PROKARYOTIC CELLS

Prokaryotic

• single cell

• unicellular cells

• in bacterias and archaea

Beneficial Bacteria

are microorganisms that promote health and support vital ecosystems. In the human body, resident flora (probiotics) aid digestion, produce essential vitamins, and defend against pathogens. They are also crucial in environmental cleanup, wastewater management, and agricultural bio-fertilization

Pathogenic

are bacteria that bring diseases, damages tissue, and toxins

External Structure

• the outer layer of a bacteria

• for mobility

• locomotion

• attachment

Cell Envelope

• protective layer of the bacteria

• responsible for gram staining

Internal Structure

• the innermost layer of a bacteria

• contains DNA (plasmids)

Glycocalyx

is a dense, gel-like network of carbohydrates, glycoproteins, and glycolipids that coats the outer surface of many cell membranes. This extracellular layer plays a critical role in protecting the cell from mechanical stress, regulating vascular permeability, and facilitating cell-to-cell recognition and communication.

Capsule Glycocalyx

it is a more-organized glycocalyx

Slime Layer Glycocalyx

it is an unorganized glycocalyx (avoids dehydration and antibiotics)

Fimbria

are short, hair-like appendages found on the surface of many bacteria, particularly Gram-negative species. Composed of a protein called pilin, these structures act like biological Velcro, allowing bacteria to adhere tightly to target tissues, host cells, or inanimate surfaces to colonize them and cause infection.

Pili

the pathway of DNA/transfer from donor to receiver

Peptidoglycan

a massive polymer mesh that acts like a molecular chain-link fence. It is composed of two repeating sugar molecules cross-linked by short chains of amino acids:

NAG & NAM

These alternating sugars form the long, rigid carbohydrate backbone.

Hans Christian Gram

he proposed the idea of Gram Staining

Gram Positive

• NOT resilient

• Purple or Blue Stains

• thick peptidoglycan

• w/ teioric acid

Gram Negative

• more resilient

• pink or red

• resilient beacause of thin peptidoglycan

• has lipophysaccaride

Inclusion

storage of nutrients

Coccus

circle bacteria

Bacillus

rod bacteria

Vibrio

comma-shaped bacteria

Spirochete

spiral; irregular-shaped bacteria

Lag Phase

stage where the bacteria is still adapting

Log Phase

when bacterias divide and does rapid growth

Stationary Phase

stage when the life of the bacteria is 50/50

Death Phase

stage when bacterias will die

Monotricous

1 flagella

Lophotrichous

2 flagellas

Amphitrichous

both sides have 1 flagella each

Peritrichous

all sides have multiple flagellas

Diplo-

Cells that divide in a single plane and remain attached in pairs (e.g., Neisseria gonorrhoeae).

Strepto

Cells that divide repeatedly in a single plane to form long chains resembling a string of beads (e.g., Streptococcus pyogenes)

Tetrad

Cells that divide in two planes at right angles to each other, forming a flat square group of four cells.

Sarcina

Cells that divide symmetrically across three planes to create a tight, cubical pocket or packet of eight cells.