Microbiology Exam 3 lecture 26 flash cards

Home > Preview

The flashcards below were created by user francis6 on FreezingBlue Flashcards.


  1. Bacteria and archaea use three main routes to
    catabolize glucose:
    • 1. Glycolysis, or the Embden-Meyerhof-Parnas
    • (EMP) pathway
    • 2. Entner-Doudoroff (ED) pathway
    • 3. Pentose phosphate pathway (PPP), also
    • known as the pentose phosphate shunt
  2. The EMP Pathway (glycolysis)
    • Glucose molecule (6C) undergoes a stepwise
    • breakdown to two pyruvate molecules (2x3C).

    •  The most common form of glycolysis.
    • - It is central for animals and plants, as well as
    • many bacteria.
    •  It occurs in the cytoplasm of the cell.
    •  It functions in the presence or absence of O2.
    •  It involves ten steps that are divided into two stages:
    • 1 - glucose activation/phosphorylation (requires
    • energy - 2ATP), glucose is split in half
    • 2 - energy-yielding: 4ATP+2NADH
    • Total: 2ATP+2NADH
  3. The ED Pathway (Entner-Doudoroff)
    • Probably evolved earlier than EMP pathway.
    •  Glucose is activated by one phosphorylation reaction,
    • and then dehydrogenated to 6-phosphogluconate.
    • - Then dehydrated and cleaved to pyruvate and
    • glyceraldedyde-3-P, which enters the EMP
    • pathway to form pyruvate
    •  The ED pathway produces 1 ATP, 1 NADH, and
    • 1 NADPH.
    •  Many gut flora use the ED pathway as their primary
    • glycolytic pathway.
    • - Escherichia coli feeds on gluconate from mucus
    • secretion.
  4. The Pentose Phosphate Pathway
    • Like the ED pathway, the pentose phosphate shunt
    • forms 6-phosphogluconate.
    • - It is then converted to the key intermediate
    • ribulose-5-phosphate, which in turn produces a
    • series of sugars, each containing three to seven
    • carbons.
    •  This pathway produces 1 ATP and 2 NADPH for
    • biosynthesis.
  5. Fermentation
    • is the completion of catabolism
    • without the electron transport system and a terminal
    • electron acceptor.
    • - The hydrogens from NADH + H+ are transferred back
    • onto the products of pyruvate, forming partly oxidized
    • fermentation products.
    •  Most fermentations do not generate ATP beyond that
    • produced by substrate-level phosphorylation.
    • - Microbes compensate for the low efficiency of
    • fermentation by consuming large quantities of
    • substrate and excreting large quantities of products.
  6. Fermentation Pathways
    •  Homolactic fermentation
    • - Produces two molecules of lactic acid
    •  Ethanolic fermentation
    • - Produces two molecules of ethanol and two CO2
    •  Heterolactic fermentation
    • - Produces one molecule of lactic acid, one ethanol,
    • and one CO2
    •  Mixed-acid fermentation
    • - Produces acetate, formate, lactate, and succinate, as
    • well as ethanol, H2, and CO2
  7. Products of the TCA Cycle
    • For each pyruvate oxidized:
    • - 3CO2 are produced by decarboxylation
    • - 4 NADH and 1 FADH2 are produced by redox reactions.
    • - 1 ATP (or GTP) is produced by substrate-level
    • phosphorylation.
  8. Aromatic Pollutants
    •  Catabolism of aromatic molecules by bacteria and
    • fungi recycles lignin and other important substances
    • within ecosystems. (also: toxic pollutants)
    •  Benzoate and related compounds undergo aerobic
    • catabolism to catechol.
    • - Catechols are degraded through several
    • alternative pathways to the TCA cycle.
    •  In anaerobic conditions, benzoate undergoes
    • reductive degradation instead of oxidation.

Card Set Information

Author:
francis6
ID:
319035
Filename:
Microbiology Exam 3 lecture 26 flash cards
Updated:
2016-04-17 05:32:03
Tags:
microbiology
Folders:

Description:
lecture 26 flash cards
Show Answers:

Home > Flashcards > Print Preview