Prokaryotics

what is a virulence factor?

A component that enhances the ability of a pathogen to cause disease.

Extracellular polymeric substances (EPS)

A sticky layer of polysaccharides and proteins that helps bacteria adhere to surfaces and form biofilms.

Endoflagella

Flagella that are located within the periplasmic space of certain bacteria, providing motility.

Peptidoglycan

A polymer that forms a protective layer in bacterial cell walls, providing structural support.

Porins

Proteins that form channels in the outer membrane of gram-negative bacteria, allowing the passage of small molecules.

Sporulation

The process by which certain bacteria form spores to survive unfavorable conditions.

Germination

The process by which a spore returns to a vegetative state and begins to grow.

Phagocytosis

The process by which cells engulf and digest foreign particles or pathogens.

Gram positive

Bacteria that retain the crystal violet stain and appear purple under a microscope.

Gram negative

Bacteria that do not retain the crystal violet stain and appear pink under a microscope.

Differences between prokaryotic and eukaryotic

Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells have both.

Similarities between prokaryotic and eukaryotic

Both have DNA, ribosomes, and a cell membrane.

Characteristics of prokaryotes

Unicellular, lack a nucleus, and have a simple structure.

Different shapes of bacterium

Cocci (spherical), bacilli (rod-shaped), and spirilla (spiral-shaped).

Required structures in all bacterial cells

Cell membrane, cytoplasm, and genetic material (DNA).

what does Infection without attachment mean?

You can not infect a host if you are not attached to it.

Diplo in microbiology

Refers to bacteria that are arranged in pairs.

Staphyl in microbiology

Refers to bacteria that are arranged in clusters.

Strepto in microbiology

Refers to bacteria that are arranged in chains.

Essential bacterial components

Cell wall, cell membrane, ribosomes, and genetic material.

What is the outermost layer of bacterial cell called?

The glycocalyx, which can be a capsule or slime layer.

Function of glycocalyx capsule

To protect bacteria from phagocytosis and assist in adherence.

Function of virulence factors

To aid in attachment and provide protection against white blood cells

What are some diseases caused by bacteria with capsules?

Pneumonia, meningitis, and anthrax.

What are some diseases caused by bacteria with NO capsules?

common cold, ear infections, cough

Why are diseases caused by bacteria with capsules?

Capsules provide protection against the immune response, making infections more severe.

Function of flagella

To provide motility to bacteria, allowing them to move toward or away from stimuli.

Different types of flagella

Monotrichous (single), lophotrichous (tuft), amphitrichous (both ends), and peritrichous (all over).

Main structures of flagella

Basal body, hook, and filament.

Axial filament defintion

A structure found in spirochetes that allows for corkscrew-like movement.

Function of an axial filament

To enable motility in a twisting motion.

Another name for axial filament

Endoflagella.

Function of fimbriae

To help bacteria adhere to surfaces and host tissues.

Define fimbriae

Short, hair-like projections on the surface of bacteria that aid in attachment.

Gram location of pilus

Found in both gram-positive and gram-negative bacteria.

Function of pilus

To facilitate attachment to surfaces and genetic exchange between bacteria.

Main structures of cell wall

Peptidoglycan layer, outer membrane (in gram-negative), and teichoic acids (in gram-positive).

How is peptidogylcan different in gram negative?

It’s thinner

How is peptidoglycan different in gram postive?

Thickness

What two bacteria cell structures are virulence factor?

capsule and fimbraie

What are the steps to perform a gram stain

Steps to Perform a Gram Stain:

1. Prepare the Slide: Place a small drop of water on a clean slide and add a small amount of bacterial culture.

2. Heat Fix: Pass the slide through a flame to fix the bacteria to the slide.

3. Crystal Violet Staining: Apply crystal violet dye for 1 minute, then rinse with water.

4. Iodine Treatment: Add iodine solution for 1 minute, then rinse with water.

5. Decolorization: Use alcohol or acetone for 10-30 seconds, then rinse immediately with water.

6. Counterstaining: Apply safranin for 1 minute, then rinse with water.

7. Dry and Observe: Allow the slide to dry and observe under a microscope.

Interpretation:

• Gram-positive: Retain crystal violet (purple).

• Gram-negative: Take up safranin (pink).