Download Cellular Respiration

Bio100 (Paddack) Lecture 7 (9/14/16)
I.
II.
Energy (Ch 5)
A. 2 Laws of Thermodynamics
B. Types of energy
1. Kinetic energy
2. Potential energy
C. Chemical Reactions
Cellular Respiration (Ch 6)
A. Overview
B. Redox reactions
C. Three key steps
1. Glycolysis
2. Citric Acid Cycle
3. Oxidative Phosphorylation
D. Fermentation (Anaerobic Respiration)
1. Lactic acid fermentation
2. Alcohol fermentation
Energy –
capacity to perform work
• Kinetic Energy
Chemical Energy
• A type of Potential Energy
- energy of motion
• Stored in bonds of molecules
– e.g., C6H12O6
• Potential Energy
• Results from arrangement of atoms
- stored energy
(from location
or structure)
Potential energy  kinetic energy
Potential Energy is
created by a concentration gradient
(H+)
How do organisms get energy?
1
Energy stored in ATP can be released
to fuel other reactions
ATP Powers Cellular Work
3 phosphate groups on ATP create HIGH POTENTIAL ENERGY
Figure 5.12 A
Energy required
Energy released
Overview of Cellular Respiration
https://www.youtube.com/watch?v=N4d7Wp9kKjA
Overview of Cellular Respiration
Isn’t
Glycolysis
simple?
(Fig. 6.6)
Figure 6.7C
2
“Grooming” pyruvate for The Citric Acid Cycle
Stage 2: The Citric Acid Cycle
(aka Krebs Cycle); in the mitochondrial matrix
Energy banked:
6 NADH
2 FADH2
Net ATP: 2
Figure 6.8
Energy banked: 2 NADH
The structure of the mitochondria is important
to cellular respiration
Stage 3: Oxidative Phosphorylation
(in cristae of mitochondria)
Energy spent:
10 NADH
2 FADH2
1 NADH  ~ 2.5 ATP
1 FADH2  ~ 1.5 ATP
Net ATP: ~ 28
https://www.youtube.com/watch?v=3y1dO4nNaKY
How does food become fuel?
Figure 6.15
How is ATP produced?
• Substrate-level phosphorylation
– during Glycolysis and Citric Acid Cycle
Figure 6.7 B
• Chemiosmosis
– during Oxidative Phosphorylation
• Food is broken down (by enzymes) into molecules that can
enter cellular respiration at some step.
3
Fermentation
What happens to the pyruvate?
In the absence of oxygen…
• Also uses glucose to convert ADP to ATP
• Occurs in absence of oxygen
• Net ATP production (per glucose): 2
Fermentation
- happens entirely in cytoplasm
- yields 2 ATP (net)
Lactic acid fermentation
Pyruvate
NADH
NAD+
But in the presence of oxygen, cells continue with
Lactate
Fermentation
Alcohol fermentation
Ethanol
CO2
How do organisms get energy?
Cellular Respiration
Glucose
Glycolysis
2 ATP
Pyruvate and NADH
Cytoplasm
-----------------------------------------------------------------------------Mitochondria
Citric
Acid
Cycle
Oxidative Phosphorylation
2 ATP
• Plants are autotrophs
- original energy source is
sunlight
• Animals are heterotrophs
– original energy source
is food
around 28 ATP
1.
Write the 1st & 2nd Laws of Thermodynamics.
2.
How does the 1st Law of Thermodynamics relate to
the topics of cellular respiration & photosynthesis?
3.
Define: Kinetic energy, potential energy, thermal
energy, chemical energy.
4.
What is the purpose of forcing a lot of protons (H+)
to one side of a cell membrane (what benefit does it have)?
5.
Write the chemical equation for cellular respiration.
6.
Where does cellular respiration take place?
7.
Define ATP.
8.
How many ATP are created per glucose in cellular
respiration?
9.
Define: oxidation, reduction, redox..
10. Name 2 co-enzymes that are used to ‘shuttle’
electrons in cellular respiration.
11. List the 3 stages of cellular respiration, state what
part of the mitochondria each occurs, and state the output
of each stage.
12. What final element is needed to have the process of
cellular respiration complete (the last thing to receive the
electrons and protons that were moving around).
13. Why does fermentation occur? Why is it less
helpful than aerobic respiration?
14. List the 2 types of fermentation – one performed by
yeasts & bacteria, the other by organisms such as us.
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