Download Chapter 8-3 Cellular Respiration

Chapter 8 Section 3 – Cellular Respiration
Overview of Cellular Respiration
 Living organisms obtain energy by breaking down
organic molecules during cellular respiration.
 It is a catabolic pathway in which organic
molecules are broken down to release energy for
use by the cell.
 The equation for cellular respiration is the opposite
of the equation for photosynthesis.
Cellular Energy
 The Reactants of Cellular Respiration are:
 Glucose (C6H12O6) – eat
 Oxygen (O2) – breathe in
 The Products of Cellular Respiration are:
 Heat – released throughout your body
 Carbon Dioxide (CO2) – breathe out
 Water (H2O) – breathe out
Cellular Energy
Cellular respiration occurs in two main stages:
 Glycolysis – occurs in the cytoplasm
 Aerobic respiration – occurs in the mitochondria
Glycolysis
• The splitting of
glucose
• Occurs in the
cytoplasm
• Does not require
oxygen
https://www.youtube.
com/watch?v=3GTjQT
qUuOw
Glycolysis
• Final products of glycolysis for each molecule of
glucose are:
– 2 ATP’s
– 2 molecules of NADH
– 2 molecules of pyruvate for each glucose molecule
that is broken down
• 4 molecules of ATP are actually produced when
glucose is split, but the energy from 2 of those are
needed for the reactions to take place.
Cellular Energy
Aerobic Respiration
 In aerobic respiration, oxygen is used to break
down glucose molecules.
 As a result 36 ATP can be made from 1
glucose molecule.
 Aerobic respiration follows glycolysis and occurs
inside the mitochondria.
 The 2 pyruvate molecules are transported to the
mitochondria.
Cellular Energy
 Two pyruvate molecules from glycolysis is
transformed into acetyl CoA and enters the
Krebs cycle.
https://www.youtube.com/watch?v=-cDFYXc9Wko
https://www.youtube.com/watch?v=-_8aYKcQZ_Q
Cellular Energy
 Krebs Cycle (sometimes referred to as the
citric acid cycle)
• Series of reactions in which pyruvate is
broken down into carbon dioxide.
• There are two “turns” of the Krebs
cycle for each glucose molecule.
Why?
Cellular Energy
 Krebs cycle results in the net
production of:
•
•
•
•
8 NADH
2 FADH2
2 ATP
6 CO2
Cellular Energy
 Electron Transport
Chain
•
•
NADH & FADH2
enter electron
transport chain in
mitochondria
cristae.
High energy
electrons and
hydrogen ions from
NADH and FADH2
produced in the
Krebs cycle are
used to convert ADP
to ATP.
Cellular Energy
 Electron Transport Chain
•
•
•
Oxygen is the final acceptor of
electrons.
Protons and electrons are transferred
to oxygen to form water.
Produce 32 more ATP.
Summary of Cellular respiration
https://www.youtube.com/watch?v=-Gb2EzF_XqA
Cellular Energy
Anaerobic Respiration
 The first step in anaerobic respiration is also
called glycolysis.
 Anaerobic = without oxygen
 Plant and animal cells cannot survive off of
anaerobic respiration.
 Not very efficient
Cellular Energy
Anaerobic Respiration
 There are 2 types of anaerobic respiration:
1. Lactic acid fermentation
• A process that occurs in animal cells
• Causes your muscles to burn when
you perform short bursts of activity
2. Alcohol fermentation
• A process that occurs in plants
• This is how alcohol, such as wine
and beer, is made
Lactic Acid Fermentation
Alcohol Fermentation
 Review the two equations for
photosynthesis and cell respiration.
 They are reversed!
Cellular Energy
Cellular Respiration & Photosynthesis are Interrelated
 Products for photosynthesis are oxygen and
glucose, the reactants for cellular respiration.
 Cellular respiration uses O2 to break the
sugars down and releases the CO2 back into
the atmosphere to be used again by plants.
Cellular Energy
Cellular Respiration & Photosynthesis are Interrelated
 Notice! Molecules such as O2 and CO2 are
recycled through the environment, however
the energy is not!
 Energy enters our environment as light
and leaves back into outer space as
heat.
Cellular Energy
Cellular Respiration & Photosynthesis