Introduction to Cell Respiration Energy and redox reactions

The Pathway of energy in living organisms Light energy from the sun Chemical energy stored in glucose, fats, or carbohydrates Chemical energy for use in the form of ATP photosynthesis cellular respiration All living organisms must perform cellular respiration (plants and animals) to get ATP. Only photosynthetic organisms like plants or blue- green alga can transform light energy into chemical energy

MMMMM….. Non-photosynthetic organisms (like humans) must consume glucose, fats, and carbohydrates to obtain the energy to produce ATP Autotrophs = Organisms that make their own food (usually from photosynthesis). Heterotrophs = Organisms that can't make their own food so they take in food produced by autotrophs (by eating autotrophs or organisms that eat autotrophs)

Energy flow and chemical recycling in ecosystems Catabolism Anabolism

Overview of Cellular Respiration The energy released from the catabolism of glucose is used to make ATP from ADP ADP + P + energy ATP

A series of reduction-oxidation reactions allow for the slow release of energy in glucose so that it can be harnessed to fuel the production of ATP. Vs. One large reaction Several smaller reactions

Redox Reactions: LEO the lion goes GER Loss of Electrons = Oxidation Gain of Electrons = Reduction Reduced compounds have higher energy because they gain the energy associated with the electrons they gain

Burning methane: an exergonic reaction

Your turn: Which molecule is reduced and which is oxidized? COOHH Energy Carbon dioxide Water 2 Hydrogen Formaldehyde O HHO C H H

Reduction (takes energy) Oxidation (releases Energy) NADH (electron carrier) Redox reactions transfer electrons and energy from carrier molecules during cellular respiration NAD + (oxidized, lower energy) NADH (reduced, higher energy) NAD+

GLYCOLYSIS KREBS CYCLE ELECTRON TRANSPORT AND OXIDATIVE PHOSPHORYLATION ATP Krebs Cycle Glucose NADH FADH 2 CO 2 H2OH2O Electron transport chain... Pyruvate Cell Respiration is separated into 3 stages Energy/electrons are transferred from glucose to convert NAD + to NADH, which is used in the ETC to make ATP

Figure 9.6 An overview of cellular respiration (Layer 1)

Figure 9.6 An overview of cellular respiration (Layer 2)

Figure 9.6 An overview of cellular respiration (Layer 3)

Cellular respiration is carefully regulated: when ATP is abundant, respiration slows down when ATP is needed, respiration speeds up