6. Nutrient and Metabolism

Question 1

What do nutrients serve as sources of?

Answer 1

Chemical elements, electrons, and energy and often components of reactions that are reacted with a chemical energy source to yield energy like TEAs.

Question 2

Define catabolism and anabolism.

Answer 2

Catabolism: The extraction of energy and electrons from nutrients for use in motility, membrane transport, biosynthesis, and other energy and electron requiring processes.
Anabolism: The use of energy and electrons from catabolism along with various chemical elements the road from nutrients to make cellular macromolecules.

Question 3

Describe the relationship between anabolism and catabolism.

Answer 3

Catabolism supplies ATP and NADPH to anabolism. The energy and electrons obtained from nutrients as part of catabolism are not used directly in anabolism. ADP is phosphorylated to ATP using the energy source and NADP plus is reduced to NADPH using the electron source. It is these molecules that are usually deliver energy and electrons to anabolic reactions.

Question 4

Define assimilation.

Answer 4

The conversion of an element from inorganic to organic form.

Question 5

Define mineralization.

Answer 5

The conversion of an element from organic to inorganic form.

Question 6

Define degradation.

Answer 6

The fragmentation of a large molecules into smaller units.

Question 7

Define decomposition.

Answer 7

The degradation of an organic molecule and a mineralization of the elements making up the molecule.

Question 8

Define fixation.

Answer 8

The conversion of an element from gaseous to liquid or solid state.

Question 9

Defined dissimilative reduction.

Answer 9

The reduction of an element in a TEA for the purpose of producing energy.

Question 10

Define assimilative reduction.

Answer 10

The reduction of an element for the purpose of converting it from inorganic to organic form.

Question 11

Define assimilative oxidation.

Answer 11

The oxidation of an element for the purpose of converting the element from inorganic to organic form.

Question 12

Define organic chemicals.

Answer 12

Contain C and at least one CH, NH, or SH bond.

Question 13

Define the groups that are split according to their source of energy.

Answer 13

Chemotroph: uses a chemical as a source of energy.
Phototroph: uses light as a source of energy.

Question 14

Defined the groups that are split up according to their electron source.

Answer 14

Lithotroph: uses an inorganic chemical a source of electrons.
Organotroph: uses an organic chemical as a source of electrons.

Question 15

Define the groups that are split according to their carbon source.

Answer 15

Autotroph: uses in organic carbon usually CO2 as a source of carbon.
Heterotroph: uses organic carbon as a source of carbon.

Question 16

Define the three groups of nutritionally obligate organisms that will be used in microbiology 201.

Answer 16

Lithotroph: energy source is inorganic chemical, electron source is inorganic chemical, carbon source is inorganic carbon.
Heterotroph: energy source is an organic chemical, electron source is an organic chemical, carbon source is an organic carbon.
Phototroph: energy source is light, electron source is inorganic chemical, carbon source is inorganic carbon.

Question 17

Describe the nutrients of chemotrophs.

Answer 17

The nutrient serving as an electron donor in an energy yielding redox reaction is termed the energy source and the nutrient serving as the electron acceptor is termed the terminal electron acceptor. Only certain energy source and TEA reactions can be used to obtain energy this is summarized in the table.

Question 18

How does energy source affect energy yield?

Answer 18

The element oxidized, the oxidation state of an element, complete versus incomplete oxidation of an element the number of carbon atoms in an organic energy source.

Question 19

How do you TEAs affect energy yield?

Answer 19

Different energy source-TEA reactions yield different amounts of energy.

Question 20

How do reaction products affect energy yield?

Answer 20

Energy source-TEA reactions the only yield energy they also use other reaction products. Even if the energy source and TEA are the same, but the products are different, different amounts of energy are produced.

Question 21

Describe the energy source of phototrophs.

Answer 21

They use light as an energy source in combination with redox reactions. They use light energy to drive electrons from a donor
an acceptor with the production of energy. The electron donor and acceptors are not nutrients but our chlorophyll-based protein complexes called photosystems.

Question 22

What nutrients are major bioelements?

Answer 22

Carbon, hydrogen, oxygen, nitrogen, sulfur, phosphorus.

Question 23

What nutrients are minor bioelements?

Answer 23

Zinc, copper, calcium, magnesium, iron.

Question 24

Describe the assimilation of major bioelements.

Answer 24

Because the oxidation state of the major bioelements in a nutrient may differ from it oxidation state in the cellular molecule, organisms using an inorganic source of carbon and some inorganic sources of nitrogen, sulfur, and phosphorus must also be able to perform either assimilative production or assimilative oxidation.

Question 25

Describe the Calvin cycle.

Answer 25

It is by far for the most common way CO2 as a carbon source is reductively a simulated by prokaryotic autotrophs. NADPH donates electrons to reduce carbon.

Question 26

Describe glutamine synthesis.

Answer 26

It requires NH4+ and if an organism is using molecules like nitrate or nitrate, it must be reduced to NH4+.

Question 27

Describe assimilative nitrite and nitrate reduction.

Answer 27

These reactions are catalyzed by the NADPH requiring enzymes assimilative nitrate or nitrate reductase. They get reduced to NH4+.

Question 28

Describe biological nitrogen fixation.

Answer 28

Some prokaryotes are able to use nitrogen gas as a nitrogen source but because it is more oxidized than NH4+, it must be reduced in the reaction with NADPH to synthesize glutamine. This reduction is catalyzed by the enzyme nitrogenase and is usually referred to as biological nitrogen fixation.

Question 29

Describe assimilative sulphate reduction.

Answer 29

Sulphur assimilation involves the synthesis of the amino acids cysteine. Synthesis of cysteine requires H2S. Sulphate must be reduced to H2S and assimilative sulphate reduction is catalyzed by the enzyme sulphate reductase.

Question 30

Describe the assimilation of phosphate.

Answer 30

Phosphate is a simulated directly into cellular organic molecules without a reductive step. An important route for phosphate assimilation is where phosphate is combined with ADP to make ATP.

Question 31

Describe assimilative phosphite oxidation.

Answer 31

Because hydrogen phosphite is less oxidized and phosphate, it must be oxidized to phosphate for ATP synthesis. This is accomplished through the enzyme phosphate dehydrogenase which uses NAD+ or NADP+ as an electron acceptor to oxidize hydrogen phosphite to phosphate.

Question 32

Describe reserve materials.

Answer 32

When nutritional resources are in excess, they are often stored as polymeric reserve materials to be used later. Reserve materials are usually visible as granules or inclusion bodies in the cytoplasm.

Question 33

What must be represented in each step (at least one) of an elemental cycle?

Answer 33

The use of a chemical as an energy source, the use of a chemical as a TEA, the use of a chemical as an electron source, the use of a chemical as a source of carbon, nitrogen, sulfur, or phosphorus.

Question 34

Describe the carbon cycle.

Answer 34

Carbon dioxide is fixed and assimilated by phototrophic prokaryotes, plants, and algae and by lithotrophic prokaryotes. Much of the carbon dioxide consumed by plants is used to make cellulose. Organic carbon is mineralized by heterotrophic prokaryotes, fungi, protozoa, and by animals.

Question 35

Describe the sulphur cycle.

Answer 35

Sulphate is used as a sulphur source by all plants and by many prokaryotes. However, sulphate must be reduced for the purpose of assimilation. When plant material containing organic sulphur is consumed by heterotrophic organisms, some sulphur remains in organic and reduced forms, and some are mineralized to H2S during the decomposition of dead plant/animal tissue by heterotrophs. The H2S is then oxidized to sulphate by some photo trust and little troops. The process is dissimilative sulphate reduction.

Question 36

Describe the nitrogen cycle.

Answer 36

NH3 and nitrate are used as nitrogen sources by most plants and by many prokaryotes. In order to use nitrate as a nitrogen source, nitrogen must be reduced. This process is called assimilative nitrate reduction. When plant or animal tissue is consumed by heterotrophic organisms, some nitrogen remains in organic and reduced forms and some are mineralized to NH3 during the decomposition of dead plant/animal tissue by heterotrophs. The N3 resulting from this is oxidized to nitrate by lithotrophs. Much nitrate is reduced to nitrogen gas by some prokaryotes and lost to the atmosphere. Diverse prokaryotes can then reduce atmospheric nitrogen gas to NH3. This process is called biological nitrogen fixation.

Question 37

Describe the phosphorus cycle.

Answer 37

Phosphate is used as a phosphorus source and a simulated by all forms of life for the purpose of building phosphorus containing cellular organic molecules. The first person these molecules are mineralized to phosphate during the decomposition of dead plant/animal tissue by heterotrophs. These reactions are called dephosphorylation reactions. Phosphate is also produced during assimilative phosphite oxidation, and from the oxidation of phosphite serving as an energy and electron first for some prokaryotes.