Lecture 2: Bacterial Morphology and Structure 2

Question 1

What is the glycocalyx of a bacterial cell

Answer 1

Polysaccharide containing material lying outside the cell wall

Question 2

What are the two forms of glycocalyx

Answer 2

1. Slime layer
2. Capsule

Question 3

What is the function of the glycocalyx

Answer 3

Promotes adherence, protects against desiccation, barrier to antibiotics, inhibits phagocytosis, virulence factor

Question 4

T or F: some bacteria species are A-virulent if capsule is absent

Answer 4

True

Question 5

What is a slime layer

Answer 5

Easily removed, diffuse, unorganized layer of extracellular material that surrounds bacterial cells

Question 6

What are the functions of a slime layer

Answer 6

Protect the bacteria cells from environmental dangers like antibiotics and desiccation, adherence, permit to survive chemical sterilization

Question 7

Is the following a slime layer or capsule

Answer 7

slime layer

Question 8

What is a capsule

Answer 8

Well organized, uniform, rigid layer outside of cell wall

Question 9

What is the Quellung Reaction

Answer 9

Test used to determine of bacteria has a capsule or not. Add anti-capsular antibodies, antigen-antibody reaction causes change in capsule so that is appears swollen and more visible

Question 10

Is the following a capsule or slime layer

Answer 10

capsule

Question 11

What is the gold standard for stereotyping pneumococcus

Answer 11

Quellung reaction

Question 12

What are flagella

Answer 12

Fliamentous appendages composed entirely of proteins

Question 13

What are the three major components of flagella

Answer 13

1. Filament
2. Hook
3. Basal body

Question 14

What is the function of flagella hooks

Answer 14

Attaches filament to the basal body

Question 15

What is the function of the basal body of flagella

Answer 15

Anchors flagellum in the cell wall/membrane

Question 16

Each flagellum is made up of several ___, composed of flagellum- ___ antigens

Answer 16

Protofilaments, H antigens

Question 17

Why are identifying H antigens useful

Answer 17

Can help dx the type of bacteria

Question 18

How many flagella in atrichous

Answer 18

None

Question 19

How many flagella in lophotrichous

Answer 19

Multiple polar flagella- one one side

Question 20

What does amphitrichous mean

Answer 20

Single flagellum or multiple flagella on both polar ends

Question 21

What does peritrichous mean

Answer 21

Multiple flagella all over cell

Question 22

Identify type of flagella 1-4

Answer 22

1. Monotrichous
2. Lophotrichous
3. Amphitrichous
4. Peritrichous

Question 23

What are pili/fimbriae

Answer 23

Rigid, hair like proteinaceous structures

Question 24

What is the function of pili/fimbriae

Answer 24

Attachment

Question 25

What are the two main classes of pili

Answer 25

1. Ordinary/common 2. Sex/conjugation/ F pilus

Question 26

What type of arrangement do ordinary/common pili have

Answer 26

Peritrichous

Question 27

What is the purpose of the ordinary/common pili

Answer 27

Serve as virulence factors- adhere to host cells

Question 28

What is the purpose of the sex/conjugation/F pili

Answer 28

Structure for conjugation, genetic exchange mechanism

Question 29

What type of bacteria are sex/conjugation/F pilus found in

Answer 29

Gram negative bacteria

Question 30

Where do prokaryotes package their DNA

Answer 30

Nucleoid

Question 31

T or F: nucleoid lacks a nuclear membrane

Answer 31

True

Question 32

What is the advantage of lacking a nuclear membrane

Answer 32

Allows for coupled transcription-translation

Question 33

What are the advantages of coupled transcription-translation

Answer 33

Protein synthesis is faster, quicker response to environment (a reason for bacterial resistance)

Question 34

Describe chromosome of bacterial

Answer 34

Single, circular chromosome, no introns in DNA no histones

Question 35

What is the benefit of no introns and no histones in chromosomes

Answer 35

Allows for quick response to environment

Question 36

What do plasmids code for

Answer 36

Non-essential information: includes genes that encode for: 1. Antibiotic resistance 2. Heavy metal resistance 3. Toxins 4. Useful metabolic enzymes

Question 37

How can bacteria acquire plasmids

Answer 37

Various genetic exchange mechanisms

Question 38

What are the bacterial ribosome subunits

Answer 38

70S: 50S and 30S

Question 39

What is the purpose of ribosomes

Answer 39

Site for protein synthesis- coupled transcription-translation

Question 40

What are inclusion bodies

Answer 40

Various granules, vesicles, and vacuoles within cytoplasm

Question 41

How can inclusion bodies be helpful clincially

Answer 41

Can help in identification of some bacteria

Question 42

What is an endospore

Answer 42

Resting stage that allows organism to survive harsh environmental conditions

Question 43

Endospore formation is triggered by ___, such as ___

Answer 43

Unfavorable conditions, such as nutrient depletion

Question 44

When a favorable condition returns an endospore will undergo __

Answer 44

Germination

Question 45

What is the core of the endospore

Answer 45

Contains complete chromosome, protein synthesizing apparatus and energy generating system based on glycolysis

Question 46

What is the spore wall

Answer 46

Innermost layer surrounding inner spore membrane, contains normal peptidoglycan and becomes the cell wall of the germinating vegetative state

Question 47

What is the cortex of endospore

Answer 47

Thickest layer of the spore envelope. Cortex peptidoglycan extremely sensitive to lysozyme and autolysis plays a role in spore germination

Question 48

What is the coat of an endospore

Answer 48

Composed of keratin like protein containing many intramolecular disulfide bonds. Impeccability of this layer is important for bacterial resistance

Question 49

What is the exosporium

Answer 49

Composed of proteins, lipids, and carbohydrates

Question 50

What is the difference between sporulation and vegetative growth

Answer 50

Sporulation: DNA replicates , eventually spore coat and spore form—> will germinate until an unfavorable condition occurs then will enter vegetative growth. Once favorable conditions return it will produce 2 new daughter cells

Question 51

What are the two clinically relevant genera that produce endospores

Answer 51

Bacillus and clostridium

Question 52

Are the genera that produce endospores gram positive or negative

Answer 52

Positive

Question 53

What is the staining technique for detecting endospores

Answer 53

1. Apply malachite green-primary stain 2. Heat 3. Water/decolarizer 4 apply safranin- counter stain

Question 54

How do aminoglycosides serve as antibiotic

Answer 54

Bind 30S ribosomes causing misreading of genetic code

Question 55

What are some examples of aminoglycosides

Answer 55

Gentamicin, tobramycin, amikacin, streptomycin, kanamycin

Question 56

How do tetrcyclines work as antibiotics

Answer 56

Binds 30S ribosomes reversibly, prevents addition of amino acids to elongating peptide chain

Question 57

How do lincosamides work as antibiotics

Answer 57

Binds to 50S ribosomes, inhibit peptidyl transferase

Question 58

What are some examples of lincosamides

Answer 58

Linomycin, clindamycin, pirlimycin

Question 59

How does chloramphenicol work as antibiotic

Answer 59

Binds 50S ribosomes inhibits peptidyl transferase