Microbial Genetics and Biotechnology Flashcards

Vocabulary practice flashcards covering key terms and concepts from lecture notes on microbial genetics and biotechnology.

Gene

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

Genome

All of the genetic material contained within a cell.

Genetics

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

Genomics

The molecular study of genomes.

Chromosome

A structure containing DNA that physically carries genetic information.

Plasmid

A self-replicating, gene-containing, circular, double-stranded DNA molecule found in bacteria.

Transposon

A small segment of DNA (also known as a jumping gene) that can move from one region of a DNA molecule to another.

Genotype

The specific genetic makeup or genes of an organism.

Phenotype

The expressed properties or physical manifestations of an organism's genes.

Conjugative plasmid (F factor)

A plasmid that carries genes encoding sex pili and facilitates the transfer of the plasmid to another cell.

Dissimilation plasmid

A plasmid encoding specialized enzymes for the catabolism of unusual compounds, such as octane.

R factor

A type of plasmid that carries genes encoding resistance to antibiotics.

Okazaki fragment

A short fragment of DNA synthesized discontinuously on the lagging strand during DNA replication, which is later joined by DNA polymerase and DNA ligase.

Codon

A triplet sequence of nucleotides in mRNA that specifies a particular amino acid or a signal to terminate translation.

Degeneracy

The redundancy of the genetic code, where multiple codons can code for the same amino acid, reducing the impact of base mutations.

Sense codon

A codon that directly codes for a specific amino acid.

Nonsense codon

A stop codon (such as UAA, UAG, or UGA) that signals the termination of translation.

Anticodon

A triplet sequence of bases on a tRNA molecule that is complementary to a corresponding mRNA codon.

Transformation

A mechanism of horizontal gene transfer in which naked DNA in solution is taken up by a bacterial cell.

Conjugation

The direct transfer of genetic material between bacterial cells through cell-to-cell contact via a sex pilus.

Transduction

The transfer of bacterial DNA from a donor cell to a recipient cell using a bacterial virus (bacteriophage) as a carrier vector.

Hfr cell

A high-frequency recombination bacterial cell formed when an F factor plasmid integrates directly into the host chromosome.

Constitutive genes

Genes that are expressed at a fixed rate (typically $60\text{--}80\%$) and whose products are continuously required by the cell.

Repressible genes

Genes whose transcription is default ON but can be turned OFF in response to an active repressor.

Inducible genes

Genes whose transcription is default OFF but can be turned ON in response to an inducer molecule.

Operon

A regulated genetic unit in bacteria consisting of promoter and operator control regions alongside structural genes that function together.

Repressor

A regulatory protein that binds to an operator site to inhibit RNA polymerase from transcribing genes.

Inducer

A small molecule (such as allolactose) that inactivates a repressor protein to initiate gene expression.

Missense mutation

A base substitution point mutation that results in a codon change that encodes a different amino acid.

Nonsense mutation

A base substitution mutation that converts a sense codon into a premature stop codon.

Frameshift mutation

A mutation involving the insertion or deletion of one or more nucleotide pairs, altering the translational reading frame.

Thymine dimer

A DNA lesion created by ultraviolet radiation that cross-links adjacent thymine bases, disrupting normal base pairing.

Ames Test

A biological assay using histidine-dependent Salmonella auxotrophs to test if a chemical substance is a carcinogen/mutagen.

Biotechnology

The use of microorganisms, cells, or cellular components to manufacture commercial or therapeutic products.

Recombinant DNA Technology

The insertion or modification of genes in an organism to synthesize desired protein products.

Restriction enzyme

A specialized bacterial enzyme that recognizes and cuts DNA at specific base sequences.

Polymerase Chain Reaction (PCR)

An enzymatic technique invented by Kary Mullis in 1983 that exponentially amplifies specific sequences of DNA.