Microbiology: Micro Bio Chp 6 Exam 2 Flashcards


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Microbiology
Chapter 6
Medical Microbiology Kingwood Tx
updated 10 years ago by salinadanley7
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medical microbiology, medical, infectious diseases, science, life sciences, biology
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1

A microbe recovered from an environment sample grows on a medium composed of agar and a mix of salts. The agar is not digested during incubation. The growth rate increases in high CO2 conditions. The organism is likely an _______.

autotroph

2

A cell that uses an organic carbon source and obtains energy from light would be called a

photoheterotroph

3

A _____ organism requires oxygen for growth.

obligate aerobic

4

An aquatic microbe that can grow only near the surface of the water is probably which of the following?

phototroph

5

An organism that produces catalase enzyme is protected from the harmful effects of

peroxide anion

6

All of the following are used to protect organisms from the toxic by-products of oxygen EXCEPT

protease

7

A microbe that grows only at the bottom of a tube of thioglycollate medium is probably a

obligate anaerobe

8

Nitrogen is a growth limiting nutrient for many organisms because

only a few microbes can extract it from the atmosphere, but all organisms require it for amino acid and nucleotide synthesis

9

An organism that requires chemical nutrients which serve as final electron acceptors is an

chemotroph

10

At temperatures higher than the maximum growth temperature for an organism,

hydrogen bonds are broken, proteins are denatured, and membranes become to fluid.

11

Human pathogens are classified as

mesophiles

12

In the process of _____ microbes detect the presence and density of other microbes and modify their metabolic activity in response.

quorum sensing

13

Which of the following organisms would be most likely to contaminate a jar of pickles?

an acidophile

14

Organisms that can grow with or without oxygen present are

either facultative anaerobes or aerotolerant anaerobes

15

A fastidious organism might be grown on which of the following types of media?

enriched media

16

Obligate anaerobes may be cultured in the laboratory

in a reducing medium

17

Joan wants to discover a microbe capable of degrading an environment contaminant. Which of the following is the process she should use?

enrichment culture

18

A microbiologist inoculates a growth medium with 100 bacterial cells/ml. If the generation time of the species is 1 hour, and there is no lag phase, how long will it be before the culture contains more than 10,000 cell/ml?

7 hours

19

An epidemiologist is investigating a new disease and observes what appear to be bacteria inside tissue cells in clinical samples from victims. The scientist wants to try to isolate the bacteria in the lab. What culture conditions are most likely to be successful?

inoculation of cell cultures

20

Microbial growth rates are controlled in a chemostat by

controlling the amount of a limiting nutrient

21

MacConkey agar plates represent ______ medium.

both a differential and a selective

22

A Petroff-Hauser counting chamber is a

glass slide containing an etched grid for counting microbes directly using a microscope

23

A means of reproduction in which duplicate DNA molecules are separated by cell elongation, followed by formation of a septum to divide the cytoplasm is called

binary fission

24

A device that removes wastes and adds fresh medium to bacterial cultures in order to prolong the log phase of a culture is called a

chemostat

25

The ______ of a population is the time it takes for the cells to double in number.

generation time

26

Which of the following is an indirect method for estimating the number of microbes in a sample?

turbidity

27

During which growth phase are bacteria more susceptible to antimicrobial drugs?

log phase

28

The use of salt and sugar in preserving various types of foods is an application of which of the following concepts?

osmotic pressure

29

A clinical sample labeled as "sputum" was collected from

the lungs

30

The method of obtaining isolated cultures that utilizes surface area to physically dilute specimens is called

the streak-plate technique

31

______ are complex communities of various types of microbes that adhere to surfaces.

Biofilms

32

The ______ method provides an estimate of the CFUs (colony-forming units) in a sample

viable plate-count

33

Blood agar plates are an example of _____ medium.

differential

34

Sodium thioglycollate is associated with which of the following types of media?

reducing media

35

Which of the following quantification techniques can distinguish living cells from dead cells in a culture?

metabolic activity

36

The correct sequence for the phases indicated by the letters A,B,C and D is

lag phase, log phase, stationary phase, death phase

37

The generation time of bacterial cells is shortest during the _____ phase.

log

38

When cells are metabolically active but not dividing, they are in the ____ phase.

lag

39

Metabolic activity is at maximum level in the _____ phase of growth.

log

40

Creating conditions in the laboratory that promote the growth of some microbes while inhibiting the growth of others is called

selective enrichment culturing

41

A laboratory protocol lists the following ingredients: 1 g sucrose, 16.4 g Na2HPO4, 1.5 g (NH4)3PO4, 0.02 g CaCO3, KNO3, water to 1 liter and autoclave. This recipe is for a ______ medium.

defined broth

42

A capnophile is a microorganism that thrives in conditions of high

carbon dioxide levels

43

A microorganism found living under conditions of high ____ is a barophile.

hydrostatic pressure

44

Microaerophiles are microbes that grow best at low

oxygen levels

45

A 100ul sample containing 1000 bacterial cells/ul in log phase growth is added to 9.9 ml of fresh culture medium broth. assuming no nutrients are in limited supply, and a generation time of 30 minutes, how many bacteria will be present in the entire broth culture after six hours?

4.096 x 108

46

The conversion of nitrogen gas to ammonia is called nitrogen (metabolism/ fixation).

fixation

47

Organisms that require organic sources of carbon and energy are called (chemoheterotrophs/ chemoautotrophs/ auxotrophs).

chemoheterotrophs

48

The (peroxide/ superoxide/ hydroxyl) radical if formed during the incomplete reduction of O2 during electron transport in aerobes.

superoxide

49

The (optimum/ range/ minimum) growth temperature is the temperature at which an organism exhibits the highest growth rate.

optimum

50

The preferred method for long term storage of bacteria is (freezing/ refrigeration/ lyophilization).

lyophilization

51

Alkalinophiles can survive in water up to pH (11.5/ 10/ 7.0).

11.5

52

Many photosynthetic organisms produce (catalase/ carotenoids/ dismutase) to protect themselves from the damaging effects of singlet oxygen (1O2).

Cartenoids

53

A (culture/ specimen/ inoculum) is a sample of microorganisms introduced into a growth medium.

inoculum

54

A pure culture is composed of cells that arise from a single ( cell/inoculum/ sample).

cell

55

A gelling agent derived from algae that is useful for crating solid growth media is called (broth/ agar/ starch)l

agar

56

A sample placed into fresh medium is initially in the (lag/ log/ stationary) phase of microbial growth in most instances.

lag

57

A growth curve plots the (number/ concentration) of viable organisms in a growing population over time.

number

58

Flow (spectrohotometry/ cytometry) is a method of counting cells that have been stained or tagged with fluorescent dyes.

cytometry

59

A clinical sample of (urine/ sputum/ tissue) is called a biopsy.

tissue

60

A (cytometer/ spectrophotometer) can measure changes in the turbidity of a bacterial culture.

spectrophotometer