Microbiology Ch 4

Question 1

Name characteristics of Prokaryotes

Answer 1

1) DNA is not enclosed in a membrane & is usually a single, circularly arranged chromosome
2) DNA is not associated with histones
3) Lack membrane enclosed organelles
4) Cell wall contain peptidoglycan
5) Divide through binary fission

Question 2

Name Characteristics of Eukaryotes

Answer 2

1) DNA is found in cell’s nucleus and is found in multiple chromosomes
2) DNA is associated with histones
3) Have membrane enclosed organelles
4) Cell walls are chemically simple
5) Cells divide through mitosis

Question 3

Histones

Answer 3

chromosomal proteins found in Eukaryotes

Question 4

Binary Fission

Answer 4

DNA is copied and cell splits into two cells

involves fewer structures and processes than eukaryotic cell division

Question 5

Mitosis

Answer 5

chromosomes replicate and identical set is distributed into each of two nuclei
*the two cells are identical to each other

Question 6

Monomorphic

Answer 6

maintain a single shape

Question 7

Pleomorphic

Answer 7

having many shapes

Question 8

Name Cocci Arrangements

Answer 8

1) diplo= in pairs
2) strepto= in chains
3) tetrads= divided in two plains and remain in groups of four
4) sarcinae= divide in three plaines and remain in cubelike group of eight
5) staphylo=clusters

Question 9

Name Bacilli Arrangements

Answer 9

1) single
2) diplo= in pairs
3) strepto=in chains
* coccobacilli-special case that look oval and rod-like

Question 10

Special Bacteria Shapes

Answer 10

1) Spiral bacteria which includes: vibrio, spirilla(flagella), spirochete (axial appendages)
2) Also star shaped and rectangular bacteria

Question 11

Glycocalyx

Answer 11

“sugar coat”

A general term to describe substances that surround the cell, protects the bacteria from phagocytosis

Question 12

Capsule

Answer 12

• glycocalyx that is firmly attached to the cell wall
• presence can be determined thru gram staining
• most important in determining bacterial virulence

Question 13

Flagella

Answer 13

-long filamentous appendages that propel bacteria

Question 14

Motility

Answer 14

the ability of an organism to move by itself

Question 15

Arrangements of Bacterial Flagella

Answer 15

1) atrichous- lacking flagella
2) peritrichous- flagella at multiple sites
3) polar- flagella at polar ends
a. monotrichous- flagella at one pole
b. lophotrichous- tuft of flagella from one pole
c. amphitrichous- flagella at both poles

Question 16

Taxis

Answer 16

movement towards or away from stimuli

e.g. phototaxis and chemotaxis

Question 17

Serovars

Answer 17

variations within a species of gram negative bacteria

Question 18

Endoflagella

Answer 18

aka axial filaments

• bundles of fibrils that arise at the ends of the cell beneath an outer sheath and spiral around the cell
• rotation causes the cell to move

Question 19

Fimbriae

Answer 19

allow bacteria to adhere to surfaces

Question 20

Pili

Answer 20

facilitate DNA transfer from one cell to another

*longer than fimbriae and only 1-2 per cell

Question 21

Bacterial Cell Wall

Answer 21

• made of peptidoglycan which is a polymer of disaccharide (NAM and NAG)
• antibiotics interfere with peptidoglycan synthesis

Question 22

Lysis

Answer 22

destruction caused by rupture of plasma membrane and loss of cytoplasm

Question 23

Gram Positive Bacteria

Answer 23

• cell wall consists of many layers of peptidoglycan

- cell wall contain “teichoic acid” which consists of an alcohol (e.g. glycerol or ribitol) and phosphate

Question 24

Gram Negative Bacteria

Answer 24

• cell wall consists of a thin layer of peptidoglycan and an outer membrane
• peptidoglycan is bonded to lipoproteins in the outer membrane and is in the periplasm

Question 25

Teichoic acid

Answer 25

• may regulate the movement of cations

- polysaccharides provide antigenic variation

Question 26

Wall teichoic acid is linked to

Answer 26

peptidoglycan

Question 27

Lipoteichoic acid is linked to

Answer 27

the plasma membrane

Question 28

Outer membrane of gram negative cells walls

Answer 28

consists of lipopolysaccharides, lipoproteins, and phospholipids
*important structure because is offers from protection against phagocytes, complement proteins, and antibiotics

Question 29

Atypical Cell Walls

Answer 29

1) mycoplasma- lack cell walls, have lipids called sterols in plasma membrane that may protect them from lysis
2) archaea- wall-less or have walls of pseudomurein (lack NAM and d-amino acids)

Question 30

Staining

Answer 30

coloring a microbe with dye that emphasizes certain structures
-stain consists of a cation and anion

Question 31

Smear

Answer 31

• a thin film of a solution of microbes on a slide

- usually fixed to attach the microbes to the slide and to kill the microbes

Question 32

Negative Staining

Answer 32

staining the background instead of the cell

Question 33

Chromophore

Answer 33

a colored ion

• in basic dyes=cation
• in acidic dyes=anion

Question 34

Simple Stains

Answer 34

• use of a single basic dye

- purpose: highlight the entire organism

Question 35

Mordant

Answer 35

a chemical additive that intensifies staining

Question 36

Differential Stains

Answer 36

used to distinguish between bacteria

-includes acid fast and gram stain

Question 37

Gram Stain

Answer 37

-classifies bacteria into gram positive and gram negative

Question 38

Acid Fast Stain

Answer 38

binds strongly only to bacteria that have a waxy material in their cells

Question 39

Special Stains

Answer 39

used to color and isolate specific parts

Question 40

Damage to cells walls

Answer 40

1) lysozyme

2) results in protoplasts or spheroplasts