Test 2 EID

Capsule

Protective layer outside of the cell wall

Cell wall

Made of sugars held together by protein (peptidoglycan)

Nucleoid

Holds bacteria’s single chromosome

Plasmids

Extrachromosomal DNA

Ribosomes

The site of protein synthesis

Pili

Appendages that extrude from the cell wall (adhesins or sex pili)

Phenotype

The physical traits of an organism

Genotype

The genetic makeup of an organism

Wild type (+)

The most common phenotype

Mutant type

Anything other than the wild type

DD-transpeptidase (aka Penicillin Binding Protein)

Enzyme in cell wall synthesis, the target of β-lactam

Peptidoglycan

Two sugar chains linked by a peptide bridge

Bacterial Genome

1 chromosome and plasmids

Bacterial conjugation

Horizontal DNA transfer; pili bridge two bacteria together to transfer plasmids

Binary fission

Asexual reproduction; genetic material duplicates and one bacteria splits into two

Mutations

Mistakes made in DNA replication

Central Dogma

One-way flow of genetic information from DNA to RNA to proteins

Biomolecules of the Central Dogma

DNA, RNA, and protein

Processes of the Central Dogma

1) Replication 2) Transcription 3) Translation

DNA Functions

Contains genetic information and is the template to make more DNA

Nucleotide

The basic structural unit of DNA: a phosophate group, pentose sugar (deoxyribose), an a nitrogenous base (A, T, C, G)

Primary structure of DNA

the linear sequence of nucleotides linked together in a single polynucleotide chain

Secondary structure of DNA

double helix, formed by two sugar phosphate backbones held together by hydogren bonds between the base pairs

Hydrogen bonds

Weak chemical bonds between two nucleotides on different polynucleotide strands

DNA polymerase

An enxyme that builds new DNA strands in the 5’ to 3’ direction

DNA gyrase (topoismerases)

The enzyme that unwinds DNA

DNA Replication Process

1. Initiation = DNA gyrase unwinds the DNA

2. Elongation = DNA polymerase adds nucleotides

3. Termination = The two replication forks meet and fuse, creating two new DNA molecules

Messenger RNA (mRNA)

Encodes amino acid sequence of a polypeptide (carries genetic material from DNA to the cytoplasm)

Structure of RNA

Single-stranded, comes in many shapes, does not last long in the cell

Codon

Sets of 3 nucleotides on mRNA that code for an amino acid

Structure of Protein

The amino acid sequence bound by peptide bonds

Amino acid

The building block of proteins

Point Mutation

Substitution, Insertion, or Deletion

Missense mutation

Codes for a new amino acid

Nonsense mutation

The sequence stops too early

Silent mutation

The change does not affect the phenotype

Frameshift mutation

Insertion or deletion causes the DNA sequence to shift one over

Susceptible Bacteria

Bacteria will be killed

Resistant Bacteria

Bacteria can block the function of the antibiotic

β-lactam function

Targets cell wall synthesis (peptidoglycan); cells explode because of imbalance fluids

Quinolones function

Target DNA gyrase

Resistance to β-lactam

Bacteria acquire an enzyme called β-lactamase that breaks the β-lactam ring

Quinolone Resistance

Bacteria acquire different receptors that the antibiotic cannot attach to

Vertical gene transfer

Parent to offspring

Horizontal gene transfer

From cell to cell, ex: conjugation

Griffith experiment

study that first demonstrated bacterial transformation — where a bacterium takes up external genetic material and changes its traits

Population bottleneck

A sharp decrease in the population (from antibiotics, for example)

Mutations effect on resistance

The more mutations there are, the more resistant the bacteria is

Gram negative vs. gram positive

Gram negative have less peptidoglycan and an outer membrane

Common bacteria shapes

Cocci, bacilli, spirilla, vibrios