Flow of Energy through the Respiration Process Cellular Respiration Flow of Energy through the Respiration Process

Review: Producers Producers get their energy from the sun. Producers convert this light energy into stored chemical energy (glucose). This process is called photosynthesis.

Review: Consumers Consumers get their energy from the producers. Consumers convert stored chemical energy (glucose) into usable chemical energy (ATP). This process is called cellular respiration.

Energy Storing Molecules Energy Review Energy Storing Molecules ATP, NADPH (NAD+), FADH (FAD+), FADH2 ATP supplies most of the energy that drives metabolism in living things ATP releases energy when converted into ADP

Cellular Respiration Overview Living things get most of the energy they need from glucose. Autrotrophs make glucose using photosynthesis Heterotrophs get glucose from food they eat Cellular Respiration The process that releases energy by breaking down glucose and other food molecules in the presence of oxygen.

Cellular Respiration (aerobic) Cellular respiration is the process by which glucose (C6H12O6) is broken down to release energy for making ATP, another form of chemical energy.

Aerobic Respiration – Equation C6H12O6 + 6 O2 6 H2O + 6 CO2 + 36 ATP food (glucose, a carbohydrate) oxygen water carbon dioxide Does this look familiar?

Cellular Respiration Overview Cellular Respiration Overall Equation 6O2 + C6H12O6  6CO2 + 6H2O + Energy Three Stages Glycolysis Kreb’s Cycle Electron Transport Chain The Main form of Energy produced = ATP

Cellular Respiration: An Overview Mitochondrion Electrons carried in NADH Electrons carried in NADH and FADH2 Pyruvic acid Glucose Electron Transport Chain Krebs Cycle Glycolysis Mitochondrion Cytoplasm

Diagram Mitochondria In Cytoplasm 2 2 32 Electrons carried in NADH Electrons carried in NADH and FADH2 Krebs Cycle Electron Transport Chain Glucose Glycolysis 2 2 32

Glyco = Glucose lysis = Breakdown Occurs in the cytoplasm of the cell Glycolysis (1st Stage) Glyco = Glucose lysis = Breakdown Occurs in the cytoplasm of the cell Molecules of GLUCOSE are broken down into 2 molecules of Pyruvic Acid. Cell must use (invest) 2 ATP Produces Energy Carrier Molecules 4 ATP 2 NADH

To the Electron Transport Chain Glycolysis (1st Stage) Glucose Pyruvic Acid Pyruvic Acid To the Electron Transport Chain

The “Mighty” Mitochondria Plant and animal cells contain mitochondria: cell structures that transform chemical energy from glucose to ATP. The mitochondria is the organelle where the final stages of cellular respiration occurs. Kreb’s Cycle Electron Transport Chain Cells that use a lot of energy have high numbers of mitochondria. Example: Muscle cells in the heart!!

Kreb’s Cycle (2nd Stage) Aerobic Process = Only if oxygen is present!! Occurs in the MATRIX of the mitochondria Pyruvic Acid from Glycolysis enters to form 1 ATP 3 NADH 1 FADH2 CO2 (which is released when we exhale!!) AKA….Citric Acid Cycle

Electron Transport Chain (3rd Stage) Energy carrier molecules produced during Glycolysis and the Kreb’s Cycle enter the ETC NADH FADH2 Occurs in the folds of the Inner Membrane of the Mitochondria The electrons are passed down a chain of proteins until they reach the final electron acceptor…..oxygen! So this step is aerobic (requires oxygen) The ETC produces 32 ATP and H2O

Cellular Respiration Flowchart Inputs 1st Stage 2nd Stage 3rd Stage Outputs Glucose (C6H1206) + Oxygen (02) Glycolysis Krebs Cycle Electron Transport Chain Carbon Dioxide (CO2) + Water (H2O)

BioTheme: Interdependence BioTheme: Interdependence! Processes are opposites (or compliments of one another) Photosynthesis: 6 H2O + 6 CO2 + energy (sun) → C6H12O6 + 6 O2 Aerobic Cellular Respiration: C6H12O6 + 6 O2 → 6 H2O + 6 CO2 + energy (ATP)

Why ATP? An analogy to money… Glucose in our food is a great source of energy! ($100 bill) However, individual cell processes may only require a small amount of energy ($1 bill) Analogy: most vending machines do not accept $100 bills! We need a smaller form of “currency” for these processes. ATP (adenosine triphosphate) is this important cellular “currency” for life. ATP releases more appropriate amounts of energy for the individual cellular processes that require energy.

Do only animals respire? Or do plants respire too? The BIG Question is… Do only animals respire? Or do plants respire too? Only plants perform photosynthesis Plants AND animals perform cellular respiration! (Can you explain why??)

Significant ATP Production Aerobic cellular respiration releases energy SLOWLY, using oxygen to convert ONE molecule of glucose to 36 ATP!

Aerobic Training Ex: long runs, biking, swimming Can increase the size and number of mitochondria in muscle cells Can increase the delivery of O2 to muscles by improving the heart and lungs

Cellular Respiration (anaerobic) What happens when cells don’t have enough oxygen? Some organisms live in an oxygen-free environment. How do they get their energy?

Cellular Respiration (anaerobic) Anaerobic respiration is also called fermentation, or the process by which energy is released from glucose when oxygen is NOT available. This process allows organisms to continue to produce energy until oxygen is available. However, this process only releases 2 ATP per molecule of glucose.

Anaerobic Training Ex: sprints, strides, quick bursts of energy Increase the glycogen levels in the muscles Increase body’s tolerance to lactic acid

Minimal ATP Production In the absence of oxygen, anaerobic respiration only releases 2 ATP for each molecule of glucose broken down.

Lactic Acid Fermentation Anaerobic way of converting energy in animal cells and some microorganisms Glucose broken down to produce lactic acid, CO2 and energy (ATP) C6H12O6  lactic acid + CO2 + 2 ATP EX: muscle cells during strenuous exercise fermenting cheese, yogurt, sour cream

Strenuous Exercise Lactic acid is produced by your muscle cells during rapid exercise when the body cannot supply enough O2 to tissues. Without enough O2, the body is NOT able to produce all of the ATP that is required. The buildup of lactic acid can cause painful burning in your muscles!

Lactic acid fermentation—occurs in muscle cells Lactic acid is produced in the muscles during rapid exercise when the body cannot supply enough oxygen to the tissues—causes burning sensation in muscles glucose lactic acid + carbon dioxide + 2 ATP

Comparing ATP Production First, your body breaks down glucose through aerobic respiration to produce 36 ATP per glucose molecule; however, this is a slow process. When muscle cells cannot get enough O2 they break down glucose through lactic acid fermentation to produce 2 ATP per glucose… Therefore, AEROBIC RESPIRATION is much more efficient in terms of ATP production – 36 ATP compared to 2 ATP!

Anaerobic Respiration: occurs when no oxygen is available to the cell (2 kinds: Alcoholic and Lactic Acid) Also called fermentation Much less ATP produced than in aerobic respiration

Alcoholic Fermentation Anaerobic way of converting energy for yeast and other microorganisms Glucose broken down to produce alcohol, CO2 and energy (ATP) C6H12O6  ethanol + CO2 + 2 ATP EX: baking bread with yeast fermenting wine & beer

Alcoholic fermentation—occurs in bacteria and yeast Process used in the baking and brewing industry—yeast produces CO2 gas during fermentation to make dough rise and give bread its holes glucose ethyl alcohol + carbon dioxide + 2 ATP

3rd Electron Transport Chain (ETC) Summary: 3 steps: 1st glycolysis 2nd Krebs cycle 3rd Electron Transport Chain (ETC)

First step in anaerobic respiration is also glycolysis Diagram Anaerobic Respiration Cytoplasm Alcoholic fermentation Bacteria, Yeast 2 ATP C6H12O6 glucose glycolysis Lactic acid fermentation Muscle cells 2 ATP ETC Mitochondria Krebs Cycle Aerobic Respiration 36 ATP