Lesson 2.1 Phenetic and Phenotypic Classification

Question 1

This system suceeded in bringing order to biological diversity and clarify the morphological structures .

Answer 1

Phenetic or Phenotypic classification

Question 2

Refers to the size and shape of the bacteria

Answer 2

Morphology

Question 3

What are the common shapes of bacteria

Answer 3

Cocci- spherical
Bacili- rod
Spirilla- spiral
Vibrios- comma
Spirochaetes- corkscrew-shaped

Question 4

Staining technique that is used to distinguish bacteria based on their cell wall structure

Answer 4

Gram staining

Question 5

What are the two outcomes of gram staning

Answer 5

Gram positive- thick peptidoglycan would stain purple
Gram-negative- thin peptidoglycan, would stain pink. have outer membrane

Question 6

What are the process of gram staining

Answer 6

Crystal violet - 60 sec
Iodine- 60 sec
Ethyl Alcohol - 5-10 sec
Safranin - 45 sec

Question 7

Function of cell wall

Answer 7

protect against cell lysis and confer shape and rigidity

Question 8

____ and ____ are antibiotics that targets the bacterial cell wall synthesis.

Answer 8

Penicillin and cephalosporin

Question 9

What is the repeating unit of peptidoglycan is called _______.

In some bacteria, other amino acids are present such as _______

Answer 9

glycan tetrapeptide

Cross-linkers

Question 10

It is a rigid polysaccharide and confers structural strength on the cell

Answer 10

Peptidoglycan

Question 11

Alternating repeats of two modified
glucose residues

Answer 11

N-acetylglucosamine (first hydroxide)

N-acetylmuramic acid (fourth hydroxide)

Question 12

Difference in peptidoglycan between E.coli and Staphylococcus aureus

Answer 12

Gram negative and E.coli: no interbridge
S.aureus:

Question 13

Which bond confers strength on peptidoglycan in X-direction____
and ____ in Y-direction

Answer 13

X- glycosidic bond
Y- peptide bond

Question 14

Gram-negative bacteria cross link
Gram- positive bacteria cross link

Answer 14

Gram-negative: DAP Diaminopimelic acid from the glycan strand to another carbonyl of d-alanine to the adjacent glycan

Gram-positive: inter bridge, five glycines

Question 15

What are some components found only in gram-positive

Answer 15

Teichoic acid and lipoteichoic acids

Question 16

The structure of teichoic acid is consists of repeating ____ unit

Answer 16

ribitol

Question 17

Gram-positive bacteria has ___ of peptidoglycan

Answer 17

90%

Question 18

Gram-positive bacteria can form ____ about ____ wide consisting of several glycan strands

Answer 18

cables, 50 nm

Question 19

______ have proteins that are
involved with the peptidoglycan along with the cytoplasmic membrane

Answer 19

Gram-positive

Question 20

are composed of glycerol
phosphate or ribitol phosphate with
attached molecules of glucose or
d-alanine (or both).

Answer 20

Teichoic acid

Question 21

Lipoteichoic acids are anchored in _________
Teichoic acids are covalently bonded to _________

Answer 21

Lipoteichoic acids are anchored in the cell membrane via glycolipids

Teichoic acid is bonded to membrane lipids and not peptidoglycan

Question 22

Location of teichoic and lipoteichoic acid

Answer 22

teichoic- external
lipoteichoic- cytoplasmic membrane

Question 23

The stucture found only in gram-negative bacteria

Answer 23

LPS- the outer membrane

Question 24

The second lipid bilayer, containing lipid
and polysaccharide, is linked to form this complex

Answer 24

lipopolysaccharide

Question 25

It acts as an effective barrier against many substances such as antibiotics

Answer 25

lipopolysaccharide

Question 26

The important biological activity of LPS is ____ and found in the following:

Answer 26

toxicity; endotoxins
Salmonella, shigella and e.coli

Question 27

LPS is composed of two polysaccharides

Answer 27

Core polysaccharide
O-specific polysaccharide
Lipid A

Question 28

Which structure of the LPS contains endotoxin complex

Answer 28

Lipid A

Question 29

Composition of LPS that has
components present in sugar form. It possesses a chain of KDO that stands as keto deoxy octanoate relating to Lipid A

Answer 29

core polysaccharide

Question 30

Another component of LPS that anchors the outer membrane and peptidoglycan

Answer 30

Braun lipoprotein