functions

Diverse roles including enzymes, structural/motor functions, signaling, receptors, transport, defense, and storage.