Test 2 Questions Flashcards
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?
Transglycosylase- Polymeries Glycan
Transpeptidase- Crosslinks peptide chains
Autolysins- Cleave existing wall to allow insertion of more PG.
BRIEFLY describe the TWO defining characteristics that differentiate Passive and Active transport.
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).
In E. coli cells, the proteins that cause cell division to happen precisely at the cell center are called the ____ system.
Min
The sugar-rich outermost layer of Gram-negative bacterial cells is called:
LPS (lipopolysaccaride)
Peptidoglycan precursor molecules are attached to ____ while being transported across the cell membrane.
Bactoprenol
Abundant fixed protein filaments on a cell surface are called:
fimbriae
When a bacterial culture no longer has sufficient energy available for cellular repair, it will enter____phase.
death
Directional motility with respect to a chemical gradient is called:
chemotaxis
The energy source for ABC transporters is:
ATP
An organism that grows optimally at pH 3.7 is classified as a:
acidophile
The time between inoculation of a batch culture and the beginning of growth is called the _____ phase.
lag
The arrangement of flagella all over the cell surface is called:
peritrichous
Organisms that require oxygen but are killed by full atmospheric oxygen concentration are called:
Microaerophiles
During ____, a chemical is transported in the same direction as a proton.
symport
____ are the filamentous structures involved in twitching motility.
pilli
Gram-positive bacteria have _____ -linked lipids.
ester
The polymers that comprise the capsule of a bacterial cell are called:
polysaccharides
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
Both selective and differential
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
1.8 x 10^6 cfu/ml
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
Halophile
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
Smaller cells have more nutrient transport capacity per unit of cell mass
An Archaeal S-layer is composed of:
1)Glycosidic bonds
2)Proteins
3)Sugars
4)Nucleic acids
5)Only DNA
Proteins
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
30 min
What class of organism might grow in your refrigerator?
1)Psychrophile
2)Alkaliphile
3)Halophile
4)Thermophile
Psychrophile
BOTH peroxide and catalase work to remove ___ from bacterial cell.
1)oxygen
2)hydoxyl radical
3)hydrogen peroxide
4)NADH
5)water
hydrogen peroxide
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
Lipid A
Lysozyme causes death of bacterial cells by:
1)Degrading the DNA
2)Cleaving membrane lipids
3)Degrading the peptidoglycan
4)Blocking ATP synthesis
Degrading the peptidoglycan
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
Formation and constriction of the cell division site
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
They are relatively stable at high temperatures
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
Involves serial dilutions and spread or pour plates
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%
50%
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
Protein secretion
Which morphology of bacteria is described as a curved rod?
1)Spirillum
2)Vibrio
3)Spirochete
4)Coccus
Vibrio
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
L-Proline
Prokaryotes reproduce via what process?
1)Mitosis
2)Meiosis
3)Spore formation
4)Binary fission
Binary fission
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
60C and pH 9.5
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
Negative charges on the teichoic acids
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
All of the above
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.
The process cannot differentiate live and dead cells
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
Direct count
The type of medium sometimes made with yeast extract is:
1)Complex medium
2)Defined medium
3)Minimal medium
4)selective medium
Complex medium
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
They only live in an isotonic environment
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
Random bunches of cells
The energy for group translocation comes from?
1)ATP
2)NAD
3)FAD
4)Pyruvate
5)Phosphenolpyruvate
Phosphenolpyruvate
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
Stationary phase
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
It is not possible to isolate a pure culture from a mixed sample
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
1.6 x 10^5 cells
