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Energy. Energy. Energy can be described as the ability to do work Energy that is stored in organic molecules is known as chemical energy Glucose the energy living organisms use to do work is called free energy without a constant source of energy, living systems would not survive.
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Energy • Energy can be described as the ability to do work • Energy that is stored in organic molecules is known as chemical energy • Glucose • the energy living organisms use to do work is called free energy • without a constant source of energy, living systems would not survive
Three kinds of work: • Chemical • constructing and breaking down large complex molecules • proteins and nucleic acids • Transport • the movement and concentration of materials • Materials and nutrients required for building complex molecules, and growth of cellular structures • Mechanical • includes movement such as muscle contractions.
Obtaining Energy • Autotrophs • use the sun’s energy to convert carbon dioxide and water into food in the form of carbohydrates • green plants that make their own food through the process of photosynthesis
Obtaining Energy • Heterotrophs • Must take in food that is already made • food comes from plants or other animals that have eaten plants • break the chemical bonds in large food molecules and release energy through the process of cellular respiration • Autotrophs also undergo cellular respiration
Energy Storage - ATP • the carrier of energy is the molecule adenosine triphosphate or ATP • there are 3 components to the ATP molecule:
Cellular Respiration • breakdown of glucose (C6H12O6) in the presence of oxygen (O2) to produce cellular energy (ATP) • C6H12O6 + 6O2 -->6 CO2 + 6H2O + 38 ATP • 3 Main Parts to the reaction…
Cellular Respiration • Glycolysis: • occurs in the cytoplasm, converts glucose to pyruvic acid • an anaerobic process - O2 is not requiredpyruvic acid diffuses into the mitochondrion • Citric Acid or Krebs Cycle • occurs in the mitochondria • an aerobic process; only occurs in the presence of O2 • Releases CO2 as a product
Cellular Respiration • Electron Transport System: • Actual production of ATP molecules, • 6 H2O are formed when the electrons unite with O2* at the end of electron transport chain. • * Note: This is the function of oxygen in living organisms!
Release of Energy • Energy is released when ATP loses the endmost phosphate group • Results in adenosine diphosphate (ADP) • If energy is not immediately needed phosphate groups are re-attached • The energy in an ATP molecule is stored in the bonds between the phosphate groups