005 Molecular Microbiology Lecture Notes Review

This set of flashcards is designed to help review key vocabulary and concepts from the Molecular Microbiology lecture notes.

chromosome

A discrete unit of the genome carrying many genes.

structural gene

A gene that encodes any RNA or polypeptide product other than a regulator.

allele

One of several alternative forms of a gene occupying a given locus on a chromosome.

locus

The position on a chromosome at which the gene for a particular trait resides.

genetic recombination

A process by which separate DNA molecules are joined into a single molecule.

transforming principle

DNA that is taken up by a bacterium and changes the properties of the recipient cell.

transfection

The acquisition of new genetic markers by incorporation of added DNA in eukaryotic cells.

nucleoside

A purine or pyrimidine base linked to the 1′ carbon of a pentose sugar.

nucleotide

A nucleoside linked to a phosphate group on either the 5′ or 3′ carbon of the ribose.

supercoiling

The coiling of a closed duplex DNA in space so that it crosses over its own axis.

replication fork

The point at which the parental strands of DNA are separated.

denaturation

The separation of two strands of DNA due to breaking of hydrogen bonds.

renaturation

The reassociation of complementary single strands of a DNA double helix.

DNA polymerases

Enzymes that synthesize DNA by adding nucleotides to a growing strand.

RNA polymerase

An enzyme that synthesizes RNA using a DNA template.

central dogma

Information cannot be transferred from protein to protein or protein to nucleic acid, but can be transferred among nucleic acids.

melting temperature (Tm)

The midpoint of the temperature range for denaturation of double-stranded DNA.

mutation

A change in the sequence of DNA.

point mutation

A mutation that changes a single base pair.

transition mutation

Replaces a G-C base pair with an A-T base pair or vice versa.

transversion mutation

Replaces a purine with a pyrimidine.

forward mutation

A mutation that alters the function of a gene.

true reversion

A mutation that restores the original sequence of the DNA.

cistron

The genetic unit defined by the complementation test; equivalent to a gene.

homomultimer

A molecular complex composed of identical subunits.

heteromultimer

A molecular complex composed of different subunits.

open reading frame (ORF)

A sequence of DNA that can be translated into proteins.

frameshift mutation

A mutation caused by the insertion or deletion of bases, shifting the reading frame.

cis-acting

Refers to mutations that affect only the contiguous stretch of DNA.

trans-acting

Refers to gene products (RNA or polypeptides) that can act on any copy of a gene.

exon

Any segment of an interrupted gene that is represented in the mature RNA product.

intron

Segments of a gene that are removed during RNA splicing.

gene expression

The process by which information in a sequence of DNA is used to produce an RNA or polypeptide.

codon

A set of three nucleotides that code for an amino acid.

nonsense mutation

A mutation that converts a codon into a stop codon.

silent mutation

A mutation that does not change the amino acid sequence.

missense mutation

A mutation that changes one amino acid in a protein.

duplication mutation

A mutation that results in the repetition of a segment of DNA.

deletion mutation

A mutation that removes a segment of DNA.

genetic hotspot

A region in the genome where mutations occur more frequently.

polymorphism

The presence of two or more variants of a particular DNA sequence.

transposable elements

Segments of DNA that can move from one location in the genome to another.

dominant mutation

A mutation that results in the gain of function.

recessive mutation

A mutation that results in the loss of function.

RNA processing

The modifications to RNA transcripts of genes.

ribosome

A large assembly of RNA and proteins that synthesizes polypeptides.

transfer RNA (tRNA)

Molecules that interpret the genetic code and link amino acids to the peptide chain.

genetic code

The set of rules by which information encoded in genetic material is translated into proteins.

complementarity

The ability of DNA or RNA strands to pair with each other based on their nucleotide sequences.

quaternary structure

The arrangement of multiple polypeptide or protein subunits.

splicing

The process of removing introns from the pre-mRNA transcript.

lethal mutation

A mutation that leads to the death of the organism.

epigenetics

The study of heritable changes in gene expression that do not involve changes to the underlying DNA sequence.

codon bias

The preference of an organism to use certain codons over others in the coding of amino acids.

plasmid

A small DNA molecule that is physically separated from chromosomal DNA and can replicate independently.

genome

The complete set of genes or genetic material present in a cell or organism.

epistasis

The interaction between genes that influences the expression of phenotypic traits.

Haploidy

The state of having a single set of unpaired chromosomes.