Introduction to Microbiology

Question 1

What are microorganisms ?

Answer 1

creatures that are too small to be seen with the naked eye
- includes both prokaryotes and eukaryotes
- range in size

Question 2

What is an example of the smallest microorganism ?

Answer 2

viruses

Question 3

What is an example of the largest microorganisms ?

Answer 3

parasites and fungi

Question 4

What are prokaryotes ?

Answer 4

means pre-nucleus
- no membrane bound organelles
- have no true nucleus
- Ex.) bacteria

Question 5

What are Eukaryotes ?

Answer 5

means “true-nucleus”
- possess membrane bound organelles
- Ex.) parasites, amoeba, paramecium, man

Question 6

Are viruses microorganisms as well ?

Answer 6

yes
- consist of protein and nucleic acid
- viroids and prions as well

Question 7

What is the function of the Flagellum ?

Answer 7

provides some motility
- Protus Miriabilis is an example of a bacteria that has high motility because of the flagellum

Question 8

What is the function of the Fimbria ?

Answer 8

helps bacteria stick to each other and surfaces
- small bristle like fibers on surface

Question 9

What is the function of the Pillus ?

Answer 9

for sexual reproduction through conjugation
- elongated, rigid tubular structure

Question 10

What is conjugation ?

Answer 10

where DNA is transferred from one cell to another
- bacteria become resistant to drugs through this

Question 11

What is the function of the cell envelope ?

Answer 11

protects the cell
- composed of the glycocalyx, cell wall, and cell membrane

Question 12

What is the function of the cell membrane ?

Answer 12

controls in/out transport of substances
- via proteins in membrane
- right on the surface of the cell

Question 13

What is the function of the cell wall ?

Answer 13

provides rigidity, strength, and protection
- site of action of some of the most effective antibiotics
- in many species causes symptoms of disease

Question 14

What is the function of the glycocalyx (external layer) ?

Answer 14

helps protect cell, and helps cell adhere to its environment
- consists of the slime layer and capsule

Question 15

What is the function of the slime layer ?

Answer 15

aids bacteria in colonizing surfaces (attaches to surface)
- not bound to cell
- lets bacteria slide along surface

Question 16

What is the function of the capsule ?

Answer 16

makes bacteria more virulent and protects bacteria from phagocytosis by the cells of the host
- protects the bacteria from WBC which can easily destroy the bacteria without the capsule
- bound to cell
- thick gummy consistency
- prevents bacteria from drying out
- aids in attachment to surfaces for colonization

Question 17

What is the purpose of phagocytosis ?

Answer 17

cells engulfs and destroy microorganisms
- way for the immune system to destroy bacteria

Question 18

What is the function of Protoplasm ?

Answer 18

site of biochemical and synthetic activity
- contains: 70-80% H2O, sugars, amino acids, salts, enzymes, chromatin body, ribosomes, mesosomes, granules

Question 19

What is the function of the Chromatin Body ?

Answer 19

DNA aggregates in dense area called the nucleoid
- bacterial chromosome in prokaryotes
- don’t have a true nucleus
- where most genetic material is found

Question 20

What is the purpose of the Plasmid ?

Answer 20

circular piece of genetic material in prokaryotes that is outside of the chromosome
- provides resistance to drugs
- Advantage of man: use this in genetic engineering techniques
- not every bacterium has one

Question 21

What is the function of the ribosomes ?

Answer 21

used in protein synthesis

Question 22

What is the function of Inclusion Granules ?

Answer 22

concentrate nutrients inside the cells, storage. & are not permanent
- where bacteria will store excess material when not needed (temporary)

Question 23

Do viruses have DNA or RNA ?

Answer 23

their genetic material can be either
- but never both

Question 24

Do viruses contain a true cell ?

Answer 24

no
- they do have a protein coat

Question 25

What are viroids ?

Answer 25

infectious genetic material

Question 26

What are prions ?

Answer 26

infectious proteins that infect others and makes them infectious as well
- always fatal
- no cure
- Ex.) Mad Cow Disease

Question 27

Where is the genetic material of a prokaryote ?

Answer 27

in the nucleoid
- only about 1 chromosome

Question 28

Does every bacteria has a pilus ?

Answer 28

no

Question 29

How does a donor bacteria exchange it’s genetic material ?

Answer 29

through the donor’s pilus

Question 30

What genetic material can be exchanged by the pilus ?

Answer 30

the plasmid (the circular genetic material in prokaryotes)
- not the chromosomes

Question 31

Why can conjugation cause bacteria to become resistant to drugs ?

Answer 31

the plasmid tend to have factors that make bacteria more resistant

Question 32

What is the outermost later of the bacteria ?

Answer 32

glycocalyx

Question 33

What is the innermost layer of the bacteria ?

Answer 33

cell membrane

Question 34

What gives the bacteria cell its shape ?

Answer 34

cell wall

Question 35

What is the difference between the cell wall in a Gram + and - bacteria ?

Answer 35

the cell wall is way thicker in Gram +

Question 36

What makes up the glycocalyx ?

Answer 36

coating of macromolecules

Question 37

What makes up the slime layer ?

Answer 37

loose soluble polysaccharides

Question 38

What in the bacteria can cause it to be more virulent ?

Answer 38

the capsule

Question 39

What is chemotaxis ?

Answer 39

chemical attraction of phagocyte to the bacteria
- the way the phagocyte looks for the bacteria they are trying to destroy

Question 40

What is adherence ?

Answer 40

attachment of phagocyte plasma membranes to microorganisms

Question 41

Where in the cell is most antibiotics most effective ?

Answer 41

cell wall

Question 42

What is the chemical structure of the cell wall ?

Answer 42

peptidoglycan
- what gives the cell wall that structure
- only found in bacteria
- similar to chitin (which gives lobster insects that crunch)