Cellular Respiration

What Is ATP? Energy used by all Cells Adenosine Triphosphate Organic molecule containing high-energy Phosphate bonds Copyright Cmassengale

ATP for energy ATP powers cellular work- made in photosynthesis and cellular respiration A cell does three main kinds of work: Mechanical work, beating of cilia, contraction of muscle cells, and movement of chromosomes(produces heat) Transport work, pumping substances across membranes against the direction of spontaneous movement Chemical work, driving endergonic reactions such as the synthesis of polymers from monomers

Electron Carrier: a molecule that picks up the High Energy Electrons and Molecules Electron Carrier: a molecule that picks up the electron and uses this energy to break apart bonds. Examples of electron carriers: NADP and ATP NADP captures two electrons of H and becomes NADPH. ADP becomes ATP!!!

How Does ATP Work? So what? Energy is stored in these bonds. So? The breaking of the chemical bond releases the energy ATP + H2O→ ADP + P + ENERGY ATP is made in photosynthesis and respiration!!! ATP (adenosine triphosphate) is a a molecule that carries energy that cells can use.

The bonds between phosphate groups can be broken by hydrolysis which produces energy!!! ATP has 3 phosphate groups The bond to the third bond is easily broken. When the third bond is broken, energy is released. Becomes ADP – no energy!! How Does ATP Work?

Chemical Structure of ATP Adenine Base 3 Phosphates Ribose Sugar Copyright Cmassengale

What Does ATP Do for You? It supplies YOU with ENERGY! Copyright Cmassengale

How Do We Get Energy From ATP? By breaking the high- energy bonds between the last two phosphates in ATP Copyright Cmassengale

What is the Process Called? HYDROLYSIS (Adding H2O) H2O Copyright Cmassengale

How Does That Happen? An Enzyme! ATPase Copyright Cmassengale

How is ATP Re-Made? The reverse of the previous process occurs. Another Enzyme is used! ATP Synthase Copyright Cmassengale

The ADP-ATP Cycle ATP Synthase ATP-ase Copyright Cmassengale

When is ATP Made in the Body? During a Process called Cellular Respiration that takes place in both Plants & Animals Copyright Cmassengale

Cellular Respiration The process in which cells turn food into usable energy in the form of ATP.

Cellular Respiration RELEASES CHEMICAL ENERGY FROM SUGARS AND OTHER CARBON-BASED MOLECULES TO MAKE ATP WHEN OXYGEN IS PRESENT!!!! NO OXYGEN – FERMENTATION!!!!

The Purpose of Cellular Respiration It is to make and break bonds to generate ATP and electrons. You end up with ATP, H ions and electrons. The electrons are sent to the Electron Transport Chain where they help to make ATP through ATP synthase. ****Hydrogen ions are bonded with oxygen to make water which is used in photosynthesis.

Cellular Respiration Overview Transformation of chemical energy in food into chemical energy cells can use: ATP These reactions proceed the same way in plants and animals. Process is called cellular respiration Overall Reaction: C6H12O6 + 6O2 → 6CO2 + 6H2O

Overall Equation for Cellular Respiration C6H12O6 + 6O2 YIELDS 6CO2 + 6H20 + e- + 36-38ATP’s

What are the Stages of Cellular Respiration? Glycolysis The Krebs Cycle The Electron Transport Chain Copyright Cmassengale

Fermentation (without oxygen) Cellular Respiration Glycolysis – Occurs before Cell. Resp. Krebs Cycle (Citric Acid Cycle) Electron Transport Chain (ETC) Glucose Krebs cycle Electron transport Glycolysis Fermentation (without oxygen) Alcohol or lactic acid

Overall Reaction C6H12O6 + 6O2 → 6CO2 + 6H2O + 38 ATP Overall this is a three stage process Glycolysis: before cellular respiration Occurs in the cytoplasm Glucose is broken down Krebs Cycle Breaks down pyruvate into CO2 Occurs in mitochondrial matrix Electron Transport Chain ATP is synthesized - Occurs in mito membrane

Electron Transport Chain Section 9-2 Flowchart Cellular Respiration Carbon Dioxide (CO2) + Water (H2O) ATP Glucose (C6H1206) + Oxygen (02) Glycolysis Krebs Cycle Electron Transport Chain

Where Does Cellular Respiration Take Place? It actually takes place in two parts of the cell: Glycolysis occurs in the Cytoplasm Krebs Cycle & ETC Take place in the Mitochondria Copyright Cmassengale

Glycolysis Definition: The process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid, a 3-carbon compound.

Glycolysis Occurs in ALL eukaryotic cells… Glyco = glucose Lysis = break down LOCATION: Occurs in the cytoplasm This stage occurs in BOTH aerobic and anaerobic respiration Occurs in ALL eukaryotic cells…

Glycolysis- ATP Production In the pathways beginning, 2 ATP molecules are used up. At the end of glycolysis, 4 ATP molecules are formed. NET GAIN- 2 molecules!!!

Glycolysis- NADH Production Process removes 4 high energy e- and passes them to nicotinamide adenine dinuclueotide (NAD+), which is an electron carrier. NAD+ turns into NADH while transferring electrons to other molecules.

Steps of Glycolysis Two ATP molecules are used to energize a glucose molecule. 2. Glucose is split into 2 3-carbon molecules. Enzymes rearrange the molecules. 3. Electrons are transferred to NADP. The carbon molecules are converted to pyruvate which enters cellular respiration.

Glycolysis Location= Cytoplasm NO O2 required Energy Yield net gain of 2 ATP at the expense of 2 ATP 6-C glucose  TWO 3-C pyruvates Free e- and H+ combine with organic ion carriers called NAD+  NADH + H+ (nicotinamide dinucleotide)Used in ETC. Hydrogen attached to water.

Glycolysis: Get a sheet of paper to review the process of glycolysis. Video: Glycolysis

To the electron transport chain Glycolysis: Step 1 Figure 9–3 Glycolysis Glucose 2 Pyruvic acid To the electron transport chain

Glycolysis Reactants and Products 1 glucose Enzymes are needed 2 ATP are needed to start Products 2 Pyruvates (go to next step) 4 ATP (2 are gained) 2 NADH (go to ETC) Really 10 steps with 10 different enzymes involved.

Anaerobic Respiration (without oxygen): Fermentation ***fermentation does not make ATP for the cell, it cycles the ATP for glycolysis*** (does not release energy in cell) Two Main types: Lactic Acid fermentation- converts pyruvic acid and NADH to lactic acid and NAD+ -muscle cells Alcoholic fermentation- converts pyruvic acid and NADH to ethyl alcohol, CO2, NAD+ -yeast (air bubbles in bread)

Main Goals of Krebs Cycle Transfer high energy electrons(NADH and FADH2) to molecules that can carry them to the electron transport chain. Form some ATP molecules. Takes place in mitochondria

Krebs Cycle- Part A (Citric Acid Production) From glycolysis, the 3carbon molecule (pyruvic acid/pyruvate) enters the mitochondria (innermost layer- Matrix) 3carbon pyruvic acid is broken down into 2carbon (Acetyl-CoA) molecules. CO2 and NADH are produced Hint: anytime the number of carbons are reduced, CO2 and NADH are produced Acetyl-CoA (2carbon) combines with 4 carbon compounds forming a 6 carbon molecule Citric acid.

Krebs Cycle Part B (Energy Extraction) The 6carbon Citric Acid broken down into 5 carbon compound (releasing CO2 & NADH) 5 carbon compound broken down into 4 carbon compound (releasing CO2 & NADH) In a series of 4carbon to 4carbon reactions, ATP, CO2, NADH & FADH2 are produced Remember: NADH & FADH2 are electron carriers that will take the electrons to the ETC

Kreb Cycle

Krebs Cycle Reactants and Products 2 Acetyl CoA (pyruvic acid) Remember when you form a bond energy is released!! This is the key!! Products 2 ATP 8 NADH (go to ETC) 2 FADH2 (go to ETC) 6 CO2 (given off as waste)

Krebs Cycle

Electron Transport Chain Where inner membrane of mitochondria called cristea. Energy Yield Total of 32 ATP O2 combines with TWO H+ to form H2O Exhale - CO2, H2O comes from cellular respiration Video: ETC

Electron Transport Chain Section 9-2  Electron Transport Chain Electron Transport Hydrogen Ion Movement Channel Mitochondrion Intermembrane Space ATP synthase Inner Membrane Matrix ATP Production

Electron Transport - Step 3 1. Proteins inside the membrane of the mito. Remove electrons from NADPh and FADH. Electrons(hydrogen) are transported down the chain of the membrane to be pumped across. ATP synthase(enzyme) puts a P on ADP to make ATP(END GOAL!!). Oxygen enters the cycle to pick up electrons and hydrogen ions to make water that leaves the cycle.

Electron Transport Chain Electron carriers loaded with electrons and protons from the Kreb’s cycle move to this chain-like a series of steps (staircase). As electrons drop down stairs, energy released to form a total of 32 ATP – Final Goal!! Oxygen waits at bottom of staircase, picks up electrons and protons and in doing so becomes water

Energy Tally 36 ATP for aerobic vs. 2 ATP for anaerobic Glycolysis 2 ATP Kreb’s 2 ATP Electron Transport 32 ATP 36 ATP Anaerobic organisms can’t be too energetic but are important for global recycling of carbon

Electron Transport Chain Section 9-2 Flowchart Cellular Respiration Carbon Dioxide (CO2) + Water (H2O) ATP Glucose (C6H1206) + Oxygen (02) Glycolysis Krebs Cycle Electron Transport Chain