Download Respiration Power Point

Breathing and Cellular
Respiration
INTRO
• Fast and slow twitch
muscles
What kind of runner are you?
• LONG
DISTANCE
RUNNING
• Slow-twitch
fibers
• for repeated
long
contractions
• SPRINTING or
WEIGHT
LIFTING
• Fast-twitch
fibers
• Contract more
quickly and
powerfully
What makes these muscle fibers
so different?
• SLOW TWITCH • FAST TWITCH
• breaks down
• breaks down glucose to
glucose to get ATP get ATP
AEROBICALLY ANAEROBICALLY
(using oxygen)
(not using oxygen)
SLOW MUSCLES
• 1. Thin fibers
• 2. have many
mitochondria
• Many
myoglobin
FAST MUSCLES
• Thicker fibers
• Fewer
mitochondria
• Less myoglobin
• (“white meat)
What happens if not enough
oxygen is available?
• Glucose is not
completely
broken down and
lactic acid is
formed (a larger
molecule) that
makes muscles
ache
Big Question for Chapter 6
• How do our cells obtain O2
for cellular respiration and
dispose of CO2?
6.1 Breathing
• Isn’t that how we obtain
oxygen?
• Breathing = taking in oxygen
in our lungs and removing
carbon dioxide as we exhale
Respiration Really is...
• Cellular respiration =
breakdown of organic
molecules (for energy) in the
presence of oxygen (in
mitochondrion)
6.2 Cellular Respiration
• C6H12O6 + 6O2
6CO2 + 6H2O + ATP
>
Glucose Bank
• Break glucose bonds
• Stored in ATP
ATP
glucose
Glucose contains Energy:
• 1 gram glucose = 4 kcal of energy
• What are kcal? Kilocalories
• 1 kilocalorie = 1000 calories
6.3 Need heat to stay alive
• 75% of
energy of
daily food
just to
maintain
• 2,200 kcal of
energy per
day needed
for average
adult
Calculate
• Walking at 3
mph, how far
• HINT: (p. 91)
would you have
Walking 3 mph
to travel to
consumes per
“burn off” the
hour 158 kcal
equivalent of an
• 475/158 = 3 hrs.
extra slice of
pizza, which has • 3 mph X 3 = 9mi
about 475 kcal?
6.4 Just how DO our cells
extract energy from organic fuel
molecules?
• The glucose is dismantled
and the energy stored in the
bonds is carried by electrons.
We don’t see e-, but we see H
atoms.
• C6H12O6 + 6O2
6CO2 + 6H2O + ATP
• (hydrogen atom =
• one proton and one electron)
>
What drives this to happen?
• OXYGEN
• A strong tendency to pull
electrons from other atoms
6.5 Redox Reaction
• Movement of electrons
from one molecule to
another is an oxidationreduction reaction
Redox reaction
• Oxidation
• Reduction
• loss of
• addition of
electrons from
electrons to
one substance
another
substance
• Loss of H
• Gain of H
• "Leo goes Ger”
• Loss of electrons = oxidation
• Gain of electrons = reduction
Key Players of Redox Reactions
• Dehydrogenase • NAD+
• Enzyme
• nicotinamide
adenine
• Remove H atoms
dinucleotide
• coenzyme
• used to shuttle
electrons
How NADH becomes a
“Hydrogen Carrier”
• NAD+ + 2H
• picks up 2 e- and
• e- 2H+ and 2e-
dehydrogenase
NADH2
Electron Carrier
• A.k.a. “hydrogen carrier”
• Empty
With e-/H
eNAD+
NADH
NADH
p. 93
• C4H6O5
• Oxidized
• NAD+
• Reduced
C4H2O5
NADH
How do we get energy?
• Big molecules in food
break apart
• Released electrons
carried to NADH
• Energy to ATP’s
• You can now use ATP
energy
6.6
• Which has more energy?
NAD+
NADH
Why?
NADH has picked up an e-
6.6 ETC
• Electron
Transport
Chain
NADH brings e-
• Pass e- from
higher energy
to lower
energy state
NAD+
So…
•NAD+ can be
recycled over and
over
ETC
• ETC Animation (click)
• Note each carrier
molecule has a greater
affinity for e- than its
uphill neighbor
Where is the ETC?
• Inner membrane of the Mitochondrion
Sing the ETC Song
• To the tune of “Buffalo
Gals Won’t you Come
Out Tonight”?
6.7 Chemiosmosis
• Movement of solutes across a
membrane from where they are MORE
concentrated to where they are LESS
concentrated.
• Movement of H+ ions (click here to
see the proton H+ pumps)
“Down the Gradient”
Note more H+
ions on one side
of the membrane
Went “against
the gradient”
and see energy
was used to do
this
Chemiosmosis
• Diffusion of
excess H+ ions
across a
membrane from
high to low
concentration
• ADP + Pi = ATP
ATP Synthase
• ATP Synthase
Animation (click
here to see the ATP
synthase move H+
ions “against the
gradient”)
• ATP Synthase
Animation (click
here)
Makes ATP
• Energy is generated from the
movement of H+ ions
…enough to cause a phosphate
to join ADP to form ATP
Chemiosmosis and ETC working
together on inner membrane
• ETC and Chemiosmosis Together
NADH and FADH2 carry
protons (H+)
and electrons (e-) to
the electron transport chain
Mitochondrion: Site of Cellular
Respiration
• Mitochondrion Cellular Respiration (be sure
to see the cool rotating ATP Synthase and
the end of the program)
• Peter Mitchell (1920 - 1992)
• Developed the theory of
chemiosmosis
• Nobel Prize
1978
2 Ways to Make ATP
• Substrate-level
• Chemiosmosis
phosphorylation
• does not involve a
membrane
• makes only small
amounts of ATP
• diffusion
through a
membrane of
particles
produces more
ATP
6.8
3 Stages of Cellular Respiration
1. Glycolysis
2. Krebs Cycle
3. ETC/Chemiosmosis
Glycolysis
-Breaks down glucose
into pyruvic acid
-Occurs in cytoplasm
-means “splitting of sugar”
Glycolysis
• Start with 6-carbon
glucose and breaks into
two 3-carbon pyruvic
acid molecules (or
pyruvate)
Glycolysis Animation
• Glycolysis actually
has 9 steps…but you
only need to learn
that these molecules
formed between
glucose and pyruvic
acid are called
• intermediates
Glycolysis: What do I need to
know?
• Needs 2 ATP to get
started
• Makes 4 ATP
• Splits glucose into two
pyruvates
• Makes NADH (an
e- carrier)
• NET GAIN
2 ATP’s
But...
•Pyruvic acid itself
does not enter the
Krebs cycle
6.10 “Grooming” Pyruvic Acid
Haircut and Conditioning
“HAIRCUT”
“CONDITIONING”
As NADH is
reduced to
NAD+…pyruvic
acid is oxidized
(carbon atom
removed as
Coenzyme A
CO2)
(from B vitamin)
joins the 2-c fragmen
MAKES-Acetyl
Coenzyme A or
CoA
6.11 Ready to GO
• The Acetyl-CoA is now ready to
enter the Krebs cycle
Hans Krebs
(1900-1981)
Yeah, he got a
Nobel Prize, too
Krebs Cycle
• Only 2-C of acetyl
participates
• (Coenzyme A
is recycled)
• Occurs in
mitochondrial matrix
Also Called TCA cycle
tricarboxylic acid
which is also citric acid (the
other 4-C)…so also called
citric acid cycle
Krebs cycle (cont.)
• strips off a carbon as CO2
• makes 4 ATP
• makes 10 NADH
• makes 2 FADH2
One cycle
6.12 Mitochondrion
Note many
folds (cristae)
of inner
membrane
This increases
surface area
Electron Transport Chain in inner
membrane of the Mitochondrion
Electron Carriers
• In Glycolysis
• NAD+
• In Cellular
Respiration
• NAD+
• FAD
Final Electron Acceptor
• Oxygen
• It is what drives the reaction
and pulls the electrons away
from their bonds.
Final Products
• Water (from oxygen and hydrogens)
• CO2 when it was pulled out of Krebs
cycle
• ATP formed mostly from
chemiosmosis/ETC
6.12 Chemiosmosis/ETC
Powers Most of ATP Produced
• Glycolysis -2 ATP
• Krebs Cycle - 2 ATP
• Chemiosmosis/ ETC - 34 ATP
• NET TOTAL = 38 ATP
Chemiosmosis and ETC
• H+ ions can only pass through a
special port ATP synthase (see
knobs
on cristae)
ATP synthase
• As H+ ions move through the ATP
synthase port it powers the
formation
of ADP
+ Pi to ATP
•
•
Animation of ATP
synthesis in Mitochondria
OVERALL ANIMATION
• Cellular Respiration Animation and
Explanation
Burn 1 glucose molecule
• ~ 100 ATP molecules
• 100% energy released
Glucose in the body
• Only about
40% goes to
use in ATP
molecules
• Rest lost as
heat
6.15 YEAST FERMENTATION
• In yeast, can they make enough
energy without oxygen?
• YES
• Is this aerobic or anaerobic?
• anaerobic
Remember the Yeast Lab?
• Put glucose with yeast and
what were the two byproducts?
• Carbon dioxide and ethyl
alcohol
What was the side step?
• NAD+ was replenished
• The taxi cab loses its e- and is now
available to pick up more electrons. If all
the taxi cabs are full, the reaction would
stop.
Alcoholic Fermentation
• Is using yeast
or bacteria to
convert
glucose to
alcohol.
Ethanol is Toxic to Yeast
• So what do they do with it?
• Yeast release the waste to the
surroundings.
What happens if …
• The yeast
makes too
much ethanol?
• They die
XX
XX
Lactic Acid Fermentation
• In your muscles
• As you exercise,
lactic acid is
formed.
• You also breath
out carbon
dioxide.
Where does the lactic acid go?
• Carried to liver
• Here lactic acid
is converted back
to pyruvic acid.
Where is lactic acid used?
• Commercially:
• Lactic acid
fermentation is
used by bacteria in
the dairy industry
to produce:
Cheese and yogurt
Strict Anaerobes
• Require anaerobic conditions and are
poisoned by oxygen
• Methanogens are strict anaerobes that
release methane as a waste product of
cellular metabolism. Many live in mud at
the bottom of lakes and swamps because it
lacks oxygen, and some (enteric bacteria)
live in the intestinal tracts of animals
Facultative Anaerobes
• Can make ATP either by fermentation or by
chemiosmosis, depending on whether
oxygen is available or not
Facultative Example
• Vibrio
parahaemolyticus halophilic, facultative
anerobic, rod
bacterium that causes
a foodborne illness
known as seafood
poisoning.
Making Beer
• Large fermentation
tanks to make beer
and wine have a
one-way valve so
no oxygen gets
in…only the
carbon dioxide out.
6.13 ROTENONE POISON
• Binds with first of the proteins of the ETC
• used to kill insects and fish pests
• Cyanide and carbon monoxide
bind with third protein of ETC
• Antibiotic oligomycain blocks H+
ions through ATP synthase channel
• Used to combat fungal infections on the
skin
Uncouplers
• Make the membrane of the mitochondrion
leaky to H+ ions
• So…can’t make ATP
• DNP prescribed as weight-loss
pills, but banned
6.14 Review of ATP YIELD
(Ideally)
•
•
•
•
Need 4 ATP to start glycolysis
Glycolysis makes 2 ATP
Krebs Cycle makes 2 ATP
ETC/Chemiosmosis makes 34 ATP
• TOTAL about 38/
molecule of glucose
Where does it all come from?
• 1 NADH = 3 ATP
• 1 FADH2 = 2 ATP