Chapter 9 Study Guide

facultative anaerobe

Staphylococcus

aerotolerant

Streptococcus

1. Which of the following best describes why extracellular polymeric substances are important?

They are components of a biofilm secreted by the microbes present

1. Which of the following best describes the cell membranes of microbes that thrive at low temperatures?

They have relatively high amounts of unsaturated fatty acids

1. Which of the following best describes the enzymes of extreme alkaliphiles?

They have relatively high isoelectric points.

The largest component of the dry weight of a biofilm is usually extracellular polymeric substances. T/F

True

facultative anaerobe

an organism that can grow without oxygen but that grows best with oxygen

aerotolerant anaerobes

an organism that grows equally well with or without oxygen

microaerophile

an organism that requires a low concentration of oxygen (less than the oxygen concentration in the atmosphere)

obligate anaerobe

an organism that requires an oxygen-free environment

Bacteria most commonly reproduce using which of the following methods?

binary fission

When a spread plate is used to estimate bacterial numbers, the numbers are reported

colony forming units per milliliter (CFU/mL)

1. If you grow two species of bacteria on mannitol salt agar to determine which can ferment mannitol, and you know both species can grow on the medium, which type of medium is the agar?

differential

psychrotroph

grows well between 4 °C and 25 °C

1. What is the goal number of CFUs on a spread plate if a serial dilution is done correctly?

30-300 per plate

1. Which microbial pathogen has an unusually long doubling time?

Mycobacterium leprae

1. Which type of organism can survive at great depths in the ocean?

barotolerant

A candle jar is often used to grow which type of bacteria?

capnophiles

1. Which type of system is used to maintain bacteria in a relatively constant environment, allowing them to stay in the log phase of growth?

chemostat

Which of the following is another term for generation time?

doubling time

1. Which best describes bacterial growth during the log phase of the growth curve?

exponential

1. Which type of microbes thrive in the Great Salt Lake?

extreme halophiles

The process of division by which cells split from a parent filament is called

fragmentation

1. Which range of the electromagnetic spectrum is considered photosynthetically active radiation?

from visible light to near infrared

The generation time for a particular bacterial species in a particular batch culture is called the

intrinsic growth rate

1. Which of the following is the correct order of phases of growth in the growth curve of a batch culture?

lag phase>log phase>stationary phase>death/decline phase

1. In batch culture, how does the log phase of the bacterial growth curve appear?

linear on a semi-log scale

1. Human pathogens are generally which type of microbe?

mesophiles

1. Which of the following is the most common category of bacteria?

neutrophiles

. mesophile

optimal temperature range for growth: approximately 20-40 °C

1. Which of the following is not an example of an enzyme used to detoxify reactive oxygen species?

permeases

1. Which of the following is the term for free-living bacteria?

planktonic

1. Which of the following would be the best choice for distinguishing living and dead bacteria in a cell count?

primary and secondary fluorescent stains

1. Food spoilage is often caused by which type of microbe?

psychrotrophs

1. Capnophiles are bacteria that grow best under which of the following conditions?

relatively high CO2 and relatively low oxygen concentrations

Turbidity is measured using a

spectrophotometer

1. Which of the following is not a common way bacteria divide?

sporulation

psychrophile

temperature range for growth: approximately 0-15 °C

thermophile

temperature range for growth: approximately 50-80 °C

hyperthermophile

temperature range for growth: approximately 80-110 °C

Which structure separates new daughter cells in binary fission?

the division septum

The initial cells added to a batch culture are called which of the following?

the inoculum

1. Which of the following best describes culture density?

the number of cells per unit volume

1. Which of the following best describes FtsZ?

the protein that assembles the Z ring, which forms a divisome before division by binary fission

1. Which of the following media is commonly used to determine the oxygen requirements of a bacterial species?

thioglycolate medium

1. Which of the following is an indirect method of measuring numbers of bacterial cells?

turbidity measurements

selective media

a medium that favors the growth of some organisms over others

1. Which of the following is not a reactive oxygen species?

atmospheric oxygen

1. Which of the following is not a common step in preparing a pour plate to make a count of microbial numbers?

Bacteria are spread across the agar, using a sterile spreader.*

microaerophile

Campylobacter pylori

obligate anaerobe

Clostridium difficile

1. Halotolerant microbes cannot grow without high concentrations of salt.T/F

False

1. MacConkey agar can be used to select for the growth of gram-positive bacteria, making it especially useful to study Enterobacteriaceae. T/F

False

Quorum sensing always occurs between members of the same species. T/F

False

____________ organisms do not require high salt concentrations for growth but can grow in salty environments.

Halotolerant

1. Which of the following is true of using a Petroff-Hausser chamber to do a direct cell count?

If the sample was diluted, then the concentration must be corrected accordingly.

1. Estimates of coliforms in water are often made using most probable number techniques.T/F

True

Generation time in prokaryotes refers to the amount of time required for the doubling of the population through a single round of binary fission. T/F

True

chemically defined medium

a medium for which the entire composition is exactly known

complex medium

a medium made from the digests of yeasts, meats, or plants, meaning that the exact composition is unknown

differential medium

a medium that allows colonies of bacteria to be distinguished based on one or more characteristics

enriched medium

a medium with growth factors added to promote the growth of fastidious organisms

1. Which of the following best describes how a microaerophile would grow in a thioglycolate tube culture?

a short distance below the top of the medium, but not at the top

obligate aerobe

an organism that requires oxygen to survive