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51 Cards in this Set

  • Front
  • Back
Metabolism is the...
sum total of all the chemical rxns in the cell.
The energy required to run cellular metabolism is derived from...
redox reactions.
Energy from redox rxns is used to make.....
high energy phosphate bonds (ATP) and to generate ion gradients (usually PMF).
The metabolic fueling pathways generate what for us?
1. 12-13 carbon precursor metabolites
2. reducing power (NADH/NADPH)
3. cellular energy (ATP, PMF)
What pathways do respiring micro-organisms use?
glycolysis, TCA, pentose phosphate, and Electron transport.
What pathways do fermenting micro-organisms use?
Glycolysis and some specific parts of the pentose phosphate and TCA.
Electrons from redox rxns is released and used to make what?
ATP and/or PMF
Movement of electrons from glucose to NAD+/NADP+ generates...
reducing power (NADH/NADPH) for biosynthesis, photosynthesis, and initial electron donor for respiration.
List in order from better electron donors to better electron acceptors (Hint: 5 needed to know).
1. CO2/glucose
2. NAD+/NADH
3. FAD/FADH2
4. Cytochromes (in the middle of the chart).
5. O2/H2O
Max energy extracted is related to...
maximal change in E0'
Aerobes extract maximal energy by using...
O2as the final electron acceptor.
How do microbes use electron donors and acceptors?
they use many different ones to allow energy extraction in many different environments.
Most common pathway used by most organisms in all domains.
Glycolysis
What happens as glucose is oxidized in glycolysis?
electrons are transferred to NAD+, liberating energy that is trapped by making high energy P bonds. The P bond is then used to make ATP from ADP (substrate level phosphorylation).
Staring points of glycolysis and ending products.
Start with glucose and ATP. Make 2 ATP and 2 Pyruvate.
What is the step between Glycolysis and the TCA cycle?
Pyruvate is converted to Acetyl-CoA by making NADH
What is the products of the TCA cycle?
For fermenting microbes it depends because they only do certain parts.
For respiring microbes they generate GTP, NADH, and FADH2
What happens to the NADH and FADH2 created via TCA cycle?
diffuse to respiratory system on cytoplasmic membrane.
What cycle interconnects with glycolysis?
Pentose Phosphate pathway.
Starting products & ending products for pentose phosphate pathway.
1. 3 carbon sugars or 6 carbon sugars
2. 5 carbon sugars and NADPH
Pentose phosphate pathway provides precursors for.....
aromatic AA's and vitamins.
Alternative pathway to glycolysis.
Entner-Doudoroff Pathway
What does the Entner-Doudoroff Pathway produce?
ATP, NADH, and NADPH
Fermentation is associated with microbes that grow _______.
anaerobically
How is energy for fermentation generated?
via SLPs (substrate level phosphorylation), not respiration
What happens to the protons (H+) in fermentation?
They build up inside the cell and have to be pumped out via ATP. NADH can also build up.
Explain homolactic fermentation
Fermenting microbes have to find a way to regenerate NAD+, so they change pyruvate to lactate (lactic acid) and get NAD+.
What are some of the most common end products of Pyruvate via fermentation?
1. removal of CO2 = ethanol
2. Isopropanol
3. Butanol
4. Butyrate
5. H2 + CO2
What is respiration?
the moveoment of electrons through an electron transport chain (captures and uses liberated energy for proton motive force)
How are the electron transfer chains arranged?
according to reduction potentials (most negative first). this allows electrons to move spontaneously.
Energy liberated from ETC does what?
pumps H+ out of the cell to make proton motive force
aerobic respiration vs. anaerobic respiration
in aerobic O2 is the final electron acceptor.
in anaerobic, they use non-oxygen final acceptors
FADH2 & NADH are produced _______ and diffused _______.
in the cytoplasm; throughout the cytoplasm.
For each listed, how does it accept/transfer electrons and protons?
Coenzyme Q (ubiquinone), FADH2, NADH, and Heme. Which are diffusible?
Coenzyme Q a/t 2e-s and 2 H+s (not diffusible)
Same for FADH2 (diffusible)
NADH a/t 2 e-s and 1 H+s as well as releases an H+ to the cytoplasm. (diffusible)
Heme a/t 1 e- at a time. (not diffusible)
Energy from spontaneous redox reactions is used to...
take up and then pump H+s out of the cell as electrons move between the 2 types of carriers.
Tasks that occur via PMF
make ATP for metabolism and photosynthesis, run flagella, active transport, etc.
Explain the PMF of the last complex in ETC.
Two parts to the complex:
F0: proton pump in membrane, it turns as H+ flows through
F1: gamma (y) subunit of F1 interacts with F0, it also turns and synthesizes ATP
Can work in reverse with ATP as an energy source.
Chemolithotrophs use a variety of __________ for respiration; typically in nutrient deficient environments.
inorganic electron donors
In chemolithotrophs respiration is usually....
aerobic, but may be anaerobic. reverse respiration can happen to create NAD(P)H
Phototrophs use special molecules like chlorophyll and bacteriochlorophyll that....
absorb light energy and raise the reduction of e-s. They then flow through the ETC and make a PMF to make ATP. This occurs by photophosphorylation.
Explain rhodopsin-based phototrophy.
Microbes that contain bacteriorhodopsins create light driven H+ pumps that directly generate PMF's to create ATP (without chains).
Chlorophylls are for ______ photosynthesis. Bacteriophylls are for ______ photosynthesis. All use ____ for the main part of the structure.
oxygenic; non-oxygenic; Magnesium
Accessory pigments surround the _______ and they....
chlorophylls; absorb & transfer energy.
In cyclic photophosphorylation what happens to the initial electron donor?
it becomes the final acceptor, however electrons can be funneled in and out.
Specifics of Cyclic Photophosphorylation.
(Hint: 4 things)
1. Reduction potentials allow flow of e-s to make PMF
2. NAD+ can be reduced and leave the system.
3. Reverse e- flow can generate NADH/NADPH
4. These systems always use bacteriochlorophylls.
Specifics of noncyclic photophosphorlyation. (Hint: 5 things)
1. Two photosystems are used.
2. Chlorophylls are used. (oxygenic, so oxygen is produced)
3. Light is absorbed and transfered to electrons in two phases.
4. A PMF is generated.
5. NADP+ is the final e- acceptor. Produces NADPH.
Members of the rhodopsin family all.....
use light absorbed by retinal.
In bacteriorhodopsins, how does the H+ get pumped out of the cell?
light induced conformational changes.
Some bacteriorhodopsins can act as _____.
photoreceptors
During aerobic metabolism, what is formed?
reactive oxygen intermediates (O2- and H2O2)
Two enzymes used in O2 utilization and their purpose.
1. Superoxide dismutase (SOD) converts O2- into O2
2. Catalase converts H2O2 into O2 and H2O.