Transcript Cell Respiration - Life is a journey: Mr. T finding his way

Cell Respiration
Song Hee Bae
IB1 Biology
What is Cell Respiration?
• The way to convert energy into a form that can be used within
the cell.
• : Controlled release of energy from organic compounds to form
ATP.
• Require energy for
– Synthesizing
– Active transport
– Movement inside the cell
• Energy is supplied by ATP
• When ATP is split into ADP, energy released
Glycolysis
•
•
•
•
•
•
•
All cells using glucose begin in the same way.
Glucose enters the cell
Takes place in cytoplasm
Enzyme reactions
6 carbon glucose → two 3 carbon molecules
2 “Pyruvate” molecules
Some energy released from breaking
of the covalent bonds
• Net gain of 2 ATP
Anaerobic Cell Respiration
• Cell deriving ATP completely without the use of oxygen
• Glycolysis possible only if pyruvate is converted
• “Fermentation”
– Alcoholic fermentation
– Lactic Acid fermentation
Alcoholic Fermentation
•
•
•
•
•
•
•
•
Yeast
Generate net gain of two ATP
Converts pyruvate to ethanol
Ethanol is 2-carbon molecule
One carbon atom in each is lost
Given off as carbon dioxide
Both are waste products
Why put yeast in baking? Helps the dough to rise
Lactic Acid Fermentation
•
•
•
•
•
•
•
•
Occurs when insufficient supply of oxygen
Ex) running person
Excess pyruvate molecules are converted
Pyruvate molecules are converted to
lactic acid molecules
No production of carbon dioxide
Glycolysis possible only if pyruvate is converted
Allows glycolysis to continue
Used in food
– Yogurt, kimchi, kefir, etc
Aerobic Cell Respiration
•
•
•
•
•
•
Occurs in cells with mitochondria
Two pyruvate molecules enter mitochondria
Each pyruvate loses a carbon
→ Acetyl CoA
Each Acetyl CoA enters Krebs cycle
Much efficient than anaerobic respiration
– Breaks down (completely oxidizes) glucose
– Products are carbon dioxide and water
– Leaves no by-products
– ATP per glucose is much higher
The Krebs Cycle
• Two more carbon dioxide
molecules from each
original pyruvate.
• Some ATP is directly
generated
• Some is indirectly through
later series of reactions
Vocabulary
•
•
•
•
•
•
Glucose: is a type of sugar the body uses for energy
Glycolysis: is the metabolic pathway that converts glucose into
pyruvate.
Cell respiration: the process by which the chemical energy of "food"
molecules is released and partially captured in the form of ATP.
Aerobic cell respiration: The process by which the energy from
glucose is released in the presence of oxygen
Anaerobic cell respiration: The process by which the energy from
glucose is released in the absence of oxygen
Fermentation: process of deriving energy from the oxidation of
organic compounds.
Reference
• Pearson Biology HL page 70-73
• Course Companion page 83-93
• Study Guide page 34
Thank You