Chapter 8 Photosynthesis & Chapter 9 Respiration

Section 8-1 Energy and Life

I. Energy – the ability to do work A. Many types of energy, mechanical, electrical, chemical, light, and heat, etc. B. Most organisms ultimately use the sun’s energy

II. Autotrophs v Heterotrophs A. Autotrophs are organisms that make their own food, usually powered by the sun’s energy B.Heterotrophs feed on other organisms for their direct source of energy, but they ultimately depend on the sun’s energy too. How is this?

III. ATP (Adenosine Triphosphate) A. ATP is considered the energy currency of the cell. ATP ADP + Phosphate   Energy stored Energy Released B. ATP provides the energy that powers cellular processes. Such as? ADP = Adenosine Diphosphate

Section 9-1 Chemical Pathways

I. Overview of Cellular Respiration A. The first step in respiration is always glycolysis. B. If Oxygen is present glycolysis proceeds to the Krebs cycle and the electron transport chain.

1.This is known as aerobic respiration and can be written as: 6O 2 + C 6 H 12 O  6CO 2 + 6H 2 O + Energy Oxygen + glucose ----  carbon dioxide + water + Energy C. If oxygen is not present then fermentation may occur.

II. Glycolysis A. In glycolysis 1 6-carbon glucose is broken down into 2 3-carbon pyruvic acid molecules. B. A Net gain of 2 ATPs and 2 NADH 1. NADH is an electron carrier that carries 2 electrons (each) to the Electron Transport Chain 2 ATP 2 ADP4 ADP 4 ATP Glucose 2 G3P 2 Pyruvic Acid 2 NAD + 2 NADH

III. Fermentation A. Keeps Glycolysis going under anaerobic (oxygen-less) conditions by producing NAD + B. Two Major Types 1.Alcoholic Fermentation Pyruvic acid + NADH  alcohol + CO 2 + NAD + 2. Lactic Acid Fermentation Pyruvic acid + NADH  lactic acid + NAD +

Formation of acetyl coenzyme A includes formation of citric acid. The Citric Acid cycle is also known as the Krebs cycle.

Section 9-2 The Krebs Cycle & Electron Transport

I.The Krebs Cycle (an overview) A. Pyruvic acid (from glycolysis) is broken down into carbon dioxide in a series of energy-extracting reactions B. Takes place in the mitochondria

C. The Process 1. Acetyl-CoA is formed as a CO 2 and an NADH are produced 2. Two carbons of acetyl-CoA are added to a 4-carbon compound forming a 6-carbon Citric Acid 3. A 5-carbon Compound is created as another CO 2 and NADH are given off. 4. The 4-carbon compound mentioned in step 2 is recreated, as a CO 2, an NADH, and an ATP are produced. 5. Lastly before another Acetyl CoA enters the cycle an FADH 2 and an NADH are released.

Totals: Per Pyruvic Acid 3 CO 2 (exhaled) 1 ATP (used by cells) 1 FADH 2 (to electron 4 NADH transport) In glycolysis two pyruvic acids are produced, so to get the number of these products per glucose we must multiply by two.

II. The Electron Transport Chain (ETC) A.The electron carriers (FADH 2 and NADH) generated in the Krebs cycle pass their electrons through the ETC B. This generates ATP from ADP C. Occurs in the mitochondria

D. As electrons are passed through the proteins of the ETC, hydrogen ions (H + ) are pumped from the matrix to the intermembrane space. 1.H + builds up in the intermembrane space, creating a reservoir of H + 2. This reservoir “turns a turbine” called ATP synthase which makes ADP into ATP

E. After the electrons have passed through the ETC they are passed on to OXYGEN and paired with H + to form H 2 O.

III. Grand Totals of ATP produced aerobically Vocabulary Review: Aerobically- in the presence of oxygen Per Glucose Glycolysis2 ATP 2 NADH4 ATP Citric Acid Production2 NADH x3 ATP each6 ATP Krebs Cycle2 ATP 6 NADH x3 ATP each 18 ATP 2 FADH 2 x2 ATP each4 ATP 36 ATP

Section 8-2 Photosynthesis: An Overview

I. The Photosynthesis Equation C. Equation is reverse of that for respiration. B. 6CO 2 + 6H 2 O + light energy  C 6 H 12 O 6 + O 2 Carbon dioxide + water + light energy  sugars + oxygen A. Photosynthesis uses the energy of sunlight to convert water and carbon dioxide into high energy sugars and oxygen

II. Light and Pigments A. Photosynthesis requires, in addition to carbon dioxide and water, light and chlorophyll B. Chlorophyll absorbs violet and blue and red light strongly, reflects green light and thus leaves appear green. C.When light hits chlorophyll high energy electrons are created. These high energy electrons power photosynthesis.

Section 8-3 Part One The Reactions of Photosynthesis

A. Thylakoids – saclike photosynthetic membranes in the chloroplast I. Inside a Chloroplast

B. Grana – a stack of thylakoids C. Photosystems- 3. light collecting units of the chloroplast 1. organized proteins, chlorophyll and other pigments 2. located in the thylakoid membrane D. Stroma – region outside the thykaloid membrane

II. Light Dependent Reactions A.The light dependent reactions produce oxygen gas and convert ADP and NADP + into energy carriers ATP (chemical) and NADPH (electron) B. The Process (pp ) (A =1, B=2... ) 1. Light hits photosystem II electrons become higher in energy as H 2 O is broken down into H + and O 2, the electrons enter the photosynthetic ETC

2. Electrons move from photosystem II to photosystem I, causing H + to be pumped from the stroma to the inner Thylakoid space. 3. In photosystem I electrons are reenergized by light. NADP + picks up electrons and H + generating NADPH. 4. During steps 2 and 3 H + builds up in inner thylakoid space making it positively charged and the stroma negatively charged. Creates a reservoir of H +.

5. H + passes to stroma through ATP synthase generating ATP from ADP

Section 8-3 Part 2 The Reactions of Photosynthesis

III. Calvin Cycle A. ATP and NADPH are only stable for a few minutes B. The Calvin cycle uses ATP and NADPH from the light dependent reactions to produce high-energy sugars which are stable

C. The Process 1. Six CO 2 combine with six 5-carbon molecules, ultimately resulting in 12 3-carbon molecules 2. The twelve 3-carbon molecules are “energized” by ATP and NADPH 3. Two of the 3-carbon molecules are removed from the cycle for use by the plant 4. The remaining ten 3-carbon molecules are converted back to six 5-carbon molecules to repeat the cycle

D. 6 CO 2 molecules enter the Calvin cycle and a single 6-carbon sugar is produced IV. Factors that Affect Photosynthesis A. Availability of water C. Light intensity B. Temperature