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Cellular Respiration
Energy From Electrons Atom nucleus
Positive Attracts/pulls electrons Potential energy released when nucleus pulls electrons to it (makes bond)
Think of the atomic structure of the following atoms Oxygen (make up the oxygen molecule in cell resp) Hydrogen and Carbon (bonded to each other in glucose) Which has a stronger attraction for electrons? What happens in cell respiration?
Oxygen molecule reacts with glucose Carbon and hydrogen leave each other and become bonded to oxygen's,
creating the carbon dioxide and water produced in cellular respiration The electrons in hydrogen and carbon are pulled toward the nucleus
of the oxygen atoms, thus releasing potential energy Occurs when you burn sugar, lots of energy released almost
instantaneously In cellular respiration, occurs in controlled steps to prevent a massive
release of energy
Electron Transport Chain (etc) Cell respiration releases E in small amounts in the form of
ATP molecules Several steps Oxygen is only involved in the end Electrons=energy Electrons are carried by electron carrier molecules
Electron carrier is a molecule that can accept a pair of high-E electrons and transfer them along with most of their energy to another molecule
Oxygen is the final electron acceptor that joins with hydrogen ions to make water
This transfer of electrons throughout cellular respiration is called the electron transport chain (ETC)
For every transfer of electrons between molecules in the chain, a little E is released
Cellular Respiration A cellular process (part of metabolism) Metabolism
Set of chem. rxns through which an organism builds up or breaks down materials as it carries out life’s processes
C6H12O6 (aq) + 6O2 (g) → 6CO2 (g) + 6H2O (l) Glucose reacts with oxygen to produce carbon
dioxide and water REQUIRES OXYGEN
Aerobic
Cellular Respiration: 3 parts
1. Glycolysis cytoplasm
2. Kreb’s Cycle Mitochondrian
matrix
3. Electron Transport Chain Within the inner
mitochondrial membrane
GlucoseGlycolysis
Cytoplasm
Pyruvic acid
Electrons carried in NADH
Krebs Cycle
Electrons carried in
NADH and FADH2 Electron
Transport Chain
Mitochondrion
Mitochondrion
Glucose(C6H1206)
+Oxygen
(02)
GlycolysisKrebsCycle
ElectronTransport
Chain
Carbon Dioxide
(CO2)+
Water(H2O)
Cellular Respiration
Glycolysis summary endergonicinvest some ATP
exergonicharvest a little ATP & a little NADH
net yield2 ATP2 NADH
4 ATP
ENERGY INVESTMENT
ENERGY PAYOFF
G3PC-C-C-P
NET YIELD
like $$in the bank
-2 ATP
Glycolysis Greek word “glukus” sweet Latin word “lysis” loosening or decomposing Def: the process in which one molecule of glucose is broken in
half, producing two molecules of pyruvic acid (a three-carbon compound)
Takes place outside mitochondria, in cytoplasm of cell Energy releasing process Does NOT require oxygen Requires an investment of 2 ATP molecules at beginning to get
it going These 2 atp’s are like an investment that pays back with interest In order to earn money from a bank, you have to put $$ in
4 molecules of ATP produced at the end of Glycolysis What is the “net” gain?
2 ATPs
NADH production 4 high-E e- are removed and passed to two
electron carriers called NAD+ (nicotinamide adenine dinucleotide) (each NAD+ carries 2 e-)
Each NAD+ molecule accepts a pair of high-E e-
Once e- are accepted, NAD+ becomes NADH, which will transfer e- to other molecules
NAD+ helps pass energy from glucose to other pathways in the cell
Glycolysis Glucose, a six-carbon sugar, receives 2 phosphates from the
first 2 ATPs invested in Glycolysis Glucose now becomes fructose 1,6-biphosphate (highly
energized) Fructose 1,6-biphosphate splits to become two molecules of
CCC-P (glyceraldehyde 3-P) Each of these molecules transfers electrons and hydrogen ions
to NAD+ molecules that come in Accepting two e- and hydrogen ion changes NAD+ to NADH,
which carry electrons to the next part of Glycolysis An inorganic phosphate is added to the CCC-P molecule
changing it to P-CCC-P (1,3-biphosphoglycerate) 2 ADP molecules will come in and snatch off the phosphates
from P-CCC-P and the molecule has now become PYRUVATE or PYRUVIC ACID
Pyruvate is then sent on to the next phase, the Kreb’s Cycle
Reactants and Products of Glycolysis
In 1 glucose 2 ATP 2 NAD+
Out 2 NADH (to ETC) 4 ATP 2 Pyruvates (to Kreb’s cycle) (Net ATPs 2)
Glucose
To the electron transport chain
2 Pyruvic acid
