Chapter 7 Cellular Respiration

7.1 Energy and Metabolism

The C – C bonds store energy Burning reaction with oxygen; release energy from organic molecules Cells break organic molecules apart in small, manageable steps Most of these steps are oxidation–reduction reactions (redox reactions) Electrons removed carry energy used to make ATP

7.2 Glycosis

In the Cytoplasm Glycolysis found in ALL cells Net yield of 2 ATP per glucose Electrons from glucose are transferred to 2 electron carrier NADH Produces 2 three-carbon pyruvate molecules

7.3 Oxidation of Pyruvate and Citric Acid Cycle

Inside the Mitochondria Each pyruvate is split into CO2 and a two-carbon acetyl group (Acetyl CoA) Electrons are removed combine with NADH Citric Acid Cycle Each acetyl groups are transferred forming citric acid ATP formed Three NADH form and 1 FADH2 Two CO2 released

7.4 Oxidative Phosphorylation

Electron Transfer Chain Last stage occurs on the inner mitochondrial membrane NADH and FADH2 deliver electrons and H+ to electron transfer chains E.T.C. move H+ actively across the inner membrane Ion gradient causes the ions to flow through the ATP synthase Oxygen accepts electrons at the end of mitochondrial electron transfer chains

For each glucose molecule, 4 ATP form in the first- and second-stage reactions The twelve electron carriers produce 32 additional ATP during the third stage 36 net ATP are produced in total

7.5 Metabolism without oxygen

Fermentation Pyruvate is not fully broken down to CO2 No additional ATP forms The net yield is two ATP Alcoholic fermentation: pathway that produces ATP, CO2, and ethanol Lactate fermentation: pathway that produces ATP and lactate

Chapter 8 Photosynthesis

8.1 Overview

Most autotrophs use light Photosynthesis converts light energy into the energy of chemical bonds Bond energy can then power the reactions of life.

In eukaryotes, photosynthesis takes place in chloroplasts Light-dependent reactions on thylakoid membrane Converts light energy to ATP and NADPH Light-independent reactions in the stroma ATP and NADPH drive synthesis of sugars from water and CO2

8.2 Light Dependent

Light Light is organized in packets of energy called photons which move in waves Visible light: Small range of the light spectrum Photosynthesis use pigments to capture light of specific wavelengths Chlorophyll α: most common photosynthetic pigment

Light Dependent Reaction Thylakoid membranes contain millions of photosystems Photosystem contain hundreds of chlorophylls and other molecules Water is the electron donor; electrons are energized by light absorbed by chlorophyll Light energy energizes electrons in photosystem II E.T.C. creates ion gradient, ATP is formed in the stroma Light energy energizes electrons in photosystem I transferred to NADPH

8.3 Light-Independent

The Calvin–Benson cycle: Build sugars in the stroma of chloroplasts Driving force is ATP and NADPH that formed in the light-dependent reactions Uses carbon atoms from CO2 to make sugars (Carbon fixation)