Microbial Growth Pt.2

Question 1

These are acid-vast, which prevents dessication

Answer 1

Mycobacterium

Question 2

These microbes are resistant to dessication because they are non-living

Answer 2

Viruses

Question 3

As water leaves the cell, plasma membrane shrinks away from the cell wall. Cell may not die, but usually stops growing (known as wilting in plants)

Answer 3

Plasmolysis

Question 4

What are the three types of radiation that kill microbes

Answer 4

Ionizing Radiation, Ultraviolet light (Non-ionizing Radiation) and Microwave Radiation

Question 5

Gamma rays, X-rays, electron beams or higher energy rays; Have short radiations; Used to sterilize disposable medical supplies

Answer 5

Ionizing Radiation

Question 6

What is a disadvantage of using Ionizing Radiation

Answer 6

It penetrates human tissues; May cause genetic mutations

Question 7

Damages DNA by producing thymine dimers which cause mutation; Their wavelengths are no longer than 1 nanometer; Used to disinfect operating rooms, nurseries and cafeterias

Answer 7

Ultraviolet light (Non-ionizing Radiation)

Question 8

What is a disadvantage of using Ultraviolet light

Answer 8

It damages skin, eyes; Does not penetrate paper, glass or cloth

Question 9

Wavelength ranges from 1 millimeter to 1 meter; Heat is absorbed by water molecules; may kill vegetative cells in most foods; Bacterial endospores are not damaged by this type of radiation; Solid foods are unevenly penetrated b/c water is not evenly distributed in solid foods

Answer 9

Microwave Radiation

Question 10

Do not sterilize, but reduce microbial population

Answer 10

Disinfectant

Question 11

Name some qualities of disinfectant

Answer 11

Does not stain the object being disinfected; Acts rapidly; Attacks a wide range of microbes; Readily mixes with water; Does not damage body tissue

Question 12

What are the different types of disinfectants

Answer 12

Phenols and Phenolics, Halogens- Iodine and Chlorine, Alcohols, Aldehydes, Peroxygens (Oxidizing Agents)

Question 13

Effective against gram-positive staphylococci and streptococci

Answer 13

Biphenols

Question 14

Destroys plasma membranes and denature proteins; Advantages: Stable, persist for long times after applied, and remain active in the presence of organic compounds.

Answer 14

Phenols

Question 15

Compounds with iodine that are slow releasing, takes several minutes to act. Used as skin antiseptic in surgery; Not effective against bacterial endospores.

Answer 15

Iodophors

Question 16

When mixed in water forms hypochlorous acid:
Cl2 + H2O ——> H+ + Cl- + HOCl ; Used to disinfect drinking water, pools, and sewage; easily inactivated by organic materials

Answer 16

Chlorine

Question 17

Kill bacteria, fungi, but not endospores or naked viruses; Act by denaturing proteins and disrupting cell membranes; Used to mechanically wipe microbes off skin before injections or blood drawing

Answer 17

Alcohol

Question 18

Drinking alcohol

Answer 18

Ethanol

Question 19

Rubbing alcohol

Answer 19

Isopropanol

Question 20

Irritates mucous membranes, strong odor; Excellent disinfectant

Answer 20

Formaldehyde Gas

Question 21

Used as an antiseptic; Not good for open wounds because quickly broken
down by catalase present in human cells

Answer 21

Hydrogen Peroxide

Question 22

Designed to suppress growth of unwanted bacteria and encourage growth of desired microbes.

Answer 22

Selective Medium

Question 23

Designed to make it easier to distinguish colonies of a desired organism from other colonies growing on same medium plate

Answer 23

Differential Medium

Question 24

The time required for bacterial population to double through binary fission. Generation times can range from about 10 minutes to several days

Answer 24

Generation Time

Question 25

Time period from the division of a cell until that cell divides again

Answer 25

Cell Cycle

Question 26

Two individuals who introduced the concept of microbial control

Answer 26

Ignatz Semmelweis and Joseph Lister