Lecture 3 Outline (Ch. 9, 10)
I.
Recap of Glycolysis, Coenzyme Junction
II.
Cellular Respiration continued
A. Citric Acid Cycle (aka Krebs/TCA cycle)
B. Electron Transport Chain (ETC)
C. Chemiosmosis
III. Anaerobic respiration
IV. Respiration using other biomolecules
V.
Introduction to Photosynthesis
A. Chloroplasts
B. Light wavelengths
VI. Preparation for next lecture
Steps of Respiration
Steps of Respiration
• Stages of respiration:
2. Citric acid cycle
Mitochondrial matrix
e- transfer: redox
Cellular Respiration
2. Citric acid cycle
• few ATP so far
• now in mitochondrial
matrix
• 2 Acetyl CoA (2C) join
oxaloacetate (4C)
• 2 citrate (6C)
converted several steps,
4C lost (CO2)
• 2 ATP made
• e- to carriers
(NAD+, FAD)
Citric acid cycle
-inputs: 2 Acetyl CoA (2C)
-outputs:
[2 oxaloacetate (4C)]
2 ATP
6 NADH
2 FADH2
4 CO2
(H2O
= none)
Where do outputs go?
Which step so far has loaded the most
electron carriers?
A.
B.
C.
D.
E.
Glycolysis
Coenzyme junction
Citric acid cycle
They are all equal so far
No electron carriers have
been loaded yet
Steps of Respiration
• Stages of respiration:
3. ETC
Proton
Motive
Force
Cellular Respiration
3. Electron transport
chain (ETC)
• lots of energy
harvested
• released in stages
• so far, 4 ATP –
made by substrate
phosphorylation –
not as efficient
• now, many ATP – made by oxidative phosphorylation
Steps of Respiration
• Stages of respiration:
4. Chemiosmosis
ATP produced!
Cellular Respiration
Electron transport chain (ETC)
• ETC  e- collection molecules
• embedded on inner
mitochondrial membrane
• accept e- in turn
• e- ultimately
accepted by O2
(O2 reduced to H2O)
Electron transport chain (ETC)
-inputs: per glucose,
10 NADH
2 FADH2
-outputs:
ATP (none yet)
~100 H+ (stored)
10 H2O
Where do outputs go?
Cellular Respiration
4. Chemiosmosis
• ATP synthase: inner mitochondrial membrane
• H+ stock-piled in inner membrane space = gradient
• chemiosmosis – ion gradient to do work
Cellular Respiration
4. Chemiosmosis
• ATP synthase: enzyme that
makes ATP using H+ gradient
• H+ must enter matrix here
• Generates 1 ATP per ~3.4 H+
Where is the electron transport chain
located in the diagram?
A.
B.
C.
D.
Green area
Blue area
Yellow area
Pink area
Cellular Respiration
Summary of respiration
KNOW THIS DIAGRAM – EXCELLENT SUMMARY 
Cellular Respiration - anaerobic
• no O2 – no oxidative
phosphorylation
• fermentation
= extension of glycolysis
Cellular Respiration - anaerobic
• Types of fermentation 1. alcohol
• brewing & baking
• pyruvate
converted to
acetaldehyde
• acetaldehyde
accepts e• ethanol produced
Cellular Respiration - anaerobic
• Types of fermentation 2. Lactic acid
• muscle fatigue
• pyruvate
accepts e-
• lactate
produced
Cellular Respiration
• Comparison of aerobic vs. anaerobic respiration:
Aerobic
• e- carriers
loaded:
• ATP per
glucose:
• initial eacceptor:
• final eacceptor:
Anaerobic
Cellular Respiration – other biomolecules
• Glucose catabolism – one option
• Proteins: Catabolized into a.a.
Amino group removed
(pee out in urine)
• Fats: enter CAC or before
• If have more glucose than
needed, can run “backward” to
store energy as glycogen or fats!
Self-Check
Step of
Respiration
Inputs
Outputs
CO2/H2O
ATP
produced
e- carriers
loaded
Glycolysis
1 glucose
2 pyruvate
(2H2O)
2 net
2 NADH
Coenzyme
Junction
Citric Acid
Cycle
Electron
Transport Chain
Oxidative
phosphorylation
Fermentation
Which cells perform aerobic cellular respiration?
A.
B.
C.
D.
E.
Plant cells only
Animal cells only
Bacteria only
Plant and animal cells
Plant, animal and bacterial cells
Photosynthesis - overview
Photosynthesis - overview
Overall purpose:
• photosynthesis:
light chemical energy
• complements
respiration
- light rxn: solar
energy harvest
- “dark” rxn:
energy to organics
Cellular Respiration vs. Photosynthesis
Cellular Respiration:
(Exergonic)
Photosynthesis:
(Endergonic)
chloroplast recap
Outer membrane
Inner membrane
Thylakoid membrane
Intermembrane space
Stroma
Thylakoid space
Photosynthesis - overview
Chloroplast model:
• Photosynthesis 1. light rxn: store
energy & split water
NADPH & ATP
given off
Redox Reactions
Equation for photosynthesis
CO2 + H2O + light energy
photo
C6H12O6 + O2
synthesis
In photosynthesis, which of the
following happens to H2O?
A.
B.
C.
D.
Oxidized to oxygen gas
Reduced to oxygen gas
Oxidized to glucose
Reduced to glucose
Photosynthesis – light absorption
• visible light ~380 to 750 nm
• chloroplast pigments – absorb blue-violet & red/orange
- transmit and reflect green
Photosynthesis – light absorption
• pigments:
• chlorophyll a
-energy-absorbing ring
-hydrocarbon tail
• accessory pigments
- chlorophyll b
- carotenoids
- photoprotective
Photosynthesis – light absorption
• chlorophyll a –
abs blue-violet, red
~400-450, 650-700
• chlorophyll b &
carotenoids – abs
broadly blue-violet
450-500 & 600-650
• more wavelengths used for photosynthesis =
more light energy absorbed
If a car is red, which light wavelengths
are reflected (NOT absorbed)?
A.
B.
C.
D.
E.
Green (500-550 nm)
Red (650-700 nm)
Blue (450-500 nm)
All wavelengths are reflected
All wavelengths absorbed
Things To Do After Lecture 3…
Reading and Preparation:
1.
Re-read today’s lecture, highlight all vocabulary you do not
understand, and look up terms.
2.
Read chapter 9, focus on material covered in lecture (terms, concepts,
and figures!)
3.
Ch. 9 Self-Quiz: 1-7 (correct using the back of the book).
4.
Skim next lecture.
“HOMEWORK”:
1.
Draw a diagram similar to the cell on the next slide, and show where
each step of cellular respiration occurs.
2.
Match up the three boxes each for the citric acid cycle and oxidative
phosphorylation (from last lecture).
3.
Compare and contrast aerobic respiration and fermentation for three
things that are similar/shared AND three things that are different!
4.
Diagram a chloroplast labeling the three membranes and three spaces.
5.
In the spectrum of visible light (380 to 750 nm), indicate which
wavelengths (number AND color) are absorbed by chloroplasts and
which are not absorbed.
Self-Check