E2 - Microbial Genomes and Central Dogma

DNA

deoxyribonucleic acid - contains genetic information and instructions to make proteins

DNA Polymerase

Catalyze polymerization of deoxynucleotides and proof read

Exons

Coding region of a gene - segments of DNA/RNA that contains information for coding a protein or peptide sequence that are joined together after splicing of Introns in Eukaryotes

Histone

protein that provides structural support for chromosomes - DNA wraps around them

Introns

Non-coding region of a gene - is spliced during RNA processing in Eukaryotes

Methionine

Start codon encodes for this in archaea and eukarya

mRNA

Eventually converted into protein after being transcribed from DNA

Monocistronic mRNA

Each gene is transcribed individually into a single mRNA - Eukaryotes

n-formylmethionine

Start codon encodes for this in bacteria

Nucleic Acids

Main information carrying molecules of the cell - include DNA and RNA

Open Reading Frame (ORF)

Triplet code that requires translation to begin at the correct nucleotide - includes start and stop codons

Origin of Replication

Particular sequence in a genome where replication is initiated

Plasmid

Extrachromosomal - DNA with extra genes - Circular, double stranded DNA that replicate independently from the main chromosome - Can provide advantages like antibiotic resistance (bacteria, some fungi, some protozoa)

Polycistronic mRNA

Operons are transcribed into a single mRNA called ? - contains multiple ORF (genes) that encode amino acids (multiple proteins) - bacteria and archaea

Polysome

Multiple ribosomes on a single RNA (Eukaryotes 80S , Prokaryotes 70S)

Replication

Universal process (basically the same in Eukaryotes and Prokaryotes) - Process where a single DNA is copied to produce 2 identical DNA

Ribonucleases

type of nuclease that catalyzes the degradation of RNA into smaller molecules

RNA

single stranded nucleic acid molecule made of ribonucleotides - Carries genetic info, helps in translation of proteins, or is a component of ribosomes

RNA Polymerase

The enzyme that carries out transcription - uses DNA as a template - Bacteria/Archaea have 1 , Eukaryotes have 3

rRNA

type of non-coding RNA the is the primary component of ribosomes

Shine-Dalgarno Sequence

Ribosome-binding site - Ensures proper reading frame - mRNAs start here, is crucial for ribosome lining up with reading frame so it reads the triplet correctly

Spliceosome

Does the splicing of introns, occurs in nucleus of Eukaryotes (RNA + Protein)

Transcription

Carried out by RNA polymerase - Process of copying DNA sequence into RNA

Translation

Process where mRNA is decoded to produce a specific sequence of amino acids

Transposable Element

“Jumping genes” - segments of DNA that can move to any other segment of DNA in a cell (plasmid or chromosome)

tRNA

code for a specific amino acid - single stranded with extensive secondary structure creating cloverleaf shape - Contains “anticodon” region that recognizes/pairs with mRNA codon (3 nucleic acids that ID a specific amino acid)

Start Codon

Codon where translation begins AUG

Stop Codon

Nonsense codons that terminate translation UAA, UAG, UGA

Capping

Addition of Methylated Guanine to 5’ end - initiates translation

short

RNA Half-life is

Polyadenylation

Addition of 100-200 adenylate residues - stabilizes mRNA

Nucleus

Splicing occurs in the ? of Eukaryotes

Bidirectional

All DNA synthesis is

one

Bacteria have how many origins resulting in 2 replication forks moving in opposite directions

Multiple

Archaea/Eukaryotes have how many origin sites

Primer

DNA polymerase requires a ? - short stretch of RNA created by RNA polymerase

5

Bacteria have how many different DNA polymerases

9

Eukaryotes have how may DNA polymerases

Replication Fork

zone of unwound DNA where replication occurs

DNA Helicase

unwinds the DNA during replication