Microbiology Chapter 4 Mastering

Prokaryotic Cell - Peptidoglycan-containing cell wall Circular chromosome, not enclosed within a nuclear envelope 70s ribosomes Flagella that rotate, composed of flagellin Eukaryotic Cell - Cellulose or chitin-containing cell wall 80s ribosomes Mitochondria Linear chromosomes enclosed within a nuclear envelope Flagella that wave, composed of microtubules Lysosomes Endoplasmic reticulum Golgi apparatus

External -> Internal capsule -> cell wall -> plasma membrane

The cytoplasm, plasma membrane, nucleoid, and ribosomes are found in all bacterial cells. Capsules, fimbriae, pili, flagella, and even the cell wall are not found in all bacteria.

Surface components (capsule, cell wall, fimbriae, flagella) are more likely to be "visible" to the host as antigens. Components in the cell's interior (ribosomes, nucleoid, plasmid), are not as likely to serve as useful antigens for the host since they are sequestered within the bacterial cell. Even though they may be antigenic, antibodies against them will not be able to tag the SURFACE of a bacterial cell.

Those structures of processes that are unique to bacterial (prokaryotic) cells make excellent targets for antibacterial drugs. These include the peptidoglycan of the bacterial cell wall, the 70s bacterial ribosome, and potentially the bacterial fimbriae. Lysosomes and microtubules are found in eukaryotic cells and would not be appropriate targets for antibacterial drugs.

It will be readily phagocytized upon entering the host

It will be unable to adhere to host tissue and establish infection

E. coli uses its fimbriae to attach to surfaces such as to the epithelial cells that line the urethra. This attachment allows E. coli to colonize the surface, inducing inflammation and causing the signs and symptoms of a urinary tract infection.

Streptomycin prevents protein synthesis by binding to and disabling 70s ribosomes, which are used primarily by prokaryotic cells.

The highly selective outer membrane of the Gram-negative cell wall prevents the uptake of penicillin, rendering it ineffective in the treatment of most Gram-negative infections.

The classic signs and symptoms of a urinary tract infection are: pain due to inflammation of the urethra and bladder, pain or burning during urination, and an urgency to urinate frequently.

the flagella rotate clockwise

Monotrichous

the flagella turn counterclockwise and become bundled

Lophotrichous and monotrichous

Flagella can rotate 360 degrees.

movement towards or away from a stimulus.

Positive phototaxis

runs to become more frequent.

The receptors sense the stimulus and send signals to the flagella.

Filament

A Gram-positive flagellum has only two rings in its basal body; Gram-negatives each have four.

anchor the flagellum to the cell membrane.

Rod and Rings

can be identified and classified by differences in their flagellar proteins.

A bacterium moving towards a food source

spirochetes.

The axial filament is located between the cell membrane and the outer membrane.

It allows the cells to move more easily through viscous human tissues and fluids, such as mucus.

endoflagella.