Cellular Respiration
Guiding Questions:
1. Why do you need to breathe?
2. What happens to the fat when you lose weight � (where does it go?)
Cellular respiration is the set of the metabolic reactions and processes that take place in the cells of organisms to convert energy from nutrients into adenosine triphosphate (ATP), and then release waste products.
What is CELLULAR RESPIRATION?
C6H12O6 + 6O2 → 6CO2 + 6H2O + ~38 ATP
Stages of Cellular Respiration
1. Glycolysis
2. Kreb’s Cycle
3. Electron Transport Chain
Protein Complexes involved in Cellular Respiration
Phospholipid Bilayer
Transmembrane proteins
AEROBIC RESPIRATION occurs in the presence of oxygen
Without oxygen, another path is taken ....this path is called fermentation, or anaerobic respiration
Fermentation
Byproducts of fermentation include lactic acid and alcohol
Lactic Acid in muscle cells can cause muscle cramps.
This happens when the Krebs cycle cannot occur due to lack of oxygen
Fermentation is used in making food products and alcohol products.
Glycolysis
- nearly all organisms can perform glycolysis
- breaks down glucose with an enzyme called pyruvate kinase
--releases 2 ATP
What are the overall products of glycolysis?
Occurs in the cytoplasm.
Kreb’s Cycle (citric acid cycle)
Pyruvate → Acetyl CoA
Acetyl CoA is reshuffled
(2 carbon) - but there are 2 of them!
3 NADH is created (x2) = 6�1 ATP (x2) = 2�1 FADH2 (x2) = 2
The oxidation of glucose produces CO2
Occurs in the matrix of the mitochondria.
Citric Acid or Krebs Cycle (mitochondrion)
Key points:
Occurs in the matrix of the mitochondria
Pyruvate → Acetyl CoA
FADH (another carrier) and NADH are created
The oxidation of glucose produces CO2
3. Electron Transport System:
a) consists of a series of enzymes on the inner mitochondrial membrane (cristae)�
b) electrons are released from NADH and FADH2, passed along the series of enzymes, they give up energy which is used to fuel a process called chemiosmosis
which drives ATP synthesis!
Net yield of 36-38 ATP
ATP synthase makes ATP from ADP
38 ATP�(total)
Also called CHEMIOSMOSIS
Why do we need oxygen?
Electrons finally unite with O2 at the end of electron transport chain.
Without oxygen to serve as the final electron acceptor, the process shuts down.
What are the 3 stages of cellular respiration?
1.
2.
3.
CO2
O2
H2O
Cellular Respiration Overview
How would you measure respiration rate?
How would this rate differ between a cricket and a mouse?
Explain this graph.
Yeast and Sugars
Explain this graph.
RMR = resting metabolic rate
MMR = maximum metabolic rate
BMR = basal metabolic rate
BMR is defined as the rate at which your body uses energy when you are resting in order to keep vital functions going.
Food for thought
1. What is the purpose of cellular respiration?
2. Where does cellular respiration occur within the cell?
3. What is the waste product of cellular respiration?
Guiding Questions:
�1. Why do you need to breathe?
2. What happens to the fat when you lose weight? (where does it go?)�
Checkpoint
1. In order to produce energy, cells start with glycolysis. If oxygen is NOT present after glycolysis, what process occurs next?�� a) Electron Transport Chain b) Krebs Cycle c) Fermentation��2. If oxygen IS present after glycolysis, what process occurs next?� a) Electron Transport Chain b) Krebs Cycle c)Fermentation
3. A process that does NOT require oxygen is known as what?� a) Aerobic b) Anaerobic�
4. In glycolysis, glucose is broken into 2 molecules of _____________
5. Where does the Krebs cycle occur? _________________
6. What gas is a waste product produced in the Krebs cycle? ____
7. What enzyme is used in the electron transport chain to create ATP?
a. citric acid b. pyruvate c. ATPase
8. Where does glycolysis occur?
a. cytoplasm b. mitochondria c. chloroplast
9. Which process produces the largest amount of ATP?
a. fermentation b. Krebs Cycle c. ETC
10. The oxygen required by cellular respiration is reduced and becomes part of which molecule?
a. ATP b. CO2 c. H20