UNIT 3 Cell Processes: ATP, Cellular Respiration, Photosynthesis

Food=chemical energy All living things need energy Energy in the form of… Food=chemical energy Cell energy=ATP

What is ATP? Adenosine triphosphate (ATP) is the usable form of energy produced by respiration. Respiration: transporting oxygen and carbon dioxide between cells and the external environment

ATP is like electricity: it contains the same energy as coal, but it’s easier to transport and is just what’s needed when the cell needs some power to carry out a task

Cells need energy for… Movement Metabolism Homeostasis Active Transport Bioluminescence Muscle cells Heart muscle cells Brain cells ETC!

How do organisms get their energy??? Autotrophs Also called producers Use energy from the sun or chemicals to make organic food molecules (carbohydrates – glucose!) Plants! Heterotrophs Also called consumers Eat other organisms US!

Energy flow Energy flows from autotrophs to heterotrophs, and from prey to predator

ATP as energy currency Cells can’t use all of their organic molecules energy at once. Energy is transferred from organic molecules to be stored in adenosine tri- phosphate (ATP). The energy in ATP is released and used as needed.

ATP - Importance It's the main molecule supplying the energy that cells need to carry out their day-to-day business. It takes the chemical energy from our food and makes it available for useful work.

When muscles contract, they use _____ When cells make proteins, they use _____ When a firefly lights up, it uses _____ When a sperm propels itself towards an egg, guess what it uses? _____

ATP Adenosine triphosphate contains stored energy. A single molecule of ATP contains ten carbon atoms, sixteen hydrogen, five nitrogen, thirteen oxygen and 3 phosphorus atoms. The shorthand formula is C10H16N5O13P3

Chemical Structure of ATP Adenine Base 3 Phosphates Ribose Sugar

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

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

MAKING ATP ATP is formed by ADP (adenosine and two phosphates) bonding with another phosphate. This bond stores the energy. When the bond is broken the energy is released to be used by the cell ADP can be reused to store more energy and released when required

How Does That Happen? An Enzyme! ATPase

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

The ADP-ATP Cycle ATP Synthase ATP-ase

When is ATP Made in the Body? During a Process called Cellular Respiration

Cellular Respiration is the process that releases energy by breaking down food molecules in the presence of oxygen. 6O2 + C6H12O6  6CO2 + 6H2O + Energy Oxygen + Glucose  Carbon Dioxide + Water + Energy

Cellular Respiration Requires oxygen Glucose is oxidized and O2 is reduced Glucose breakdown is an oxidation-reduction reaction Breakdown of one glucose results in up to 38 ATP molecules

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

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

Mitochondria Structure Smooth outer Membrane Folded inner membrane Folds called Cristae Space inside cristae called the Matrix

Making ATP Two processes that can occur depending on if oxygen is present or not. Aerobic respiration needs oxygen 1 molecule of glucose has the ability to convert 38 molecules of ADP to ATP (storing lots of energy). It completely breaks down glucose. Anaerobic respiration does not require oxygen and makes only 2 ATP molecules

Glycolysis Requires input of 2 ATP Takes place in the Cytoplasm Anaerobic = Doesn’t Use Oxygen Requires input of 2 ATP Glucose split into two molecules of Pyruvate or Pyruvic Acid

Fermentation Occurs when O2 NOT present (anaerobic) 1. Lactic Acid fermentation in muscle cells (makes muscles tired) 2. Alcoholic fermentation in yeast (produces ethanol) Nets only 2 ATP

A Little Krebs Cycle History Discovered by Hans Krebs in 1937 He received the Nobel Prize in physiology or medicine in 1953 for his discovery Forced to leave Germany prior to WWII because he was Jewish

Krebs Cycle Summary During the Krebs Cycle, pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions. Citric Acid is created in this cycle thus giving it the nickname Citric Acid cycle. Net ATP Production is 2 ATP. Takes place in matrix of mitochondria

Electron Transport Chain Summary The electron transport chain uses the high-energy electrons from the Krebs Cycle to convert ADP to ATP. Total ATP 32. Occurs Across Inner Mitochondrial membrane

Totals Gycolysis 2 ATP Krebs Cycle 2 ATP Electron Transport Chain 32-34 ATP Total = 36-38 ATP

ATP-ADP cycle – two types of energy Potential Energy is stored energy that is currently not in use, but it is available and can be released at a later point. Chemical bonds contain potential energy because when they are broken their energy stored within them is released. Kinetic Energy is also called free energy. This is energy that is being used now and it is doing work.

Aerobic/Anaerobic Anaerobic Aerobic Glycolysis in cytoplasm No oxygen 2 ATP molecules Animals: Lactic acid Plants: Ethanol and Carbon Dioxide Aerobic Glycolysis in cytoplasm With oxygen - mitochondria Produces up to 38ATP molecules

A Crash Course video with our friend Hank http://www.youtube.com/watch?v=00jbG_cfGuQ&index=7&list=PL3EED4C1D684D3ADF

Comparing Photosynthesis & Respiration Cellular Respiration Function Energy Storage Energy Release Location Chloroplasts Mitochondria Reactants CO2 and H2O C6H12O6 and O2 Products Equation 6CO2 + 6H2O  C6H12O6 + 6O2 C6H12O6 + 6O2 6CO2 + 6H2O

And now an entertaining youtube video! http://www.youtube.com/watch?v=00jbG_cfGuQ&list=SP3EED4C1D684D3ADF&index=7

Discussion Questions What do organisms need energy for? Explain the difference between an autotroph and a heterotroph. Which organisms are on the bottom of a food web? Which direction does energy flow in a food web?

Discussion questions Who has the most energy available in a food web? In a food web, what is the ultimate source of energy? What is ATP? How is ATP formed?