3 Anatomy of a Typical Bacterial (Prokaryotic) Cell

Question 1

Avg size of a bacterium?

Answer 1

2 micron diameter

Question 2

What is the advantage of having a high surface-to-volume ratio?

Answer 2

Nutrients and wastes can move into and out of the bacterial cell, respectively, quite efficiently

Question 3

3 main bacterial shapes?

Answer 3

1. Bacillus (rod)
2. Coccus (round)
3. Spirochete (spiral)

Question 4

How can bacteria be arranged? (4)

Answer 4

1. Singles
2. Pairs
3. Clusters
4. Chains

Question 5

T or F: Bacteria are relatively complex compared to eukaryotic cells.

Answer 5

F

They are, in fact, simpler than eukaryotic cells.

Question 6

Name the 3 typical structures of a bacterial cell.

Answer 6

1. Cytoplasm
2. Cell envelope/wall
3. “External”/optional structures

Question 7

T or F: Prokaryotic and eukaryotic ribosomes have the same function since they both have the same structure.

Answer 7

F

The prokaryotic ribosome DOES indeed have the same fn as the eukaryotic ribosome. However, their structures are different.

Question 8

The cell envelope of Gram _____ bacteria has three layers: An inner plasma membrane, a thin peptidoglycan layer, and an outer plasma membrane.

Answer 8

negative

Question 9

The cell envelope of Gram _____ bacteria has two layers: An inner plasma membrane and a thick outer peptidoglycan layer.

Answer 9

positive

Question 10

T or F: The INNER plasma membrane of prokaryotes are basically the same as the plasma membrane of eukaryotes in both structure and function.

Answer 10

F

They ARE similar in general structure, but NOT in function

(they contain “metabolic” proteins [i.e. they’re “active” membranes])

Question 11

Name the component of prokaryotic cell walls that’s not found in eukaryotic cells.

Answer 11

Peptidoglycan

Question 12

What is a peptidoglycan monomer composed of?

Answer 12

Two carbohydrates and four amino acids.

Question 13

How many layers of peptidoglycan does a Gram negative bacteria have?

Answer 13

1-2 layers

Question 14

How many layers of peptidoglycan does a Gram positive bacteria have?

Answer 14

Multiple

Question 15

Name an enzyme that can break peptidoglycan apart. In what location does it cleave?

Answer 15

Lysozyme.

It cleaves the bond b/w NAG and NAM

Question 16

What determines whether a cell is Gram positive or negative?

Answer 16

Thickness of peptidoglycan component of the cell wall

Question 17

Why do Gram negative cells not remain purple during the Gram staining process?

Answer 17

Because they have fewer layers of peptidoglycan, and so the dye is not as easily trapped.

Question 18

What colour are Gram positive bacteria after staining?

Answer 18

Purple

Question 19

What colour are Gram negative bacteria after staining?

Answer 19

Red

Question 20

Do Gram positive or negative bacteria have an outer cell membrane?

Answer 20

Gram negative

Question 21

What unique molecule (not found in eukaryotes) is embedded in the outer membrane of a Gram negative bacterium?

Answer 21

Lipopolysaccharide (LPS)

Question 22

What are the three parts of a LPS?

Answer 22

1. O-antigen
2. Core polysaccharide
3. Lipid A

Question 23

What is the fn of LPS molecules?

Answer 23

Protect the bacterium. It repels toxic compounds in the envir

Question 24

The human immune sys recognizes the _____ part of LPS.

Answer 24

O-antigen

Question 25

This part of the LPS causes shock, inflammation, and fever; hence, LPS is also known as ENDOTOXIN

Answer 25

Lipid A

Question 26

What is a pyrogenic?

Answer 26

Anything that can induce fever.

Question 27

What part of a Gram negative bacterium is considered to be a pyrogenic agent?

Answer 27

LPS (its lipid A component, specifically)

Question 28

Name 2 structural diffs b/w Gram positive and Gram negative bacteria.

Answer 28

1. Gram positive bacteria have a much thicker peptidoglycan layer 2. Gram negative bacteria have an outer membrane and LPS

Question 29

Name two bacterial species that deviate from the typical Gram (-) and (+) cell envelope structures.

Answer 29

1. Mycobacteria species | 2. Mycoplasma species

Question 30

Name the 3 typical structures of a bacterial cell.

Answer 30

1. Cytoplasm 2. Cell envelope/wall 3. "External"/optional structures

Question 31

T or F: ALL bacteria have external structures.

Answer 31

F They're optional (i.e. not necessarily there)

Question 32

Name 4 optional structures of bacteria.

Answer 32

1. Flagella 2. Pili (aka fimbriae) [sing. pilus] 3. Capsular polysaccharide (aka capsule) 4. Bacterial spores (aka endospores)

Question 33

What are flagella?

Answer 33

Long, thick filaments that can cause movement due to whip-like or propeller-like movements

Question 34

T or F: Flagellar bacteria only have ONE flagellum.

Answer 34

F The number of flagella vary in location and number per cell. It depends on species.

Question 35

What are pili?

Answer 35

Filaments used to ATTACH bacteria to other cells

Question 36

What're the two types of pili?

Answer 36

1. Sex pili | 2. Common pili

Question 37

What're sex pili used for?

Answer 37

Attaching bacteria to other bacteria

Question 38

What're common pili used for?

Answer 38

Attaching bacteria to eukaryotic cells & tissues

Question 39

What structure is necessary for many bacteria to cause disease?

Answer 39

Common pili

Question 40

What are capsular polysaccharides? (aka "capsules"?)

Answer 40

Viscous, sticky polysaccharide material surrounding the bacterial cell

Question 41

T or F: Capsular polysaccharide structure is constant across species and strains.

Answer 41

F The chemical structure of the polysaccharide varies b/w species (and s.times b/w strains too).

Question 42

What are the two main fns of capsules?

Answer 42

1. Protection | 2. Attachment

Question 43

What do we call a community of bacteria attached to a living or non-living surface via capsular polysaccharide?

Answer 43

Biofilm

Question 44

What are single-species biofilms mostly involved in?

Answer 44

Human infections

Question 45

Where are multi-species biofilms mostly found?

Answer 45

Natural envirs

Question 46

Name three areas where biofilms can form, making them medically-relevant problems.

Answer 46

1. Biofilms form on human tissues during infection > makes it more difficult to treat 2. Biofilms form on implanted medical devices 3. Biofilms form on tooth surfaces (i.e. plaque)

Question 47

T or F: Biofilms can detach and become established elsewhere.

Answer 47

T

Question 48

Name 4 optional structures of bacteria.

Answer 48

1. Flagella 2. Pili (aka fimbriae) [sing. pilus] 3. Capsular polysaccharide (aka capsule) 4. Bacterial spores (aka endospores)

Question 49

What are endospores?

Answer 49

Dormant, non-growing form of bacteria

Question 50

What causes endospore conversion?

Answer 50

Environmental stress

Question 51

Endospore formation is mostly a _____ mechanism

Answer 51

survival

Question 52

T or F: Spores multiply faster than bacteria.

Answer 52

F Spores are DORMANT. They don't multiply.

Question 53

When do spores become vegetative ("growing state") again?

Answer 53

When environmental stresses are gone and growth conditions are favourable.

Question 54

How long can a spore stay dormant before it's no longer able to revert to a growing, vegetative cell?

Answer 54

AT LEAST several decades (maybe longer)

Question 55

T or F: Spores are more easily killed by pasteurization, boiling, and some germicides.

Answer 55

F Spores are NOT killed by these things.