PROKARYOTIC CELLS: CELL SURFACE STRUCTURES, MOTILITY, & ENDOSPORES

What is the function of glycocalyx?

Slimy polysaccharide layer that helps with attachment, prevents desiccation and phagocytosis

What are the two types of glycocalyx?

Slime layer, loose, unorganized, thin and easily removed and capsule thick, firmly attached

What is a biofilm?

Communities of bacteria inside a polysaccharide layer that stick to surfaces

Example of biofilm related infection

Streptococcus mutans and hospital acquired infections

What is the function of an S-layer?

Protein or glycoprotein geometric pattern that acts as a protective barrier, selective sieve and helps with adhesion

What are pili and fimbriae?

Hair-like structures used for adhesion and genetic exchange

What is the function of pili in conjugation?

Transfers DNA between bacterial cells, increasing genetic diversity

What is the primary function of flagella?

Locomotion

What are the types of flagella arrangements?

Monotrichous: One flagellum at one end, Amphitrichous: One flagellum at each end, Lophotrichous: A tuft of flagella at one or both ends, Peritrichous: Flagella spread all over the surface

What is the function of the basal body in flagella?

It acts as the motor that rotates the flagellum

What powers flagellar movement?

Proton motive force, the movement of protons through Mot A and Mot B

What is taxis?

Directed movement toward or away from stimulus

Example of positive taxis

Moving toward nutrients

What are runs and tumbles in bacterial movement?

Run: smooth forward movement CCW, Tumble: reorient CW

How do bacteria move in a chemical gradient?

They move towards attractants and away from harmful substances

What are endospores?

Highly resistant dormant structures that protect bacteria

Which bacteria produce endospores?

Gram-positive bacteria like Bacillus and Clostridium

What makes endospores resistant?

Calcium-dipicolinate, Small acid-soluble proteins, dehydrated core, multiple protective layers

What triggers endospore germination?

Presence of nutrients like sugars and AA

How can endospores be destroyed?

Autoclaving

Name three diseases caused by endospore-forming bacteria:

Anthrax, Tetanus and Botulism