Exam Review – Molecular Biology, Biochemistry & Physiology

Vocabulary flashcards summarizing key molecular biology, biochemistry, and physiology terms from the lecture notes.

Perfusion

The process of delivering oxygen- and nutrient-rich blood to tissues and organs.

Ventilation–Perfusion Matching

The adjustment of breathing rate so that air flow equals the blood flow reaching the alveoli.

Competitive Inhibition

An inhibitor resembles the substrate and binds to the enzyme’s active site, raising Km while leaving Vmax unchanged.

Non-competitive (Allosteric) Inhibition

An inhibitor binds at a site other than the active site, lowering Vmax without affecting Km.

Uncompetitive Inhibition

The inhibitor binds only to the enzyme–substrate complex at an allosteric site, decreasing both Km and Vmax.

Mixed Inhibition

An inhibitor binds either the free enzyme or the enzyme–substrate complex at a non-active site, altering Vmax and usually Km.

Km (Michaelis Constant)

Substrate concentration at which an enzyme operates at half of its Vmax; reflects binding affinity.

Vmax

The maximum reaction velocity achieved by an enzyme at saturating substrate concentration.

RT-PCR (Reverse Transcription PCR)

Technique that converts mRNA to cDNA and amplifies it to measure gene expression levels.

qPCR (Quantitative PCR)

Real-time PCR that quantifies DNA amplification using fluorescent dye each cycle.

Southern Blot

Laboratory method used to detect specific DNA fragments within a sample.

Northern Blot

Technique for identifying specific RNA sequences in a sample.

Western Blot

Protein detection method that reveals size and relative expression of target proteins.

ELISA

Enzyme-linked immunosorbent assay used to quantify proteins such as antibodies or hormones.

Native PAGE

Polyacrylamide gel electrophoresis that separates folded proteins by size and charge without denaturation.

SDS-PAGE

Gel electrophoresis that denatures proteins, coats them with negative charge, and separates solely by molecular weight.

Gel Filtration Chromatography

Size-exclusion method in which large molecules elute first and small molecules are delayed within porous beads.

Ion-Exchange Chromatography

Separation technique based on charge interactions between proteins and oppositely charged resin.

Cation-Exchange Chromatography

Negatively charged resin that binds positively charged proteins, allowing acidic or neutral proteins to elute first.

Anion-Exchange Chromatography

Positively charged resin that binds negatively charged proteins, letting positively charged proteins elute first.

Isoelectric Focusing

Electrophoretic separation of proteins by their isoelectric point (pI) along a pH gradient.

X-Chromosome Inactivation

Random silencing of one X chromosome in female mammals to equalize X-linked gene dosage.

Barr Body

Condensed, transcriptionally inactive X chromosome visible in female cell nuclei.

Unconditioned Media

Fresh cell-culture medium that has never been exposed to living cells; serves as a negative control.

Conditioned Media

Culture medium collected after incubation with cells, containing secreted factors.

Ligase (Enzyme Class)

Enzyme that joins two molecules together using ATP hydrolysis.

Isomerase

Enzyme that converts a molecule into one of its isomers.

Lyase

Enzyme that breaks chemical bonds without water or redox involvement, often forming double bonds.

Hydrolase

Enzyme that cleaves bonds by adding water, e.g., proteases or lipases.

Oxidoreductase

Enzyme class that catalyzes electron-transfer (redox) reactions.

Transferase

Enzyme that transfers functional groups from one molecule to another.

DNA Polymerase

Enzyme that synthesizes new DNA strands using a DNA template.

RNA Polymerase

Enzyme that transcribes DNA into RNA.

Reverse Transcriptase

Enzyme that synthesizes DNA from an RNA template.

Helicase

Protein that unwinds the DNA double helix ahead of replication or transcription.

Topoisomerase

Enzyme that relieves DNA supercoiling by cutting and rejoining strands.

DNA Ligase

Enzyme that seals nicks by forming phosphodiester bonds, e.g., between Okazaki fragments.

Nuclease

Enzyme that degrades DNA; endonucleases cut internally, exonucleases from ends.

Protease (Peptidase)

Enzyme that hydrolyzes peptide bonds in proteins.

Lipase

Enzyme that hydrolyzes triglycerides into glycerol and fatty acids.

Carbohydrase

Digestive enzyme that breaks carbohydrate polymers into sugars.

Intron

Noncoding sequence removed from pre-mRNA during splicing.

Exon

Coding sequence that remains in mature mRNA after splicing.

Tripeptide

Short peptide consisting of three amino acids linked by peptide bonds.

Purine

Double-ring nitrogenous base; includes adenine and guanine.

Pyrimidine

Single-ring nitrogenous base; includes cytosine, thymine, and uracil.

Transition Mutation

Base substitution that replaces a purine with another purine or a pyrimidine with another pyrimidine.

Transversion Mutation

Base substitution that replaces a purine with a pyrimidine or vice versa.

Test Cross

Cross between an organism of unknown genotype and a homozygous recessive individual to determine genotype.

Boyle’s Law

Inverse relationship between pressure and volume of a gas (PV = constant at constant temperature).

Alveoli

Tiny air sacs in the lungs that provide large surface area for gas exchange.

Partial Pressure

Individual pressure exerted by a specific gas in a mixture; drives gas dissolution in liquids.

Hemoglobin

Tetrameric protein in red blood cells that transports O₂ to tissues and CO₂ to lungs; affinity modulated by pH (Bohr effect).

Oxygen as Terminal Electron Acceptor

Final electron recipient in the mitochondrial electron-transport chain, enabling aerobic ATP production.