Transcript File

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Cellular Respiration Overview
Lecture 1
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AUTOTROPHS
___________ use energy from
sunlight or chemicals to make
their own food
In the last chapter green plants
PHOTOSYNTHESIS
used ________________
sunlight
trap energy from __________
food (glucose)
and make ______________
http://206.173.89.42/REALTYWITHALOHA_COM/piphoto/funny%20sun%20with%20sunglasses.gif
Image from: http://ag.ansc.purdue.edu/sheep/ansc442/Semprojs/2003/spiderlamb/eatsheep.gif
In this chapter we will learn how
HETEROTROPHS
______________
get their energy by
consuming other
organisms.
GLUCOSE
We get our energy from the __________
plants made during _______________
PHOTOSYNTHESIS
when we eat plants or eat animals
that ate the plants.
http://www.cibike.org/Eating.htm
In this chapter, we will learn how
broken down by
this glucose is ____________
energy
organisms and the _______
is stored
as _______
ATP
What kind of organisms do this?
ALL LIVING THINGS NEED ENERGY!
All organisms burn glucose for fuel
plants
fungi
Animals
(Including humans)
bacteria
PHOTOSYNTHESIS
6___________
CO2 +6_________
H2O
+ ___________
C6H12O6 + __________
6O2
→_______________
CELLULAR RESPIRATION
C6H12O6 + _________
6 CO2 + __________
6 H2O + __________
6O2 →________
_____________
The two equations are exact opposites!
______________________________________________________________
CELLULAR RESPIRATION
happens __________
slowly
in ________________.
many steps
If all the energy was released in
one step… most would be lost as
____________________!
light and heat
See why cells
use cellular respiration
http://plato.acadiau.ca/COURSES/comm/g5/Fire_Animation.gif
ELECTRON TRANSPORT CHAIN
• Prevents energy release in 1 explosive step
• Allows energy to be released slowly in steps and
captured as ATP
• Electron route:
food → NADH → ETC → oxygen
• Similar to photosynthesis ETC, just different electron
acceptor
MITOCHONDRIA = cell power plant
Surrounded by ___________
DOUBLE membrane
Outer membrane & Inner membrane
CRISTAE
(called _______________
)
Space between inner membrane
& outer membrane
INTERMEMBRANE SPACE
= ____________________
Space inside cristae folds
= _________________
MATRIX
HIGH ENERGY ELECTRON CARRIERS
FAD → FADH2
NAD+ → NADH
Steps of Cellular Respiration
Lecture 2
The first step in cellular respiration
= _______________
GLYCOLYSIS
•
CYTOPLASM
•happens in the ________________
outside the mitochondria
• occurs _________________________
with or without oxygen
See glycolysis movie
Glycolysis
(GLYKOS = ________
sweet LYSIS= ___________
Split apart )
ENERGY
Requires ____________to
get it started.
Evolutionary Significance
• Most widespread metabolic pathway… suggests ancient
prokaryotes probably used glycolysis to make ATP before
oxygen was present
• Earliest fossil bacteria present 3.5 billion years ago but large
amounts of oxygen not present until 2.7 billion years ago
• Glycolysis happens in cytoplasm without membrane bound
organelles suggests it was found in early prokaryotic cells
since eukaryotes appeared 1 billion years after prokaryotes
(Endosymbiotic theory)
SUBSTRATE LEVEL PHOSPHORYLATION
= using energy from
breaking a chemical
bond to add MITOCHONDRION
aP
directly from a
phosphorylated
molecule
to ADP without
a proton gradient
PYRUVIC ACID MOVES TO NEXT STEP
= ANAEROBIC
IF THERE IS NO OXYGEN (______________)
IF THERE IS OXYGEN (_____________)
= AEROBIC
Cellular respiration
•Glycolysis:
cytosol;
glucose → pyruvate
•Kreb’s Cycle:
•mitochondrial matrix;
•pyruvate → CO2
•NADH made
Electron Transport Chain:
cristae;
NADH & FADH2 donate
electrons → oxygen
Pyruvate is transported into mitochondrion
and Acetyl CoA produced
For each pyruvate converted into acetyl CoA
1 molecule of CO2 is released;
NAD+ ---> NADH;
Krebs Cycle AnimationCoenzyme A (from B vitamin)
Kreb’s Cycle =
Citric Acid Cycle
Krebs Cycle Animation
OAA
CITRIC ACID
Kreb’s Cycle
• Oxaloacetate (OAA) combines with 2 C’s
from Acetyl CoA to make Citric acid
• CoA recycles
• 2 C atoms from pyruvate → exit as CO2
For each pyruvate that enters:
2 CO2 released
3 NAD+ reduced to 3 NADH;
1 FAD+ reduced to 1 FADH2
(riboflavin, B vitamin);
1 ATP molecule
Electron transport chain
NADH
More on Making ATP
FADH2
• 3 places in the
chain make ATP
• Electrons from NADH start “higher” in the waterfall, so they
generate more ATP than FADH2 electrons, which
start “lower” in the waterfall and miss one ATP-generating step.
Electron transport chain
• ETC includes
Cytochromes
Ubiquinone (Q)
• NADH & FADH2 pass electrons pass down ETC
• Energy from moving electrons concentrates H+
ions in __________________
intermembrane space
ATP synthase
• ________________:
harnesses the flow of H+
back into the matrix make ATP
(oxidative phosphorylation)
H O
2
Oxygen is final electron acceptor → ________
• ________
Cellular Respiration Grand Total
• Glycolysis: →2 ATP
(substrate-level phosphorylation)
• Kreb’s Cycle:→ 2 ATP
(substrate-level phosphorylation)
• Electron transport & oxidative phosphorylation:
2 NADH (glycolysis) → 6ATP
2 NADH (acetyl CoA) →6ATP
6 NADH (Kreb’s) → 18 ATP
2 FADH2 (Kreb’s) → 4 ATP
38 TOTAL ATP from 1 molecule of glucose
(-2 ATP to transport 2 pyruvate into mitochondria)
NET of 36 ATP
CHEMIOSMOSIS
= Generation of ATP from a proton gradient.
It occurs in all living things
Chloroplasts
do it to make ATP
in light reactions
Mitochondria do it
to make ATP
following ETC
http://student.ccbcmd.edu/~gkaiser/biotutorials/energy/atpsynthase_il.html
Prokaryotes create
gradient across cell
membrane to make ATP
to pump nutrients & waste
and move flagella
PHOTOPHOSPHORYLATION
= Using hydrogen gradient generated by
thylakoid membrane during the light
reactions of photosynthesis to make ATP
CHLOROPLAST
OXIDATIVE PHOSPHORYLATION
= using proton gradient created by electron
transport chain in cristae membrane to
make ATP
MITOCHONDRION
• In cellular respiration, decoupling oxidative
phosphorylation from electron transport is
involved in thermoregulation
• ADD MORE DETAILS
Fermentation
WHAT IF THERE IS NO OXYGEN?
= ANAEROBIC
IF THERE IS NO OXYGEN (______________)
IF THERE IS OXYGEN (_____________)
= AEROBIC
Related metabolic processes
Fermentation:
• alcohol~
pyruvate →ethanol
• lactic acid~
pyruvate → lactate
ALCOHOLIC FERMENTATION
PYRUVIC
_______
ACID +_____
ALCOHOL + ______
CO2 + NAD
→__________
_____+
• Happens when yeast makes bread dough rise
• CO2 bubbles make air spaces in bread
• Alcohol evaporates during cooking
http://www.deliciousdelicious.com/archives/herb%20bread%201.jpg
ALCOHOLIC FERMENTATION
PYRUVIC
_______
ACID +_____
ALCOHOL+ ______
CO2 + NAD
→__________
_____+
Used to make
alcoholic beverages
http://www.firstpath.com/images/alcohol.jpg
LACTIC ACID FERMENTATION
PYRUVIC
_______
ACID +_____
+
LACTIC
ACID
NAD
→______________ + ________
Happens in muscles during exercise
when body
can’t get oxygen to tissues
fast enough.
Lactic acid builds up in
muscles causing soreness
http://www.miranda.com/library.en/Images/Pictures/girls-runners.jpg
LACTIC ACID FERMENTATION
PYRUVIC
_______
ACID +_____
+
LACTIC
ACID
NAD
→______________ + ________
Happens when bacteria are
used to make foods and
beverages like yogurt, cheese,
buttermilk, sauerkraut, kimchi
http://chronicle.augusta.com/images/headlines/032200/DANNON_YOGURT.jpg
http://www.reillydairy.com/natural_cheese.html
WHY DO FERMENTATION?
WHY NOT JUST KEEP MAKING ATP USING
GLYCOLYSIS?
WITHOUT OXYGEN,
PYRUVIC ACID
builds up
___________
and all the
NAD+ carriers get full.
_______
Eventually glycolysis will
NAD+
PYRUVIC
ACID +_____
_______
+
CO
NAD
→ALCOHOL
__________ + ______
2 + _____
LACTIC ACID
+
NAD
______
You get the NAD+ carriers back
FERMENTATION HAPPENS so cells
+
REGENERATE
the
NAD
can ____________________
needed to keep glycolysis going
FACULTATIVE ANAEROBES
__________________________
= organisms that can make ATP using
either fermentation or cellular respiration
Ex: yeast and many bacteria
With oxygen pyruvate → Krebs cycle
Without oxygen → fermentation
Organisms can use a variety of molecules for fuel
Beta oxidation=
__________________=
breakdown of fatty acids
into 2 carbon fragments
that enter Krebs cycle
as acetyl CoA
1 g of fat → twice as much
ATP as 1 g of carbohydrate