Lesson%20Overview

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Lesson Overview

• 9.1 Cellular Respiration An Overview

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THINK ABOUT IT

• You feel weak when you are hungry because food
  serves as a source of energy. How does the food
  you eat get converted into a usable form of
  energy for your cells?

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Chemical Energy and Food

• Food provides living things with the chemical
  building blocks they need to grow and reproduce.
• Food molecules contain chemical energy that is
  released when its chemical bonds are broken.

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Chemical Energy and Food

• Energy stored in food are calories.
• A Calorie is the amount of energy needed to
  raise the temperature of 1 gram of water by 1
  degree Celsius.
• 1000 calories 1 kilocalorie, or Calorie.
• Cells use the energy from fats, proteins, and
  carbohydrates..
• Cells break down food molecules to make ATP

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Comparing Photosynthesis and Cellular Respiration

• What is the relationship between photosynthesis
  and cellular respiration?

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PHOTOSYNTHESIS AND RESPIRATION
Mitochondria
Chloroplast
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How ATP is Produced Cellular Respiration
IN
Out
Mitochondrion
Glucose
Carbon Dioxide
Oxygen
Water
ADP
ATP
Free Phosphate (P)
The ATP can be used directly to power life
processes
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Capturing Light Energy Photosynthesis
Requirements and products of photosynthesis
Out
IN
Chloroplast
Glucose
Carbon Dioxide
Oxygen
Water
Water
Light Energy
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Overview of Cellular Respiration

• What is cellular respiration?
• Cellular respiration is the process that releases
  energy from food in the presence of oxygen.
• In symbols
• 6 O2 C6H12O6 ? 6 CO2 6 H2O Energy
• In words
• Oxygen Glucose ? Carbon dioxide Water
  Energy

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What forms of energy?
ATP Adenosine
Triphosphate
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How ATP provides energy
ATP links Anabolism (building molecules) and
catabolism (breaking down molecules)!!!!!
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Stages of Cellular Respiration

• The three main stages of cellular respiration
  are
• Glycolysis,
• the Krebs cycle,
• the Electron Transport Chain.

WE START HERE!!
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Glycolysis

• Glycolysis produces only a small amount of
  energy.
• Glycolysis takes place in the cytoplasm of a
  cell.
• Gylcolysis is an anaerobic process (no O2
  needed)

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Glycolysis
Cytoplasm
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Glycolysis

• During glycolysis, we start with
• 1 molecule of glucose
• We end with
• 2 ATP
• 2 NADH
• 2 molecules of pyruvic acid
• (these 2 will be used for the Krebs cycle)

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Glycolysis

• ATP production
• 2 ATP are used to get it started
• 4 ATP are produced during Glycolysis
• SO, a total of 2 ATP are produced for each
  molecule of glucose that enters glycolysis

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NADH Production

• 2 NADH molecules are produced for every molecule
  of glucose that enters glycolysis.
• During glycolysis, the electron carrier NAD
  (nicotinamide adenine dinucleotide)
• accepts a pair of high-energy electrons and
  becomes NADH.
• - Electrons are carried by NADH to the electron
  transport chain to make more ATP.

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The Advantages of Glycolysis

• Glycolysis produces ATP very fast, which is an
  advantage when the energy demands of the cell
  suddenly increase.
• Glycolysis does not require oxygen, so it can
  quickly supply energy to cells when oxygen is
  unavailable.

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NET PRODUCTION OF ATP 2
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Stages of Cellular Respiration

• What molecule is entering the Krebs Cycle?
• 2 Pyruvic Acid Molecules
• During the Krebs cycle, a little more energy is
  generated from pyruvic acid.

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Stages of Cellular Respiration

• Glycolysis takes place in cytoplasm and
  requires no oxygen
• Krebs Cycle takes place in mitochondria and
  requires oxygen
• Electron Transport Chain takes place in
  mitochondria, requires oxygen and produces A LOT
  of energy

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Krebs Cycle

• The Process of Cellular Respiration

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The Krebs Cycle

• During the Krebs cycle, pyruvic acid is broken
  down into CO2
• The Krebs Cycle is also known as the citric acid
  cycle due to the citric acid that is formed

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Citric Acid Production

• pyruvic acid enters the mitochondria..
• NADH, CO2 and acetyl-CoA form from electrons and
  carbon atoms.
• Acetyl-CoA combines with a 4-carbon molecule to
  produce citric acid.

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Energy Extraction

• Citric acid breaks down into a 5-carbon compound
  and a 4-carbon compound.
• The 4-carbon compound can then start the cycle
  again by combining with acetyl-CoA.

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Energy Extraction

• Breaking bonds causes a release of energy.
• ATP, NADH, and FADH2 catch and store this
  released energy.

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Energy Extraction

• Remember!
• Each molecule of glucose results in 2 pyruvic
  acids..
• 2 pyruvic acids two complete turns of the
  Krebs cycle.
• 2 pyruvic acids make.
• 6 CO2
• 2 ATP
• 8 NADH
• 2 FADH2

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2 pyruvic acids enter the Krebs Cycle, but what
would only ONE pyruvic acid produce?

• 3 CO2
• 1 ATP
• 4 NADH
• 1 FADH2

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Electron Transport and ATP Synthesis

• How does the electron transport chain use
  high-energy electrons from glycolysis and the
  Krebs cycle?
• The electron transport chain uses the
  high-energy electrons from glycolysis and the
  Krebs cycle to convert ADP into ATP.

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Electron Transport

• NADH and FADH2 bring their high-energy electrons
  to electron carrier proteins in the electron
  transport chain.

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Electron Transport

• At the end of the ETC, electrons combine with H
  ions and oxygen to form water.

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Electron Transport

• Energy from the ETC moves H ions up the
  concentration gradient into the intermembrane
  space.
• H ions are building up

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ATP Production

• H ions pass back quickly across the
  mitochondrial membrane through the ATP synthase
• This causes ATP synthase molecule to spin.
• With each rotation, the ATP synthase makes 1ATP.
• For every glucose molecule, ATP synthase will
  spin 34 times and 34 ATP are produced.

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• Fermentation

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Fermentation

• How do organisms generate energy when oxygen is
  not available?
• In the absence of oxygen, fermentation releases
  energy from food molecules by producing ATP.

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Fermentation

• Fermentation is a process by which energy can be
  released from food molecules in the absence of
  oxygen.
• Fermentation occurs in the cytoplasm of cells.

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Fermentation

• Under anaerobic conditions, fermentation follows
  glycolysis.
• During fermentation, cells convert NADH
  produced by glycolysis, which allows glycolysis
  to continue producing ATP.

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Alcoholic Fermentation

• Yeast and a few other microorganisms use
  alcoholic fermentation that produces ethyl
  alcohol and carbon dioxide.
• This process is used to produce alcoholic
  beverages and causes bread dough to rise.

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Alcoholic Fermentation

• Chemical equation
• Pyruvic acid NADH ? Alcohol CO2 NAD

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Lactic Acid Fermentation

• Most organisms, including humans, carry out
  fermentation using a chemical reaction that
  converts pyruvic acid to lactic acid.
• Chemical equation
• Pyruvic acid NADH ? Lactic acid NAD

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Energy and Exercise

• How does the body produce ATP during different
  stages of exercise?
• For short, quick bursts of energy, the body uses
  ATP already in muscles as well as ATP made by
  lactic acid fermentation.
• For exercise longer than about 90 seconds,
  cellular respiration is the only way to continue
  generating a supply of ATP.