Bacterial Structure and Function

Question 1

• It is formed when large amounts of EXTRACELLULAR POLYMERIC SUBSTANCES forms a condensed, well-defined layer closely surrounding the cell.
• Thicker, gummy consistency
• Prominently sticky (mucoid) character.

Answer 1

Capsule

Question 2

• The EPS forms a LOOSE MESHWORK of fibrils extending outward from the cell.
• Slimy, gelatinous material.
• produced by the plasma membrane.

Answer 2

Glycocalyx

Question 3

• The EPS appears to be TOTALLY DETACHED from the cell but in cell may be entrapped.

Answer 3

Slime Layer

Question 4

A polymers of glucose and fructose that can be synthesized by the several strains of Streptococci

Answer 4

Polysaccharide

Question 5

• A polysaccharide that may be complexed2 with various proteins.
• Some polypeptides occupies spaces produced by the polysaccharide frameworks.

Answer 5

Polysaccharide complexes

Question 5

It produces capsules that are mixed polymers of glucose, galactose, and glucuronic acid

Answer 5

Streptococcus pneumonia

Question 6

• Capsule that may consist of polypeptides of one or two amino acids.

Answer 6

Polypeptides

Question 7

An organism that produces a capsule consisting of polyglutamic acid

Answer 7

Bacillus anthracis

Question 8

• Capsules, glycocalyx, and slime layer are synthesized by..

Answer 8

An enzyme located at the surface of a bacterial cell wall

Question 9

• Protects cell from phagocytosis, UNLESS they are coated with anti-capsular antibiotics.
• Prevents some viruses to attach at the bacterial cell walls (bacteriophage)
• Glycocalyx plays a major role in the adherence of bacteria to the surfaces in their environment.

Answer 9

Function of capsule

Question 10

• The degree to which some organisms are able to cause disease.

Answer 10

Virulence

Question 11

• Are not essential in terms of life of the bacteria, but makes survival longer due to its protective activity.

Answer 11

Capsule

Question 12

• Stains used to visualize the capsules.

Answer 12

• India Ink
• Nigrosin

Question 12

• Can be source for vaccines

Question 13

Smooth and Mucoid culture appearance

Answer 13

Capsulated bacteria

Question 14

Rough

Answer 14

Non-capsulated

Question 15

To study the morphological shape, size, and arrangement of the bacterial cells that is difficult to stain

Answer 15

Purpose of negative staining

Question 16

Used to stain cells that are too delicate to be heat fixed.

Answer 16

Negative staining

Question 17

It is used to prepare sample for the electron microscopy

Answer 17

Negative staining

Question 18

Used to view viruses, bacteria, flagella, biological membrane structures and protein aggregated which has low scattering power

Answer 18

Negative staining

Question 19

It’s principle requires an acidic dye

Answer 19

Negative staining

Question 20

Are acidic stain

Answer 20

• Nigrosin
• India Ink
• Nigrosin 100gm/L, Formalin 5ml/L in water

Question 21

This means that the stain readily gives up a hydrogen ion (proton) and the chromophore of the dye becomes negatively charged.

Answer 21

Principle of negative staining

Question 22

• Found beneath the capsule, lying between the cytoplasmic membrane and the capsule

Answer 22

Cell wall

Question 23

Major structural component of the bacterial cell

Answer 23

Cell wall

Question 24

Rigid and non-elastic but highly DUCTILE, high TENSILE strength structure

Answer 24

Cell wall

Question 25

Contains pores 1nm in diameter which allows diffusion of metabolites to the plasma membrane

Answer 25

Cell wall

Question 26

Also known as murcin and mucopeptide , which is a layer of high tensile strength.

Answer 26

Peptidoglycan

Question 27

It allows the differentiation of 2 distinct types of bacteria

Answer 27

Peptidoglycan

Question 28

The 2 distinct differentiation of bacteria

Answer 28

Gram positive and Gram negative

Question 29

The outer most component of the cell wall of a bacterium, and can be found in both gram positive and gram negative bacteria

Answer 29

Slime layer

Question 30

• A lattice made up of protein or glycoprotein molecules.
• Believed to protect the cell wall from
  1. Wall degrading enzymes
  2. Invasion by predatory bacteria
  3. Bacteriphages

Answer 30

Slime layer

Question 31

• A complex polymer consisting of 3 parts
  1. Backbone - has alternating sugars
  2. Set of identical tetrapeptide
  3. Set of identical tetrapeptide cross bridges
• A backbone for all bacterial species, however the the tetrapeptide side chain and peptide cross bridges varies from species to species

Answer 31

Peptidoglycan layer

Question 32

Position 1 : L-alanine
Position 2 : D-glutamate
Position 4 : D-alanine
Position 3 : most variable

Answer 32

The common tetrapeptide chain

Question 33

An acid that carries in a gram negative bacteria

Answer 33

Diaminopimelic acid

Question 34

As many as 40 sheets of sheets of peptidoglycan comprising up to 50-90% of the cell wall materials (10-20% of the total dry weight of the cell)

Answer 34

Gram Positive Bacteria

Question 35

Only 1-2% comprising 5-10% of the wall material

Answer 35

Gram Negative Bacteria

Question 36

• A water soluble polymer, containing ribitol or glycerol residues joined through PHOSPHODIETHER LINKAGES
• Believed to be covalently linked to sugar

Answer 36

Teichoic acid

Question 37

Composed of …
- Neutral sugars, mannose, arabinose, and rhamnose.
- Acidic sugar, glucoronic acid and mannuronic acid.

Answer 37

Polysaccharide