Section 24.3 (Exam 1)

Question 1

___________ usually live in communities of many different microbial species.

Answer 1

Prokaryotes

Question 2

What are biofilms?

Answer 2

A gel-like polysaccharide matrix that traps other cells; forms when cells contact a solid surface.

Question 3

Human health depends in part on the health of the communities of what that live in our body? What is this called?

Answer 3

Communities of bacteria. Microbiome.

Question 4

Babies born by C-section or bottle-fed artificial formula have higher incidences of what? Why?

Answer 4

Auto-immune disease. Because they never acquired the proper bacteria, and don’t have a healthy microbiome.

Question 5

How do you get vitamins B12 and K?

Answer 5

They are absorbed by your gut microbiome.

Question 6

The biofilm that lines human intestines functions like a specialized “tissue” in what way?

Answer 6

By facilitating nutrient uptake.

Question 7

Name Koch’s Postulates to establish that a specific organism causes a specific disease.

Answer 7

Microorganism is found in afflicted individual.

Microorganism is isolated and grown in PURE culture.

A sample of the pure culture can infect a healthy individual successfully.

The victim yields a PURE culture.

Question 8

For an organism to become a pathogen it must:

Answer 8

Arrive at the body surface of a host.
Enter the host’s body.
Evade the host’s defenses.
Multiply inside the host.
Infect a new host.

Question 9

What is a pathogen’s invasiveness?

Answer 9

Its ability to multiply.

Question 10

What is a pathogen’s toxigenicity?

Answer 10

Its ability to produce toxins.

Question 11

Diptheria bacteria has low or high toxigenicity and low or high invasiveness?

Answer 11

high toxigenicity; low invasiveness

Question 12

Bacillus anthracis (anthrax bacteria) has low or high toxigenicity and low or high invasiveness?

Answer 12

low toxigenicity; high invasiveness

Question 13

Endotoxins are released when Gram-___________ bacteria are lysed.

Answer 13

Gram-negative

Question 14

Endotoxins are ___________________________ from the outer membrane.

Answer 14

lipopolysaccharides

Question 15

Are endotoxins fatal?

Answer 15

Rarely.

Question 16

Exotoxins are soluble __________ released by living bacteria.

Answer 16

proteins

Question 17

List 5 examples of exotoxin induced diseases.

Answer 17

Tetanus (Clostridium tetani)
Botulism (Clostridium botulinum)
Cholera (Vibrio cholerae)
Plague (Yersinia pestis)
Anthrax (Bacillus anthracis)

Question 18

Prokaryotes have more or less metabolic pathways than eukaryotes?

Answer 18

more

Question 19

Name some (10) prokaryote metabolic pathways?

Answer 19

Anaerobic
Aerobic
Photoautotrophs
Photoheterotrophs
Chemoautotrophs
Chemoheterotrophs
Decomposers
Denitrifiers
Nitrogen-fixers
Nitrifiers

Question 20

What are facultative anaerobes?

Answer 20

Can shift metabolism between aerobic and anaerobic modes, such as fermentation.

Question 21

What are aerotolerant anaerobes?

Answer 21

They are not damaged by oxygen, but do not conduct cellular respiration.

Question 22

What are obligate aerobes?

Answer 22

They cannot survive without oxygen.

Question 23

Photoautotrophs perform _____________, meaning they obtain carbon from _____________.

Answer 23

photosynthesis; Carbon dioxide (CO2)

Question 24

Bacteriochlorophyll is used as a photosynthetic pigment by some members of which prokaryote group defined by their metabolic pathway?

Answer 24

Photoautotrophs

Question 25

Bacteriochlorophyll absorbs _________ wavelengths of light than chlorophyll. This means they can live in water under dense layers of algae.

Answer 25

longer

Question 26

Bacteriochlorophyll use something in place of H2O as an electron donor. What is it?

Answer 26

Hydrogen Sulfide (H2S)

Question 27

Photoheterotrophs use light for ___________ and obtain carbon from ______________.

Answer 27

energy; organic compounds

Question 28

____________________ get energy by oxidizing inorganic compounds and get carbon by using that energy to fix CO2.

Answer 28

Chemoautotrophs

Question 29

Chemoheterotrophs obtain both energy and carbon from __________________________________________.

Answer 29

complex organic compounds that were synthesized by other organisms.

Question 30

A few species of chemoheterotrophs get energy from the breakdown of inorganic molecules. What are they called?

Answer 30

Lithotrophs

Question 31

_______________ metabolize organic compounds in dead organisms and other organic materials.

Answer 31

Decomposers

Question 32

______________ convert N2 gas into ammonia (NH3). Which organisms perform this action?

Answer 32

Nitrogen-fixers Nitrogen fixing is done by archaea and bacteria like cyanobacteria, but NOT done by eukaryotes.

Question 33

___________ are chemoautotrophic bacteria. They oxidize ammonia (NH3) into nitrite (NO2-) and then oxidize nitrite (NO2-) into nitrate (NO3-).

Answer 33

Nitrifiers

Question 34

What are some common nitrifiers that oxidize ammonia? Which ones oxidize nitrite?

Answer 34

Nitrosomonas and Nitrosococcus oxidize ammonia. Nitrobacter oxidizes nitrite.

Question 35

____________ use nitrate (NO3-) as an electron acceptor in anaerobic conditions. They use the oxygen for themselves and release nitrogen gas (N2) to the atmosphere. Almost all of them could be considered _________________________.

Answer 35

Denitrifiers; facultative anaerobes

Question 36

What are some examples of denitrifiers?

Answer 36

Bacillus and Pseudomonas

Question 37

Why is it hard to classify viruses?

Answer 37

Tiny genomes, mutate fast, no fossils, very diverse

Question 38

How do we classify viruses?

Answer 38

Genome structure