Microbial Metabolism

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Microbial Metabolism

• I. Metabolism of Microbes
• A. Metabolism
• 1. Refers to all chemical reactions
  that occur in living cell
• 2. The chemical reactions sustain life
• 3. Allows microbe to grow, reproduce,
  maintain their structures,
• and respond to their environments
• B. Metabolism is usually divided into two
  categories
• 1. Catabolism
• a. breaks down organic matter into
  smaller products to harvest energy
• b. respiration, digestion, conversion
  of glycogen to glucose
• 2. Anabolism
• a. uses energy to construct
  components of cells (synthesize large molecules
  from smaller molecules)
• b. photosynthesis, protein synthesis,
  DNA synthesis

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II. Transfer of Energy in Reactions A. The
Universal Energy Compound 1. Adenosine
triphosphate (ATP) a.
Multifunctional energy molecule referred to as
the molecular unit of
currency 2. Transports chemical
energy within cells for metabolism
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B. ATP- ADP Cycle
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• III. Enzymes
• A. Enzyme Characteristics
• 1. Proteins that catalyze reactions
• 2. The active site of an enzyme
  recognizes a particular substrate
• to change it to the products

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• 3. The enzyme structure does not change in a
  reaction and can be reused
• for additional reactions
• 4. Enzymes work by lowering the activation energy
  for a reaction, thus
• dramatically increasing the rate of the
  reaction

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• 5. Enzymes are usually very specific as to
  which reactions they catalyze and are
  specific as to the substrates that are involved
  in these reactions
• 6. Complementary shape, charge and
  hydrophilic/hydrophobic characteristics of
  enzymes and substrates are responsible for this
  specificity
• 7. Factors Influencing Enzyme Reaction Rates
  -temperature -pH -substrate concentration

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• B. Enzyme Inhibitors
• 1. Competitive inhibitors
• 2. Noncompetitive inhibitors

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• C. Coenzymes 
• 1. Some enzymes require a coenzyme for
  activation
• 2. Coenzymes are not proteins and are often
  vitamins or are made from
• vitamins

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• 3. Many contain the nucleotide , adenosine
  monophosphate (AMP) as
• part of their structures, such as ATP,
  coenzyme A, FAD, and NAD
•   Some Organic Coenzymes -Vitamin
  Source
• NAD Nicotinamide adenine dinucleotide -
  niacin
• FAD Flavin adenine dinucleotide -
  riboflavin
• CoA Coenzyme A - pantothenic acid
  

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• higher.mcgraw_hill.com/sites/0072507470/student_vi
  ew0/chapter25/animation_how_the_nad_works.html

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• 4. Oxidation-Reduction (Redox)

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5. Apoenzymes are enzymes without their
coenzymes 6. Holoenzymes are enzymes combined
with their coenzyme

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• IV. Aerobic Verses Anaerobic Respiration
• A. Aerobic Respiration
• 1. Cellular respiration is the set of
  the catabolic reactions and processes
• that convert biochemical energy
  from nutrients into ATP and release
• waste products
• 2. The reactions involved in
  respiration are catabolic reactions that
• involve the redox reaction
• 3. Respiration is one of the key ways a
  cell gains useful energy to fuel
• cellular events
• 4. Organisms that use oxygen as a final
  electron acceptor in respiration
• are aerobic while those that do not
  are referred to as anaerobic
• B. Anaerobic Respiration
• 1. Anaerobic respiration is used mainly
  by prokaryotes that live in
• environments devoid of oxygen.
• 2. Many anaerobic organisms are
  obligate anaerobes and will die in the presence
  of oxygen

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• V. Aerobic Respiration Differences
• A. Aerobic Respiration in the Eukaryotic Cell
• B. Aerobic Respiration in the Prokaryotic
  Cell
• Eukaryotic cell
  Prokaryotic
  cell

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Mitochondrion
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• VI. Aerobic Respiration
• A. Glycolysis

Glucose (C6H12O6)
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Glucose 6-phosphate
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Fructose 6-phosphate
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Fructose 1,6-diphosphate
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Glyceraldehyde 3-phosphate (GP)

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1,3-diphosphoglyceric acid
3-phosphoglyceric acid
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2-phosphoglyceric acid
Phosphoenolpyruvic acid (PEP)
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Pyruvic acid
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VII. Intermediate Step and the Krebs Cycle
A. Intermediate Step B. Krebs Cycle
http//www.youtube.com/watch?vWcRm3MB3OKwfeature
related
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VIII. Oxidative Phosphorylation

http//www.tudou.com/programs/view/iccpBeO_Ijw/
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• IX. ATP Ledger

Pathway By substrate-level phosphorylation By oxidative phosphorylation By oxidative phosphorylation
Pathway By substrate-level phosphorylation From NADH From FADH2
Glycolysis 2 6 0
Intermediate step 0 6 0
Krebs cycle 2 18 4
Total 4 30 4
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X. Fermentation
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Fermentation and their end products