Photosynthesis & Respiration

Cells usable source of energy is called ATP Cell Energy: Cells usable source of energy is called ATP ATP stands for adenosine triphosphate Adenine Ribose 3 Phosphate groups

ADP stands for adenosine diphosphate Adenine Ribose 2 Phosphate groups

All energy is stored in the bonds of compounds—breaking the bond releases the energy When the cell has energy available it can store this energy by adding a phosphate group to ADP, producing ATP

ATP is converted into ADP by breaking the bond between the second and third phosphate groups and releasing energy for cellular processes.

What is Photosynthesis? The process of photosynthesis is a chemical reaction. It is the most important chemical reaction on our planet.

What do plants need for photosynthesis? Water Carbon dioxide Light chlorophyll

Chlorophyll is the pigment inside the chloroplast the absorbs light for photosynthesis As the chlorophyll in leaves decays in the autumn, the green color fades and is replaced by the oranges and reds of carotenoids.

What is the equation for the chemical reaction of photosynthesis?

Describe Photosynthesis The process of changing light energy to chemical energy Energy stored as sugar Occurs in plants and some algae Plants need light energy, CO2, and H2O Takes place in the chloroplasts, using chlorophyll, the green pigment in plants

What is it like inside a chloroplast? Inside the chloroplasts are stacks of things called thylakoids – they look like smarties. The part of the chloroplast that is around the thylakoids is called the stroma. THE CALVIN CYCLE is in the stroma!

What are the two types of reactions in photosynthesis? The first reaction is called light-dependent (occurs in the thylakoids) The second reaction is light-independent (occurs in the stroma)

What do electron carriers do? Sunlight makes electrons in the chlorophyll (located in the thylakoids) very excited! They are so excited they have to be carried by a special carrier molecule called NADP+ NADP+ carries two electrons at a time. It also grabs an H+ ion, and this turns the NADP+ into NADPH

What does the NADPH do? The NADPH carries the very excited high-energy electrons to reactions in the cell. These electrons can be used in making FOOD. This is the LIGHT-DEPENDENT Reaction

What is the dreaded Calvin Cycle? The Calvin Cycle uses ATP and NADPH from light-dependent reactions to produce high- energy sugars (FOOD) The Calvin Cycle is a LIGHT- INDEPENDENT reaction

What are the products of photosynthesis? High-energy sugars (FOOD) oxygen

Why is this important to us? We cannot make our own food (glucose, energy), we must get our food from plants. Plants are the first step in the food chain. The oxygen released during photosynthesis is necessary for all living things.

Reactants Diagram H2O CO2 Light Chloroplast C6H12O6 Glucose O2 NADP+ ADP + P Light Dependent Reaction Calvin Cycle ATP NADPH Chloroplast C6H12O6 Glucose O2 Products

Summary: Light Dependent Reaction—H2O is broken down and light energy is stored temporarily in inorganic energy carriers, ATP and NADPH Calvin Cycle—energy is transferred from ATP and NADPH to the organic compound glucose

Quiz Describe what it’s like inside a chloroplast. Why is it said that photosynthesis is one of the most important chemical reactions on Earth? What happens during the Calvin Cycle? What are the products of photosynthesis? What is needed for photosynthesis? What happens to electrons during photosynthesis? Which happens first, light-dependent reactions or light-independent ones? What does NADP+ do?

What is Cellular Respiration? Once the energy that was in sunlight is changed into chemical energy by photosynthesis, an organism has to transform the chemical energy into a form that can be used by the organism. Cellular respiration is the process that releases energy by breaking down food molecules in the presence of oxygen.

Describe Cellular Respiration The breakdown of glucose molecules to release energy Takes place in all living things Is a step by step process

Where does cellular respiration happen? In the mitochondria of living things.

What is the chemical equation for cellular respiration?

Respiration occurs in ALL cells and can take place either with or without oxygen present.

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

Aerobic Respiration: requires oxygen Occurs in the mitochondria of the cell Total of 36 ATP molecules produced General formula for aerobic respiration: C6H12O6 + 6O2 6 CO2 + 6H2O + 36 ATP glucose + oxygen carbon dioxide + water + energy Human cells contain a specialized structure – the mitochondrion – that generates energy.

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

Anaerobic Processes No oxygen is required for these processes. Includes glycolysis, the breakdown of glucose, and fermentation. Some bacteria and yeast are examples of anaerobes. http://www.biol.vt.edu/research/images/C._perfringens_in_mac._jpg.jpg http://www.utoronto.ca/greenblattlab/images/a/yeast%201.jpg

Glycolysis Occurs in the cytoplasm. Breaks down glucose into 2 molecules of pyruvate 2 ATP molecules are formed. The series of reactions in which pyruvate is broken down into carbon dioxide is called the Krebs cycle. http://www.emc.maricopa.edu/faculty/farabee/BIOBK/enyld1.gif

Yikes! There’s another cycle? Yes. The Krebs cycle. The Krebs cycle is where energy is released. Kind of like the Calvin Cycle in reverse…

What happens during the Krebs cycle? Energy is freed from the chemical bonds. The excited electrons are FREEE! The electrons make ATP. Carbon dioxide is released. You get rid of it by exhaling…

Where do the electrons go? On the train! The electrons get to ride the electron transport train, the Final step in the breakdown of glucose. Point at which ATP is produced

What happens to ADP on the train? Ions rush back and forth and spin the ADP in circles. This creates enough energy to produce three molecules of ATP per molecule of ADP. ATP and ADP are special molecules that store energy

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

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—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

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

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

Diagram of the Process Occurs across Cristae Occurs in Cytoplasm Occurs in Matrix

Quiz 1. Where does cellular respiration take place? 2. What is the chemical equation for cellular respiration? 3. What are the products of cellular respiration? 4. What is the Krebs Cycle? 5. What happens during the Krebs Cycle? 6. What happens to electrons during cellular respiration? 7. How much ATP is produced from one molecule of ADP?

Complementary processes Photosynthesis is an important part of the carbon cycle. The processes of photosynthesis and cellular respiration are complementary processes, meaning they work together to benefit living organisms.

Plants and animals contribute… Autotrophs, such as plants, produce glucose using the carbon in carbon dioxide. Both autotrophs and heterotrophs, such as grasshoppers that eat plants, use those carbohydrates in cellular respiration. Respiration, in turn, produces carbon dioxide.

Energy renewal Energy captured from sunlight by photosynthetic organisms is used and released in the cellular respiration of living things. The energy that living things use, must continually be renewed through photosynthesis.