Ch 5, 6, 7 Homework questions

Which of the following uses glucose for carbon and energy?

chemoheterotroph

Gallionella bacteria can get energy from the reaction Fe²⁺ → Fe³⁺. This reaction is an example of:

oxidation

How is ATP generated in the reaction shown in Figure 5.4?

substrate-level photophosphorylation

How would a non-competitive inhibitor interfere with a reaction involving an enzyme?

it would bind to the allosteric site

Which of the following is the best definition of oxidative phosphorylation?

a protein gradient allows hydrogen ions to flow back into the cells through transmembrane protein channels, releasing energy that is used to generate ATP

What is the fate of pyruvic acid in an organism that uses aerobic respiration?

it is converted into acetyl CoA

Which of the following is the best definition of fermentation?

the partial oxidation of glucose with organic molecules serving as electron acceptors

The graph on the left shows the reaction rate for an enzyme at its optimal temperature. Which graph shows enzyme activity at a higher temperature? (within range)

b

Which of the graphs best illustrates the activity of an enzyme that is saturated with substrate?

c

Most enzymes have the suffix:

-ase

Salts and sugars work to preserve foods by creating a:

hypertonic environment

Which line best depicts a psychotroph incubated at 0^oC?

b

Which line best depicts a facultative anaerobe in the absence of O₂?

b

Which of the following is an example of a metabolic activity that could be used to measure microbial growth?

glucose consumption

Which group of microorganisms is most likely to spoil a freshwater trout preserved in salt?

facultative halophiles

Three cells with generation times of 60 minutes are inoculated into a culture medium. Assuming no lag phase takes place, how many cells are there after 5 hours?

96

Which of the following pairs of microbe classification terms and optional growth temperatures are mismatched?

thermophile - growth at 37C

A culture medium consisting of agar, peptone, and beef heart is a:

complex media

Most bacteria grow best at pH

7

Consider a culture medium on which only gram-positive organisms such as Staphylococcus aureus colonies can grow due to an elevated NaCl level. A yellow halo surrounds the growth, indicating the bacterium fermented a sugar in the medium, decreasing the pH as a result and changing the color of a pH indicator chemical. This type of medium would be referred to as a(n)

selective and differential medium

Which graph in the figure best depicts the effect of placing the culture in an autoclave for 15 minutes at time x?

b

Which concentration of ethanol is the most effective bactericide?

70%

The pH of the medium has no effect on the activity of the disinfectant being applied. (T/F)

false

A disk-diffusion test using Staphylococcus gave the following results ~ which compound was the most effective against staphylococcus?

c

All of the following substances are effective against non-enveloped viruses EXCEPT

alcohol

Which of the following is the best method to treat/try to sterilize heat-labile solutions?

membrane filtration

Which graph best depicts the effects of placing the culture at 7^oC at time x?

d

The most resistant of the bacterial endospores can withstand boiling for up to

20 hours

A disk-diffusion test using staphylococcus gave the following results - which compound was the most effective against E. coli?

e. the answer cannot be determined based on the information provided

Which of the following does NOT achieve sterilization?

pasteurization