Microorganisms & Medical Microbiology

Question 1

bacteria

Answer 1

• prokaryotes: one-celled organisms w/ no nucleus or membrane-bound organelles
• ribosomes and genetic material are free floating in the cytoplasm

Question 2

coccus

Answer 2

spherical shaped bacteria the can join together to make:

• diplococci (2 bacteria together)
• strepococci (chains)
• staphylococci (clusters)

Question 3

bacillus

Answer 3

rod-shaped bacteria that can join together to form diplobacilli, streptobacilli (chains), etc

Question 4

spirillum

Answer 4

spiral-shaped bacteria

Question 5

Gram staining

Answer 5

• application of crystal violet and iodine, which create a complex that adheres to the outermost layer of bacteria
• can help determine what antibiotic will be effective

Question 6

Gram positive

Answer 6

• outermost layer: thick peptidoglycan cell wall

- purple color when stained b/c the bacteria cell wall is dehydrated and traps stain inside

Question 7

Gram negative

Answer 7

• outermost layer: thin and composed of lipids
• outer membrane is removed, second red dye (safranin) is used
• lighter, pink color

Question 8

bacteria reproduce:

Answer 8

• asexually
• transformation (DNA from environment)
• transduction (injected by bacteriophage)
• conjugation (DNA transfer from F+)

Question 9

viruses

Answer 9

• cannot reproduce without a host and are not considered living particles
• genetic material held in a protein capsid
• lack most organelles b/c they do not reproduce or maintain cellular functions

Question 10

lytic cell

Answer 10

• when a virus infects a cell
• induces cell to reproduce viral DNA instead of its own
• eventually the cell will lyse and release viral DNA into he matrix, can infect a new cell

Question 11

virulent

Answer 11

-viruses that replicate by the lytic cycle, killing their host cell

Question 12

lawn

Answer 12

a plated culture

Question 13

lysogenic cycle

Answer 13

• bacteriophage does not lyse its host, and become integrated into the bacterial genome as a provirus, lying dormant for awhile
• ex: HIV
• environmental cues can cause it to enter lytic cycle

Question 14

latent infection

Answer 14

virus does not spread as quickly during the lysogenic phase

Question 15

superinfection

Answer 15

-cells containing proviruses are normally resistant to further infection by similar phages

Question 16

fungi

Answer 16

• heterotrophic, eukaryotic organisms, most of their organelles mimic human cells
• have cells walls that contain chitin

Question 17

fungi reproduce:

Answer 17

• sexually: diploid cells, undergo meiosis to create 4 haploid spores
• asexually (fission): one organism divides into 2 daughter cells

Question 18

spore production

Answer 18

-spores are more resilient to hostile conditions so it occurs when conditions are not favorable

Question 19

parasites

Answer 19

-organisms that live off of and harm a host that receives no benefit from it

Question 20

helminths

Answer 20

• parasitic worms (tapeworms, roundworms)

- injested via contaminated food or water

Question 21

protozoa

Answer 21

-unicellular eukaryotes that have many different features, many cause diseases

Question 22

nitrogen cycle

Answer 22

• plants produce waste and decompose, releasing ammonia and ammonium ions into the environment
• bacteria then break them down into nitrate and nitrite which can replenish plants or be converted to atmospheric nitrogen

Question 23

carbon cycle

Answer 23

-microbes contribute to the transfer of carbon molecules thru the cycle via fermentation, catabolism, and anabolism

Question 24

photosynthesis

Answer 24

-sunlight, water, and CO2 are utilized by chlorophyll cells are utilized to produce sugars, which serve as an energy source

Question 25

transmission

Answer 25

-spread of disease from one host to another

Question 26

direct contact

Answer 26

touching the contaminated person and spreading the disease thru physical contact

Question 27

indirect contact

Answer 27

transmission via droplets, vectors, soil, food, or water

Question 28

sterilization

Answer 28

• kills all pathogens

- extreme heat, radiation, or ethylene gas

Question 29

disinfection

Answer 29

• kills some pathogens but not all microbes present

- microwaves, pasteurization, or alcohols

Question 30

antiseptics

Answer 30

-kills pathogens on living tissue

Question 31

active immunity

Answer 31

-experiencing an infection once gives the host a natural immunity and the host does not experience the disease as long as the memory cells remain

Question 32

vaccine

Answer 32

• when a virus is involved, natural process may not be useful
• an attenuated (weakened) pathogen is injected that forms memory cells but not the disease

Question 33

passive immunity

Answer 33

-immunity acquired thru direct transmission of antibodies from one source to another

Question 34

antibacterials

Answer 34

-work on certain types of bacteria because of the structure of the bacteria or mechanism of action

Question 35

bactericidal agents

Answer 35

-kill bacteria

Question 36

bacteriostatic agents

Answer 36

• stop bacteria from dividing

- patient needs to have a functional immune system

Question 37

resistance

Answer 37

-some bacteria have developed this to certain types of antimicrobials and are no longer effective

Question 38

antivirals

Answer 38

• viruses are more difficult to treat because they are neither cells nor alive
• to destroy a virus you usually have to destroy the host cell it is in
• prevention of viruses is much more effective

Question 39

antifungals

Answer 39

-many work by destroying cell walls to eliminate the infection and maintain the host cells

Question 40

antiparasitics

Answer 40

-number of different mechanisms of action, but they destroy the parasite without damage to the host

Question 41

broad-spectrum antimicrobial

Answer 41

• one that treats many different species of a microbe

- hospitals want to use antimicrobials specific to the microbe