Download Cell Energyrespiration

Cellular Respiration
• Is a series of reactions
where fats, proteins,
and carbohydrates,
mostly glucose, are
broken down to make
CO2, water, and
energy.
• Occurs in the
mitochondria
Cellular Respiration: (2 kinds—Aerobic and Anaerobic)
• The energy produced is released in the cell to be used
for life processes (movement, breathing, blood
circulation, etc…)
• Cells require a constant source of energy for life processes but
keep only a small amount of ATP on hand.
• Cells can regenerate ATP as needed by using the energy stored
in foods like glucose.
• The energy stored in glucose by photosynthesis is released by
cellular respiration and repackaged into the energy of ATP.
• Respiration occurs in ALL cells and can take place
either with or without oxygen present.
Aerobic Respiration: requires oxygen
• Occurs in the mitochondria of the cell
• Total of 36 ATP molecules produced
• General formula for aerobic respiration:
C6H12O6 + 6O2
6 CO2 + 6H2O + 36 ATP
glucose + oxygen
carbon dioxide + water + energy
Human cells contain a
specialized structure – the
mitochondrion – that
generates energy.
Cellular Respiration
Stage One: Breakdown of Glucose
•Glycolysis Glucose is
broken down to
pyruvate (3 carbon
molecule) during
glycolysis, making
some ATP.
•NADH-carriers for
energy and electrons
during glycolysis
•Produces 2 ATP
Cellular Respiration
Stage Two (2 steps): Production of ATP
•Krebs Cycle The Krebs
cycle is a series of
reactions that produce
energy-storing molecules
during aerobic respiration.
•Electron Transport
Chain During aerobic
respiration, large amounts
of ATP are made in an
electron transport chain.
Preparation for the Citric Acid Cycle
C
The pyruvate loses a
carbon leaving the 2
carbon molecule
C
Acetyl CoA
CO2
products:
CO2, Acetyl CoA and NADH
The Krebs Cycle (Citric Acid )
• Occurs in the matrix of the mitochondrion
• Aerobic phase (requires oxygen)
• 2-carbon acetyl CoA (formed from pyruvate)
joins with a 4-carbon compound to form a 6carbon compound called Citric acid
The Citric Acid Cycle
Products:
CO2 ATP, NADH, FADH
Electron Transport Chain
The mitochondria has
two membranes--the
outer one and the inner
membrane which is
convoluted.
The H+
which are brought to
mitochondria accumulate
between these two
membranes.
electrons
The electrons are passed
back and forth across the
membrane where their energy
is gradually decreased and used
to transport H+ through the
membrane.
Oxygen is the final
electron acceptor and it joins with
the H+ to produce H2O.
If there is no oxygen, the electron chain cannot continue
because there is no way to release electrons .
• Diagram
Electrons carried in NADH
Mitochondria
In Cytoplasm
Glucose
Krebs
Cycle
Glycolysis
2
2
Electrons
carried in
NADH and
FADH2
Electron
Transport Chain
32
Anaerobic Respiration:
occurs when no
oxygen is available to the cell (2 kinds: Alcoholic and
Lactic Acid)
• Also called fermentation-the breakdown of
carbohydrates by enzymes, bacteria, yeasts, or
mold in the absence of oxygen
• Fermentation regenerates the NAD+ needed
for glycolysis to continue
• Much less ATP produced than in aerobic
respiration
•Alcoholic fermentation—occurs in bacteria and
yeast
Process used in the baking and brewing
industry—yeast produces CO2 gas during
fermentation to make dough rise and give bread
its holes
glucose
ethyl alcohol + carbon dioxide + 2 ATP
• Lactic acid fermentation—occurs in muscle cells
Lactic acid is produced in the muscles during rapid
exercise when the body cannot supply enough oxygen
to the tissues—causes burning sensation in muscles
glucose
lactic acid + carbon dioxide + 2 ATP
• First step in anaerobic respiration is also glycolysis
Diagram
Anaerobic Respiration
Cytoplasm
C6H12O6
glucose
Alcoholic fermentation
Bacteria, Yeast 2 ATP
glycolysis
Lactic acid fermentation
Muscle cells
2 ATP
Aerobic Respiration
36 ATP
Krebs
Cycle
ETC
Mitochondria