Microbiology Bacterial Structures and Functions

Study Notes

A person can be infected but show no symptoms. This is known as a subclinical infection.

Binary fission is the primary mode of bacterial reproduction.
In gram-positive bacteria, the DNA attached to the septal mesosome divides in both directions, and the septum (cytoplasmic membrane) forms.
In gram-negative bacteria, the entire bacterial cell constricts from the middle to form a septum.

This is an active transport process for sugars.
A plasma membrane carrier protein becomes phosphorylated, binds to a sugar, and transports it across the membrane as a phosphorylated sugar.
This process requires energy.
The "Phosphotransferase System" is a name for this process..

Lipopolysaccharide (LPS) can activate the coagulation pathway, leading to clotting.
LPS induces platelet aggregation through alternate complement pathway activation.
LPS activates coagulation reactions through Hageman factor (factor XII) activation.
This leads to a series of factors converting to proteolytic enzymes until prothrombin changes into thrombin.
Thrombin cleaves fibrinogen into fibrin, which forms clots.
Fibrinogen has glycoprotein receptors on platelets which aids in aggregation.

Plasminogen is cleaved to plasmin, leading to fibrinolysis.
This can result in disseminated intravascular coagulation (DIC).
DIC causes thrombosis of capillaries (micro thrombi), leading to hypoperfusion, hypoxia, and hemorrhages (due to a lack of platelets).