What is Cellular Respiration?
- Series of metabolic reactions converting food energy into a usable form - ATP
What is ATP?
- Adenosine Tri Phosphate
- ATP is unstable
- Cells make ATP all the time
Read
- In cells, glucose is oxidized through a long series of carefully controlled reactions, during these process energy is released.
- The released free energy is used to synthesize ATP (by adding phosphate group to ADP to make ATP)
- Cells generally contain enough ATP to sustain from 30 secs to a few mins of activity
How is ATP regenerated? (see slide 5)
- energy to phosphorylate ADP comes
from catabolic reactions in the cell. - Cellular respiration regenerate ATP when used
in the cell.
What is Catabolism?
- The breakdown of molecules.
- Stored chemical energy to produce ATP.
What is Anabolism?
- The synthesis of larger molecules from smaller components.
- Uses energy to form ATP.
How do cells make ATP?
- By obtaining glucose to make ATP
- ATP comes from glycolysis ONLY.
Read
- Plants produce glucose during photosynthesis.
- Other organisms obtain glucose from food.
What do organisms store excess glucose?
- Glycogen
- Starch
What is breathing?
- Inhalation of oxygen into lungs to be delivered to cells
- Exhalation of carbon dioxide.
What is cellular respiration?
- Needs oxygen from breathing as part of the metabolic process; carbon dioxide waste is returned to the lungs.
What is Aerobic Cellular Respiration?
- Occurs mainly in the mitochondria.
- Needs Oxygen.
- Glucose (C6H12O6) + 6O2 → 6H2O + 6CO2 + Energy
What are the stages in cellular respiration?
- Stage 1: Glycolysis
- Stage 2: Citric Acid (Krebs Cycle)
- Stage 3: Electronic transport chain and ATP synthesis.
What happens in stage 1 : Glycolysis?
- Occurs in the cytosol/cytoplasm
- Doesn’t require Oxygen
- 6-carbon glucose molecule is broken down into two 3-carbon pyruvic acid molecules.
- Produces 2 ATP.
What happens in the Citric acid cycle (Krebs cycle)
- The Pyruvic acid loses a carbon dioxide (decarboxylated).
- The now 2-carbon molecule enters Citric acid cycle, 2-carbon fragment is metabolized inside mitochondrion
- The Citric acid cycle completes the oxidation of glucose.
- Series of enzyme-catalyzed reactions in the mitochondrial matrix.
- Produces 2 ATP
- Releases CO2 + NADH
Read
- Most of glucose’s original energy is contained in the electrons transferred to NADH and FADH2.
- The electrons (and protons) are
ultimately transferred to oxygen to form water.
Nicotinamide adenine dinucleotide.
: NAD+ - Empty Taxicab for electron
- The empty taxicab (NAD+) picks up electrons + hydrogen ions (H+).
- Then becomes a full taxicab (NADH) that carries electrons to their final destinations.
What is The Electron Transport Chain?
- Series of proteins in the mitochondrion acting like a
conveyor belt for electrons.
What happens in The Electron Transport Chain and ATP Synthesis?
- Proteins oxidize NADH and FADH2 (where all
electrons come from) - NADH drops off electrons and H+ ions.
- Electrons move through the chain.
- H+ conc increases as the ions are moved into the
intermembrane space. - Electrons from NADH and FADH2 are passed from one protein to the next, releasing energy for ATP synthesis.
- ( read) As the electrons travel through the chain, they go from a higher to a lower energy level. Energy is released in these “downhill” electron transfers, and several of the
protein complexes use the released energy to pump protons (H+) from the mitochondrial matrix to the intermembrane space.
What is the non-protein used for oxidation in the Electron Transport Chain?
- Ubiquinone or coenzyme Q
Where does glycolysis occur and what does it produce?
- Cytoplasm
- 2 pyruvate, 2 ATP, 2 NADH
Where does The citric acid cycle occur and what does it produce for both 1 + 2?
Cycle 1
- Mitochondrial matrix
- 2 Acetyl CoA, 2 NADH, 2 CO2
Cycle 2
- Mitochondrial matrix
- 4 CO2, 6 NADH, 2 FADH2, 2 ATP
Where does The electron transport chain occur and what does it produce?
- Mitochondria; inner membrane
- 30-34 AT, 6 H2O
What happens when carbs aren’t available for ATP production?
- For ATP production, cells first use carbohydrates → then fats → and finally proteins.
