Lecture 2. The Bacterial World

Question 1

What can microbes like other animals do ?

Answer 1

1. Defend against predators
2. Avoid parasites
3. Adapt to harsh environments
4. Find food
5. Reproduce

Question 2

What types of microbes are the most abundant ?

Answer 2

Unicellular organisms

Question 3

What are some disadvantages to being multicellular ?

Answer 3

1. Increased disease transmission
2. Competition for resources
3. Social exploitation

Question 4

What states can microbes constantly flux between ?

Answer 4

Unicellular and multicellular states

Question 5

Where are bacteria found ?

Answer 5

1. Plants
2. Animals
3. Soil
4. Water
5. Artic ice
6. Air
7. Volcanic vents

Question 6

What is the function of the pilus ?

Answer 6

Stick to mucosal cells

Question 7

What is the function of the capsule ?

Answer 7

Causative agent of infection

Question 8

What are the three features of a bacterial cell ?

Answer 8

1. No mitochondria
2. Ribosomes free in the cytoplasm or bound to the inner face of the cytoplasmic reticulum
3. Single chromosome

Question 9

What do bacterial cells lack that other cells may have ?

Answer 9

1. Endoplasmic reticulum
2. Nuclear membrane
3. Mitochondria

Question 10

What is the ribosome that bacterial cells have ?

Answer 10

70s

Question 11

What is the 70s ribosome composed of ?

Answer 11

30S and 50S subunits

Question 12

What is another name for multiple extracellular layers ?

Answer 12

Bacterial cell envelope

Question 13

What is the function of the bacterial cell envelope ?

Answer 13

Help bacteria survive in inhospitable environments

Question 14

What is the bacterial cell envelope made up of ?

Answer 14

The cell wall and associated membranes

Question 15

What do gram positive cells have ?

Answer 15

1. A thick cell wall

2. Plasma membrane

Question 16

What do gram negative cells have ?

Answer 16

1. Outer membrane
2. Thin cell wall
3. Periplasmic space
4. Plasma membrane

Question 17

What is the cell wall essential for ?

Answer 17

1. Essential for structural integrity

2. Provides cell shape

Question 18

What is the cell wall primarily composed of ?

Answer 18

Peptidoglycan

Question 19

What is another name for peptidoglycan ?

Answer 19

Murein

Question 20

What is peptidoglycan unique to ?

Answer 20

Bacteria

Question 21

What does peptidoglycan provide to cells ?

Answer 21

Mechanical cells

Question 22

What are some features of peptidoglycan ?

Answer 22

1. Not a hard shell
2. Flexible
3. Elastic.
4. Porous

Question 23

What are glycan chains connected by ?

Answer 23

Peptide crosslinks

Question 24

Why is the biosynthesis of peptidoglycan the target of anti-microbials ?

Answer 24

Disrupts cell walls which are essential structures

Question 25

What is a glycan chain composed of ?

Answer 25

Individual sugars linked by B-1,4 glycosidic linkages

Question 26

What are peptide cross links composed of ?

Answer 26

Amino acids

Question 27

What is the most basic subunit of glycan chain ?

Answer 27

Peptidoglycan monomer

Question 28

What are the two types of peptidoglycan monomers in a glycan chain ?

Answer 28

1. N-acetyl muramic acid | 2. N-acetyl glucosamine

Question 29

What does N-acetyl muramic acid have in its structure ?

Answer 29

Lactic acid

Question 30

What is the function of the peptide side chain ?

Answer 30

Allows 3D structures to form

Question 31

What are glycan side chains formed by ?

Answer 31

Cross links between peptide side chains

Question 32

What do cross links between peptide side chains provide ?

Answer 32

Strength

Question 33

What is there in the structural details of peptidoglycan from different species ?

Answer 33

Variation

Question 34

What is an example of the 5 amino acids in a peptide side chain and what position are they in ?

Answer 34

1. L-alanine 2. D-glutamate 3. L-diaminopimelic acid 4. D-alanine 5. D-alanine

Question 35

What amino acid are present in most species and what positions are they usually in ?

Answer 35

1. L-alanine (1) 2. D-glutamate (2) 3. D-alanine (5)

Question 36

What amino acid in the peptide side chain never varies and what position is it in ?

Answer 36

1. D-alanine | 2. Position 4

Question 37

What position is the amino acid that varies in ?

Answer 37

Third position

Question 38

What must the amino acid in third position have ?

Answer 38

A free amino acid group

Question 39

What happens to the peptide chain when it joins to another one ?

Answer 39

It is turned upside down ie. position 1 is at the bottom

Question 40

What does the position 3 amino acid bind to ?

Answer 40

Position 4

Question 41

How does the amino acid in position 3 bind to the amino acid in position 4 ?

Answer 41

Direct cross link

Question 42

What happens to the peptide side chain after two peptide chains join together by direct cross linkage ?

Answer 42

The 5th amino acid on both peptide side chains disappears

Question 43

What type of linkage does gram negative bacteria have ?

Answer 43

Direct peptide cross links

Question 44

What is a peptide cross bridge comprise of ?

Answer 44

A series of amino acids

Question 45

What is the advantage of peptide cross bridge ?

Answer 45

Can attach things to it

Question 46

What type of linkages do gram positive bacteria contain ?

Answer 46

Peptide cross bridge

Question 47

What can disrupt cell walls ?

Answer 47

1. Lysozyme | 2. Penicillin/B-lactams

Question 48

What do lysozyme do to disrupt the cell wall ?

Answer 48

Hydrolyses every second glycosidic bond

Question 49

How does penicillin/ B-lactams do to disrupt the cell wall ?

Answer 49

Prevents linking two side chains together