Chapter 8 - Microbial Nutrition

Question 1

Process by which chemical substances (nutrients) are acquired from the environment and used in cellular activities

Answer 1

Nutrition

Question 2

Must be provided to an organism

Answer 2

Essential nutrients

Question 3

What are two categories of essential nutrients?

Answer 3

1. Macronutrients

2. Micronutrients or trace elements

Question 4

96% of cell is composed of what 6 elements?

Answer 4

1. Carbon
2. Hydrogen
3. Oxygen
4. Phosphorous
5. Sulfur
6. Nitrogen

Question 5

What are the sources of essential nutrients?

Answer 5

• Carbon sources
• Nirtogen sources
• Oxygen sources
• Hydrogen sources

Question 6

Heterotroph vs. Autotroph

Answer 6

Carbon sources

Question 7

• Main reservoir is nitrogen gas (N2); 79% of earth’s atmosphere is N2
• Nitrogen is part of the structure of biological molecules – these are the primary source of N for heterotrophs
• Inorganic N sources
• NH3 -only form that can be combined with carbon to synthesize amino acids, etc

Answer 7

Nitrogen Sources

Question 8

• Major component of biological molecules
• Component of inorganic salts (sulfates, phosphates, nitrates) and water
• O2 makes up 20% of atmosphere
• Essential to metabolism of many organisms

Answer 8

Oxygen Sources

Question 9

• Major element in all organic compounds and several inorganic ones
• Roles of hydrogen:

Answer 9

Hydrogen Sources

Question 10

Essential to protein synthesis and membrane function

Answer 10

Potassium

Question 11

Important to some types of cell transport

Answer 11

Sodium

Question 12

Cell wall and endospore stabilizer

Answer 12

Calcium

Question 13

Component of chlorophyll; membrane and ribosome stabilizer

Answer 13

Magnesium

Question 14

Cmponent of proteins of cell respiration

Answer 14

Iron

Question 15

______ _______ must be provided as a nutrient

Answer 15

Growth factors

- Essential amino acids, vitamins

Question 16

Main determinants of nutritional type are

Answer 16

• Carbon source

- Energy source

Question 17

Heterotroph or Autotroph

Answer 17

Carbon source

Question 18

Chemotroph or Phototroph

Answer 18

Energy source

Question 19

• Oxygenic photosynthesis

- Anoxygenic photosynthesis

Answer 19

Photoautotrophs

Question 20

Chemoautotrophs (lithoautotrophs) survive totally on _________ substances

Answer 20

Inorganic

Question 21

Methanogens, a kind of chemoautotroph, produce methane gas under ________ conditions

Answer 21

Anaerobic

Question 22

Majority are chemoheterotrophs

- Aerobic respiration

Answer 22

Heterotrophs

Question 23

What are the two categories of heterotrphs?

Answer 23

1. Saprobes

2. Parasites

Question 24

Free-living microorganisms that feed on organic detritus from dead organisms

• Opportunistic pathogen
• Faculative parasite

Answer 24

Saprobes

Question 25

Derive nutrients from host - Pathogens - Some are obligate patasites

Answer 25

Parasites

Question 26

What factor influences microbes?

Answer 26

Niche

Question 27

What environmental factors affect the function of metabolic enzymes?

Answer 27

- Temperature - Oxygen requirements - pH - Osmotic pressure - Barometric pressure

Question 28

What metabolism do microbes have?

Answer 28

Catabolism or anabolism

Question 29

- Cellulase - Amylase - Penicillinase - What are most of the others?

Answer 29

Exoenzymes | - Most others: Endoenzymes

Question 30

- Repeatedly accept and release electrons and hydrogen to facilitate the transfer of redox energy - Most carriers are coenzymes

Answer 30

Electron and Proton Carriers = redox pair

Question 31

- Metabolic "currency" - Three part molecule - ATP utilization and replenishment is a constant cycle in active cells - Removal of the terminal phosphate releases energy

Answer 31

Adenosine Triphosphate: ATP

Question 32

ATP can be formed by what three different mechanisms?

Answer 32

1. Substrate-level phosphorylation 2. Oxidative phosphorylation 3. Photophosphorylation

Question 33

Study of the mechanisms of cellular energy release

Answer 33

Bioenergetics

Question 34

Primary catabolism of fuels (glucose) proceeds through a series of three coupled pathways. What are they?

Answer 34

1. Glycolysis 2. Kreb’s cycle 3. Respiratory chain, electron transport

Question 35

ETS shuttles electrons down the chain, energy is released and subsequently captured and used by ATP synthase complexes to produce ATP

Answer 35

Oxidative phosphorylation

Question 36

Functions like aerobic respiration except it utilizes oxygen containing ions, rather than free oxygen, as the final electron acceptor

Answer 36

Anaerobic Respiration

Question 37

Most obligate anaerobes use the H+ generated during glycolysis and the Kreb’s cycle to reduce some compound other than O2

Answer 37

Anaerobic Respiration

Question 38

- Incomplete oxidation of glucose or other carbohydrates in the absence of oxygen - Uses organic compounds as terminal electron acceptors - Yields a small amount of ATP - Production of ethyl alcohol by yeasts acting on glucose - Formation of acid, gas, and other products by the action of various bacteria on pyruvic acid

Answer 38

Fermentation

Question 39

Many pathways of metabolism are bi-directional or ___________

Answer 39

Amphibolic

Question 40

Catabolic pathways contain molecular intermediates (metabolites) that can be diverted into ________ ________

Answer 40

Anabolic pathways

Question 41

Pyruvic acid can be converted into amino acids through _________

Answer 41

Amination

Question 42

Amino acids can be converted into energy sources through ___________

Answer 42

Deamination

Question 43

Glyceraldehyde-3-phosphate can be converted into precursors for _____ _____, _____________, and ____

Answer 43

Amino-acids, carbohydrates, and fats