Cell Respiration

1
Cell Respiration

• Releasing Chemical Energy

2
Introduction

• All organisms must have energy to carry out life
  processes.
• Where does this energy come from?

Autotrophs collect energy from the sun and store
it as organic compounds.
3
The Need for Energy

• No Energy no work

• Energy Work

4
Respiration An Overview

• Metabolism is all of the chemical reactions in
  the body.
• These reactions are either
• Synthesis combining small molecules to make
  complex molecules OR
• Decomposition reactions breaking down molecules
  into simpler forms.

5
Reactions Continued

• Synthesis reactions require energy example
  photosynthesis.
• Decomposition reactions release energy.
• This energy can be used to make ATP
• ATP is a small, useable packet of energy.

6
Cellular Respiration

• Cell Respiration is a decomposition reaction that
  provides the energy cells need to function.
• In this series of reactions, sugars, proteins,
  and lipids are broken down (decomposed) and
  energy is released.

7
Types of Cellular Respiration

• There are two types of cell respiration aerobic
  and anaerobic.
• Aerobic respiration occurs in the presence of
  oxygen.

2. Anaerobic respiration occurs in the absence of
oxygen.
8
Raw Materials for Cell Respiration

• What are the raw materials for cell respiration?

Carbohydrates, proteins, and lipids
9

• How does the food become the raw materials?

• Food is digested into carbohydrates, lipids, and
  proteins.

10
Glucose and Glycogen

• Glucose is the form in which animals transport
  carbohydrates through the blood stream.

• Glycogen is the form in which it is stored in
  animals.
• Glycogen is stored in the liver and muscles.

11
Mitochondria

• Mitochondria are the energy factories of the
  cells.

12
Mitochondria

• Cellular Respiration occurs in the mitochondria-
  an organelle in the cytoplasm of cells.
• They have
• an outer membrane that encloses the entire
  structure
• an inner membrane that encloses a fluid-filled
  matrix
• between the two is the intermembrane space
• the inner membrane is elaborately folded with
  shelf-like cristae projecting into the matrix.

13
Stages of Cell Respiration

• Glycolysis
• Krebs Cycle
• Electron Transport System

14
Glycolysis

• Glycolysis happens in the cytoplasm.
• Glucose is split into 2 three-carbon molecules.
• Enzymes partially oxidize glucose and this
  partial oxidation releases energy that forms a
  small amount of ATP.
• This is an anaerobic process and 2 net ATP are
  generated.
• This ATP is used to start the Krebs Cycle.

15
Glycolysis Animations

• http//www.science.smith.edu/departments/Biology/B
  io231/glycolysis.html
• http//instruct1.cit.cornell.edu/courses/biomi290/
  ASM/glycolysis.dcr
• http//science.nhmccd.edu/biol/glylysis/glylysis.h
  tml
• http//instruct1.cit.cornell.edu/Courses/biomi290/
  MOVIES/GLYCOLYSIS.HTML

16
Krebs Cycle

• The Krebs cycle completes the decomposition and
  oxidation of glucose to carbon dioxide.
• The carbon dioxide is released as a gas.
• The oxidation of one glucose molecule yields up
  to 38 ATP molecules under ideal conditions (this
  occurs infrequently)

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• The reaction of acetyl CoA with oxaloacetate
  starts the cycle by producing citrate (citric
  acid).
• In each turn of the cycle, two molecules of CO2
  are produced as waste products, plus three
  molecules of NADH, one molecule of GTP, and one
  molecule of FADH2.
• The number of carbon atoms in each intermediate
  is shown in a yellow box. (see picture next slide)

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Krebs Cycle Animations

• http//www.science.smith.edu/departments/Biology/B
  io231/krebs.html
• http//www.wiley.com/legacy/college/boyer/04700037
  90/animations/tca/tca.htm

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The Electron Transport Chain

• It is composed of the mitochondrial enzymes that
  transfer electrons from one complex to another,
  eventually resulting in the formation of ATP.
• In the first part, electrons are transferred from
  protein to protein and energy is lost as free
  energy along the way.

21
ATP Synthetase

• This free energy is used to move protons into the
  matrix of the mitochondria.
• As they pass through the matrix, they pass
  through the ATP synthetase enzyme.
• This causes a charge differential (gradient)
  which drives the forming of ATP from ADP.

22
Electron Transport

• http//www.wiley.com/legacy/college/boyer/04700037
  90/animations/electron_transport/electron_transpor
  t.htm
• http//www.science.smith.edu/departments/Biology/B
  io231/etc.html
• http//www.sp.uconn.edu/terry/images/anim/ETS.htm
  l

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ATP Synthesis

• http//telstar.ote.cmu.edu/biology/animation/ATPSy
  nthesis/biochem.html
• http//www.sp.uconn.edu/terry/images/anim/ATPmito
  .html