Infections Final Exam

What is binomial nomenclature?

• Identify by genus (capitalized) and species (not capitalized)

• Staphylococcus epidermidis

What are strains?

Subtypes of one species of microorganism

What are microbes?

Unicellular and not visible to the naked eye

How big must objects be to be visible without magnification?

~100 micrometers

What domains are microorganisms found in?

Archaea, bacteria, and eukarya

What do prokaryotic organisms lack?

A nucleus and other organelles

What kind of organism are bacteria?

Single-celled organism (unicellular)

Can bacteria be harmless or pathogenic?

It can be both and cause disease

What do most cell walls contain in bacteria?

Peptidoglycan

Where is bacteria mostly found?

Human flora

What is an acute infection?

Condition that begins suddenly and is often short-lived. Rapid onset of symptoms

What is a chronic infection?

Condition that develops gradually and persists over time. Symptoms develop slowly and are slow to resolve

What are examples of an acute infection?

Influenza and UTI

What are examples of a chronic infection?

Hepatitis B & C and Lyme disease

What is a subacute infection?

Symptoms develop more slowly than acute, but faster than chronic

What is a focal infection?

Initial site of infection from which organisms spread

What are bacteria of a round circular shape called?

Coccus

What are bacteria of a rod shape called?

Bacillus

What are bacteria of a comma shape called?

Vibrio

What are bacteria of a round short rod shape called?

Coccobacillus

What are bacteria in a squiggle shape called?

Spirillum

What are bacteria in a spiral shape called?

Spirochete

What are bacteria described by?

General shape (cell morphology)

What are the wide range of capabilities that bacteria has?

Metabolic capabilities and can grow in many different environments

Are bacteria anaerobic or aerobic?

Both anaerobic and aerobic

What is maintained by the cell wall?

Morphology

What protects cell from changes in osmotic pressure?

Cell wall

What is an isotonic solution?

A solution that has the same solute concentration as another solution. There is no net movement of water particles, and the overall concentration on both sides of the cell membrane remains constant

What is a hypertonic solution?

A solution that has a higher solute concentration than another solution. Water particles will move out of the cell, causing crenation

What is a hypotonic solution?

A solution that has a lower solute concentration than another solution. Water particles will move into the cell, causing the cell to expand and eventually lyse

What is a nucleoid?

An irregularly shaped region within a prokaryotic cell that contains its genetic material, the DNA organized into one or more chromosomes

What are characteristics prokaryotic chromosomes?

Circular shape, haploid (unpaired), and not bound by a nucleus

What is the purpose of nucleoid-associated proteins (NAPs)?

Interact with DNA to aid organization and chromosomal packing

What is the plasma membrane?

A flexible, lipid bilayer composed of proteins and phospholipids. It regulates movement of substances in and out of the cell

What are the roles of proteins on the surface of plasma membrane?

• Cell-to-cell communication

• Sensing environmental conditions and pathogenic virulence

What are glycoprotein/glycolipids?

Associated carbohydrates (sugars) that interact with the external environment

What is simple diffusion of the plasma membrane?

A passive transport process where small, non-polar molecules move from an area of high concentration to an area of low concentration, down their concentration gradient, without the help of membrane proteins

What is facilitated diffusion of the plasma membrane?

A type of passive transport where molecules move across a cell membrane with the help of protein channels or carriers, following their concentration gradient without requiring energy input

What is active diffusion of the plasma membrane?

An energy-requiring process where molecules move against their concentration gradient (from low to high), using membrane proteins and ATP

What does the cell wall do?

Protects the cell from outside environment

Where are peptidoglycan (or murein) found?

Only found in bacteria

What is peptidoglycan (or murein)?

• Long chains of alternating molecules

• Crosslinked heteropolymer of alternating sugars

What are some alternating sugars found in crosslinked heteropolymer?

N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM)

What are NAM and NAG connected by?

Peptide bridges that vary based on the type of bacteria

How does cross-linking happen?

Via transpeptidase

What does peptidoglycan give to the cell?

Its shape

What do many antibacterial drugs target?

Peptidoglycan

What is the purpose of gram staining?

Differentiates two common types of cell wall structures

What is gram-positive bacteria?

• Thick peptidoglycan layer (30-100 nm)

• Teichoic acid

  • Pathogenicity

• Purple

What is gram-negative bacteria?

• Outer and inner membrane

• Thin peptidoglycan (<4 nm)

• Lipopolysaccharide (LPS)

  • Acts as endotoxin

• Pink

What are glycocalyces?

Additional envelope structure exterior to the cell wall

What is glycocalyx?

A sugar coat

What is a capsule?

Organized layer comprised of polysaccharides or proteins

What is a slime layer?

Loosely attached layer composed of polysaccharides, glycoproteins, or glycolipids

What allows cells to adhere to surfaces, aiding in formation of biofilms?

Glycocalyx, capsule, and slime layer

What do fimbriae and pili do?

Aid in attachment to surfaces

What do flagella do?

Aid in movement in aqueous environments

What is binary fission?

A simple form of asexual reproduction where a single-celled organism, primarily prokaryotes like bacteria, divides into two identical daughter cells

What is doubling time?

Amount of time it takes for the population to double through one round of binary fission

What is generation time dependent on?

Species and growth environment

How does generation time work?

Number of generations, Number of cells; 0, 1; 1, 2; 2, 4; 3, 8

What is the growth curve?

Microorganisms grown in batch culture

• No nutrients added or removed

• Predictable curve

What is culture density?

Number of cells per unit volume

• Can calculate population in fixed volume

What is lag phase?

No increase in number of living bacterial cells

What is log phase?

Exponential increase in number of living bacterial cells

What is stationary phase?

Plateau in number of living bacterial cells; rate of cell division and death roughly equal

What is the death or decline phase?

Exponential decrease in number of living bacterial cells

What is the order of the growth curve?

1. Lag phase

2. Log phase

3. Stationary phase

4. Death or decline phase

What is virulence?

Ability of a microorganism to cause disease (pathogenicity)

• ID50 and LD50

What is an infection?

Occurs when a microbe overcomes the defense barriers and lives inside the host

What is disease?

Infections that result in damage to the host tissue or disruption of normal function

What is pathogenicity?

Ability of a microbial agent to cause disease

What is a primary pathogen?

Cause disease in a host regardless of the host’s resident microbiota or immune system

What is an opportunistic pathogen?

Can only cause disease in situations that compromise the host’s defenses, such as the body’s protective barriers, immune system, or normal microbiota

What is attachment?

To infect a host, microbes must first attach to a specific receptor

• No receptor = no attachment

What is tissue tropism?

Specificity of microbe to attach to tissue

• Why a specific infectious disease only involves specific tissues

What are attachment sites?

Areas of microbial attachment, may be animal species specific

• Includes pili and specialized surface proteins

What does cellular tropism affect?

Macrophage, neuron

What does tissue tropism affect?

Lung, brain

What does host tropism affect?

Rabbit, human

What is metabolism?

Chemical reactions that occur within a cell

What are exergonic reactions?

Spontaneous and release energy

What is catabolism?

Break down complex molecules into smaller ones

• Released energy can be stored in bonds of complex molecules that is then released to drive anabolic reactions

What are endergonic reactions?

They require energy

What is anabolism?

Converts simple (small) molecules into more complex molecules, fueled by cellular energy

What is glycolysis?

Catabolism of glucose; it produces energy (ATP), reduces electron carriers, and precursor molecules for cellular metabolism

Where does glycolysis take place?

In the cytoplasm

What is the krebs cycle?

• Acetyl CoA → CoA

• 3 NAD+ → 3 NADH

• FAD → FADH2

• → 2 CO2

• ADP → ATP

What is chemiosmosis?

Chemical gradient created by [H+]

• Flow of hydrogen ions acorss the membrane

What is ATP synthase?

Membrane-bound enzyme complex that channels H+

What is the size of bacteria?

1 um

What are cellular bioenergetics?

ATP is produced from pH and electrostatic charge gradients (∆𝑝𝐻 and ∆𝜓) set up across the cytoplasmic membrane

What is proton motive force (∆𝑝)?

∆𝑝=∆𝑝𝐻+∆𝜓

What does charge regulation effect change?

Surface pH affecting ∆𝑝𝐻 and ultimately ∆𝑝

What happens if the H+ ions are neutralized by hydroxide ions in pH and microbial growth?

The concentration gradient collapses and impairs energy production

What does pH influence?

Proteins and disrupts hydrogen bonding

• Alters folding pattern, alters activity

What is optimum growth for pH?

Neutrophile, between 5 and 9

What is the range of an alkaliphile?

7.5-11.5 for pH

What is the range for an acidophile?

1-5.5 for pH

What is the temperature range for a psychrophile?

-5 to 20 celsius