YIJC [H2] CI3.2_Respiration (N)(S)(vetted)

2025 JC2 BIOLOGY LECTURE NOTES 1 CORE IDEA 3: ENERGY AND EQUILIBRIUM TOPIC 3.2: CELLULAR RESPIRATION Learning Outcomes: (a) Identify components of mitochondria in drawings, photomicrographs and electronmicrographs. (f) Outline the process of glycolysis, highlighting the location, raw materials used and products formed. (Knowledge of details of the intermediate compounds and isomerization is not required.) (g) Outline the process of the link reaction and Krebs cycle, highlighting the location, raw materials used and products formed. (In terms of dehydrogenation and decarboxylation.) (h) Outline the process of oxidative phosphorylation including the role of oxygen and the electron transport chain in aerobic respiration (names of complexes in the ETC are not required). (i) Explain the production of a small yield of ATP from respiration in anaerobic conditions in yeast and in mammalian muscle tissue. (j) Explain the significance of the formation of ethanol in yeast and lactate in mammals in the regeneration of NAD. (k) Investigate the effect of factors such as substrate concentration, type of substrate and temperature on the rate of respiration. (l) Outline chemiosmosis in respiration. (Names of complexes in the ETC are not required.) References: Campbell and Reece. Biology. (11th edition). Chapter 10 : Cell Respiration, P. 2 36 – 256 (or corresponding chapter in other editions) Note: This textbook is available in our library. You may wish to borrow it to supplement your reading when necessary. 1) Introduction 1.1 Energy and ATP 1.2 The Mitochondrion 1.3 Cellular Respiration 2) Aerobic Respiration 2.1 Glycolysis 2.2 Link Reaction 2.3 Krebs Cycle 2.4 Oxidative Phosphorylation 3) Anaerobic Respiration 3.1 Alcoholic Fermentation 3.2 Lactate Fermentation 4) Respiratory Quotient 5) Factors Affecting Rate of Respitation H2

2 1 INTRODUCTION • Life processes in every cell are driven by energy. Energy flows into the ecosystem as sunlight and leaves as heat, while chemical elements essential to life are recycled. • Photosynthesis allows plants to convert energy from light into chemical ener gy stored in organic molecules, while cellular respiration occurs to break down the organic molecules to yield adenosine triphosphate (ATP), which drives many cellular processes. Fig 1.1: Energy flow and chemical recycling in ecosystems

3 1.1 ENERGY AND ATP • Respiration involves the release of chemical energy, in the form of adenosine triphosphate (ATP), from organic molecules through a series of oxidation-reduction (redox) reactions. Fig. 1.1.1: Structure of ATP, ADP and AMP The roles of ATP in cells include: (a) Energy Currency – ATP serves as the energy currency of the cell. Energy is released when ATP is hydrolysed to ADP (30.6 kJ per mole of ATP, 1 J = 0.239 cal). The energy released can be used in various cellular processes, such as enzyme r