Test 2 Questions

Question 1

What three enzymatic activities are required outside of the cytoplasmic membrane in order to complete peptidoglycan polymerization and insertion into the cell wall, and what are the roles of those three enzymatic activities?

Answer 1

Transglycosylase- Polymeries Glycan
Transpeptidase- Crosslinks peptide chains
Autolysins- Cleave existing wall to allow insertion of more PG.

Question 2

BRIEFLY describe the TWO defining characteristics that differentiate Passive and Active transport.

Answer 2

Passive transport does not require energy, goes from high concentration to low concentration (with concentration gradient). Active transport requires energy and goes from low to high concentration (against concentration gradient).

Question 3

In E. coli cells, the proteins that cause cell division to happen precisely at the cell center are called the ____ system.

Answer 3

Min

Question 4

The sugar-rich outermost layer of Gram-negative bacterial cells is called:

Answer 4

LPS (lipopolysaccaride)

Question 5

Peptidoglycan precursor molecules are attached to ____ while being transported across the cell membrane.

Answer 5

Bactoprenol

Question 6

Abundant fixed protein filaments on a cell surface are called:

Answer 6

fimbriae

Question 7

When a bacterial culture no longer has sufficient energy available for cellular repair, it will enter____phase.

Answer 7

death

Question 8

Directional motility with respect to a chemical gradient is called:

Answer 8

chemotaxis

Question 9

The energy source for ABC transporters is:

Answer 9

ATP

Question 10

An organism that grows optimally at pH 3.7 is classified as a:

Answer 10

acidophile

Question 11

The time between inoculation of a batch culture and the beginning of growth is called the _____ phase.

Answer 11

lag

Question 12

The arrangement of flagella all over the cell surface is called:

Answer 12

peritrichous

Question 13

Organisms that require oxygen but are killed by full atmospheric oxygen concentration are called:

Answer 13

Microaerophiles

Question 14

During ____, a chemical is transported in the same direction as a proton.

Answer 14

symport

Question 15

____ are the filamentous structures involved in twitching motility.

Answer 15

pilli

Question 16

Gram-positive bacteria have _____ -linked lipids.

Answer 16

ester

Question 17

The polymers that comprise the capsule of a bacterial cell are called:

Answer 17

polysaccharides

Question 18

A particular growth media inhibits the growth of all gram-positive bacteria. Gram-negative bacteria that are capable of fermenting the sugars present in the media produce a visible color change while bacteria that cannot ferment the sugars produce no color change. This growth media is best described as:
1)Selective
2)Differential
3)Neither selective or differential
4)Both selective and differential

Answer 18

Both selective and differential

Question 19

A serial dilution was performed on a liquid bacterial culture, and 1 mL of each dilution was spread on plates. The plates were incubated overnight and gave the following results:
16 colonies from the 10^-5 dilution
180 colonies from the 10^-4 dilution
720 colonies from the 10^-3 dilution
How many cfu/ml were in the original culture?
1)1.8 x 10^-2 cfu/ml
2)1.6 x 10^6 cfu/ml
3)1.8 x 10^6 cfu/ml
4)1.2 x 10^7 cfu/ml
5)1.8 x 10^-6 cfu/ml
6)1.02 x 10^7 cfu/ml

Answer 19

1.8 x 10^6 cfu/ml

Question 20

The species Aliivibrio fischeri requires a ~7% NaCl environment to survive and would be classified as which of the following?
1)Nonhalophile
2)Halotolerant
3)Halophile
4)Macrohalophile

Answer 20

Halophile

Question 21

How does cell size impact bacterial growth rate?
1)Larger cells are able to bind more tightly to surfaces
2)Smaller cells are able to swim faster
3)Smaller cells have more nutrient transport capacity per unit of cell mass.
4)Larger cells are more effective pathogens
5)Smaller cells are more buoyant in aquatic environments

Answer 21

Smaller cells have more nutrient transport capacity per unit of cell mass

Question 22

An Archaeal S-layer is composed of:
1)Glycosidic bonds
2)Proteins
3)Sugars
4)Nucleic acids
5)Only DNA

Answer 22

Proteins

Question 23

At time zero the optical density of a culture is 0.15
120 min later, the optical density is found to be 2.4
What is the generation time of this culture?
1)15 min
2)20 min
3)30 min

Answer 23

30 min

Question 24

What class of organism might grow in your refrigerator?
1)Psychrophile
2)Alkaliphile
3)Halophile
4)Thermophile

Answer 24

Psychrophile

Question 25

BOTH peroxide and catalase work to remove ___ from bacterial cell. 1)oxygen 2)hydoxyl radical 3)hydrogen peroxide 4)NADH 5)water

Answer 25

hydrogen peroxide

Question 26

Which of the following is not found in the gram-positive cell envelope? 1)Peptidoglycan 2)Phospholipids 3)Teichoic acids 4)Lipid A 5)Transmembrane proteins

Answer 26

Lipid A

Question 27

Lysozyme causes death of bacterial cells by: 1)Degrading the DNA 2)Cleaving membrane lipids 3)Degrading the peptidoglycan 4)Blocking ATP synthesis

Answer 27

Degrading the peptidoglycan

Question 28

The role of the FtsZ protein is in: 1)Identification of the center of the cell 2)Formation and constriction of the cell division site 3)Separation of two chromosomes following replication 4)Synthesis of the septum peptidoglycan 5)Maintenance of the rod shape of the cell

Answer 28

Formation and constriction of the cell division site

Question 29

An advantage of membranes made of biphytanyl monolayers is that: 1)They are relatively stable at high temperatures 2)They allow easier transport of nutrients 3)They are more permeable to dissolve gasses 4)They require less energy to synthesize 5)They are less permeable to antibiotics

Answer 29

They are relatively stable at high temperatures

Question 30

A viable cell count: 1)Uses a Petroff-Hausser counting chamber 2)Involves serial dilutions and spread or pour plates 3)measures optical density 4)Is a quick way to perform a cell count 5)Requires a spectrophotometer

Answer 30

Involves serial dilutions and spread or pour plates

Question 31

Approximately what percentage of the mass of a prokaryotic cytoplasmic membrane is made up of protein? 1)100% 2)50% 3)20% 4)5% 5)2%

Answer 31

50%

Question 32

In bacteria, the Sec system is directly involved in what process? 1)Peptidoglycan synthesis 2)Membrane assembly 3)Motility 4)Protein secretion 5)Secondary metabolism

Answer 32

Protein secretion

Question 33

Which morphology of bacteria is described as a curved rod? 1)Spirillum 2)Vibrio 3)Spirochete 4)Coccus

Answer 33

Vibrio

Question 34

Which of the following molecules is NOT found in peptidoglycan? 1)N-acetylglucosamine 2)N-acetylmuramic acid 3)Diaminopimelic acid 4)D-Alanine 5)L-Alanine 6)L-Proline

Answer 34

L-Proline

Question 35

Prokaryotes reproduce via what process? 1)Mitosis 2)Meiosis 3)Spore formation 4)Binary fission

Answer 35

Binary fission

Question 36

A thermophilic alkaliphile would prefer which of the following growth conditions? 1)60C and pH 9.5 2)15C and pH 10 3)55C and pH 3 4)10C and pH 3.5 5)None of the above

Answer 36

60C and pH 9.5

Question 37

Diffusion of protons near the outer surface of the gram-positive bacterial cytoplasmic membrane is limited by: 1)Positive charges on the peptidoglycan 2)Negative charges on the teichoic acids 3)Impermeability of the outer membrane 4)Limited availability of the membrane protein channels 5)All of the above

Answer 37

Negative charges on the teichoic acids

Question 38

Achieving steady state growth in a chemostat involves: 1)The addition of fresh media into the culture vessel 2)The elimination of media from the culture vessel 3)The removal of microbial cells from the culture vessel 4)Maintaining an overall constant volume 5)All of the above

Answer 38

All of the above

Question 39

A disadvantage of measuring culture growth as a change in optical density is: 1)The process takes a long time 2)The process is expensive 3)The process cannot differentiate live and dead cells 4)The measurements are not reproducible from one day to the next.

Answer 39

The process cannot differentiate live and dead cells

Question 40

Which method of counting bacterial cells is the best able to identify the growth of cells in chains? 1)Viable count 2)Optical density 3)Direct count 4)Selective medium 5)Serial dilution

Answer 40

Direct count

Question 41

The type of medium sometimes made with yeast extract is: 1)Complex medium 2)Defined medium 3)Minimal medium 4)selective medium

Answer 41

Complex medium

Question 42

What allows bacteria of the genus Mycoplasma to survive without a cell wall? 1)They only live in a low temperature environment 2)They only live in a isotonic environment 3)They produce an extensive layer of extracellular polysaccharide 4)They produce an S-layer 5)All of the above

Answer 42

They only live in an isotonic environment

Question 43

Staphylococci grow in: 1)Pairs of two cells 2)groups of four cells 3)linear chains of cells 4)Random bunches of cells 5)Cubic arrangements of cells

Answer 43

Random bunches of cells

Question 44

The energy for group translocation comes from? 1)ATP 2)NAD 3)FAD 4)Pyruvate 5)Phosphenolpyruvate

Answer 44

Phosphenolpyruvate

Question 45

During bacterial growth in batch culture, growing inhibition due to waste product accumulation results in the bacteria entering: 1)Lag phase 2)Inhibition phase 3)Log phase 4)Waste phase 5)Stationary phase

Answer 45

Stationary phase

Question 46

Which is a disadvantage of growing in shaken liquid medium? 1)Not all cells are exposed to the same nutrient concentration 2)The shaking will damage the cells 3)The concentration of the cells cannot be easily determined 4)It is not possible to isolate a pure culture from a mixed sample 5)It is difficult to recover the cells out of the liquid

Answer 46

It is not possible to isolate a pure culture from a mixed sample

Question 47

What is the final cell number of a culture if it had an initial cell number of 1.0 x 10^4 and has grown for 200 minutes with a generation time of 50 min? 1)4.0 x 10^4 cells 2)4.0 x 10^5 cells 3)1.0 x 10^5 cells 4)1.6 x 10^4 cells 5)1.6 x 10^5 cells

Answer 47

1.6 x 10^5 cells