lecture 3 outline (ch. 9, 10) i.recap of glycolysis, coenzyme junction ii.cellular respiration...
TRANSCRIPT
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
• Stages of respiration:
2. Citric acid cycle
Mitochondrial matrix
e- transfer: redox
Cellular Respiration
2. Citric acid cycle
• 2 Acetyl CoA (2C) join oxaloacetate (4C)
• few ATP so far
• e- to carriers
(NAD+, FAD)
• now in mitochondrial matrix
• 2 citrate (6C) converted several steps, 4C lost (CO2)
• 2 ATP made
-inputs:
4 CO2
(H2O = none)
-outputs:
2 Acetyl CoA (2C)
2 ATP
6 NADH
2 FADH2
[2 oxaloacetate (4C)]
Where do outputs go?
Citric acid cycle
Which step so far has loaded the most electron carriers?
A. Glycolysis
B. Coenzyme junction
C. Citric acid cycle
D. They are all equal so far
E. No electron carriers have been loaded yet
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 phosphorylationoxidative phosphorylation
Cellular Respiration
• ETC e- collection molecules
• embedded on inner mitochondrial membrane
Electron transport chain (ETC)
• accept e- in turn
• e- ultimately accepted by O2
(O2 reduced to H2O)
~100 H+ (stored)
10 H2O
-outputs:
ATP (none yet)
Where do outputs go?
Electron transport chain (ETC)
-inputs: per glucose,
10 NADH
2 FADH2
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
• ATP synthase: enzyme that makes ATP using H+ gradient
4. Chemiosmosis
• H+ must enter matrix here
• Generates 1 ATP per ~3.4 H+
Where is the electron transport chain located in the diagram?
A. Green area
B. Blue area
C. Yellow area
D. Pink area
Cellular Respiration - anaerobic
• no O2 – no oxidative phosphorylation
• fermentation = extension of glycolysis
Cellular Respiration - anaerobic
• Types of fermentation -
1. alcohol
• pyruvate converted to acetaldehyde
• acetaldehyde accepts e-
• ethanol produced
• brewing & baking
Cellular Respiration - anaerobic
• pyruvate accepts e-
• lactate produced
• Types of fermentation -
2. Lactic acid
• muscle fatigue
Cellular Respiration
• Comparison of aerobic vs. anaerobic respiration:
• e- carriers loaded:
• ATP per glucose:
Aerobic Anaerobic
• initial e- acceptor:
• final e- acceptor:
Cellular Respiration – other biomolecules
• Glucose catabolism – one option
• Proteins:
• Fats: enter CAC or before
Catabolized into a.a.
Amino group removed (pee out in urine)
• 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. Plant cells only
B. Animal cells only
C. Bacteria only
D. Plant and animal cells
E. Plant, animal and bacterial cells
Overall purpose:
Photosynthesis - overview
• photosynthesis:
light chemical energy
• complements respiration
- light rxn: solar energy harvest
- “dark” rxn: energy to organics
Cellular Respiration:(Exergonic)
Photosynthesis:(Endergonic)
Cellular Respiration vs. Photosynthesis
chloroplast recap
Outer membrane
Inner membrane
Thylakoid membrane
Intermembrane space
Stroma
Thylakoid space
Photosynthesis - overview
• Photosynthesis -
1. light rxn: store energy & split water
NADPH & ATP given off
Chloroplast model:
In photosynthesis, which of the following happens to H2O?
A. Oxidized to oxygen gas
B. Reduced to oxygen gas
C. Oxidized to glucose
D. Reduced to glucose
Photosynthesis – light absorption
• visible light ~380 to 750 nm
• chloroplast pigments – absorb blue-violet & red/orange
- transmit and reflect green
• pigments:
• chlorophyll a
• accessory pigments
-energy-absorbing ring
-hydrocarbon tail
- carotenoids
- photoprotective
Photosynthesis – light absorption
- chlorophyll b
• 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
Photosynthesis – light absorption
If a car is red, which light wavelengths are reflected (NOT absorbed)?
A. Green (500-550 nm)B. Red (650-700 nm)C. Blue (450-500 nm)D. All wavelengths are reflectedE. 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.