Download BioCore II lecture20-S2015

1. Sit with Lab Group
Find members of your group
2. Attendance with your phone
Launch your Top Hat app on your smart phone or
load the TopHat.com website, or text to the course’s
phone number.
3. Get out your notebook
Prepare to add additional notes to those you took
on last night's reading assignment.
A couple BioCore students want to celebrate
“graduation” from BioCore. They wanted to hear if you
might be interested in a semi-formal(?) banquet.
Question 1: Are you interested in attending an End of the Year banquet for
the completion of Biocore?
A) I would Attend
B) I would not Attend
Question 2: I would be Willing to pay to attend this banquet for at most …
A) $20
B) $15
C) $10
D) I answered that I am not interested
Question 3: It would be best if the banquet took place on this date
A) April 30th (The last thursday before Finals week)
B) May 1st (Friday before finals)
C) May 2nd (Saturday)
Announcements
• Today your assigned readings were these:
Announcements
• The learning goals from the textbook are:
Glycolysis
• Describe the overall result in terms of molecules produced in
the breakdown of glucose by glycolysis
• Compare the output of glycolysis in terms of ATP molecules
and NADH molecules produced
•
•
Citric Acid Cycle (Krebs)
Explain how a circular pathway, such as the citric acid cycle,
fundamentally differs from a linear pathway, such as glycolysis
Describe how pyruvate, the product of glycolysis, is prepared
for entry into the citric acid cycle
Announcements
• Outline of lecture notes provided once again
for this topic in Course Pack
Our goals are not achieved by only listening
to a lecturer—you must actively do things
in order to learn (Bio or Kung Fu)
Last time we asked:
Why do you breathe?
What does this remind you of?
The electron transport chain
occurs in the inner membrane of
the mitochondrion (in regions
called “cristae”)
ELECTRON TRANSPORT CHAIN
H+ H+
H+ H+ H+
H+ + H+
H
H+
H+
H+
+
+
+
H+H H H
H+
H+
H+
H+
H+
H+
Q
H+
H+
H+
H+
H+
H+
H+ H+
H+
H+
Cyt c
Q
NADH
NAD+
H+
Complex I
Inner membrane
FADH2
FAD
H+
Complex II
O2
H+
H2O
Complex III
Complex IV
1. What is backwards? 2. How much ATP? 3. Poke hole?
This is why we breathe
rat poison
cyanide & CO
The electron transport chain occurs in
the inner membrane of the
mitochondrion (in regions called
“cristae”)
ELECTRON TRANSPORT CHAIN
H+
H+
H+ H+
H+
H+
H+
H+
H+
H+
H+H
H+ H+
H+
+
H+
H+
H+
H+
H+
H+
Q
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+
Cyt c
Q
NADH
Inner membrane
FADH2
NAD+
FAD
H+
H+
O2
H+
H2O
Complex I
Complex II
Complex III
Complex IV
NADH-Q Reductase, FADH-Q Reductase, Cytochrome Reductase, Cytochrome Oxidase
(NADH dehydrogenase, FADH dehydrogenase, Cytochrome complex, Cytochrome Oxidase)
The electron transport chain occurs in
the inner membrane of the
mitochondrion (in regions called
“cristae”)
ELECTRON TRANSPORT CHAIN
H+
H+
H+ H+
H+
H+
H+
H+
H+
H+
H+H
H+ H+
H+
+
H+
H+
H+
H+
H+
H+
Q
H+
H+
H+
H+
H+
H+
H+
H+
H+
H+
Cyt c
Q
NADH
Inner membrane
FADH2
NAD+
FAD
H+
H+
O2
H+
H2O
Complex I
Complex II
Complex III
Complex IV
NADH-Q Reductase, FADH-Q Reductase, Cytochrome Reductase, Cytochrome Oxidase
Cellular respiration
If oxygen (aerobic)
is present
GLYCOLYSIS
Glucose
KREBS CYCLE
ELECTRON TRANSPORT AND
OXIDATIVE PHOSPHORYLATION
Pyruvate
If oxygen is NOT
present
(anaerobic)
FERMENTATION
0.2 µm
Mitochondria
0.2 µm
Intermembrane space
Outer
membrane
Free ribosomes
Inner
membrane
Cristae
?
0.1 µm
Electron
transport chain
SUMMARY OF CELLULAR RESPIRATION
Electrons
2 NADH
Glucose
2 NADH
2 Pyruvate
2 ATP
Cytoplasm
2 Acetyl CoA
2 CO2
Oxidative
phosphorylation
H+ + + + +
H H H HH
+ H+ +
+
H
H+ H+ H H+
H+
H+
NADH
6
2 FADH2
KREBS
CYCLE
O2
4 CO2
2 ATP
Mitochondrion
So are the H+s really trapped?
H 2O
26 ADP
25 ATP
Maximum yield of ATP
per molecule of glucose:
29
SUMMARY OF GLUCOSE OXIDATION
2 NADH
Glucose
2 NADH
2 Pyruvate
2 ATP
Cytoplasm
2 Acetyl CoA
2 CO2
Mitochondrion
6 NADH
2 FADH2
KREBS
CYCLE
2 ATP
4 CO2
Where do we go next?
SUMMARY OF GLUCOSE OXIDATION
2 NADH
Glucose
2 Pyruvate
2 ATP
Cytoplasm
Mitochondrion
Pyruvate Dehydrogenase
Multienzyme Complex
If you have O2, enter the Matrix
SUMMARY OF GLUCOSE OXIDATION
2 NADH
Glucose
2 Pyruvate
2 ATP
Cytoplasm
Mitochondrion
Where do we go next?
SUMMARY OF GLUCOSE OXIDATION
2 NADH
Glucose
2 NADH
2 Acetyl CoA
2 Pyruvate
2 CO2
2 ATP
Cytoplasm
Mitochondrion
SUMMARY OF GLUCOSE OXIDATION
2 NADH
Glucose
2 NADH
2 Acetyl CoA
2 Pyruvate
6 NADH
2 FADH2
KREBS
CYCLE
2 CO2
2 ATP
Cytoplasm
2 ATP
Mitochondrion
4 CO2
The two red carbons enter
the cycle via acetyl CoA
Acetyl CoA
Citrate
All 8 reactions
of the citric
acid cycle
occur in
the
mitochondrial
matrix, outside
the cristae
Isocitrate
In each turn of
the cycle, the
two blue
carbons are
converted to
CO2
α-Ketoglutarate
Oxaloacetate
The CITRIC ACID
CYCLE
runs twice for each
glucose precursor
In the next cycle
this red carbon
becomes a blue
carbon
Succinyl CoA
Malate
Each reaction is catalyzed
by a different enzyme
Fumarate
Succinate
What about this?
Actually…
Electrons
carried
via NADH
Glycolysis
Pyruvate
Glucose
Cytosol
ATP
Substrate-level
phosphorylation
Electrons carried
via NADH and
FADH2
Electrons
carried
via NADH
Citric
acid
cycle
Glycolysis
Pyruvate
Glucose
Mitochondrion
Cytosol
ATP
ATP
Substrate-level
phosphorylation
Substrate-level
phosphorylation
Electrons carried
via NADH and
FADH2
Electrons
carried
via NADH
Citric
acid
cycle
Glycolysis
Pyruvate
Glucose
Oxidative
phosphorylation:
electron transport
and
chemiosmosis
Mitochondrion
Cytosol
ATP
ATP
ATP
Substrate-level
phosphorylation
Substrate-level
phosphorylation
Oxidative
phosphorylation
All 10 reactions of
glycolysis occur
in cytosol
GLYCOLYSIS
What
goes in: ATP
ATP
1
Glucose
What
comes out:
2
Glucose6-phosphate
ADP
3
Fructose6-phosphate
4
Fructose1,6-bisphosphate
ADP
Glycolysis begins with an energyinvestment phase of 2 ATP
5
PIP
• Think of the beginning
of “Glyco-lysis” as
eating a pizza
Think Glucose = Pizza
The common ‘hexo-pyranose’ form of Pizza
Meet PIP (Phosphorylate-Isomerize-Phosphorylate)
•
Is that really the best way to hold on to your pizza?
Aldolase =
Fructose 1-6 Bisphosphate -> DHAP (ick) and G-3-P (tasty!)
Isomerase ->
DHAP (ick)
G-3-P (tasty!)
Isomerase ->
G-3-P (tasty!)
G-3-P (tasty!)
GLYCOLYSIS
Energy-investment phase
What
goes in: ATP
ATP
P
I
1
2
Glucose6-phosphate
Glucose
What
comes out:
P
3
Fructose6-phosphate
ADP
Hexokinase
(capture)
4
Fructose1,6-bisphosphate
ADP
phosphoglucoisomerase
PFK*
??????
[ATP] high
5
PFK is highly regulated
ATP at
active
site
ATP at
regulatory
site
Fructose- 1,6bisphosphate at
active site
GLYCOLYSIS
Energy-investment phase
aldolase
What
goes in: ATP
P
I
1
P
2
Glucose6-phosphate
Glucose
What
comes out:
DHAP
ATP
3
Fructose6-phosphate
ADP
hexokinase
4
stimulates
isomerase
Fructose1,6-bisphosphate
ADP
phosphoglucoisomerase
5
PFK*
G-3-P
G-3-P
inhibits
Glyceraldehyde-3-phosphate (G3P)-dehydrogenase
[ATP] high
[ADP] [AMP]
Phosphoglycero(PG)-kinase
Glyceraldehyde-3-phosphate(G3P)-dehydrogenase
PIP
All 10 reactions of
glycolysis occur
in cytosol
GLYCOLYSIS
What
goes in: ATP
ATP
1
Glucose
What
comes out:
2
Glucose6-phosphate
ADP
3
Fructose6-phosphate
4
5
Fructose1,6-bisphosphate
ADP
G-3-P
G-3-P
Glyceraldehyde-3-phosphate(G3P)-dehydrogenase
Glycolysis begins with an energyinvestment phase of 2 ATP
Energy payoff phase
Phosphoglycero(PG)-kinase
The “2” indicates that glucose has
been split into two 3-carbon sugars
2 NAD+
2 ADP
2
6
2 G-3-P
2
2
7
1,3-BisPGA
8
2
9
2 ADP
2
10
Pyruvate
3-PGA
pyruvate
kinase
2 NADH
2 ATP
2 ATP
G-3-P-dehydrogenase
During the energy payoff phase, 4 ATP are produced for a
net gain of 2 ATP