Basic Cahracteristics Of Bacteria

Question 1

Bacterium

Answer 1

Single cell prokaryotic organism, small, has cell wall, lacks membrane bound nucleus, ribosomes present, no other organelles, active metabolism, and multiply at rapid rate.

Question 2

Common apparatus for observing bacteria

Answer 2

Light microscope

Question 3

Types of bacteria

Answer 3

Coccus
Bacillus
Spirochete 
Vibrio
Mycoplasma

Question 4

Coccus

Answer 4

Spherical
Size 1 micrometer
Types: diplococcus, streptococcus, staphylococcus, tetrad, sarcina.

Question 5

Diplococcus

Answer 5

Divides in one plane and arranges in pairs.

Eg: neisseria meningitides, streptococcus pneumoniae.

Question 6

Streptococcus

Answer 6

Divides along one plane and arranges like a chain.

Eg: beta-haemolytic streptococci.

Question 7

Staphylococcus

Answer 7

Divides along multi-planes and arranges as grape like clusters.

Question 8

Tetrad

Answer 8

Group of four cells formed from a coccus, divides along two perpendicular planes and arranges like a square.

Question 9

Sarcina

Answer 9

Individual coccus undergoes division along three perpendicular partitions, so that multiplication takes place in three directions, giving groups of eight cells.

Question 10

Bacillus

Answer 10

Distinct sizes, straight rod shaped with blunt ends, some pleomorphic, types: streptobacillus, coccobacilli, fusiform bacilli, corynebacteria, bifidobacteria, & mycobacteria.

Question 11

Streptobacillus

Answer 11

Arranges like a chain

Question 12

Coccobacilli

Answer 12

Very short rods that can be mistaken for cocci.

Question 13

Fusiform bacilli

Answer 13

Bacilli with tapered ends

Question 14

Corynebacteria

Answer 14

Bacilli with inflated club-shaped ends

Question 15

Bifidobacteria

Answer 15

Bacilli possessing bifurcated ends

Question 16

Mycobacterium

Answer 16

Bacilli

Have branching tendency during growth

Question 17

Vibrio

Answer 17

Comma shaped bacteria

Question 18

Spirillum

Answer 18

Spiral shaped bacteria

Eg: helicobacterium.

Question 19

Structure of bacteria

Answer 19

Basic structure: cell wall, cell membrane, cytoplasm, & nucleoid.
Specific structure: capsule, flagellum, pilus, & spore.

Question 20

Cell wall of bacteria

Answer 20

Gram + cell wall consists of peptidoglycan, teichoic acid.

Gram - cell wall consists of peptidoglycan, outer membrane.

Question 21

Peptidoglycan layer of gram +

Answer 21

backbone (N-acetylglucosamine & N-acetylmuramic acid), set of tetra peptide side chains (a. L-alanine, b. D-glutamate, c. L-lysine, d. L-lysine) & set of pentapeptide cross bridges (link between c. and d. of an adjacent side chain).

Question 22

Peptidoglycan of gram-

Answer 22

Backbone, a set of tetrapeptide side chains ( A. alanine, E. glutamic acid, DAP. diaminopimelic acid; DAP links with terminal alanine of a second side chain directly).

Question 23

Gram positive cell wall

Answer 23

Cell membrane 7.5 nm,
Cell wall 20~80nm, consisting of peptidoglycan, wall teichoic acid & membrane teichoic acid. (Teichoic acid & teichuronic acid)

Special proteins include alpha-protein of staphylococcus & M-protein of streptococcus.

Question 24

Gram negative cell wall

Answer 24

Consists of:
Inner membrane;
Periplasm containing MDO (membrane derived oligosaccharides), peptidoglycan;
(lipoprotein cross linking by a peptide link to the periplasm and by non-covalent link with outer membrane)
Outer membrane containing lipoprotein, lipopolysaccharide which consists of lipid A, core polysaccharide, & specific polysaccharide/ O antigen.

Question 25

Gram + cell wall contains

Answer 25

Teichoic acid and teichuronic acid

Question 26

Functions of lipoprotein

Answer 26

Stabilise the outer membrane, | Anchor it to peptidoglycan layer.

Question 27

Endotoxin of gram negative bacteria

Answer 27

LPS i.e. Lipopolysaccharide

Question 28

Is responsible for endotoxin activity of LPS

Answer 28

Lipid A

Question 29

Effects of endotoxin produced by different bacteria are similar because

Answer 29

Basic structure of lipid A is identical for all gram negative bacteria

Question 30

Beta- hydroxymyristic acid

Answer 30

Present uniquely in lipid A of gram-

Question 31

2-keto-3-deoxyoctanoic acid KDO

Answer 31

Present in core polysaccharide of gram -, covalently linked to lipid A.

Question 32

Represents a major surface antigen of gram - bacterial cell

Answer 32

O antigen

Question 33

Antigenic specificity conferred by

Answer 33

``` Category Location Arrangement Configuration - of the sugars in repeating units. ```

Question 34

On surface of cell wall may induce immune responses

Answer 34

Epitopes

Question 35

Important surface antigen of gram - bacteria

Answer 35

Teichoic acid

Question 36

Effective barrier for killing substances such as digestive enzymes, bile salts, & antibiotics in gram -

Answer 36

Outer membrane

Question 37

Important virulence factor of gram - bacteria

Answer 37

LPS