Lecture 16 - prokaryote morphology

Question 1

Glycocalyx -

Answer 1

a layer of molecules that allows bacteria to stick to the environment and interact with the environment, the outer layer

Question 2

Nucleoid -

Answer 2

Dna localized region in cytoplasm

Question 3

Plasmid-

Answer 3

small DNA molecules with additional genes ( situation-specific )

Question 4

Pilus -

Answer 4

structure formed in conjugation allowing DNA transfer between bacterial cells

Question 5

Flagellum -

Answer 5

used for movement

Question 6

Cell wall -

Answer 6

made of peptidoglycan, made of modified glucose (polysaccharide)

Question 7

Outer Membrane -

Answer 7

lipid bilayer, additional boundary

Question 8

Gram-positive bacteria

Answer 8

have a thick cell wall

Question 9

Gram-negative bacteria

Answer 9

have a thin ( or no ) cell wall, more dangerous due to double cell membrane

Question 10

4 phases of growth…

Answer 10

Lag
Logarithmic
Stationary
Death (not all species)

Question 11

Lag Phase

Answer 11

Cells adjusting to a new environment

Question 12

Logarithmic/Exponential

Answer 12

Cells divide a lot

Question 13

Stationary

Answer 13

Competition increase, growth slows

-Prod. of endospores/spores
-Biofilm production
-Toxin production

Question 14

Death (not all species)

Answer 14

Toxins build-up

Question 15

Quorum Sensing

Answer 15

Method bacteria use to determine how full their environment is
-Cells release signals to detect each other
-Governs transition from individual to colony

Question 16

Bacteria can coordinate the production of…

Answer 16

-Biofilm components
-Enzymes
-Toxins
-Based on changes in gene expression

Question 17

Bacterial Colonies

Answer 17

Form during the stationary phase
-High density
-Group behaviors

Question 18

Production of endospore

Answer 18

-Resistant structure
-Form inside cell
-Survive strong adverse conditions
-Uneven split

Question 19

Biofilms

Answer 19

-Layer of polysaccharides, proteins, and other molecules
-Adhesion is created among cells to stick together
-At the mature stage, biofilms can host communities of different species

Question 20

Examples of Biofilms

Answer 20

-Biofilms grow often in pipes, reducing the flow
-Grow on catheters and other medical devices
-Biofilms on teeth cause decay
-Can cause chronic infection

Question 21

Endotoxins

Answer 21

-Not actively secreted
-General symptoms ( fever, lethargy, malaise, etc. )
-LPS ~ lipid portion is the toxin
-Typically less toxic than exotoxins
-Symptoms are less specific
-Large doses can cause hemorrhagic shock and tissue necrosis

Question 22

Exotoxins

Answer 22

-Secreted
-Very specific targets