Term
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Definition
| Generate energy by oxidizing organic fuels |
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Term
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Definition
| Partial degradation of sugars without the presence of O2 |
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Term
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Definition
| Consumes organic compounds and O2, yields ATP |
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Term
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Definition
-Includes both aerobic and anaerobic
-Often used to refer to just aerobic respiration |
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Term
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Definition
Transfer of electrons
Releases energy stored in organic chemicals
Ultimately used to synthesize ATP |
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Term
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Definition
OiL RiG
Oxidation is Loss, Reduction is Gain |
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Term
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Definition
The compound that loses and electron is call the reducing agent
The compound that gains an electron is the oxidizing agent |
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Term
| Oxidation in Cellular Respiration |
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Definition
| During cellular respiration the fuel (such as glucose) is oxidized and the oxygen is reduced |
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Term
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Definition
Electrons from organic molecules are transfered to NAD+
NAD+ functions as a reducing agent in cellular respiration
Each NADH (reduced NAD+) is used to synthesize ATP |
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Term
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Definition
NADH passes the electrons to the Electron Transport Chain
Passes electrons in a series of controlled reactions
"O2 pulls the electrons down the chain in an energy-yielding tumble"
Energy used to regenerate ATP |
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Term
| Three Stages of Cellular Respiration |
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Definition
Glycolysis - breaks glucose into two molecules of pyruvate
Citric Acid Cycle - completes the breakdown of glucose
Oxidative Phosphorylation - accoutns for most of ATP synthesis |
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Term
Location of the Stages
of Cellular Respiration |
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Definition
Glycolysis - Cytosol of the cell
Citric Acid Cycle - Mitochondrial Matrix
Oxidative Phosphorilation - Mitochondrial Matrix
Electron Transport Chain - Intermembrane space (in mitochondria) |
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Term
| Oxidative Phosphorylation |
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Definition
Accounts for 90% of the ATP generated by cellular respiration
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Term
| Substrate-Level Phosphorylation |
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Definition
Smaller amount of ATP generated in
Glycolysis and the Citric Acid Cycle |
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Term
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Definition
Breaks glucose down into two molecules
of pyruvate
Two Major Phases:
Energy Investment Phase - uses 2 ATP
Energy Payoff Phase - forms 2 pyruvate, 4 ATP, 2 NADH, 2 H2O and 2 H+ |
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Term
Citric Acid Cycle
(aka Kreb's Cycle) |
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Definition
Pyruvate enters the mitochondrion
Pyruvate is converted to Acetyl CoA (which links
the cycle to glycolysis)
Oxidizes organic fuel (generates 1 ATP, 3 NADH, 1 FADH2) |
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Term
How is the Citric Acid Cycle a "cycle"
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Definition
-Acetyl group of acetyl CoA joins the cycle
by combining with oxaloacetate
forming citrate
- Rest of the steps decompose back to
oxaloacetate making it a cycle
-The NADH and FADH2 relay electrons
from food to the electron transport chain
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Term
Pathway of Electron Transport
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Definition
-Most of the components are proteins which exist
in multiprotein complexes
-Carriers alternate reduced and oxidizied states
-Electrons drop in free energy as they transfer
-Finally pass to O2 and form H2O |
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Term
| What is the Electron Transport Chain doing? |
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Definition
-It is not synthesizing ATP during the chain
-Each step causes proteins to pump H+into the
intermembrane space
-H+ then flows back out of the membrane through
ATP synthase channels
-ATP synthase uses the exergonic flow of
H+ to drive the phosphorylation of ATP |
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Term
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Definition
The use of energy in an H+ gradient used to drive
cellular work |
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Term
Energy flow seqeunce in
cellular respiration |
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Definition
glucose → NADH → electron transport chain
→ proton-moative force → ATP |
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Term
How much of the energy in glucose is
transferred to ATP?
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Definition
| 40%, creating 38 ATP in optimal conditions |
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Term
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Definition
Consists of glycolysis plus reactions that
regenerate NAD+, reused by glycolysis
Two common types are lactic acid fermentation
and alcohol fermentation
Fermentation takes place entirely int he cytosol
unlike respiration which takes place largely
in the mitochondria |
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Term
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Definition
Pyruvate is converted into ethanol in two steps
The first step releases CO2 |
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Term
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Definition
Pyruvate reduced to NADH forming lactate as an
end prodcut and no release of CO2 |
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Term
Obligate Anaerobes
Facultative Anaerobes |
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Definition
Obligate anaerobes carry out fermentation and
cannot survive in the presence of O2
Facultative anaerobes can survive using either
fermentation or respiration
Pyruvate is a form in the metabolic pathway leading
to either respiration or fermentation |
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Term
| Versatility of Catabolism |
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Definition
-Catabolic pathways funnel electrons from many
kinds of organic molecules into cellular
respiration
-Glycolysis accepts a wide range of carbohydrates
-Proteins can be broken down to amino acids
and feed glycolysis or the citric acid cycle
-Fats are digested to glycerol (for use in glycolysis)
-Fatty acids (used in generating acetyl CoA)
-An oxidized gram of fat produces more than twice the ATP od an oxidized gram of carbs |
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Term
| Evolutionary Significance of Glycolysis |
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Definition
Occurs in nearly all organisms
Probably evolved in early prokaryotes when oxygen was relatively scarce on earth |
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Term
| Regulation of Respiration |
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Definition
-Most common form of control is feedback inhibition
When there is plenty of ATP feedback slows down respiration
-Control of catabolism is mainly the control of enzymes
at strategic points in the catabolic pathway |
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Term
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Definition
-Example of an enzyme that is inhibited or stimulate
as part of a regulatory mechanism
-Is one of the early enzymes that participates
in glycolysis
-ATP and citrate inhibit it from operating
-AMP (A-mono-P) stimulates it
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