Holmes lectures 1 2

Question 1

T or F: Bacteria have a nucleus.

Answer 1

FALSE

Question 2

T or F: Bacteria have a Golgi apparatus.

Answer 2

FALSE

Question 3

T or F: Bacteria do not have mitochondria.

Answer 3

TRUE

Question 4

What are the three branches of the tree of life (possibly outdated material).

Answer 4

Bacteria, Archaea, Eukarya

Question 5

What does Gram positive and Gram negative mean?

Answer 5

The response to the Gram stain. Gram+ retain the stain and look blue and purple. Gram? no not retain the stain and look pink.

Question 6

Describe the difference between the surface characteristics of Gram+ and Gram? bacteria.

Answer 6

Gram+: one membrane covered in peptidoglycan strands, many layers of cross linked peptidoglycans and teichoic acid strands. Gram ?: two membranes (inner and outer), fewer peptidoglycan strands, not as much cross linking.

Question 7

What determines the shape of a bacteria?

Answer 7

The rigid peptidoglycan layer and the cytoskeleton. Proteins: FtsZ (equiv to tubulin), MreB (actin), CreS (intermediate filaments)

Question 8

What is peptidoglycan?

Answer 8

Very unique to bacteria, composed of alternating hexose sugars cross-linked by amino acids. Sugars: N-acetylglucosamine, N-acetylmuramic acid Cross-links: DAP (Gram-) and L-Lys (Gram+) to D-alanine

Question 9

What is endotoxin made of?

Answer 9

Lipopolysaccaride from the cell outer leaflet of the outer membrane.

Question 10

What type of bacteria make endotoxin?

Answer 10

Gram negative

Question 11

How can you visualize capsules?

Answer 11

Stain with India ink - capsule excludes the india ink.

Question 12

What do capsules do?

Answer 12

Help a bacteria become slimy and resistant to phagocytosis.

Question 13

What amino acids are only found in bacteria peptidoglycans?

Answer 13

meso-diaminopetide (DAP), D-glutamic acid, D-alanine

Question 14

Where is the bacteria electron transport chain?

Answer 14

Plasma membrane

Question 15

Where to bacteria transport H+ from their electron transport chain?

Answer 15

Outside of their plasma membrane.

Question 16

What is polycistronic?

Answer 16

The ability to encode more than one protein on a single RNA, unique to bacteria

Question 17

T or F: Extrachromosomal plasmids often encode genes for antibiotic resistance.

Answer 17

TRUE

Question 18

What is a prophage?

Answer 18

A senescent virus within a bacteria.

Question 19

What are the differences between the lytic and lysogenic cycle?

Answer 19

Lytic means the virus takes over and uses the bacteria to make more viruses, which then break out of the cell resulting in lysis. Lysogenic means that the virus is dormant within the cell and is replicated along with the bacteria.

Question 20

What is phage conversion?

Answer 20

The ability of an encoded phage to alter a bacteria. Ex. C. diphtheria produces diphtheria toxin due to phage.

Question 21

What are the major types of secretion systems in Gram-negative bacteria?

Answer 21

Type 2, 5: Specific for individual proteins, proteins are transported through a pore, protein is free between membranes. Type 1, 3,4: Needle systems which deliver protein or plasmids through a channel directly into other cells or into extracellular environment.

Question 22

What is the lag phase of bacteria growth?

Answer 22

The phase in which the bacteria is sensing its environment and turning on genes necessary to survive in its environment.

Question 23

What are the typical phases of bacteria growth?

Answer 23

Lag, exponential, stationary, death

Question 24

Which types bacteria can grow in both aerobic and anaerobic conditions?

Answer 24

Indifferent (ferment in presence or absence of O2), facultative (respires with O2, ferments in absence of O2), microaerophilic (grows best at low conc of O2) bacteria

Question 25

What are the two forms of energy in a bacteria?

Answer 25

ATP (biosynthetic interconversion) and PMF (proton motive force, flagellar rotation, transport)

Question 26

What is fermentation?

Answer 26

Catabolic process win which organic compounds serve as both electron donor and electron acceptor.

Question 27

What is respiration?

Answer 27

Process in which the terminal electron acceptor is typically molecular O2. Usually need a non-organic molecule to reduce, which is usually O2, but some bacteria can use nitrates.

Question 28

What is a spore?

Answer 28

Form of dormant bacteria which allows long term survival under adverse environmental conditions.

Question 29

Which drugs target the peptidoglycan layer?

Answer 29

fosfomycin, cycloserine, vancomycin, penicillin. Makes the bacteria unstable and prone to lysis.

Question 30

What ribosome subunits do bacteria have?

Answer 30

30S and 50S