Molecular Biology (BIOL 475): Genomes & The Flow of Biological Information

Vocabulary practice flashcards covering foundational concepts, key historical milestones, genome structure, molecular mechanisms, and gene regulation from Chapter 01 lecture notes.

Molecular Biology

The branch of biology that deals with the molecular basis of biological activity, focusing on understanding interactions between various cellular systems (including DNA, RNA, and protein biosynthesis) and how these interactions are regulated.

LUCA

The Last Universal Common Ancestor, from which all living organisms share common descent.

Nucleic Acids

Biological macromolecules composed of nucleotide monomers (such as DNA and RNA) that store, transmit, and express genetic information.

Proteins

Biological macromolecules composed of amino acids that carry out the majority of cellular functions.

Lipids

Biological molecules comprised of fatty acids that form cellular and organellar membranes.

Carbohydrates

Biological molecules composed of small sugars that perform diverse roles, including energy storage.

Genome

The complete set of DNA sequences in an organism, representing the complete genetic blueprint for that organism.

Gene

A discrete region of DNA that controls a specific hereditary characteristic, containing coding sequence for products like proteins as well as regulatory instructions for when and where products are made.

Histones

Eukaryotic packing proteins around which DNA wraps to achieve efficient spatial compaction in the nucleus.

Plasmids

Small, extrachromosomal DNA elements that are common in prokaryotes and often encode nonessential genes.

Transposable Elements

Mobile pieces of DNA (informally called jumping genes) that can replicate or move within a genome, contributing to genome size expansion and structural evolution.

Satellites

Large arrays of highly repetitive, non-coding DNA with repeat units of $100\text{--}1000\text{ bp}$, typically located in heterochromatic, centromeric, or telomeric regions.

Minisatellites

Tandemly repeating non-coding DNA sequences (also called VNTRs) featuring repeat units of $15\text{--}50\text{ bp}$ spanning total array lengths of $50\text{--}20000\text{ bp}$.

Short Tandem Repeats (STRs)

Tandemly repeating non-coding DNA sequences (also called microsatellites) composed of $2\text{--}6\text{ bp}$ repeat units spanning total array lengths of $50\text{--}500\text{ bp}$.

Central Dogma

The fundamental framework formulated by Francis Crick in 1956 detailing the directional flow of genetic information within a biological system from DNA to RNA to protein.

Transcription

The biological process in which DNA sequence regions are copied into complementary RNA molecules by RNA polymerase.

Primary Transcript

The initial, unrefined RNA molecule produced directly by RNA polymerase during transcription before undergoing processing.

Messenger RNA (mRNA)

A class of RNA molecules that carries the genetic sequence information required for protein synthesis.

Translation

The cellular process carried out by ribosomes where mRNA genetic code is decoded to synthesize specific protein amino acid chains.

Codon

A sequence of three consecutive nucleotides in an mRNA molecule that specifies a particular amino acid or translation stop signal.

Transfer RNA (tRNA)

An RNA molecule that interprets the mRNA codon sequence and delivers the corresponding amino acids to the ribosome during translation.

Ribosome

A molecular machine consisting of ribosomal RNA and protein components that catalyzes translation; its RNA components possess catalytic activities.

Hy5 Protein

A regulatory protein in Arabidopsis that controls seedling height by maintaining short stems under high light intensity and degrading under low light to allow tall seedling growth.

Nucleoid

The non-membrane-bound region within prokaryotic cells where the circular chromosomal DNA is concentrated and condensed.

Cytoplasm

The non-specialized internal cellular fluid and matrix outside the nucleus or nucleoid region.

Phenotype

The observable physical or functional characteristics of an organism produced by its genotype and environment.

Genotype

The underlying full DNA sequence or specific genetic constitution of an organism.

Ploidy

The number of complete sets of chromosomes or genome copies contained within a cell or organism.

Forward Genetics

An experimental genetic approach where an investigator begins with an observed mutant phenotype and works to identify the underlying gene responsible.

Reverse Genetics

An experimental genetic approach where a specific gene of interest is targeted and mutated or disrupted in order to analyze the resulting phenotypic effect.

Alleles

Alternative sequence variants or forms of the same gene.

Recessive Mutation

A genetic mutation that displays a mutant phenotype only when both gene copies are mutated, because a single wild-type copy can compensate.

Dominant Mutation

A genetic mutation in which a single mutated gene copy is sufficient to produce a mutant phenotype because the wild-type copy cannot compensate.

Loss-of-Function Mutation

A mutation (also called a null mutation) that completely eliminates the functional capacity or production of a gene product.

Missense Mutation

A single nucleotide point mutation that alters a codon so that it encodes a different amino acid.

Nonsense Mutation

A single nucleotide point mutation that converts an amino acid codon into a premature stop codon.

Silent Mutation

A single nucleotide point mutation that changes a codon sequence without altering the resulting amino acid sequence.

Monogenic Disease

A disease caused by a mutation in a single gene, such as phenylketonuria (PKU).

Polygenic Disease

A disease resulting from cumulative alterations across multiple genes, such as Alzheimer's disease or diabetes.

Penetrance

The percentage of individuals carrying a specific disease-associated gene mutation who actually express the clinical disease phenotype.

Natural Selection

The evolutionary mechanism in which genetic variants (alleles) that provide functional or reproductive advantages preferentially persist and spread within a population.

Viruses

Non-self-replicating biological entities composed of small nucleic acid genomes surrounded by a protein coat that rely on host cell machinery to reproduce.

Photo 51

The famous X-ray diffraction image of DNA produced by Maurice Wilkins and Rosalind Franklin that provided critical structural evidence for Watson and Crick's 1953 double helix model.

Four Core Features of Life

The essential requirements conserved across all living organisms: 1) separation from the environment, 2) stable information storage, 3) reliable replication and inheritance, and 4) extraction of energy from surroundings.

Polymerase Chain Reaction (PCR)

A molecular biology technique invented by Kary Mullis in 1985 that enables exponential amplification of specific DNA sequences.

ENCODE Project

A research initiative launched in 2003 aimed at identifying all functional coding and non-coding elements in the human genome.

1000 Genomes Project

An international initiative launched in 2008 to sequence and catalog human genetic variation across diverse populations.

Vasopressin Receptor ($V1aR$)

A neuropeptide receptor concentrated in the ventral pallidum of monogamous prairie voles that plays a key role in pair-bonding behavior.

Organellar Genomes

Extranuclear DNA located inside specific eukaryotic organelles, specifically mitochondria and chloroplasts.

Germline Mutations

Heritable genetic mutations occurring in reproductive cells that are passed on to offspring.

Somatic Mutations

Non-heritable genetic mutations occurring in body cells that affect only the individual organism.

Model Organisms

Non-human species (such as $E.\,coli$, $D.\,melanogaster$, and $M.\,musculus$) studied in research to understand fundamental biological mechanisms.

Phylogenetic Tree

A branching diagram showing evolutionary relationships among biological entities, where branch lengths reflect genetic divergence.