Chapter 4 Cells and Energy Chemical Energy and ATP Overview of Photosynthesis Photosynthesis in Detail Overview of Cellular Respiration Cellular Respiration in Detail Fermentation

Learning Goals Addressed BIO.A.3.1 Identify and describe the cell structures involved in processing energy. BIO.A.3.1.1 Describe the fundamental roles of plastids (e.g., chloroplasts) and mitochondria in energy transformations. BIO.A.3.2.1 Compare the basic transformation of energy during photosynthesis and cellular respiration. BIO.A.3.2 Identify and describe how organisms obtain and transform energy for their life processes. BIO.A.3.2.2 Describe the role of ATP in biochemical reactions. BIO.B.4.2.1 Describe how energy flows through an ecosystem (e.g., food chains, food webs, energy pyramids). BIO.B.4.2.3 Describe how matter recycles through an ecosystem (i.e., water cycle, carbon cycle, oxygen cycle, and nitrogen cycle).

Chemical Energy and ATP: All cells need chemical energy ATP (Adenosine Triphosphate) A molecule that provides energy for cellular reactions and processes. ATP releases energy when one of its high energy bonds is broken to release a phosphate group. ADP (Adenosine Diphosphate): a lower-energy molecule that can be recycled into ATP by adding a phosphate group.

Chemosythesis: a process by which some organisms use chemical energy – instead of light energy– as a source to make their own food. Photosynthesis: A process in which solar radiation is chemically captured by chlorophyll molecules and results in chemical energy in the bonds of carbohydrate molecules.

Cellular Respiration A set of chemical reactions involving an energy transformation where energy in the chemical bonds of “food” molecules is released and captured in the bonds of ATP.

Chemical Energy and ATP The chemical energy used by cells is in ATP Adenosine triphosphate Stores energy that cells can use. Energy in food is transferred to ATP so that the cell can use it When the cell needs energy, ATP is slightly broken down to ADP

ATP  ADP  ATP  ADP  ATP has three phosphate groups. The third phosphate group is held on with a high energy bond When the bond is broken, energy is released ADP is recycled to become ATP again. Another phosphate is added to ADP, it becomes ATP again This requires energy

Organisms break down carbon-based molecules to produce ATP. Your food supplies the energy for the conversion of ADP  ATP IMPORTANT!!! Foods that you eat do NOT contain ATP that your cells can use. Your digestive system breaks the food down into molecules of carbohydrates, lipids and proteins.

What you eat is burned to make ATP The amount of ATP produced depends on the type of molecule you ingest Sugar provides about 36 molecules of ATP Fat provides about 146 molecules of ATP Protein can provide about 36 molecules of ATP However, protein is usually broken down into amino acids and they are used to build more proteins.

Plants need ATP too! Plant cells also need ATP However, plants are producers, they do not eat food the way consumers (animals) must Plants make their own sugar to create ATP They are autotrophs (animals are heterotrophs) Through the process of photosynthesis in their chloroplasts, plants use energy from sunlight to make sugars. Plant cells then break down the sugars they make to produce ATP just like animals.

A few types of organisms do not need sunlight as a source of energy Not all autotrophs use sunlight and photosynthesis to make their own source of energy However, this is the most common way for organisms to get energy Some aquatic environments in the deep ocean do not have sunlight as a resource, but organisms still live there. These organisms live near cracks in the ocean floor that release chemicals, like sulfur Chemosynthesis is a process by which those organisms produce ATP from chemical energy, instead of light energy. The way these organisms make ATP is very similar to terrestrial organisms One Class period. Assign the questions at the end of the notes for homework. Focus on the common ancestry, link because all life depends on carbohydrates and ATP. Good follow up is the textbook questions page 102.

Photosynthesis vs Chemosynthesis Instead of photosynthesis, vent ecosystems derive their energy from chemicals in a process called “chemosynthesis.” Both methods involve an energy source (1), carbon dioxide (2), and water to produce sugars (3). Photosynthesis gives off oxygen gas as a byproduct, while chemosynthesis produces sulfur (4).

From “Planet Earth” Bacteria on the ceiling of caves Bacteria at the hydrothermal vents

Review of Goals Addressed BIO.A.3.2 Identify and describe how organisms obtain and transform energy for their life processes. BIO.B.4.2.1 Describe how energy flows through an ecosystem (e.g., food chains, food webs, energy pyramids). BIO.B.4.2.3 Describe how matter recycles through an ecosystem (i.e., water cycle, carbon cycle, oxygen cycle, and nitrogen cycle).

10 point Vocabulary Quiz Take out a sheet of lined paper. Write the entire definition, filling in the blanks in the definition. A word bank is provided. On the second slide, answer the question in a full sentence.

ATP energy releases lower-energy broken reactions ADP recycled ___ (Adenosine Triphosphate) A molecule that provides ___ for chemical ___ and processes. It ____ energy when one of its high energy bonds is ____ to release a phosphate group. ____ (Adenosine Diphosphate): a ______ molecule that can be _____ into ATP by adding a phosphate group.

Answer the Question in one or more sentences. (2 points) Compare and contrast Chemosynthetic organisms to Photosynthetic organisms. Bonus: Explain why this is important to the understanding of how all life on earth is related.

Basic Photosynthesis = carbohydrates

Overview of Photosynthesis Photosynthesis: A process in which solar radiation is chemically captured by chlorophyll molecules and results in chemical energy in the bonds of carbohydrate molecules. Chlorophyll: a molecule in chloroplasts that can absorb light energy. There are two types, chlorophyll a and b. They absorb red and blue wavelengths of light, and reflect green light.

Chloroplasts: plant organelles that carry out photosynthesis Chloroplasts: plant organelles that carry out photosynthesis. Chloro- means “green”. They contain chlorophyll, a green pigment that absorbs light energy. Chloroplasts have their own ribosomes and DNA.

Thylakoid: a part of the chloroplast Thylakoid: a part of the chloroplast. Flattened disks enclosed by membranes that contain chlorophyll. The light-dependent reactions happen here. Stroma: fluid that surrounds the thylakoids in the chloroplast. The light-independent reactions happen here.

Light-dependent reactions: a part of the two-step process of photosynthesis that absorbs light energy. Happens in the thylakoid membrane of the chloroplast.

Light-independent reactions: begin because of the energy absorbed in the light-dependent reaction. Happens in the stroma of the chloroplast. Carbon dioxide molecules are bonded together, creating sugar, usually glucose.

Photosynthesis – a video introduction Complete the quiz for a class work grade

KEY CONCEPT The overall process of photosynthesis produces sugars that store chemical energy.

Photosynthetic organisms are producers. Producers make their own source of chemical energy. Plants use photosynthesis and are producers. Photosynthesis captures energy from sunlight to make sugars.

Chlorophyll Chlorophyll is a molecule that absorbs light energy. chloroplast leaf cell leaf Chlorophyll is a molecule that absorbs light energy. In plants, chlorophyll is found in organelles called chloroplasts.

Photosynthesis in plants occurs in chloroplasts. stroma grana (thylakoids) Photosynthesis takes place in two parts of chloroplasts. grana (thylakoids) Stroma – the liquid in the space surrounding the thylakoids

Light-dependent reactions The light-dependent reactions capture energy from sunlight. take place in thylakoids water and sunlight are needed chlorophyll absorbs energy Energy is moved to light-independent reactions oxygen is released

Light-independent reactions Simple sugar is made happens in stroma needs carbon dioxide from atmosphere use energy to build a sugar in a cycle of chemical reactions

The equation for the overall process is: 6CO2 + 6H2O  C6H12O6 + 6O2 granum (stack of thylakoids) thylakoid sunlight 1 six-carbon sugar 6H2O 6CO2 6O2 chloroplast 1 2 4 3 energy stroma (fluid outside the thylakoids)

KEY CONCEPT Photosynthesis requires a series of chemical reactions. Watch the video explain the basic concepts of the light dependent and light independent reactions and answer the questions on the quiz.

The first stage of photosynthesis captures and transfers energy. The light-dependent reactions include groups of molecules called photosystems.

Photosystem II captures and transfers energy. chlorophyll absorbs energy from sunlight energized electrons enter electron transport chain water molecules are split oxygen is released as waste hydrogen ions are transported across thylakoid membrane

Photosystem I captures energy and produces energy-carrying molecules. chlorophyll absorbs energy from sunlight energized electrons are used to make NADPH NADPH is transferred to light-independent reactions

The light-dependent reactions produce ATP hydrogen ions flow through a channel in the thylakoid membrane ATP synthase attached to the channel makes ATP

Light-independent reactions occur in the stroma and use CO2 molecules. The second stage of photosynthesis uses energy from the first stage to make sugars. Light-independent reactions occur in the stroma and use CO2 molecules.

A molecule of glucose is formed as it stores some of the energy captured from sunlight. carbon dioxide molecules enter the Calvin cycle energy is added and carbon molecules are rearranged a high-energy three-carbon molecule leaves the cycle

A molecule of glucose is formed as it stores some of the energy captured from sunlight. two three-carbon molecules bond to form a sugar remaining molecules stay in the cycle

Overview of Cellular Respiration - vocabulary Cellular respiration- A chemical process where mitochondria break down food molecules (glucose) to produce ATP. The three stages are: 1) glycolysis (2 ATP: in cytoplasm) 2) Citric Acid/Krebs cycle (forms 2 ATP, CO2, energized electrons, NADH: in mitochondria) 3)Electron Transport chain (forms 34 ATP, H20: in mitochondria)

Glycolysis- first step in cellular respiration; series of anaerobic chemical reactions in the cytoplasm that break down glucose into pyruvic acid; forms a net profit of 2 ATP molecules.

Aerobic respiration- a chemical reaction that requires oxygen; breaks down glucose to form 36 ATP from each glucose molecule Anaerobic respiration- a chemical reaction that does not require the presence of oxygen; breaks down glucose (glycolysis) to form 2 ATP from each glucose molecule

Citric acid cycle/Krebs- in cellular respiration; series of chemical reactions that break down glucose and produce ATP in the mitochondria; energizes electron carriers (NADH) that pass the electrons on to the electron transport chain; CO2 is produced

Electron Transport Chain – the third step in creating ATP from glucose; takes place in inner membrane of the mitochondria; requires oxygen and produces large amounts of ATP and creates water in the process

Oxygen, Water, Carbon dioxide and Sugar These four molecules are cycled through ecosystems constantly.

Watch the video about how important Oxygen is to processes on Earth Answer the questions on the video quiz before you watch the video. Correct any misconceptions you have while you watch. Your quiz will be graded as a classwork grade.

KEY CONCEPT The overall process of cellular respiration converts sugar into ATP using oxygen.

Cellular respiration makes ATP by breaking down sugars. Cellular respiration is aerobic, or requires oxygen. Aerobic stages take place in mitochondria. mitochondrion animal cell

Glycolysis must take place first. anaerobic process (does not require oxygen) takes place in cytoplasm splits glucose into two three-carbon molecules produces two ATP molecules Cytoplasm of Cell

Cellular respiration is like a mirror image of photosynthesis. The Krebs cycle transfers energy to an electron transport chain. takes place in mitochondrial matrix breaks down three-carbon molecules from glycolysis 6H O 2 6CO 6O mitochondrion matrix (area enclosed by inner membrane) inner membrane ATP energy energy from glycolysis 1 4 3 and Krebs Cycle makes a small amount of ATP releases carbon dioxide transfers energy-carrying molecules

The electron transport chain produces a large amount of ATP. takes place in inner membrane energy transferred to electron transport chain oxygen enters process ATP produced water released as a waste product 6H O 2 6CO 6O mitochondrion matrix (area enclosed by inner membrane) inner membrane ATP energy energy from glycolysis 1 4 3 and Electron Transport

The equation for the overall process is: C6H12O6 + 6O2  6CO2 + 6H2O The reactants in photosynthesis are the same as the products of cellular respiration.