Microbial Genetics and Chemical Principles Practice Flashcards

A set of 100 vocabulary flashcards covering microbial genetics, chemical principles, and bacterial morphology based on the lecture notes.

DNA Polymerase

An enzyme that joins nucleotides in one direction ($5' \rightarrow 3'$) only during DNA replication.

Leading Strand

The strand of DNA that is synthesized continuously during replication.

Lagging Strand

The strand of DNA that is synthesized discontinuously and started by an RNA primer.

Bacterial DNA Replication

A process that proceeds bi-directionally around the bacterial chromosome with multiple replication forks possible.

Degeneracy

A property of the genetic code where multiple different DNA sequences can encode for the same amino acid sequence.

Feedback Inhibition

A regulatory mechanism that stops the action of preexisting enzymes and is faster acting than repression.

Repression

A regulatory mechanism that stops the synthesis of new enzymes.

Inducer

A substance that combines with a repressor to allow transcription of an inducible enzyme.

Conjugation

The transfer of DNA from a donor to a recipient cell via cell-to-cell contact.

Transcription

The process of making an RNA copy of a gene.

Transduction

The transfer of DNA from a donor to a recipient cell by a bacteriophage.

Transformation

The transfer of DNA from a donor to a recipient as naked DNA in solution.

Catabolite Repression

The mechanism by which the presence of glucose inhibits the expression of the lac operon.

Induction

The mechanism by which the presence of lactose controls the lac operon.

Codon

A three-base sequence in mRNA that specifies a particular amino acid.

Anticodon

The three-base sequence on a tRNA molecule that binds to the mRNA codon.

Pyrimidine Dimers

Molecular lesions formed from thymine or cytosine bases in DNA as a result of exposure to ultraviolet radiation.

Inducible Operon

A group of genes whose transcription is turned on by the presence of a specific substance, such as lactose.

Repressible Operon

A group of genes encoding enzymes in a biosynthetic pathway that is typically turned off in the presence of an end-product.

Lac Operon Maximal Expression

Occurs when lactose is present and glucose is absent.

Genotype

The specific genetic makeup of a cell which remains constant regardless of environmental influences.

Phenotype

The observable characteristics of a cell which change in response to environmental influences.

DNA Gyrase

The enzyme responsible for relaxing supercoiled DNA to allow for the initiation of replication.

Nucleoside Analog

A chemical mutagen structurally similar to a nucleotide but with different base-pairing rules.

Photolyase

An enzyme used in light repair to split thymine dimers caused by UV radiation.

Horizontal Gene Transfer

Mechanisms that allow for the introduction of genetic material from one organism to another within the same generation.

Operator

The DNA sequence located between the promoter and the first structural gene to which repressors may bind.

Semiconservative Replication

The process of DNA replication where each new double-stranded DNA molecule consists of one original strand and one new strand.

R Factors

Plasmids that carry genes for antibiotic resistance, important in the treatment of infectious diseases.

Coccus

A spherical or round-shaped bacterium.

Bacillus

A rod-shaped bacterium.

Spirillum

A spiral-shaped bacterium.

Diplo-

A prefix denoting bacterial arrangement in pairs.

Strepto-

A prefix denoting bacterial arrangement in chains.

Staphylo-

A prefix denoting bacterial arrangement in clusters.

Tetrad

A bacterial arrangement of four cells in a square.

Sarchinae

A cubelike bacterial arrangement of eight cells.

Genetics

The study of what genes are, how they carry information, how information is expressed, and how genes are replicated.

Genome

The entire genetic information of a cell.

Chromosome

A structure containing DNA that physically carries hereditary information.

Gene

A segment of DNA that encodes a functional product, usually a protein.

Genetic Code

The set of rules that determines how a nucleotide sequence is converted into an amino acid sequence of a protein.

Genomics

The molecular study of genomes.

DNA Ligase

An enzyme that joins DNA fragments together, particularly on the lagging strand.

Promoter

The specific DNA sequence where RNA polymerase initiates transcription.

Terminator

The DNA sequence that signals the end of transcription.

mRNA

Messenger RNA; the RNA transcript used as a template for translation.

Operon

A set of operator and promoter sites and the structural genes they control.

Corepressor

An end-product that causes a repressor to bind to the operator, inhibiting transcription.

cAMP

Cyclic AMP; a molecule that builds up when glucose is low to help regulate gene expression via catabolite repression.

Plasmid

A small, circular, extrachromosomal DNA molecule that functions independently of the bacterial chromosome.

Vertical Gene Transfer

The flow of genetic information from one generation to the next (parent to offspring).

Natural Selection

The process by which the environment favors the survival of specific genotypes.

Ionic Bond

A chemical bond formed when one or more electrons are transferred from one atom to another.

Covalent Bond

A chemical bond formed by the sharing of electrons between atoms.

Hydrogen Bond

A weak attraction between a hydrogen atom and an electronegative atom like oxygen or nitrogen.

Acid

A substance that dissociates into one or more $H^+$ ions.

Base

A substance that dissociates into one or more $OH^-$ ions or accepts protons.

Salt

An inorganic compound that dissociates into cations and anions, neither of which is $H^+$ or $OH^-$.

pH

A measure of the hydrogen ion concentration in a solution, representing acidity or alkalinity.

Synthesis Reaction

A chemical reaction where atoms or molecules combine to form a new, larger molecule ($A + B \rightarrow AB$).

Decomposition Reaction

A chemical reaction where a molecule is broken down into smaller parts ($AB \rightarrow A + B$).

Exchange Reaction

A chemical reaction where parts of two different molecules are swapped ($AB + CD \rightarrow AD + CB$).

Monosaccharide

Simple sugars like glucose that serve as the building blocks of carbohydrates.

Disaccharide

A carbohydrate formed by the combination of two monosaccharides.

Polysaccharide

Complex carbohydrates consisting of many monosaccharides joined together, like starch or cellulose.

Simple Lipids

Fats or triglycerides consisting of glycerol and fatty acids.

Complex Lipids

Lipids that contain phosphorus, nitrogen, or sulfur in addition to carbon, hydrogen, and oxygen (e.g., phospholipids).

Steroids

Lipids characterized by a carbon skeleton consisting of four fused rings.

Phospholipid

A complex lipid that forms the structural basis of cell membranes.

Amino Acids

The building blocks of proteins, containing an amino group and a carboxyl group.

ATP

Adenosine triphosphate; the principal energy-carrying molecule of all cells.

ADP

Adenosine diphosphate; the molecule formed when ATP releases energy by losing a phosphate group.

Atomic Number

The number of protons in the nucleus of an atom.

Atomic Mass

The total number of protons and neutrons in an atom ($A \approx p^+ + n^0$).

Isotope

Atoms of the same element that have the same number of protons but different numbers of neutrons (e.g., $^{14}C$ vs $^{12}C$).

Functional Group

Specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules.

Ethanol

An organic compound produced by adding a hydroxyl group ($-OH$) to an ethyl group.

Acetic Acid

An organic acid produced by adding a carboxyl group ($-COOH$) to a methyl group.

Acetaldehyde

An organic compound produced by adding a carbonyl group ($-CHO$) to a methyl group.

Diethyl Ether

An organic compound where an oxygen atom bridges two ethyl groups.

Organic Compounds

Compounds that contain carbon and hydrogen, often associated with living systems.

Inorganic Compounds

Compounds that typically lack carbon and are often simple, such as water or salts.

Replication Fork

The Y-shaped region where the DNA double helix is being unwound and new strands are synthesized.

RNA Primer

A short segment of RNA that serves as the starting point for DNA synthesis by DNA polymerase.

Excision Repair

A mutation repair mechanism sometimes referred to as 'dark repair' (implied by context of ways to repair).

Bacteriophage

A virus that infects and replicates within bacteria, used as a vector in transduction.

Donor Cell

A cell that gives a portion of its total DNA to a recipient cell.

Recipient Cell

A cell that receives DNA from a donor cell during genetic recombination.

Mutation

A permanent change in the base sequence of DNA.

5' to 3' Direction

The specific polarity in which DNA and RNA polymerases synthesize new nucleic acid strands.

Biosynthetic Pathway

A series of enzymatic reactions in a cell that builds complex molecules from simpler ones.

Polarity of Water

The property caused by uneven distribution of charges in a water molecule ($H_2O$), making it an excellent solvent.

Nucleic Acids

Macromolecules (DNA and RNA) consisting of nucleotides that carry genetic information.

Supercoiling

The over- or under-winding of a DNA strand, which is relaxed by DNA gyrase.

Naked DNA

DNA that is released into the environment and is not contained within a cell or virus.

DNA Transcript

The mRNA molecule produced during transcription (which cannot be used for translation in eukaryotes without processing).

Derepression

The process of lifting repression so that a repressible gene or operon can be transcribed.

Genetic Recombination

The exchange of genes between two DNA molecules to form new combinations of genes on a chromosome.

Hfr Cell

'High frequency of recombination' cell, a donor cell in conjugation where the F factor is integrated into the chromosome.