A colony is a ___1____ microbial growth on a solid medium that originated from a ______2______ and through cell division produced a multitude of identical daughter cells.

1. Visible 

2. Single parent 

Useful colony characteristics for differentiation of bacterial species include    1    ,     2    ,     3    ,          4   ,     5    ,    6    . For example, Serratia marcescens luteus colonies are red, irregular in shape, and have a strong odor. Micrococcus colonies, on the other hand, are yellow, opaque, round, and dome-shaped.

1. size

2. color

3. shape

4. texture

5. opacity

6. odor 

When working with culture that may contain millions of cells, dilution on to a solid medium is essential for    1     the cell with enough space so that they grow into    2     colonies.

1. separating

2. isolated 

The streak plate method does not require any additional      1     for dilution and only requires

      2        for inoculation

1. media

2. one plate

The loop is flamed before entering a culture tube to ensure that         1         microbes are introduced in to the culture. The loop is flamed afterward so that           2          are introduced into the          3            .

1. no contaminating

2. no culture microorganisms

3. working environment

Plates are inverted during incubation so that

         1      accumulate on the lid and drop on to the agar surface. This will cause the organisms 

        2         the dilution effect.

1. moisture does not

2. to spread and negate

 Refrigeration is used to control spoilage microbes in food but psychrotrophs, such as         1       , are still capable of growth at these temperatures.

Most human pathogens grow best at      1      , which is     2      temperature. 

1. 37°C

2. human body

Temperature affects metabolism by influencing

      1       ,        2      , and      3     .

1. enzymes

2. cell membranes

3. ribosomes

UV radiation causes the formation of     1       in DNA that result in     2     errors during reproduction. These errors cause        3       which ultimately lead to cell death.

1. thymine dimmers 

2. replication

3. genetic defects 

Endospores are     1      cells and are not subject to the same effects as      2      vegetative cells.

1. non-dividing

2. reproducing 

UV radiation is most germicidal at        1         because that is the wavelength at which DNA

       2          UV light.

1. 260 nm

2. maximally absorbs

UV radiation can cause damage to     1     and can cause      2     . It also can cause        3      . In this experiment, goggles are worn to protect the eyes and one should avoid looking directly at the UV light source. In everyday life, wearing long clothing, a hat, and/or sunscreen will protect against the damaging UV rays of the sun.

1. skin cells

2. skin cancers

3. cataracts and eye injury

 A  B. megaterium culture in stationary phase will contain more     1     as nutrients become limited and therefore would demonstrate the best survival following exposure to UV radiation.

For antisepsis of skin, alcohol has advantages over soap because it is a     1     agent, does not require water, and does not need to be wiped off because it readily    2   .

1. killing

2. evaporates

Antiseptics, such as alcohol or iodine, are used on 

         1          . Disinfectants, such as bleach, are used on         2           . Most antiseptics (e.g. alcohol, iodine, peroxide) can be used as disinfectants, but most disinfectants are

  3   recommended for use     4    (e.g. bleach, 

Lysol, ammonia).

1. living tissues (e.g. skin)

2. inert surfaces (e.g. tabletops)

3. not

4. on skin

The size of the zone of inhibition is influenced by the        1         of the agent and its         2         in the agar.

1. molecular weight

2. rate of diffusion

Gram-negative bacteria have        1         that may limit penetration of chemicals that harm

         2         targets. This makes them more

        3       to being killed by those chemicals than the gram positive bacteria.

1. outer membrane

2. cytoplasmic

3. resistant

The advantages are        1      ,      2       ,

       3        ,       4      ,        5      ,       6      ,

      7      ,        8      ,       9        . The disadvantages are having to confirm questionable test results and multitest systems are designed for a particular medically important group of pathogens and are                   10                    .

1. ease of use

2. a single inoculation

3. self-containment

4. numerous tests

5. little media preparation

6. rapid results

7. reliability

8. uniformity

9. and easy interpretation

10. not available for other wide variety of microbes

The          1          is done to confirm that the unknown is a member of the family Enterobacteriaceae. These organisms test

         2           .

1. oxidase test 

2. negative for oxidase

All enterobacteria ferment glucose and produce

                1                  .

A “0” as the first number of the code indicates

       1       , i.e. not a glucose fermentor.  Gram-negative bacilli that do not      2       include Pseudomonas, Plesiomonas, Vibrio, Achromobacter, Moraxella, Pasteurella, Aeromonas, Alcaligenes, and Bordatella. These bacteria are likely oxidase      3      and should be identified with the       4       Tube II system (Exercsie 47).

1. non-enterobacteria

2. ferment glucose

3. positive

4. Oxi/Ferm

 The VP test is utilized when the 5-digit code provides        1         and the interpretation guide indicates that the VP test can

          2        .

1. more than one species

2. differentiate between the choices

 Contaminated or mixed cultures as well as

         1          may provide “nonsense” profiles that cannot be found.  

       1         in grape juice are fermented.  Fermentation produces       2      and       3      .

1. simple sugars

2. ethanol

3. carbon dioxide

Expansion of the balloon demonstrates production of       1       gas. The rubber stopper would trap gas, causing the formation of gas bubbles in 

the wine, and yield         2          or        3       .

1. carbon dioxide

2. sparkling wine

3. champagne

Acetobacter contamination would result in      1       production, which would impart a sour taste to the wine.  This change can be measured as a lowered

  2   of the wine. This process is performed in the production of       3       by some manufacturers.

1. acetic acid

2. pH

3. vinegar (dilute acetic acid)

Hydrogen sulfide production would impartan

        1         and           2        .

1. undesirable flavor

2. odor (rotten eggs)

Starches from the flour in bread dough are used for fermentation.      1     and      2     are produced.      3       causes the bread dough to rise before baking and      4      evaporates during baking. Lactobacillus sanfrancisco bacteria ferment sugars in the bread dough to produce       5      , which is responsible for the taste of sour dough bread.

1. Ethanol

2. Carbon Dioxide

3. Carbon dioxide gas

4. ethanol

5. lactic acid

Fermentation contributes to food preservation by creating       1      and       2       environment that inhibits the growth of many

       3       .  

1. an acidic 

2. reduces Oxygen

3. spoilage microbes