Transcript File - LAHS | Life Science

Notes: Cellular
Respiration
Cellular Respiration
• Cellular respiration makes ATP by breaking down
sugars and other carbon- based molecules
• aerobic (requires oxygen)
• Takes place in mitochondria
Cellular Respiration
Overall Equation:
C6H12O6 + 6O2 → →→→6CO2 + 6H2O + ATP
How is this different from photosynthesis?
Glycolysis
• Means “glucose breaking”
• C6H12O6 (glucose) broken into two 3-carbon molecules
of pyruvic acid
• Produces 2 molecules of ATP
Glycolysis
• Occurs in the cytoplasm
next to the mitochondria
• Anaerobic process
(does not require oxygen)
• Reactant: Glucose
• Product: 2 ATP and
Pyruvic Acid
• This will enter the
mitochondria for further
processing
Aerobic Respiration
• Aerobic Respiration takes place in two
main stages
• Requires oxygen (aerobic)
• Occurs in the mitochondria
Aerobic Respiration
Step 1: Kreb’s Cycle
• Takes place in interior space of mitochondria
called the matrix (liquid inside
mitochondria)
• Pyruvic acid made in glycolysis are broken
down further
Aerobic Respiration
Step 1: Kreb’s Cycle
• This produces carbon dioxide (CO2) and
ATP.
• ATP is transferred to 2nd step of aerobic
respiration.
•Reactants: Pyruvic
Acid
•Products: CO2 and
2 ATP
Aerobic Respiration
Step 2: Electron Transport Chain
• Takes place in inner
membrane (cristae)
• ATP is transferred to
electron transport chain
from Kreb’s Cycle
Aerobic Respiration
Step 2: Electron Transport Chain
• Oxygen enters process and picks up electrons
and hydrogen to make H2O (water)
• Many enzymes required for process
• 34 ATP produced for a total of 36 including
glycolysis
• Reactants: ATP and O2
• Products: H2O and 34ATP
Overall Equation
C6H12O6 + 6O2 → →→→6CO2 + 6H2O + ATP
Fermentation
• Anaerobic process
• Fermentation allows glycolysis to continue making
ATP when oxygen is unavailable
Fermentation
• Glycolysis makes 2 ATP
• Better to make two than none!
Fermentation Types
1. Lactic Acid Fermentation– occurs in muscle cells
2. Alcoholic Fermentation
Energy and Exercise
• Short Term Energy
• Cells contain only enough ATP for a few seconds of
intense activity
• Then cells rely on lactic acid fermentation (can supply
for about 90 seconds)
• Lactic acid build-up causes burning in muscles. Only
way to get rid of lactic acid is chemical pathway that
requires oxygen (why you breathe heavy after heavy
exercise.)
Energy and Exercise
• Long Term Energy
• Cellular respiration only way to produce continuous
supply of ATP
• Energy stored in muscles and other tissue in form of
carbohydrate glycogen
• Enough glycogen for about 15 to 20 min
• When glycogen used up, body breaks down other stored
molecules including fats, for energy.