BIO306 Exam 3 Review - Vocabulary

Flashcards covering key vocabulary and concepts from BIO306 Exam 3 review sheet.

Nucleoid Region

The area in bacteria where the circular genome is located.

Loop Domains and DNA Supercoiling

Methods by which bacteria compact their genome.

Eukaryotic Chromosome Components

Millions of nucleotides of dsDNA, centromeres, origins every 100 kb, telomeres, genes with introns (1-2% coding)

Transposable Elements (TEs)

Small DNAs that move from place to place in the genome and are mutagenic.

Nucleosomes

DNA wrapped around an octamer of two each of the four histones, with histone H1 as a stabilizer.

30nm Fiber

Supercoiling of nucleosomes into a shorter, thicker fiber.

DNA Matrix Attachment Regions (MARs)

Make up radial loops hooked onto a protein scaffold made of nonhistone proteins.

Heterochromatin

Typically does not contain required genes, densely packed.

Euchromatin

Contains genes, less densely packed.

Deletions (chromosome rearrangements)

Loss of a portion of a chromosome.

Duplications (chromosome rearrangements)

Replication of a portion of a chromosome.

Inversions (chromosome rearrangements)

Reversal of the order of a portion of a chromosome.

Translocations (chromosome rearrangements)

Movement of a portion of a chromosome to a new location.

Aneuploidy

Abnormal number of chromosomes (monosomies, trisomies) from meiotic NDJ or mitotic NDJ/chromosome loss.

Euploidy

Includes monoploid, diploid, triploid, other polyploids.

Forward Mutation

A mutation that changes a wild-type allele to a mutant allele.

Reverse Mutation

A mutation that changes a mutant allele back to a wild-type allele.

Germline Mutation

Mutation in a cell that produces gametes.

Somatic Mutation

Mutation in a non-germline cell.

Silent Mutation

Mutation that does not alter the amino acid sequence.

Missense Mutation

Mutation that changes one amino acid to another.

Nonsense Mutation

Mutation that introduces a premature stop codon.

Frameshift Mutation

Insertion or deletion of bases that alters the reading frame.

Null Mutation

Results in complete loss of function.

Hypermorphic Mutation

Results in increased gene expression or activity.

Depurination

Loss of a purine base.

Deamination

Removal of an amino group from a base.

Tautomeric Shifts

Temporary changes in base structure.

ROS Damage

Damage caused by reactive oxygen species.

Alkylating Agents

Chemicals that add alkyl groups to bases.

Intercalating Agents

Chemicals that insert between base pairs.

Base Analogs

Chemicals similar to normal bases that can be incorporated into DNA.

Ames Test

Test used to assess the mutagenic potential of chemicals.

Direct Repair

Repair system that directly reverses DNA damage.

Base Excision Repair (BER)

Replaces oxidized bases, damaged or inappropriate bases.

Nucleotide Excision Repair (NER)

Removes thymine dimers.

Mismatch Repair (MMR)

Replaces mistakes by DNApol not caught by proofreading.

Homologous Recombination Repair

Fixes DSBs when there is a sister chromatid.

Nonhomologous End-Joining (NHEJ)

Fixes DSBs, not perfect.

Negative Control (gene regulation)

Repressors bind to inhibit transcription.

Positive Control (gene regulation)

Activators bind to enhance transcription.

Inducible Genes

Genes that are transcribed in the presence of an inducer.

Repressible Genes

Genes that are not transcribed in the presence of a co-repressor.

Lac Operon

Inducible catabolic system with negative control by a repressor and positive control by CAP-cAMP.

Trp Operon

Repressible anabolic system with negative control by a repressor and attenuation.

Enhancers

DNA sequences that increase transcription.

Silencers

DNA sequences that decrease transcription.

Transcription Factors (TFs)

Proteins that bind to promoters, enhancers, and silencers to control transcription.

Chromatin Remodeling

Changes in chromatin structure to allow or inhibit transcription.

Histone Code

Covalent modification of histone N-terminal tails leads to remodeling.

RNA Interference (RNAi)

miRNAs/siRNAs causes degradation or translation block.