Micro Chapter 3

Front 1

Bacillus

Back 1

A rod-shaped bacterial or archaeal cell

Front 2

Capsule

Back 2

a layer of well-organized material, not easily washed off, lying outside the cell wall of some microbes

Front 3

Cell Envelope

Back 3

The plasma membrane and all surrounding layers external to it

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Chemotaxis

Back 4

The movement of a microorganism toward chemical attractants and away from chemical repellents

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Coccus

Back 5

A spherical bacterial or archaeal cell

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Endospore

Back 6

An extremely heat- and chemical-resistant, dormant, thick-walled spore that develops within some gram-positive bacteria

Front 7

Fimbriae

Back 7

Fine-hairlike protein appendages on some bacterial and archaeal cell; some help attach cells to surfaces and others are involve din a type of twitching motility; also called pili

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Fluid Mosaic Model

Back 8

The currently accepted model of the cell membranes in which the membrane is a lipid bilayer with integral proteins burid in the lipid and peripheral proteins more loosely attached to the membrane surface

Front 9

Gas Vacuole

Back 9

A proteinaceous cytoplasmic organelle composed of clusters of gas-filled vesicles; used by aquatic bacteria and archaea to change location in a water column

Front 10

Glycocalyx

Back 10

A network of polysaccharides extending from the surface of some cells

Front 11

What is the anammoxosome

Back 11

A membrane bound organelle in the bacterial phylum Planctomycetes (which isn't supposed to have it)

Site of anoxic ammonia oxidation, an unusual metabolic process that is important in the nitrogen cycle

Front 12

Why do some microbiologists think the term prokaryote should be abandoned?

Back 12

There are many exceptions to several characteristics of prokaryotes

Prokaryotes aren't supposed to have membrane bound organelles; counterexample: anammoxosome

Porkaryotes aren't supposed to have cytoskeleons; counterexample: cytoskeletal elements are widespread in both domains and that some bacteria have extensive intracytoplasmic membranes

Front 13

What are the two most common shapes in both Archaea and Bacteria

Back 13

Cocci and Rods

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What shape are cocci cells

Back 14

Roughly spherical cells

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What are diplococci?

Back 15

Cells that arise when cocci divide and remain together to form pairs

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Bacilli

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Rod shaped bacteria

Front 17

Vibrios

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Comma shaped; most closely resemble rods

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Spirilla

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Rigid, spiral-shaped cells that have tufts of flagella at one or both ends

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Spirochetes

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Flexible, spiral-shaped bacteria that have a unique, internal flagellar arrangement

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Mycelium

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A network of branched hyphae

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Pleomorphic

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variable in shape and lacking a single, characteristic form

Front 22

Can bacteria or archaea grow to be larger than the typical eukaryotic cell?

Back 22

Yes

Front 23

Describe the role of S/V ratio in bacteria?

Back 23

For many years it was thought that microbes were small because being small increases the surface area-to-volume ratio

As this ratio increases, nutrient uptake and diffusion of molecules within the cell become more efficient

Front 24

Cell envelope

Back 24

The plasma membrane and all the surrounding layers external to it

Front 25

What is the innermost layer of the cell envelope

Back 25

The plasma membrane

Front 26

Describe capsules in Archaea and Bacteria

Back 26

Many bacteria have capsules or slime layer; but capsules are not widespread among archaea

Front 27

The nucleoid

Back 27

Where genetic material is localized among bacteria and archaea; usually not separated from the surrounding cytoplasm by membranes

Front 28

What part of the bacteria is responsible for nutrient uptake, waste excretion, and protein excretion

Back 28

The plasma membrane

Front 29

The Fluid Mosaic Model

Back 29

Proposes that membranes are lipid bilayers within which proteins float

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Amphipathic

Back 30

structurally asymmetric, with polar and nonpolar ends

This is a way to describe the lipids in the lipid bilayer of the plasma membrane

Front 31

Are the polar ends of the lipids of the lipid bilayer hydrophilic or hydrophobic

Back 31

Hydrophilic because they are polar they like water

Front 32

Are the outer layers of the lipid bilayer polar or nonpolar?

Back 32

Polar and hydrophilic

Front 33

Peripheral proteins

Back 33

These are proteins in the plasma membrane that are loosely connected to the membrane and can be easily removed

20 - 30% of membrane proteins

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Integral Proteins

Back 34

Proteins of the plasma membrane; not easily extracted; make up about 70- 80% of plasma membrane proteins

Front 35

Hopanoids

Back 35

Sterol like molecules in the plasma membrane

Synthesized from the same precursors as steroids

Stabilize the membrane

Front 36

How is the plasma membrane of bacteria affected by temperature

Back 36

Lower temperatures: more unsaturated fatty acids

Higher temperatures: more saturated fatty acids

Front 37

Cell Wall

Back 37

Layer, usually fairly rigid, that lies just outside the plasma membrane

Front 38

Responsibilities of the cell wall

Back 38

determines the shape of the cell

protects the cell from osmotic lysis

protects the cell from toxic substances

can contribute to pathogenicity

Front 39

Do all bacteria have cell walls?

Back 39

No; but those that do not have other features that fulfill cell wall function

Front 40

Gram positive bacteria stain ____

Back 40

purple

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Gram negative bacteria stain ____

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pink

Front 42

Why are the walls of gram positive bacteria more resistant to osmotic pressure than the walls of gram negative bacteria?

Back 42

Gram positive cell walls have a thick homogenous layer of peptidoglycan lying outside of the plasma membrane; whereas gram negative cell walls have a thin peptidoglycan layer covered by an outer membrane

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Periplasmic space

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The space that is frequently seen between the plasma membrane and the outer membrane

Front 44

Periplasm

Back 44

The substance that occupies the periplasmic space

Front 45

Is peptidoglycan present in both gram positive and gram negative bacterial cell walls?

Back 45

Yes; however the amount differs

Front 46

To what phyla do gram-positive bacteria belong?

Back 46

Firmicutes and Actinobacteria

Front 47

Teichoic Acids

Back 47

A secondary cell wall polymer in gram-positive bacteria

Polymers of glycerol and ribitol joined by phosphate groups

Front 48

The functions of teichoic acids

Back 48

help create and maintain the structure of the cell envelope and to protect the cell from harmful substances in the environment

May be involved in binding pathogenic species to host tissues, thus initiating the infection disease process

Front 49

In gram-positive bacteria, where is the periplasmic space located

Back 49

The periplasmic space of gram-positive bacteria lies between the plasma membrane and the cell wall, and is smaller than that of gram-negative bacteria

Front 50

Are there many proteins in the periplasmic space of gram-positive bacteria

Back 50

Not really; this is because the peptidoglycan sac is porous and any proteins secreted by the cell usually pass through it

Front 51

Exoenzymes

Back 51

Enzymes secreted by gram-positive bacteria

Often serve to degrade polymeric nutrients that would otherwise be too large for transport across the plasma membrane

Front 52

Describe the outer side of the peptidoglycan layer of gram-positive bacteria

Back 52

There is a layer of proteins, which are involved in interactions of the cell and its environment

Front 53

How is the outer membrane linked to the thin peptidoglycan layer in gram-negative bacteria?

Back 53

Through Braun's lipoprotein. This small lipoprotein is covalently joined to the underlying peptidoglycan and is embedded in the outer membrane by its hydrophobic end

Front 54

What are LPSs

Back 54

Lipopolysacchardies

Present in the outer membrane of of gram-negative cell walls

Consist of a lipid, the core polysaccharide, and the O side chain

Front 55

What are LPSs functions

Back 55

LPS contributes to the negative charge on the bacterial surfaces

Helps stabilize outer membrane structure

Contributes to bacterial attachment to surfaces and biofilm formation

Helps create a permeability barrier

Protects pathogenic gram-negative bacteria from host defenses

The lipid A portion is toxic; LPS can act as an endotoxin

Front 56

Porin Proteins

Back 56

proteins on the outer membrane of gram-negative bacteria that allow small molecules such as glucose and other monosaccharides to pass through

Front 57

Do gram-negative bacteria have teichoic acids?

Back 57

No

Front 58

What cell structure is most important to gram staining?

Back 58

The cell wall

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Lysis

Back 59

The bursting of a cell due to too great of pressure on the cell membrane

Front 60

Plasmolysis

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The shriveling of a cell due to water flowing out

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Lysozyme

Back 61

enzyme that attacks peptidoglycan by hydrolyzing the glycosidic bond that connect N-acetylmuramic acid with N-acetylglycosamine

Front 62

Role of penicillin in lysing a cell

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Inhibits the enzyme transpeptidase, which is responsible for making the cross-links between peptidoglycan chains

Front 63

Spheroplasts

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gram-negative bacteria that have been treated with lysozyme or penicillin; called this because the peptidoglycan layer is lost, but the outer membrane remains

Front 64

Capsules

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Layers that are well organized and not easily washed off

Front 65

What are capsules most often composed of?

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Polysaccharides

Front 66

Functions of capsules

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help pathogenic bacteria resist phagocytosis by host phagocytes

They contain a great deal of water and can protect against desiccation

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Slime layer

Back 67

zone of diffuse, unorganized material that is removed easily

Front 68

Composition of slime layer

Back 68

polysaccharides

Front 69

Glycocalyx

Back 69

Layer consisting of a network of polysaccharides extending from the surface of the cell

The term can encompass both capsules and slime layers because they usually are composed of polysaccharides

The glycocalyx aids in attachment to solid surfaces, like tissue surfaces

Front 70

S-layer

Back 70

located on the surface of many bacteria

composed of protein or glycoprotein

In gram-negative bacteria it adheres directly to the outer membrane

In gram-positive bacteria it is associated with the peptidoglycan surface

Front 71

Function of the S-layer

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Protects the cell against ion and pH fluctuations, osmotic stress, enzymes, or predacious bacteria; maints the shape and envelope rigidity of some cells; can promote cell adhesion to surfaces; protects some bacterial pathogens against host defenses

Front 72

Why is the S-layer valuable to nanotechnology research

Back 72

The S-layer is able to self-assemble

Front 73

Where is the S-layer for many archaea

Back 73

Just outside of the plasma membrane

Front 74

Are capsules and slime layers common in archaea like they are in bacteria?

Back 74

No

Front 75

How do the lipids that constitute the plasma membrane of archaea differ from bacterial and eukaryotic lipids?

Back 75

1. They contain hydrocarbons derived from isoprene units -- five-carbon branched molecules

2. The hydrocarbons are attached to glycerol by ether links rather than ester links

Front 76

Name the two types of plasma membranes that archaea can have

Back 76

Bilayers and Monolayers, which are seen in more extreme environments because they are much more rigid

Front 77

Do Archaeal cell walls have peptidoglycan

Back 77

No

Front 78

What is the most common type of archaeal cell wall

Back 78

An S-layer comosed of either glycoprotein or protein

Front 79

Pseudomurein

Back 79

A molecule that separates the S-layer from the plasma membrane in Archael cells

Front 80

How might some Archaeal cells stain gram positive

Back 80

These unique archaea have a wall with a singl, thick homogenous layer resembling that in gram-positive bacteria. These archaea often stain gram positive. Their wall chemistry varies from species to species but usually consists of complex polysaccharides such as pseudomurein

Front 81

Protoplast

Back 81

The plasma membrane and everything within

Front 82

Cytoplasm

Back 82

material bounded by the plasma membrane; thus it is a major part of the protoplast

Front 83

Three best studied bacterial cytoskeletal proteins

Back 83

FtsZ, MreB, and CreS

Front 84

What is the bacterial and archaeal cytoskeletal protein FtsZ a homolog of?

Back 84

Tubulin

Front 85

What is the bacterial and archaeal cytoskeleton protein MreB a homolog of?

Back 85

Actin

Front 86

What is the bacterial and archael cytoskeleton protein CreS a homolog of?

Back 86

lamin and keratin, two intermediate filament proteins

Front 87

How do the internal membranes of bacteria differ from the plasma membrane

Back 87

Being enriched for proteins and other molecules involved in energy conservation

Front 88

What is the function of internal membranes?

Back 88

to provide a larger membrane surface for greater metabolic activity

Front 89

Anammoxosome

Back 89

Site of anaerobic ammonia oxidation and is unique to bacteria in the phlyum Planctomycetes

Front 90

Inclusions

Back 90

Granules of organic or inorganic material that are stockpiled by the cell for future use

Front 91

What are the purpose of inclusions

Back 91

Used for storage or to reduce osmotic pressure by typing up molecules in particulate form

Front 92

Name a few types of storage inclusions

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glycogen storage, carbon storage, phosphate storage, amino acid storage

Front 93

When are glycogen inclusions found

Back 93

When bacteria are growing in an environment that is limited for an important nutrient but contains excess carbon; thus glycogen inclusions serve to store carbon until the missing nutrient becomes available

Front 94

Microcompartments

Back 94

Inclusions that are more than simply for storage of substances for later use

Not bound by lipid bilayer

Many scientists believe they are analogous to mitochondria

Best studied microcompartment is the carboxysome

Front 95

Carboxysome

Back 95

The best studied microcompartment

Present in many cyanobacteria and other CO2-fixing bacteria

The nature of the carboxysome shell prevents CO2 from escaping; thus it concentrates CO2

It also encloses Rubisco

Front 96

Rubisco

Back 96

the critical enzyme for CO2 fixation, the process of converting CO2 into sugar

Present within the carboxysome microcompartment; thus the carboxysome serves as a site for CO2 fixation

Front 97

Gas vacuole

Back 97

microcompartment to some aquatic bacteria and archaea

Provide buoyancy; they are aggregates of enormous numbers of small, hollow, cylindrical structures called gas vesicles

Front 98

Magnetosomes

Back 98

Microcompartments in aquatic magnetotactic bacteria used to orient themselve sin Earth's magnetic field

Front 99

Ribosomes

Back 99

Site of protein synthesis; consists of protein and RNA

Front 100

What is the difference between cytoplasmic ribosomes and ribosomes attached to the plasma membrane

Back 100

Cytoplasmic ribosomes manufacture proteins that are destined to remain within the cell; whereas plasma membrane-associated ribosomes make proteins that will reside in the cell envelop or are transported to the outside

Front 101

What are the size of bacterial and archaeal ribosomes

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70S; and are made up of a 50S and a 30S

Front 102

How are archaeal ribosomes different from bacterial ribosomes

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Archaeal ribosomes have an extra 5.8S rRNA in the large subunit

Front 103

Nucleoid

Back 103

An irregularly shaped region that contains the cell's chromosome and numerous proteins

Front 104

Do all bacteria have a circular chromosome?

Back 104

No, some bacteria have a linear chromosome such as Vibrio cholerae

Front 105

How is the chromosome compacted to fit inside the nucleoid?

Back 105

Supercoiling

Front 106

HU

Back 106

A protein thought to be used in supercoiling of the chromosome in bacteria; differ from histones

Front 107

Plasmids

Back 107

Extra chromosomal DNA molecules; can be very numerous; usually small, closed circular DNA molecules, but can be linear

Exist independently of the chromosome; not essential to the host

Front 108

Can plasmid replicate autonomously

Back 108

Yes

Front 109

Episomes

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Plasmids that are able to integrate into the chromosome and thus are replicated with the chromosome

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Curing

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The loss of a plasmid because during cell division plasmids are not always equally apportioned into daughter cells

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Conjugative plasmids

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Can transfer copies of themselves to other bacteria during conjugation

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F Factor

Back 112

Type of conjugative plasmid

Front 113

R Plasmids

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Confer antibiotic resistance to the cells that contain them; important in the spread of antibiotic resistance among bacteria

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Virulence Plasmids

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Encode factors that make their hosts more pathogenic

Front 115

Metabolic Plasmids

Back 115

Carry genes for enzymes that degrade substances such as aromatic compounds, pesticides, and sugars

Front 116

Pili and Fimbriae

Back 116

Synonymous terms for short, fine, harilike appendages that are thinner than flagella

Front 117

Function of pili and Fimbriae

Back 117

Most function to attach bacteria to solid surfaces such as rock in streams and host tissues

Can be involved in motility and the uptake of DNA during the process of bacterial transformation

Front 118

What are sex pili used for

Back 118

Bacterial conjugation

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Flagella

Back 119

Threadlike locomotor appendages extending outward from the plasma membrane and cell wall

Front 120

Main function of flagella; and its other functions

Back 120

Motility

Can also be used for swarming behavior; attachment to surfaces; and virulence factors

Front 121

Monotrichous bacteria

Back 121

Means the bacteria have one flagellum

If it is located at an end, it is said to be a polar flagellum

Front 122

Amphitrichous Bacteria

Back 122

have a single flagellum at each pole

Front 123

Lophotrichous Bacteria

Back 123

Have a cluster of flagella at one or both ends

Front 124

Peritrichous Bacteria

Back 124

Flagella are spread evenly over the whole surface of the bacteria