Molecular Biology Unit Test Ultimate Study Guide

Tissue Dissociation

Process of isolating viable cells from intact tissues by breaking down cell-cell contacts and the extracellular matrix.

Trypsin

Protease that cleaves peptide bonds at the carboxyl side of lysine and arginine to detach cell surface attachments.

Collagenase

Enzyme that digests collagen fibers within the extracellular matrix.

Primary Cell Culture

Cells isolated directly from parent tissues and placed into culture, representing in vivo conditions.

Finite Lifespan

The phenomenon where normal cells undergo replicative senescence after a predetermined number of divisions.

Defined Media

Liquid formulation containing specific chemicals to support cell growth, including salts, amino acids, and vitamins.

Eukaryotic Cell Lines

Expandable populations derived from primary cultures that are often immortalized for continuous growth.

Differential Centrifugation

Technique that separates cellular components based on size and density through sequential centrifugation.

Isopycnic Sedimentation

Technique using a steep density gradient that separates particles based purely on buoyant density.

Gel-Filtration Chromatography

Separation technique based on hydrodynamic size allowing larger proteins to elute faster than smaller ones.

SDS-PAGE

Technique that resolves polypeptide chains based on molecular mass through denaturing electrophoresis.

Two-Dimensional Gel Electrophoresis

Method that separates proteins based on isoelectric point in the first dimension and molecular weight in the second.

Western Blotting

Analytical method to detect specific proteins in complex mixtures using antibodies.

Housekeeping Genes

Genes expressed universally across all cell types to maintain essential cellular functions.

Transcriptional Synergy

Phenomenon where multiple activator proteins together enhance transcription more than their individual effects.

Chromatin Remodeling

Process by which chromatin structure is altered to allow access to DNA for transcription.

RNA Interference

Regulatory mechanism involving small noncoding RNAs that mediate silencing of gene expression.

Polymerase Chain Reaction (PCR)

Technique for amplifying specific DNA sequences through thermal cycling.

Endonucleases

Enzymes that cleave the phosphodiester bonds within a nucleic acid strand.

Transcription Attenuation

Regulation process leading to premature termination of transcription based on RNA structure.

Induced Pluripotent Stem Cells (iPSCs)

Cells reprogrammed from differentiated adult cells to behave like embryonic stem cells.

Ribosomal Architecture

Structural organization of ribosomes that facilitates translation and catalyzes peptide bond formation.

Chaperones

Proteins that assist in the proper folding of other proteins, preventing aggregation.

Ubiquitin-Proteasome System

Pathway for protein degradation where ubiquitinated proteins are targeted to the proteasome.

RNA World Hypothesis

Theory suggesting that RNA was the first self-replicating molecule, paving the way for DNA and proteins.

Dideoxy Sequencing

Method of DNA sequencing that uses chain-terminating nucleotides to produce DNA fragments.

Affinity Chromatography

Separation technique that uses a specific ligand to isolate proteins that bind to it.

Gene Expression Profiling

Analysis of the expression levels of multiple genes at once.