Microbio Lab Unit 3

Front 1

Bacteriostatic agent

Back 1

inhibit the growth of bacterial cells

Front 2

Bactericidal agent

Back 2

the complete destruction or elimination of all viable organisms from an object

Front 3

Sterilization

Back 3

kill bacterial cells

Front 4

Disinfection

Back 4

the removal of pathogenic organisms such that infection or disease is prevented, it does not require the removal of all living cells

Front 5

Incineration

Back 5

burns organisms and physically destroys them. This method is used for needles, inoculating wires, glassware, et

Front 6

Boiling

Back 6

at 100oC for 30 minutes kills everything except some endospores. To kill endospores and therefore sterilize the solution, very long or intermittent boiling is required.

Front 7

Autoclaving

Back 7

steam under pressure or pressure cooker) at 121oC for 15 minutes is (15lbs/in2 pressure) good for sterilizing almost anything, but heat-labile substances will be denatured or destroyed.

Front 8

Dry heat

Back 8

(hot air oven) at 160oC/2hours or 170oC/1hour is used for glassware, metal, and objects that won't melt

Front 9

Irradiation

Back 9

usually destroys or distorts nucleic acids. Ultraviolet light is usually used to sterilize the surfaces of objects, although x-rays and microwaves are possibly useful

Front 10

Filtration

Back 10

involves the physical exclusion and removal of all cells in a liquid or gas, especially important to sterilize solutions which would be denatured by heat (e.g., antibiotics, injectable drugs, vitamins, etc.)

Front 11

Chemical and gas toxic chemicals

Back 11

such as formaldehyde, glutaraldehyde, and ethylene oxide can kill all forms of life in a specialized gas chamber.

Front 12

Aerobic Organism

Back 12

use oxygen in their metabolic pathways

Front 13

Anaerobic Organism

Back 13

do not and often cannot survive in the presence of oxygen

Front 14

Facultative Organism

Back 14

can do with or without the criteria in question

Front 15

Obligate Organism

Back 15

required to meet the criteria in

Front 16

Psychrophile

Back 16

cold-loving bacteria. Their optimum growth temperature is between -5°C and 15°C. They are usually found in the Arctic and Antarctic regions and in streams fed by glaciers

Front 17

Mesophile

Back 17

bacteria that grow best at moderate temperatures. Their optimum growth temperature is between 25°C and 45°C. Most bacteria are mesophilic and include common soil bacteria and bacteria that live in and on the body

Front 18

Thermophile

Back 18

heat-loving bacteria. Their optimum growth temperature is between 45°C and 70°C and are commonly found in hot springs and in compost heaps

Front 19

Hyperthermophile

Back 19

bacteria that grow at very high temperatures. Their optimum growth temperature is between 70°C and 110°C. They are usually members of the Archaea and are found growing near hydrothermal vents at great depths in the ocean Which type of organisms did you use in this lab - L acidophilus and S. epidermidis are both mesophiles

Front 20

What type of inoculating instrument is used to transfer a bacterial culture to an agar deep?
A) Inoculating loop
B) Inoculating needle
C) Pipette tip
D) None of the above

Back 20

B) Inoculating needle

Front 21

Which type of media should be inoculated using a zig-zag motion across the surface of the media?
A) Broth
B) Agar deep
C) Agar slant
D) All of the above

Back 21

C) Agar slant

Front 22

After removing the cap from the culture tube it is recommended that the neck of the tube is briefly passed through the flame of the Bunsen burner. What is the purpose of this step?
A) Heating up the outer surface of the tube helps maintain optimal growth temperatures for the bacterial culture
B) This sterilizes the outer portion of the tube to prevent contamination from the surface
C) This creates an upward movement of airflow out of the tube that prevents contaminating organisms from traveling into the tube from the outside air
D) Heating up the outer surface of the tube helps loosen the bacteria from the media so they are easier to transfer

Back 22

B) This sterilizes the outer portion of the tube to prevent contamination from the surface

Front 23

After incubating your culture for two days, you suspect that your culture is contaminated. Which method(s) would help you determine if this is the case?
A) Microscopic examination of cellular morphology
B) Differential staining techniques, such as the Gram stain
C) Subculture onto an agar plate
D) All of the above

Back 23

D) All of the above

Front 24

Most bacteria divide by which method?
A) meiosis
B) fusion of gametes
C) mitosis
D) binary fission

Back 24

D) binary fission

Front 25

Which of the following is NOT a step in bacterial cell division?
A) splitting apart of two new daughter cells
B) disappearance of nuclear envelope
C) replication of the genetic material
D) cell elongation

Back 25

B) disappearance of nuclear envelope

Front 26

Which of the following represent a true statement about the resulting new daughter cells?
A) Four new daughter cells result from one parental cell.
B) They are unable to divide.
C) They are genetically identical to the parent.
D) They share characteristics of both parental cells.

Back 26

C) They are genetically identical to the parent.

Front 27

Which of the following characteristics is a hallmark of bacterial growth?
A) Since the number of bacterial cells double after each round of replication, the number of cells rapidly increases.
B) All daughter cells produced will be smaller than the parent.
C) After several rounds of division, the genetic diversity of the bacterial population will be very diverse.
D) Bacterial growth is fast because all bacterial cells undergo mitosis.

Back 27

A) Since the number of bacterial cells double after each round of replication, the number of cells rapidly increases.