BIOL 230 Unit II Study Guide Flashcards: Chapters 5, 6, and 7

A complete set of vocabulary practice flashcards defining key microbiological terms, pathways, enzymes, and genetic concepts across Chapters 5, 6, and 7 of the BIOL 230 Unit II Study Guide.

Metabolism

The sum of all chemical reactions occurring within a living organism, encompassing both catabolism and anabolism.

Anabolism

Metabolic pathways that synthesize complex molecules from simpler ones, requiring an input of energy.

Catabolism

Metabolic pathways that break down complex molecules into simpler compounds (such as converting glucose to $CO_2$) and release energy.

Endergonic

A chemical reaction that absorbs energy from its surroundings and requires a net input of energy to proceed.

Exergonic

A chemical reaction that releases energy to its surroundings.

Competitive inhibition

A mechanism of enzymatic regulation where an inhibitor directly competes with the normal substrate for binding to the active site.

Non-competitive inhibition

A mechanism of enzymatic regulation where an inhibitor binds to an allosteric site rather than the active site, altering the enzyme shape and function.

Amphibolic

A metabolic pathway that can function in both catabolic (breakdown) and anabolic (synthesis) processes.

Fermentation

An anaerobic catabolic pathway that extracts energy from sugars or other organic molecules without utilizing an electron transport system or oxygen.

Oxidation

The loss of electrons from an atom or molecule during a chemical redox reaction.

Reduction

The gain of electrons by an atom or molecule during a chemical redox reaction.

Enzymes

Catalysts that speed up the rate of chemical reactions by lowering their activation energy.

Substrate

The specific molecule or molecules upon which an enzyme acts during a catalyzed reaction.

Phosphorylation

The addition of a phosphate group to an organic molecule, occurring as substrate-level, oxidative, or photophosphorylation.

Feedback inhibition

A cellular control mechanism in which the final end product of a metabolic pathway allosterically inhibits an upstream enzyme to halt further synthesis.

Autotrophs

Organisms that utilize inorganic carbon dioxide ($CO_2$) as their primary carbon source to synthesize organic compounds.

Heterotrophs

Organisms that obtain carbon by consuming organic compounds produced by other organisms.

Obligate aerobe

An organism that strictly requires oxygen for growth and aerobic cellular respiration.

Facultative anaerobic

An organism capable of growing with or without oxygen, utilizing aerobic respiration in oxygen presence and fermentation or anaerobic respiration in its absence.

Aerotolerant

Anaerobic organisms that do not utilize oxygen for metabolism but can survive and grow in its presence without toxicity.

Thermoduric

Microorganisms that normally thrive at moderate temperatures but can endure short exposure to high temperatures or heat treatments.

Quorum sensing

A density-dependent cell-to-cell communication system in bacteria that coordinates collective behaviors through chemical signaling molecules.

Mesophile

A microorganism that grows optimally at moderate temperatures, typically between $20$ and $45$ degrees Celsius.

Psychrophile

A cold-loving microorganism that thrives at low temperatures, typically with an optimal growth temperature around or below $15$ degrees Celsius.

Thermophile

A heat-loving microorganism that grows optimally at elevated temperatures, typically between $50$ and $80$ degrees Celsius.

Generation time

The duration of time required for a bacterial population to double in number through binary fission.

Reducing medium

A specialized microbiological culture medium formulated with reducing agents that deplete dissolved oxygen to facilitate obligate anaerobe growth.

Osmotic Pressure

The hydrostatic pressure required to prevent the net flow of water across a semipermeable membrane caused by differences in solute concentrations.

Biofilm

A structured consortium of microorganisms adhering to a surface and encased within a self-produced extracellular matrix.

Capnophile

A microorganism that grows best under high concentrations of carbon dioxide ($CO_2$).

CFUs (colony-forming units)

A microbiological measurement estimate representing viable bacterial cells or clumps capable of forming a visible colony.

Gene

A distinct sequence of nucleotides in DNA encoding a functional biological product, such as a protein or RNA molecule.

Phenotype

The observable physical, biochemical, and physiological traits expressed by an organism.

Genotype

The entire genetic makeup and specific combination of alleles present in an individual organism.

Heredity

The biological transmission of genetic traits and characteristics from parent organisms to their offspring.

Chromosomes

Discrete cellular structures composed of packaged DNA molecules and associated proteins that carry hereditary genetic material.

Genome

The entire genetic complement of an organism, including all of its genes and non-coding sequences.

Plasmids

Small, circular, extrachromosomal DNA molecules found in bacteria that replicate independently of the chromosomal DNA.

Transcription

The process by which the genetic code on a DNA template strand is copied into a complementary single-stranded RNA molecule by RNA polymerase.

Translation

The biological process in which ribosomes decode the sequence of codons in messenger RNA to synthesize a polypeptide chain.

DNA Replication

The biological process in which a cell synthesizes an identical replica of its DNA prior to cell division.

Okazaki fragments

Short segments of newly synthesized DNA formed discontinuously on the lagging strand during DNA replication.

Replication fork

The Y-shaped region where parental double-stranded DNA unwinds and separates into single strands for replication.

Promoter

A specific nucleotide sequence on DNA that serves as the initiation point where RNA polymerase binds to begin transcription.

Introns

Non-coding intervening sequences within a pre-mRNA transcript that are removed via splicing prior to translation.

Exons

Coding sequences in pre-mRNA that remain after splicing and are retained in mature mRNA to be translated into protein.

Anticodons

A trinucleotide sequence located on transfer RNA that is complementary to a specific codon on messenger RNA.

Mutation

A permanent and heritable change in the nucleotide sequence of an organism genome.

Point mutation

A genetic mutation that involves the alteration, insertion, or deletion of a single nucleotide base pair in DNA.

Silent mutation

A base substitution mutation that alters a codon without changing the resulting amino acid, leaving the protein unchanged.

Missense mutation

A base substitution mutation that results in a codon specifying a different amino acid than the original sequence.

Nonsense mutation

A base substitution mutation that converts an amino acid codon into a premature stop codon, yielding a truncated protein.

Frameshift mutation

A mutation caused by insertion or deletion of nucleotides not in multiples of three, which shifts the reading frame of translation.

RNA polymerase

The enzyme that synthesizes RNA polymers from ribonucleotide triphosphates using a DNA template during transcription.

Ames Test

A biological assay utilizing bacterial auxotrophs to evaluate whether a chemical compound has mutagenic and potentially carcinogenic properties.

Vertical gene transfer

The transmission of genetic material directly from parent organisms to their progeny during reproduction.

Horizontal gene transfer

The lateral transfer of genetic material between distinct organisms occurring independently of reproduction.

Transduction

A form of horizontal gene transfer where bacterial DNA is transferred from one host cell to another by a bacteriophage virus.

Central dogma

The foundational molecular principle stating that genetic information flows from DNA to RNA and subsequently to protein.

DNA Helicase

An enzyme that unwinds and separates parental DNA strands at the replication fork by breaking hydrogen bonds.

DNA Gyrase

A bacterial topoisomerase that relieves supercoiling and torsional strain ahead of the advancing DNA replication fork.

DNA Polymerase I

An enzyme in bacterial DNA replication that removes RNA primers and synthesizes DNA nucleotides in the resulting gaps.

DNA Polymerase III

The primary enzyme responsible for synthesizing new complementary DNA strands along the leading and lagging templates during bacterial replication.

DNA Ligase

An enzyme that seals nicks in the sugar-phosphate backbone by forming phosphodiester bonds to covalently join Okazaki fragments.

Operon

A functional prokaryotic genetic unit containing a cluster of genes governed by a common promoter, regulator, and operator.