Cellular Respiration and Photosynthesis

Cellular Respiration and Photosynthesis

Imagine an abandoned house that is falling apart. Restoring order to the house will require an input of energy (for example: hammering nails, applying paint). Living things also need energy in order to stay in good repair, or maintain HOMEOSTASIS. Every organism must maintain HOMEOSTASIS as long as it lives. Therefore, all organisms require a constant source of energy!

Chemical Energy Energy in organic compounds (like carbohydrates) comes from the sun. SOLAR energy (energy from our sun) enters living systems when plants make organic compounds from carbon dioxide and water through the process of PHOTOSYNTHESIS. We cannot (and other animals) cannot perform photosynthesis, so why does this matter to us? We eat plants! So we are getting our energy from the sun!

Chemical Energy Continued Food molecules that are made or consumed by an organism are the fuel for its cells. Cells use these molecules to release the energy stored in the molecules bonds. What organelle in the cell is responsible for releasing this energy? Mitochondria

So what is happening when photosynthesis takes place???? Energy enters an ecosystem when organisms use sunlight during photosynthesis to convert carbon dioxide molecules (stable) into glucose (less stable). In which organelle of a plant cell does photosynthesis take place? Chloroplast

So what is happening when photosynthesis takes place???? Once a plant has made that GLUCOSE, energy can be extracted through the process of CELLULAR RESPIRATION.

What percent of the energy in sunlight is used for photosynthesis? Only 1%!

Harvesting Light Energy Chloroplast organelles convert light energy into chemical energy. Chloroplasts have a membrane much like the plasma membrane on the outside of the cell. The space inside the membrane is called the STROMA. Within the stroma is a membrane called the THYLAKOID MEMBRANE. This membrane is folded in a way that produces flat, disc-like sacs called THYLAKOIDS. Stacks of THYLAKOIDS are called GRANUM

Harvesting Light Energy The THYLAKOIDS contain molecules that absorb light energy for photosynthesis. The first stage of photosynthesis begins when light waves hit these stacks.

Exit Slip 1. Light absorbing molecules are found inside which structure of the chloroplast? 2. During photosynthesis, Light Energy is converted into Energy. 3. Stacks of Thylakoids are called. 4. Which is a more stable molecule, Glucose or Carbon Dioxide?

Light Light travels in waves. Sunlight contains all of the wavelengths of visible light. We see these different wavelengths as different colors. For Example: The wavelength of purple light is from 400-425 nm. Green: 475-500 nm.

Pigments Why can you see light? Cells in the back of the eye contain pigments! A pigment is a substance that absorbs certain wavelengths (colors) of light and reflects all of the others. In plants, light energy is harvested by pigments that are located in the thylakoid membrane of chloroplasts. What is the pigment in chloroplasts that absorbs light energy? Chlorophyll

Pigments Cont. Chlorophyll is a green pigment in chloroplasts that absorbs light energy to start photosynthesis. Chlorophyll absorbs mostly blue and red light and reflects green and yellow light. ***look at your classmates. The pigments in their shirts are reflecting colors back at your eye. Plants have two types of chlorophyll: Chlorophyll a Chlorophyll b Plants also have pigments called carotenoids that absorb blue and green light and reflect yellow, orange, and red. Why do leaves turn redish orange in the fall? Chlorophyll regresses and carotenoids are exposed.

The organelle in which photosynthesis occurs: A. Mitochondria B. Nucleus C. Endoplasmic Reticulum D. Chloroplast E. Golgi Apparatus

While performing an experiment using green spinach leaves, Jamie identifies Chlorophyll and other pigments of several colors. What is the most accurate conclussion Jamie can make about pigments in spinach leaves. A. Chlorophyll decomposes to reveal other pigments B. Chlorophyll absorbs light while other pigments reflect light C. Chlorophyll passes light energy to other pigments in leaves D. Chlorophyll appears in higher concentrations than other pigments

Photosynthesis converts light energy into energy A. mechanical B. kinetic C. chemical D. fast

The chemical energy produced from photosynthesis is found in the bonds of: A. Glucose B. Enzyme C. Lipid D. Water

Which of the following pigments is most soluble in solvent? A. Chlorophyll b B. Chlorophyll a C. Xanthophylls D. Carotene

Which of the following pigments has the greatest affinity for chromatography paper? A. Chlorophyll b B. Chlorophyll a C. Xanthophyll D. Carotene

Checking for Alzheimers Where are these pigments found? Thylakoid (inside the Chloroplast)

The Reactions of Photosynthesis Scientists describe the reactions of photosynthesis in two parts: Light Dependent Light Independent The light dependent reaction takes place within the thylakoid membrane. Where are the thylakoids found? Inside the chloroplasts

The Reactions of Photosynthesis The light independent reaction (aka: the calvin cycle) takes place in the stroma. Where is the stroma? Space inside the membranes of the chloroplasts.

The Reactions of Photosynthesis When sunlight is captured by pigments, electrons gain a great deal of energy. The electrons come from water! What are the pigments found in the leaf? Chlorophyll A Chlorophyll B Carotein Xanthophylls These high-energy electrons require a special carrier. These carriers are called electron carriers!

The Reactions of Photosynthesis Electron Carriers One of these carrier molecules is a compound known as NADP+. (Nicotinamide adenine dinucleotide phosphate) The name is complicated, but its job is simple! Accepts and holds 2 electrons that were excited from the pigments. NADP+ is converted into NADPH when it holds the electrons NADPH then carries electrons to other parts of the chloroplast

The Reactions of Photosynthesis ATP (energy) is also produced during the light dependent reaction. When water is broke down to remove electrons used to attach to NADP+, hydrogen ions are left behind in the cytoplasm. These ions move through a protein channel to the outside of the cell. This protein is called ATP synthase. As Hydrogen ions pass through ATP synthase, ADP is convernted to ATP What is ATP? Energy!

ATP Synthase

The Reactions of Photosynthesis The light independent Reaction (aka Calvin Cycle) The ATP and NADPH formed by the light-dependent reactions contain an abundance of chemical energy, but they are not stable enough to store that energy for any more than a few minutes. During the Calvin Cycle, plants use the energy that ATP and NADPH contain to build high-energy compounds that can be stored for a long time. Sugar

Steps to the Calvin Cycle 1. Six carbon dioxide molecules enter the cycle. Where does the plant get the carbon dioxide? From the atmosphere! Through a series of reactions, ATP and NADPH provide the energy to convert Carbon dioxide into Glucose. Where did the ATP and NADPH come from? The light dependent cycle

The light independent reaction takes place within the. A. Thylakoid B. Mitochondria C. Nucleus D. Stroma

Energized electrons that initiate photosynthesis come from. A. Pigments B. Carbon Dioxide C. Water D. Oxygen

How many electrons can NADP+ capture and hold? A. 1 B. 2 C. 3 D. 4

As Hydrogen ions move through ATP synthase, ADP is converted into. A. ATP B. Oxygen C. Water D. ASP

The reaction of photosynthesis that DOES NOT require light is known as the: A. Dark Reaction B. Calvin Cycle C. Light Independent Reaction D. All of the above

Chemical Energy and Food Food provides living things with the chemical building blocks they need to grow and reproduce. Food serves as energy to the cells of the body.

Chemical Energy and Food We know food provides energy, but how is the stuff that we put in our mouth converted to energy? The process begins with a pathway called glycolysis. Glycolysis takes place in the cytoplasm. Glycolysis releases only a small amount of energy. Glycolysis is the process in which one molecule of glucose is broken in half, producing two molecules of pyruvic acid. Requries 2 ATP to get the process of glycolysis started, but 4 ATP are produced. NET OF 2!

Chemical Energy and Food Not only is ATP produced, but NAD+ accepts some electrons during this process. NAD+ is an electron carrier. What does this remind you of??? Glycolysis occurs VERY quickly. Glycolysis does NOT require oxygen to occur. When oxygen is present, the process proceeds to the Krebs Cycle

Exit Slip Half Sheet 1. The first step of cellular respiration is known as. 2. What carbohydrate must be present before this process will begin? 3. How many NET ATP are produced from glycolysis?

Chemical Energy and Food The Krebs Cycle (aka Citric Acid Cycle) At the end of glycolysis, about 90 percent of the chemical energy that was available in glucose is still unused. What was created at the end of glycolysis? If oxygen is present this pyruvic acid then moves into the Krebs Cycle. Occurs in the mitochondria. During the Krebs cycle, pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions! During this reaction 2 molecules of ATP are produced along with NADH and FADH2 (another electron carrier)

Krebs Cycle

Chemical Energy and Food Once the NADH and FADH2 are produced during the Krebs Cycle, these electron carriers move into the ELECTRON TRANSPORT CHAIN. The electron transport chain uses the high-energy electrons from the Krebs Cycle (carried by NADH and FADH2) to convert ADP into ATP.

Electron Transport Chain

Chemical Energy and Food The electron transport chain produces a total of 32 ATP. The Totals Total number of ATP molecules produced during cellular respiration ===== 36 ATP The chemical equation for Cellular Respiration:

Carbon Dioxide is produced during which step of cellular respiration. A. Glycolysis B. Krebs Cycle C. Electron Transport Chain D. Photosynthesis

How many net ATP are produced by glycolysis? A. 1 B. 2 C. 4 D. 32

How many net ATP are produced by the Krebs cycle? A. 1 B. 2 C. 4 D. 32

How many total ATP are produced by cellular respiration? A. 32 B. 34 C. 36 D. 42

The products of the equation for cellular respiration are: A. Glucose + Water B. Carbon Dioxide + Water + ATP C. ATP + Oxygen + Glucose D. Carbon Dioxide + ATP

The process that is most directly responsible for ATP production in aerobic cellular respiration is: A. Glycolysis B. Photosynthesis C. Krebs Cycle D. Electron Transport Chain

Which of the following organisms perform both cellular respiration and photosythesis? A. Pin Oak Tree B. Ky-31 Tall Fescue Grass C. African Acacia Tree D. All of the above perform both processes

Which of the following is produced in the krebs cycle? A. NADH B. FADH2 C. ATP D. CO2 E. All of the above

Bromthymol Blue is an indicator for which of the following molecules? A. Water B. Oxygen C. Glucose D. ATP E. Carbon Dioxide