Chapter 6: How Cells Harvest Chemical Energy. Muscle Fibers Fast-twitch Performs best for sprints...
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Chapter 6: How Cells Harvest Chemical Energy
Chapter 6: How Cells Harvest Chemical Energy. Muscle Fibers Fast-twitch Performs best for sprints Contract quickly but tire quickly Make ATP anaerobically
Muscle Fibers Fast-twitch Performs best for sprints Contract
quickly but tire quickly Make ATP anaerobically (not using oxygen
Slow-twitch Perform best for endurance Can sustain repeated
contractions Make ATP aerobically (using oxygen)
Slide 3
Slide 4
Slide 5
Photosynthesis vs. Cell Respiration Photosynthesis uses carbon
dioxide to produce high energy carbon molecules and oxygen Cellular
respiration uses carbon molecules and oxygen to produce energy and
carbon dioxide The products of photosynthesis are the reactants of
cellular respiration
Slide 6
Cellular respiration Function: generate ATP to be used for
cellular functions Can produce up to 38 ATP molecules which is 40%
of energy from a glucose molecule, the rest is lost in heat
energy
Slide 7
Energy consumption of the body The human brain burn about 120 g
(1/4 lb.) of glucose per day and uses 15% of oxygen consumption a
day The average human needs to take in 2200 kcal per day about 1.25
lb. of glucose per day
Slide 8
Reduction vs. oxidation Reduction reactions The addition of
electrons from a substance Oxidation reactions The loss of
electrons from a substance
Slide 9
2 key players in oxidizing glucose Dehydrogenase: an enzyme
that takes hydrogens from molecules NAD + : Nicotinamide adenine
dinucleotide, an organic molecule that cells make from the vitamin
niacin and use to shuttle electrons in redox reactions
Slide 10
Stages of cellular respiration Stage 1: Glycolysis: cytoplasm:
breaks glucose into 2 pyruvates Stage 2: Citric Acid Cycle:
Mitochondria: Stroma: makes small amounts of ATP and provides ETS
with electrons Stage 3: oxidative phosphorylation (ETS and
chemiosmosis: cristae: makes most ATP
Slide 11
Overview of cell respiration
Slide 12
Glycolysis Begins with glucose and ends with 2 pyruvates
Substrate-level phosphorylation: an enzyme transfers a phosphate
group from a molecule directly to an ADP to form ATP. This is used
in both glycolysis and citric acid cycle to produce small amounts
of ATP At the end the molecules of pyruvate still hold most of the
energy from glucose and will be oxidized in the citric acid cycle
The 2 molecules of ATP produced here are only 5% of the glucose
molecule
Slide 13
Glycolysis
Slide 14
Pyruvate for the citric acid cycle Pyruvate loses the carboxyl
group in the for of carbon dioxide (released during respiration) 2
C-compound is oxidized and NAD + becomes NADH Coenzyme A joins the
2 C- compound and becomes Acetyl coenzyme A
Slide 15
Citric Acid Cycle AKA the Krebs Cycle named for Hans Krebs
Takes place in the matrix of the mitochondria Starts with acetyl
Coenzyme A and ends with 2 CO 2, 6 NADH and 2 FADH 2
Slide 16
Citric Acid Cycle
Slide 17
Oxidative Phosphorylation Includes the electron transport chain
and chemiosmosis Takes place in the cristae (folds in the inner
membrane of the mitochondria). The cristae increase the surface
area of the membrane so that more reactions can take place
Exergonic reaction Chemiosmosis the energy of H + drives the
synthesis of ATP
Slide 18
Poisons that interrupt Cell Respiration Rotenone: binds with an
electron carrier at the first protein complex and blocks the
movement of electrons through the ETS Cyanide and carbon monoxide:
bind with an electron carrier at the 4 th protein complex blocking
the passage of oxygen ceasing the flow of H so no ATP can be formed
Oligomycin (an antibiotic): used for fungal infections: prevents
the flow of H
Slide 19
More poisons Uncouplers: causes the mitochondria to leak H DNP
(DiNitrophenol): produces an enomrous increase in metabolic rate,
profuse sweating as the body tries to cope with the excess heat
energy produced, collapse and death
Slide 20
Totals StagewhereStart With ATP Dir. ATP Indir. FADH 2 NADHCO 2
Other glycolysisCyto- plasm Glucose 2 ATP 200202 pyruvates Pyruvate
to Citric Acid Cycle Cyto to mito. pyruvate00022 (goes to the atm.
None Citric Acid Cycle (goes through 2x) Matrix of mito. Acetyl CoA
20264 (goes to the atm.) none Oxidative Phosphor ylation
cristaeNADH, FADH 2 O 2 002x2=43X10= 30 Total38434
Slide 21
Totals
Slide 22
Lactic Acid Fermentation Can be used by muscle cells to
generate NAD + Lactate builds up in muscles during strenuous
activity, carried back to the liver and converted to pyruvate Used
in the dairy industry to make cheese
Slide 23
Alcoholic fermentation Used in the winemaking industry
Slide 24
Anaerobes obligate aerobes: must have oxygen to survive
Obligate anaerobes: must have no oxygen to survive Facultative
anaerobe: can survive with or without oxygen
