Exam 3 Flashcards

Question

gram-positive cell wall

Answer 1

thick, homogenous sheet of peptidoglycan - contains teichoic and lipoteichoic acid

Answer 2

thin, sheet of peptidoglycan - thin sheet gives cells more susceptibility to lysis

Answer 3

-lipopolysaccharides signaling molecules and receptors -porin proteins special membrane channels

Answer 4

- outer membrane of gram-negative - alcohol based compounds - Treatment of infections caused by gram-negative bacteria requires drugs that can cross the outer membrane

Answer 5

- mycobacterium and norcardia - mycolic acid

Answer 6

contain peptidoglycan and stain Gram-positive, but bulk of cell wall is composed of unique lipids

Answer 7

- Found in the cell walls of acid-fast bacteria - Contributes to the pathogenicity of the bacteria - Makes bacteria highly resistant to certain chemicals and dyes

Answer 8

- Mycobacterium tuberculosis, Mycobacterium leprae, and Nocardia species - β-Lactams (include Penicillin) are ineffective

Answer 9

- All lack true peptidoglycan structure (pseudomurein) - Pseudomurein is immune from destruction by both lysozyme and penicillin - Most lack an outer membrane

Answer 10

- Found in many Bacteria and nearly all Archaea - consists of a paracrystalline monolayer of interlocking molecules of protein or glycoprotein - When present, is always the outermost layer of the cell envelope

Answer 11

- Naturally lack a cell wall - Sterols in the cell membrane stabilize the cell against lysis - Mycoplasma pneumoniae: “walking pneumonia”

Answer 12

Some bacteria that naturally have a cell wall but lose it during part of their life cycle - Role in persistent infections - Resistant to some antibiotics

Answer 13

- MUST contain steroids for membrane stability - Highly pleomorphic - Smallest prokaryotic organisms grown in cell-free culture medium - Parasitic and saprophytic - M. pneumoniae - they experience little osmotic pressure when living within the cytoplasm of another cell - absence of peptidoglycan may help evade the host immune system

Answer 14

Coating of repeating polysaccharide or glycoprotein units - Role in biofilm production - Slime layer: loose, protects against loss of water and nutrients - Capsule: more tightly bound, denser, and thicker; produce a sticky (mucoid) character to colonies on agar

Answer 15

- Formed by many pathogenic bacteria - Have greater disease-causing abilities - Protect against host white blood cells called phagocytes - Helps prevent cell dehydration

Answer 16

- Motility: flagella and axial filaments - Attachment points or channels: fimbriae, pili, hami, and nanotubes/nanowires

Answer 17

Primary function is motility * Three distinct parts: 1. Filament 2. Hook (sheath) 3. Basal body

Answer 18

Movement of bacteria in response to chemical signals

Answer 19

response to light signals

Answer 20

Runs (linear directions) and tumbles (stop and go)

Answer 21

Polar arrangement: flagella attached at one or both ends of the cell Monotrichous: single flagellum Lophotrichous: small bunches or tufts of flagella emerging from the same site Amphitrichous: flagella at both poles of the cell

Answer 22

flagella are dispersed randomly over the surface of the cell

Answer 23

Internal flagellum enclosed in the space between the cell wall and the cytoplasmic membrane

Answer 24

corkscrew-shaped bacteria - possess an unusual, wriggly mode of locomotion

Answer 25

proteins are unrelated to those of flagella, more closely related to type IV pili - Somewhat simpler than flagella - generally slower than bacterial flagella

Answer 26

Small, bristle-like fibers sprouting off the surface of many bacterial cells - Allow tight adhesion between fimbriae and epithelial cells, allowing bacteria to colonize and infect host tissues - Mutant forms of these pathogens that lack fimbriae are unable to cause infections

Answer 27

- Used in conjugation between bacterial cells - Type IV pilus can transfer genetic material, act like fimbriae and assist in attachment, and act like flagella and make a bacterium motile

Answer 28

Provides a mechanism for binding to the epithelial cells - Major contributor to the infectiousness of: * Neisseria gonorrhoeae (gonorrhea) * Vibrio cholerae (cholera) * Streptococcus pyrogenes (strep throat and scarlet fever)

Answer 29

Very thin, long, tubular extensions of the cytoplasmic membrane - Used as channels to transfer amino acids or to harvest energy by shuttling electrons to iron-rich substances (“breathing rock instead of oxygen”)

Answer 30

Present within the SM1 group of Archaea “Tiny grappling hook” - Aids in biofilm formation - Ecological strategy that helps trap scare nutrients within habitat

Answer 31

Inclusions function as energy reserves, carbon or phosphorus reservoirs, and/or have special functions - Enclosed by thin protein membrane - Reduces osmotic stress - Storing carbon or other substances in an insoluble form within the cytoplasm reduces osmotic stress and takes up less space compared with storing these substances in a soluble form

Answer 32

structures that confer buoyancy and allow the cells to position themselves in regions of the water column that best suit their metabolisms

Answer 33

impart a magnetic dipole on a cell, allowing it to orient itself in a magnetic field

Answer 34

- Dormant bodies - Produced by some Gram-positive bacilli

Answer 35

- metabolically active - Endospores resist extremes of heat, drying, freezing, radiation, and chemicals that would kill vegetative cells

Answer 36

vegetative cell → endospore → vegetative cell - Sporulation - Germination

Answer 37

The process of cellular differentiation that results in endospore formation

Answer 38

The process of an endospore converting back to a vegetative cell rapidly

Answer 39

anthrax tetanus gas gangrene botulism gastrointestinal disease

Answer 40

The hereditary material of most bacteria exists

Answer 41

- Nonessential pieces of DNA - Confer protective traits such as drug resistance and toxin and enzyme production

Answer 42

Site of protein synthesis

Answer 43

- Arranged in helical ribbons around the cell - Contribute to cell shape - Have also been identified in archaea - Unique to non-eukaryotic cells - may be a potential target for antibiotic development

Answer 44

- The domain Archaea is named for the Archaean eon - live in extreme environments (Extremophiles) - Now known to occupy a wide range of habitats - More closely related to domain Eukarya than bacteria - Share rRNA sequences not found in bacteria - Protein synthesis and ribosomal subunit structures are similar

Answer 45

- Vast majority of Archaea are difficult to grow in culture - The use of metagenomics and single-cell genome sequencing has led to an explosion in our understanding of the phylogenetic and physiological diversity of the archaeal domain

Answer 46

rRNA sequencing

Answer 47

phenotypic characteristics

Answer 48

Should share at least 95% of their genes as matches

Answer 49

Bacteria of the same species that have differing characteristics

Answer 50

Representatives of a species that stimulate a distinct pattern of antibody (serum) responses because of unique surface molecules

Answer 51

- Store energy rich compounds - Physically position cells in the environment for survival

Answer 52

kill more than 4 million people a year

Answer 53

respiratory infections

Answer 54

important for person-to-person transmission of many infectious diseases

Answer 55

Most pathogens survive poorly in air; thus, they are effectively transmitted only over short distances * Transmission can also occur via fomites * Thick cell walls have an advantage

Answer 56

offer different environmental niches and favor different microbes - Can set the stage for secondary infections

Answer 57

Typically, acute and non-life-threatening

Answer 58

Often chronic; Can be threatening in certain individuals

Answer 59

- Infections occur if host defenses are weakened or a new, highly virulent strain is introduced - Encapsulated strains are pathogenic (harder to kill) - Often treatable by antimicrobial agents - More virulent types are beta-hemolytic (lyse red blood cells)

Answer 60

Causative agent of strep throat - Can also cause infections of the inner ear, mammary glands, and skin as impetigo - Rare cases can cause severe systemic infections and necrotizing fasciitis - No vaccine currently available

Answer 61

responsible for streptococcal toxic shock syndrome and scarlet fever - produce a pyrogenic exotoxin

Answer 62

Causative agent of pneumonia - Common secondary infection - often the cause of death in elderly persons whose death is reported to be from “respiratory failure.” - Vaccine available and recommended for high- risk populations

Answer 63

Causative agent is Corynebacterium diphtheriae - (typically infects young children) - DTaP vaccine is highly effective - Toxoid: a chemically modified toxin from a pathogenic microorganism, which is no longer toxic but is still antigenic - Some strains produce an exotoxin that causes a pseudomembrane in the patient’s throat

Answer 64

Causative agent is Clostridium tetani - Common in soil contaminated with animal fecal wastes - Microbe is an obligate anaerobe → entrance wound must match growth conditions— e.g. improperly cleaned deep wounds such as those caused by rusty/dirt-contaminated nails - recovery from tetanus does not provide immunity because the amount of toxin needed to cause the symptoms is too little to be immunogenic

Answer 65

caused by an extremely potent neurotoxin, that is released upon death and lysis of the bacteria - It enters the CNS via the peripheral nerves or the blood. The bacteria themselves don’t spread from the infection site, and there is no inflammation

Answer 66

Causative agent is Bordetella pertussis

Answer 67

Causative agent is Clostridium tetani

Answer 68

Causative agent is Corynebacterium diphtheriae

Answer 69

Causative agent of pneumonia

Answer 70

An acute, highly infectious respiratory disease * Common in school-age children - There has been a consistent upward trend of infections since the 1980s - Inadequately immunized children, adolescents, and adults are at high risk for acquiring and spreading pertussis Preventable and treatable → DTaP vaccine

Answer 71

DTaP is a combination vaccine used to provide immunity against 3 serious diseases (Diphtheria, tetanus, and pertussis [whooping cough]) - children 6 weeks to 7 years

Answer 72

used to boost immunity against the same 3 diseases - Tdap contains a lower dose of vaccine - adults and children 10 or older

Answer 73

Causative agent is Mycobacterium tuberculosis

Answer 74

Transmitted by airborne droplets - top infectious disease killer worldwide - Primary infection (initial infection) - Post-primary infection (re-infection) * Chronic

Answer 75

Causative agent: Mycobacterium leprae

Answer 76

Transmitted by direct contact as well as airborne - not very contagious - Less contagious than TB - survive ingestion by macrophages and eventually invade cells of the peripheral nervous system, where their presence causes nerve damage - Death usually results not from the leprosy itself, but from complications and secondary illnesses

Answer 77

sulfone drugs

Answer 78

characterized by a vigorous immune response and a good prognosis for spontaneous recovery → Less pronounced lesions - Tuberculoid disease occurs in people with effective immune reactions

Answer 79

lepromatous (progressive) leprosy - Characterized by folded, bulblike lesions on the body - Severe untreated cases of leprosy → disfiguring lesions lead to destruction of peripheral nerves

Answer 80

inflammation of the meninges, the membranes that compose the protective covering of the central nervous system (spinal cord and brain) - Caused by many microbes: viruses, bacteria, fungi, and protists

Answer 81

Neisseria meningitidis (meningococcus)

Answer 82

frequently present in the nose and throat of carriers without causing disease symptoms → reservoir of infection → transmission by droplet aerosols or direct contact with secretions - Many produce a capsule that protects them from phagocytosis

Answer 83

sudden onset of a headache accompanied by vomiting and a stiff neck, and its seriousness is underscored by the fact that meningitis can progress to coma and death in less than a day - Most distinguishing feature → rash - Mostly caused by an endotoxin - Vaccine available (1982) - In the United States, sporadic meningococcal outbreaks occur among college students

Answer 84

a condition characterized by intravascular coagulation and tissue destruction (gangrene), shock, and death in over 10% of cases

Answer 85

Commonly infect skin and wounds - Potent virulence factors including: * Hemolysins (Lyses red blood cells) * Coagulase (Clots blood) * Leukocidins (Lyses white blood cells)

Answer 86

Symptoms of TSS result from an exotoxin → recruits large numbers of T cells → major inflammatory response (frequently fatal)

Answer 87

Penicillin

Answer 88

methicillin Methicillin worked for about 20 years * Populations evolved resistance to it. * MRSA = methicillin-resistant S. aureus

Answer 89

methicillin-resistant S. aureus

Answer 90

Doctors treat MRSA with the antibiotic vancomycin, one of the “drugs of last resort.”

Answer 91

vancomycin-resistant S. aureus

Answer 92

These enterococci contained a vancomycin-resistance gene identical to the one in MRSA → VRSA. * This suggests that VRSA had acquired vancomycin resistance from Enterococcus.

Answer 93

Caused by a variety of bacteria, viruses, protists, and even fungi - Pathogens are generally only found in body fluids from the genitourinary tract that are exchanged during sexual activity - Note the downward trend in disease incidence after the introduction of antibiotics and the upward trend in the incidence of gonorrhea after the introduction of birth control pills

Answer 94

Causative agent: Neisseria gonorrhoeae

Answer 95

Does not survive away from mucous membranes of the pharynx, conjunctiva, rectum, or genitourinary tract * Can only be transmitted via person-to-person contact asymptomatic in women: Untreated gonorrhea can lead to pelvic inflammatory disease males: painful infection of the urethral canal - Infants born to infected mothers may acquire eye infection

Answer 96

Caused by Treponema pallidum

Answer 97

Transmitted via tiny breaks in the skin epithelial layer - Can be transmitted from an infected woman to the fetus during pregnancy (congenital syphilis) - Penicillin is highly effective for primary and secondary stages Human Experiments: Tuskegee Experiment (1932-1972)

Answer 98

small bacteria that have strict intracellular existence in vertebrates - have not been cultured in artificial culture media

Answer 99

Rickettsia rickettisii – ticks

Answer 100

Rickettsia prowazekii – lice

Answer 101

Rickettsia typhi – fleas

Answer 102

a problem among troops in wartime because of the unsanitary, cramped conditions - typhus caused more military deaths than did combat - Mortality rate of as much as 30% - through the skin when a puncture caused by a louse bite becomes contaminated with louse feces - rash in the armpits - Complications from untreated typhus: damage to the central nervous system, lungs, kidneys, and heart - Vaccine is available

Answer 103

Causative agent: Borrelia burgdorferi

Answer 104

Most prevalent arthropod-borne disease in the United States - Spread by the deer tick - Initial symptoms of Lyme disease include headache, backache, chills, and fatigue - During the initial stages, Lyme disease can be treated with antibiotics - Chronic stage develops in weeks to months - No toxins or virulence factors have been identified but the pathogen triggers a strong immune response

Answer 105

Plague has caused more human deaths than any other bacterial disease in recorded history - can be treated if it is rapidly diagnosed

Answer 106

Caused by Yersinia pestis -Disease of domestic and wild rodents * Fleas are intermediate hosts and vectors that spread plague between mammalian hosts * Humans are accidental hosts

Answer 107

Y. pestis grows in lymph nodes → swelling (buboes) - treated with antibiotics

Answer 108

Y. pestis is directly inhaled or reaches the lungs via the blood or lymphatic circulation (90% of untreated cases are deadly in 48hrs)

Answer 109

rapid spread through the bloodstream → so severe that death often occurs before diagnosis

Answer 110

Causative agent is Bacillus anthracis

Answer 111

Identified by Robert Koch → used to develop his principles for linking cause and effect in infectious disease—Koch’s postulates - Natural reservoir is soils → primarily associated with farm animals - Endospores enhance ability to disseminate B. anthracis Produces a unique capsule → does not stimulate the immune system * Produces exotoxins → interfere with phagocytosis * Grows within macrophages → eventually killing it → dispersing into the bloodstream * Treatable with antibiotics (if done early) * Vaccine is available for high-risk individuals * Use as a potential bioterrorism or biological warfare agent

Answer 112

most common * Entered through break in the skin → forms pustule of necrotic tissue

Answer 113

Ingestion of endospores in undercooked meat

Answer 114

Most severe, nearly always fatal * Inhalation of endospores (systemic → septic shock)

Answer 115

Severe gastrointestinal diarrheal disease caused by Vibrio cholerae

Answer 116

Typically transmitted through ingestion of contaminated water - Largely restricted to developing countries

Answer 117

attaches to epithelial cells in the small intestine, where it grows and releases cholera toxin - causes fluid losses of up to 20 liters per person per day → severe dehydration

Answer 118

Causative agent: Salmonella enterica

Answer 119

the most important waterborne pathogenic bacteria

Answer 120

Disease that results from ingestion of foods containing preformed microbial toxins - The microorganisms DO NOT have to grow in the host

Answer 121

Microbial infection resulting from the ingestion of pathogen-contaminated food followed by GROWTH of pathogen in the host

Answer 122

Eight microorganisms account for the great majority of foodborne illness: Salmonella Listeria monocytogenes

Answer 123

gastrointestinal illness caused by foodborne Salmonella infection - Caused by eating food contaminated with Salmonella or handling Salmonella-infected animals

Answer 124

ingested in food or water invades phagocytes and grows as an intracellular pathogen

Answer 125

Causative agent: Listeria monocytogenes - Acid-, salt-, and cold-tolerant and facultatively aerobic - L. monocytogenes was known to cause stillbirth and neurological disease in animals - dangerous during pregnancy - Listeriosis is the fourth most common cause of bacterial meningitis

Answer 126

A gastrointestinal food infection that may lead to bacteremia (bacteria in the blood) and meningitis - minor foodborne pathogen - Excreted in animal feces → is widely distributed in soil and water - wide variety of foods

Answer 127

Virulence factor: Engulfment of the pathogen by phagocytes results in the growth and proliferation of the bacterium - Primarily in the liver - Unusual capability of moving directly from one phagocyte to an adjacent one

Answer 128

- appeared 1.8 billion years ago - evolved from (LUCA) - last common ancestor of all eukaryotic cells was a single-celled microorganism closely related to Archaea

Answer 129

much more genetically and ecologically diverse than larger eukaryotes - Eukarya limited range of metabolic diversity (what they can use for energy)

Answer 130

prokaryotic cells trapped inside other prokaryotic cells

Answer 131

endosymbiotic acquisition by a eukaryotic host cell of a respiring bacterium or a phototrophic cyanobacterium, followed by evolution of the endosymbiont into mitochondria or chloroplasts

Answer 132

endosymbiotic acquisition by a mitochondrion- containing eukaryotic cell of a red or green algal cell, which ITSELF contains a chloroplast derived from primary endosymbiosis - Occurred multiple times within the Eukarya, giving rise to a diversity of phototrophic eukaryotes

Answer 133

Similarity between organelles of modern eukaryotic cells and the structure of bacteria

Answer 134

- Capable of independent division - Contains a circular chromosome with bacterial DNA sequences - Prokaryotic ribosomes (70S) - Contain bacterial membranes and can be - inhibited by drugs that affect *only* bacteria

Answer 135

An intracellular bacteria - Mitochondria’s closest relative are rickettsias

Answer 136

- Similar to flagella in structure, but are smaller and more numerous - Found only in a single group of protozoa and certain animal cells

Answer 137

X10 thicker than bacterial flagella

Answer 138

An outermost layer that comes into direct contact with the environment - Composed of polysaccharides * A network of fibers * A slime layer * A capsule

Answer 139

fungi and most algae - structural support - Fungal: Thick inner layer of polysaccharide fibers composed of chitin or cellulose. Thin outer layer of mixed glycans - Algae: Varied in chemical composition: various sugars along with minerals such as silicon dioxide and calcium carbonate

Answer 140

Typical bilayer of phospholipids in which protein molecules are embedded - Contain sterols (cholesterol) of various kinds which provide stability - Cytoplasmic membranes selectively permeable barriers in transportation

Answer 141

Most prominent organelle of eukaryotic cells - Separated from the cell cytoplasm by an external boundary called the nuclear envelope which is perforated with pores - center is nucleolus

Answer 142

where components of ribosomes are made

Answer 143

ER with ribosomes attached - make membrane proteins and secretory protein

Answer 144

without ribosomes attached - makes lipids, fats - Detoxifies drugs and poisons liver has smooth ER

Answer 145

Molecule processing “the warehouse" - Receives, refines, stores, and distributes chemical products of the cell - works with transport vesicles

Answer 146

the cell’s garbage disposal * A membranous sac of hydrolytic enzymes that can digest (hydrolyze) macromolecules * work best in acidic environments * Autophagy: Lysosomes use enzymes to recycle the cell’s own organelles and macromolecules (self engulfing)

Answer 147

Membrane-bound sacs containing fluids or solid particles to be digested, excreted, or stored - storage compartments

Answer 148

Composed of a smooth, continuous outer membrane with an inner folded membrane - Generate energy for the cell - Divide independently of the cell - Contain circular strands of DNA and prokaryotic ribosomes

Answer 149

found in algae cells and plant cells - Capable of converting energy from sunlight into chemical energy through photosynthesis - Produce oxygen gas as a by-product of photosynthesis

Answer 150

Scattered freely in the cytoplasm and cytoskeleton * Attached to the rough endoplasmic reticulum * Appear inside mitochondria and chloroplasts (70S prokaryotic size) - Multiple ribosomes are often found arranged in short chains called polyribosomes (polysomes)

Answer 151

Eukaryotic ribosome is 80S Prokaryotic ribosome is 70S

Answer 152

network of fibers extending throughout the cytoplasm - It gives animal cells shape and support - Controls intracellular traffic - It gives all cells some ability to control their movement

Answer 153

Large variety and complexity

Answer 154

(mushrooms, puffballs, gill fungi)

Answer 155

fungi (molds, yeasts)

Answer 156

Sterols (ergosterol) * Target in anti-fungal drugs

Answer 157

Hyphae Yeasts

Answer 158

Round to oval shape * Asexual reproduction, budding

Answer 159

Long, threadlike cells found in the bodies of filamentous fungi (molds)

Answer 160

chain of yeast cells

Answer 161

Some fungal cells are considered dimorphic and can take either form, depending on growth conditions → particularly characteristic of some pathogenic molds

Answer 162

acquire nutrients from a wide variety of organic substrates

Answer 163

these substrates from the remnants of dead plants and animals in soil or aquatic habitats

Answer 164

grow on the bodies of current or previously living animals or plants, although very few require a living host

Answer 165

- Fungi penetrate the substrate and secrete enzymes that reduces it to small molecules that can be absorbed by the cells - often found in nutritionally poor or adverse environments, and those with high salt or sugar content

Answer 166

- decomposing organic matter - stable associations with plant roots - engineered to produce large quantities of antibiotics, alcohol, organic acids, and vitamins - eaten or used to provide flavoring to food

Answer 167

- microscopic fungi grow in loose associations or colonies - yeast: soft, uniform texture and appearance - molds: hairy

Answer 168

dormant survival structures - Can be dispersed through the environment by air, water, and living things

Answer 169

Sporangiospores Conidiospores or conidia

Answer 170

formed by successive cleavages within a saclike head - asexual

Answer 171

free spores not enclosed by a spore-bearing sac - no head - asexual

Answer 172

vary from simple fusion of fertile hyphae of two different strains, or as a complex union of male and female structures

Answer 173

sturdy diploid spores formed when hyphae of two opposite strains (called the plus and minus strains) fuse and create a diploid zygote

Answer 174

- Reduces crop production - Can cause disease in domestic animals consuming contaminated feed crops

Answer 175

a very common decomposer of citrus fruit, is known for its velvety texture and typical blue-green color

Exam 3 Flashcards

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