Exam 3

Question 1

What are reservoirs? What are the four major reservoirs?

Answer 1

Physical locations of chemical elements that are acted upon through biogeochemical cycles; major global reservoirs include terrestrial (lithosphere), aquatic (hydrosphere), atmospheric (atmosphere), and living (biosphere)

Question 2

What 2 reactions affect oxygen cycling the most? Can anaerobic bacteria affect this cycling?

Answer 2

atmospheric and dissolved O2, which is produced via photosynthesis and is used for aerobic respiration. Water (H2O), an end product of many metabolic activities, including respiration, some methanogenic reactions, and aerobic and anaerobic CH4 oxidation, represents another major source of oxygen.

Question 3

differences between and reactions of nitrogen fixation, nitrification, and
denitrification.

Answer 3

Denitrification by bacteria converts nitrates (NO3−) to nitrogen gas (N2). Nitrification by bacteria is the conversion of ammonia (NH3) into nitrite (NO2–) and then into nitrate (NO3–). Nitrogen-fixing bacteria convert nitrogen gas (N2) into organic compounds such as ammonia.

Question 4

What is methanogenesis?

Answer 4

Anaerobic metabolic process with methane (CH4) as a product

Question 5

What is the importance of methane monooxygenase (MMO) enzyme for methanotrophs?

Answer 5

It is the enzyme responsible for converting CH4 to CH3OH (methanol).

Question 6

What reactions affect carbon cycling?

Answer 6

Photosynthesis, Respiration, and Decomposition, methanogenesis, and methanotrophy

Question 7

Phosphorus and sulfur are limiting elements; where can they be found?

Answer 7

the major reserves of these elements exist in rock or are dissolved in the oceans.

Question 8

the steps of biofilm formation

Answer 8

1. Adhesion by a primary colonizer
2. cells divide aka growth
3. microcolony produces EPS
4. introduction of secondary colonizers (diversify) growth of the community
5. established biofilm structure with nutrient gradients, distinct distributions of species, and dispersing cells

Question 9

What are the advantages of biofilms? How is it regulated?

Answer 9

nutrients often bind to these solid surfaces, enabling higher cell concentrations than typically exist in bulk fluid. Moreover, the members of a biofilm interact with and support one another. Its regulated through EPS production

Question 10

ecosystem

Answer 10

A community and its physical environment

Question 11

niche

Answer 11

Specific functional role of an organism within an ecosystem

Question 12

consortia

Answer 12

two or more interacting microbial populations that can be found in many diverse environmental niches

Question 13

community

Answer 13

an interacting group of various species in a common location

Question 14

population

Answer 14

A group of organisms of one species that interbreed and live in the same place at the same time

Question 15

Microbes make up the majority of the biomass in the ocean. What role do viruses play?

Answer 15

viruses play an important role in controlling the microbial communities that exist with the marine water column. Through lysing bacteria, they supply the ocean with nutrients

Question 16

What did the Winogradsky column demonstrate?

Answer 16

how microorganisms occupy highly specific microsites according to their environmental tolerances and their carbon and energy requirements.

Question 17

Are we limited to only studying organisms we can grow in the laboratory? If not, what other
techniques can be used to study them?

Answer 17

no. the analysis of small subunit ribosomal RNA (SSU rRNA) genes amplified by PCR or by capturing DNA extracted directly from environmental samples by metagenomics

Question 18

Enrichment media can be useful for growing organisms that may be more difficult to study.
Does the enrichment process give us a true analysis of the bacteria in that environment?

Question 19

How can microbes benefit plants? How do plants benefit microbes?

Answer 19

plants create the rhizosphere and provide nutrients for microrganisms

Question 20

What is a rhizosphere? How is it different from other areas of the soil?

Answer 20

Region of soil immediately surrounding plant roots. the rhizosphere contains large amounts of organic carbon due to the considerable influence of plant root exudate.

Question 21

What are the dangers of anoxic waters (“dead zones”), and how does this occur?

Answer 21

Areas where marine animal life cannot survive due to hypoxia (low O2 levels). It occurs usually where rivers meet the ocean. It occurs because of the use of synthetic and inorganic fertilizer runoff.

Question 22

What is bioremediation? What benefit can be seen by this process?

Answer 22

Use of microorganisms to degrade environmental pollutants. Bacteria degraded toxic compounds in the oil spills.

Question 23

nodule formation.

Answer 23

bacteroids use their relationship with the plant to solve the problems of both high-energy requirements and oxygen toxicity by inducing the plant root to produce a protective structure called a root nodule

Question 24

In what order does ingested food pass through the digestive system in a cecal fermenter? What
about a rumen fermenter

Answer 24

Hindgut (Cecal) fermentation relies on host digestive processes in the stomach and small intestine first, and microbial fermentation processes last. ruminants use foregut fermentation, fermenting their food first using microorganisms. Any undigested, unabsorbed material is then passed through the stomach, the small intestine, cecum, and colon,

Question 25

What are rhizobia? What type of relationship do they have with plants?

Answer 25

bacteria characterized by their ability to form root nodules; they are endosymbiotic and mutualistic to plants

Question 26

What is the microbiome? What part of the human body contains the most bacteria?

Answer 26

The total of all the microbes living in a defined environment, such as soil, the human body, or even part of the body. the digestive tract

Question 27

How do termites obtain nitrogen?

Answer 27

Nitrogen-fixing bacteria can convert N2 into nitrogenous compounds, such as ammonia, for termite use

Question 28

What are red, white, and green biotechnologies?

Answer 28

red encompasses microbes used in pharmaceuticals through therapeutics and antibiotics; white encompasses microbes used for industrial purposes: cleaners, cosmetics, fuel, plastics; green encompasses microbes used in agriculture

Question 29

What is the difference between primary and secondary metabolites?

Answer 29

A primary metabolite is a metabolic product required for growth; produced by microorganisms during the exponential growth phase / A secondary metabolite is a metabolic product not required for growth; often produced by microorganisms during the stationary phase of the growth curve

Question 30

For optimal expression of a eukaryal gene in bacteria, the expression vector must contain what?

Answer 30

It must contain bacterial promoters and transcription terminators.

Question 31

What is CRISPR-CAS?

Answer 31

Clustered regularly interspersed short palindromic repeats and CRISPR-associated proteins that constitute an anti-viral defense system in bacteria

Question 32

The introduction of DNA into plants for the creation of transgenic plants often uses a plasmid-mediated process from which bacterium?

Answer 32

Agrobacterium

Question 33

What was the first recombinant human protein produced and marketed commercially?

Answer 33

Insulin

Question 34

What is the most common way to reduce food spoilage?

Answer 34

refrigeration

Question 35

What is lyophilization?

Answer 35

Freeze-drying: Process for preserving food, whereby food is frozen and then dried under a vacuum, allowing removal of water by sublimation

Question 36

What factors affect microbial growth? Are they intrinsic or extrinsic?

Answer 36

Intrinsic factors are a characteristic inherent quality of the food, such as water, salt content, nutrients, pH, or things such as rinds or shells. Extrinsic factors are a characteristic of the storage environment of the food, such as temperature and humidity.

Question 37

Some bacteria cause infection by toxins and others by the presence of the microbe itself.
Know the common foodborne bacteria and which produce toxins

Answer 37

1.Salmonella spp. - foodborne illness / harmful presence
2.Campylobacter spp. - foodborne illness / harmful presence
3. Clostridium perfringens - foodborne illness / harmful presence
4. Shigella spp. - foodborne illness / harmful presence
5. Staphylococcus aureus (S. aureus) - produces toxins / foodborne intoxication
6. C. botulinum - produces toxins / foodborne intoxication
7. E. Coli - foodborne illness / harmful presence

Question 38

What causes the distinct flavor of blue cheese

Answer 38

Penicillium roquefortii mold