Bacteria, structure, growth and taxonomy

Question 1

Bacteria within context of other microorganisms

Answer 1

Monera (single cells)—–> Prokaryote—–> Archeobacteria and Eubacteria

Question 2

What determines whether a bacterium is Gram+ve or Gram -ve

Answer 2

Outer membrane

Question 3

What is the flagellum linked to and what does this do

Answer 3

Cell membrane- allows it to get ATP for movement from the electron transport chain

Question 4

What do the pili do

Answer 4

Adhesive so bacteria can stick to epithelial cells

Question 5

In bacteria and eukaryotes, which has nucleic acid

Answer 5

both

Question 6

In bact and eukaryotes which has a structured nucleus

Answer 6

eukaryotes

Question 7

In bacteria and eukaryotes which has mitochondria

Answer 7

eukaryotes

Question 8

In bacteria and eukaryotes which has ribosomes

Answer 8

both

Question 9

IN bacteria and eukaryotes which has a cell membrane

Answer 9

both

Question 10

In bacteria and eukaryotes which has a rigid cell wall

Answer 10

bacteria

Question 11

In bacteria and eukaryotes which has a mesosome

Answer 11

bacteria

Question 12

In bacteria and eukaryotes which has ER/golgi

Answer 12

euk

Question 13

Whats the taxonomical hierarchy

Answer 13

kingdom
division
class
family
genus
species

Question 14

How can you classify bacteria based on its phenotype

Answer 14

• Morphology (macroscopic and microscopic)
• biotyping (dentification of different bacteria types based on reaction to biochemical tests.
• serotyping (separate groups within a species of microorganisms that all share a similar characteristic
• antibiogram patterns (resistance to antibiotics)
• Dyocin/PHage though (bacteria produce antibiotics towards other bacteria

Question 15

Whats macroscopic

Whats microscopic

Answer 15

macro- growth on agar medium

micro- morphology of single cells

Question 16

Whats alpha hemolysis

Answer 16

Incomplete destruction of RBCs

Question 17

Whats beta hemolysis

Answer 17

Complete destruction of RBCs

Question 18

In microscopic tests to see the morphology of the bacteria, what are the two stains used

Answer 18

• Gram stain (true bacteria)

- Acid fast stain (mycobacteria)

Question 19

How to assess the genotype of the bacteria to classify it

Answer 19

• % of guanine and cytosine
• DNA hybridization
• Nucleic acid sequence analysis
• Chromosomal DNA fragment analysis
• Ribotyping

Question 20

Whats DNA hybridization

Answer 20

Split DNA of bacteria adding probes specific to that certain bacteria. If binds the it is part of that bacterial group

Question 21

Whats nucleic acid sequence analysis

Answer 21

Looks at housekeeping genes and helps to distinguish sub-species

Question 22

Whats chromosomal DNA fragment analysis

Answer 22

Breaking DNA and running it in an agar to see the banding patterns

Question 23

Whats ribotyping

Answer 23

Look at ribosomal RNA characteristic

Question 24

What does the Gram stain differentiate between

Answer 24

Bacteria based on cell wall

Question 25

What does Gram +ve mean

Answer 25

Thick cell wall

Question 26

What does Gram -ve mean

Answer 26

Thin cell wall

Question 27

Process of using Gram stain

Answer 27

- fix sample onto slide - Add crystal violet to add color - Add Gram's iodine to get into cell wall - Acid decoloriser (alcohol/acetone) to remove Gram's iodine from thin cell wall (can't remove it from the thicker cell wall) - Add Safranin red (Gram -ve take up red color and the gram +ve remains purple)

Question 28

do G+ve/-ve bacteria have outer membrane

Answer 28

-ve

Question 29

do G+ve/-ve bacteria have LPS (endotoxin)

Answer 29

-ve

Question 30

do G+ve/-ve bacteria have Teichoic acid

Answer 30

+ve

Question 31

do G+ve/-ve bacteria have sporulation

Answer 31

Some strains of +ve

Question 32

do G+ve/-ve bacteria have a capsule

Answer 32

Both sometimes have it

Question 33

do G+ve/-ve bacteria have lysozyme

Answer 33

+ve is sensitive

Question 34

G+ve/-ve bacteria and penicillin susceptibility

Answer 34

Gram +ve is more susceptible and -ve is less susceptible

Question 35

How are bacterial cell walls synthesised

Answer 35

- Peptidoglycan precursors synthesized inside the cell - Exported across the cell membrane X bacitracin - A site is created in the existing wall by enzymic action PBPs - The new nucleotide minus the terminal D-ala is encorporated - cell grows

Question 36

What is the cell wall made from

Answer 36

peptidoglycan