DNA, RNA, and Microbial Genetics: Key Concepts and Processes

nucleotides

the building blocks of DNA and RNA, consisting of a sugar, a phosphate group, and a nitrogenous base.

nitrogenous bases in DNA

adenine (A), thymine (T), guanine (G), and cytosine (C).

DNA structure

two strands that twist to form a double helix, with base pairs held together by hydrogen bonds.

DNA replication

the process by which a cell makes an identical copy of its DNA, involving enzymes like helicase and DNA polymerase.

helicase

an enzyme that unwinds and separates the two strands of DNA during replication.

DNA polymerase

enzyme that synthesizes new DNA strands by adding nucleotides complementary to the template strand and has proofreading capabilities.

RNA

a single-stranded molecule made of ribonucleotides, which include ribose, phosphate, and nitrogenous bases (A, U, G, C).

main types of rna

tRNA (transfers amino acids to ribosomes), rRNA (makes up ribosomes), and mRNA (carries genetic instructions for proteins).

transcription

the process of copying a segment of DNA into RNA, facilitated by the enzyme RNA polymerase.

sigma factor

binds to RNA polymerase and helps it locate the promoter region of the DNA to initiate transcription

splicing (rna processing)

process of removing introns (non-coding regions) from the transcribed RNA and joining exons (coding regions) together.

translation

the process of synthesizing proteins from mRNA instructions, occurring at the ribosome.

translational ribosome sites

A site (arrival), P site (peptidyl), and E site (exit), which facilitate the binding and release of tRNA.

trp person

regulated by repressor proteins; is "on" by default to produce amino acids, but becomes "off" (repressed) when tryptophan is abundant

mutations

Mutations are changes in the DNA sequence that can be classified as silent, missense, nonsense, or frameshift.

horizontal gene transfer

non-hereditary movement of genetic material between bacteria, enabling rapid adaptation, evolution, and the spread of antibiotic resistance

plasmids

prokaryotic; small, circular DNA molecules found in bacteria that can replicate independently of chromosomal DNA

physical requirements for microbial nutrition

Physical requirements for microbial growth include temperature, pH, and osmotic pressure

trace elements

essential minerals required in small amounts for various biological functions, such as zinc, copper, and iron.

organic growth factors

organic compounds that some microorganisms cannot synthesize and must obtain from their environment, such as vitamins

isotonic

solutions that have equal solute concentrations

hypertonic

where its internal solute concentration is higher than the surrounding environment

hypotonic

lower solute concentration outside the cell compared to inside

dna polymerase

enzyme that makes new strand (can’t synthesize without a template (de novo))

topoisomerase/gyrase

relax the DNA to prevent supercoiling and allow for easier/more efficient

rna polymerase

makes a small piece of RNA called a primer to get DNA polymerase going and moving

dNTP

utilized by DNA polymerase; the source of energy as well as the substrate of DNA polymerase

tRNA

subunit that brings amino acids to the ribosomes

rRNA

subunit that makes up the ribosome

mRNA

carries instructions for proteins