细胞科学 蔡国平
细胞科学 Cell Science （9.1） 蔡国平
s9 Bioenergetics and metabolism The generation of metabolic energy is a major activity of all cells, and two cytoplasmic organelles are specifically devoted to energy metabolism and the production of ATP. Mitochondria are responsible for generating most of the useful energy from the breakdown of lipids and carbohydrates, and chloroplasts use energy captured from sunlight to synthesize carbohydrates from CO2 and H2O. The peroxisome contains enzymes involved in a variety of different metabolic pathways, including the breakdown of fatty acids and: the metabolism of a by-product of photosynthesis
§9 Bioenergetics and metabolism The generation of metabolic energy is a major activity of all cells, and two cytoplasmic organelles are specifically devoted to energy metabolism and the production of ATP. Mitochondria are responsible for generating most of the useful energy from the breakdown of lipids and carbohydrates, and chloroplasts use energy captured from sunlight to synthesize carbohydrates from CO2 and H2O. The peroxisome contains enzymes involved in a variety of different metabolic pathways, including the breakdown of fatty acids and the metabolism of a by-product of photosynthesis
9.1 Aerobic respirations and the mitochondrion In eukaryotes, the utilization of oxygen as a means of energy extraction takes place in a specialized organelle the mitochondrion Anaerobes: Organisms that. utilize energy-rich compounds through oxygen-independent metabolic pathways such as glycolysis and fermentation Aerobes: organisms dependent on tne presence of oxygen to utilize energy-rich compounds
9.1 Aerobic respirations and the mitochondrion In eukaryotes, the utilization of oxygen as a means of energy extraction takes place in a specialized organelle, the mitochondrion. Anaerobes: Organisms that utilize energy-rich compounds through oxygen-independent metabolic pathways such as glycolysis and fermentation. Aerobes: organisms dependent on tne presence of oxygen to utilize energy-rich compounds
8.1.1 Mitochondrial structure and function 1. Outline 1)Shape, size, amounts and location of Mit Mit. are large enough to be seen by microscopy. The amounts of mit varied from o to more than 10.000 in the cell according to their requirement of ATP, e.g. in liver cells 800-2000 Mit while even more numerous Mit. in muscle cells which require large amounts of atP to fuel their contraction Mit. are dynamic organelles with recognisable morphologic character, while exhibiting considerable variety in appearance(sausage-, sphere- or thread-like), and mobility from place to place within the cytoplasm, and undergo branching. Mit. can be seen to undergo both fusion and fission Mit. Occupy 15 to 20 percent of the cells volume, which are well-distributed in cytoplasm generally, although are located more in the aera. where the life activation is exuberant such as around myoflaments or fatty acid-fulling oil droplets and usually along the microtubules
8.1.1 Mitochondrial structure and function 1. Outline 1) Shape, size, amounts and location of Mit Mit. are large enough to be seen by microscopy. The amounts of Mit varied from 0 to more than 10,000 in the cell according to their requirement of ATP, e.g. in liver cells, 800-2000 Mit. while even more numerous Mit. in muscle cells which require large amounts of ATP to fuel their contraction. Mit. are dynamic organelles with recognisable morphologic character, while exhibiting considerable variety in appearance (sausage-, sphere- or thread-like), and mobility from place to place within the cytoplasm, and undergo branching. Mit. can be seen to undergo both fusion and fission. Mit. Occupy 15 to 20 percent of the cell’s volume, which are well-distributed in cytoplasm generally, although are located more in the aera, where the life activation is exuberant, such as around myoflaments or fatty acid-fulling oil droplets and usually along the mcrotubules
Photosynthesis Aerobic respiration Chloroplast Mitochondrion CO2+ H2O CO2+H2O Carbohydrate ATP (contains high energy electrons) NADPH ■■■■■ NADH ADP NADP+ NAD chemical energy (ATP) H20 (contains low energy electrons H20 e . e Figure 6.4 An overview of the energetics of photosynthesis and aerobic respiration
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18 Cristae Mitochondria Mitochondria
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mitochondria GRUNE contractile apparatus WAR flagellar core myofibril CARDIAC MUSCLE CELL SPERM TAIL
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2)Mit structure Mit contain Two membranes Outer membrane Inner membrane which forming Cristae structure the most as wide sheets that cut the cross section same have a more tubular shape Two aqueous compartments The matrix, appearing a gel-like consistency, owing to up to 500 mg/ml soluble proteins Intermembrane space, appearing rather limited space, which may become much more expansive under condition of active respiration
2) Mit.structure Mit contain: Two membranes: Outer membrane Inner membrane which forming Cristae structure, the most as wide sheets, that cut the cross section, same have a more tubular shape Two aqueous compartments: The matrix, appearing a gel-like consistency, owing to up to 500 mg/ml soluble proteins. Intermembrane space, appearing rather limited space, which may become much more expansive under condition of active respiration
