Chapter 9 Energy in a cell Energy- the ability to do work The food you eat is broken down into monosaccharides (simple sugars)by the digestive system Glucose enters every cell in the body.

Glucose is broken down Your cell’s mitochondria breaks down glucose molecules step by step. Each step releases energy As each chemical bond is broken, energy is released

Energy from Food This energy is stored in ATP molecules ATP-Adenosine Triphosphate (3 phosphates)

ATP ADP ATP is an energy storing molecule. The energy is stored by adding a Phosphate to ADP (adenosine DIphosphate) to form ATP.(TRIphosphate ADP + P + Energy = ATP http://www.cat.cc.md.us/courses/bio141/lecguide/unit4/metabolism/energy/adpan.html

ATP Synthesis

When is ATP needed? Photosynthesis – an energy storing process Cellular Respiration – an energy releasing process

Photosynthesis: Trapping Energy Photosynthesis-Autotrophs trap energy from sunlight and use the energy to build simple sugars

Chlorophyll Leaves - The site of Photosynthesis Chlorophyll-the green pigment found in chloroplast. traps the sun’s energy.

Formula for Photosynthesis How many molecules of water are needed to make 4 molecule of glucose (sugar)? Yields Carbon Dioxide + Water Sugar + Oxygen In the presence of: Sunlight and Chlorophyll Changing light energy into chemical energy

Parts of Photosynthesis 1. Light Dependent Reactions- the reactions which convert light energy into chemical energy (ATP). 2. Light Independent Reactions-reactions which forms sugars from C,O,H. (doesn’t need light)

Light Dependent Reactions 1. Light striking chlorophyll causes electrons to gain energy and leave orbit. 2. Electrons move down Electron Transport Chain, generating extra energy. 3. ATP is made Do Not Copy

Light Dependent Reactions Photolysis –water molecule is split Electron are used H bonds with NADP to form NADPH Oxygen is released Do Not Copy

Light Independent Reactions Calvin Cycle 1. Carbon Dioxide is split 2.Carbon, Oxygen & Hydrogen (light reaction). are used to form a sugar. 3. The energy is provided by the ATP (light reaction). This process takes: -CO2 from the air -H from water -Energy from ATP -To make food (sugar). 6CO2 +6 H2O -> C6H12O6 + 6O2

Cellular Respiration We think of respiration as breathing We take in oxygen breathe out CO2 Oxygen is delivered to every cell in the body by the circulatory system The Oxygen is used to break down food in the mitochondria of each cell-This is called Cellular Respiration

Respiration Cellular Respiration- breaking down glucose molecules to release energy. Formula Mitochondria ATP C6H12O6 +6O2 ----->6CO2 +6H2O + ENERGY Glucose + Oxygen = Carbon Dioxide + Water + NRG

Photosynthesis & Respiration Opposite Processes Respiration- C6H12O6 +O2 ---->CO2 +H2O + NRG Photosyn - CO2 + H2O+ Sunlight ---> C6H12O6 + O2

Types of Respiration Aerobic Respiration-requires Oxygen (air) Anaerobic Respiration-Breaking down food without oxygen

Step 1 Glycolysis The first stage in respiration. It is Anaerobic-no O2 is required Breaks a 6-carbon sugar into 2, 3-carbon Pyruvic Acid molecules. 2 molecules of ATP are made. Do Not Copy

Step 2 Break Pyruvic Acid Do Not Copy When Oxygen is present. Aerobic Respiration Begins 3-carbon pyruvic acid is broken into a 2-carbon compound and CO2.

3. Citric Acid Cycle Do Not Copy 2. Carbon molecules are combined and broken apart. This produces free electrons which convert NAD to NADH and FAD to FADH

4. Electron Transport Chain 3. NADH and FADH release their extra electrons Electrons are moved along a series of molecules called the Electron Transport Chain. The electrons combine with Oxygen to form water. 32 ATP are made Do Not Copy

Step 2 -Anaerobic Respiration What if No Oxygen is present after glycolysis? Fermentation occurs Fermentation- breaking down food without oxygen 2 types Lactic Acid Fermentation Alcohol Fermentation

Lactic Acid Fermentation Produced by humans when they exercise harder or faster than their body can deliver oxygen. Lactic Acid causes muscle soreness and fatigue

Alcohol Fermentation Bacteria and Yeast carry out this type of respiration. The end products are alcohol and CO2. Used to make: Beer, Wine, Bread rising,