Biology: digestive and urinary system

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  • Publicado : 4 de noviembre de 2011
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Nutrients: Substances obtained from the environment that organisms need for their growth and survival
• Energy
o Measurement
▪ A calorie is the amount of energyrequired to raise the temperature of 1 gram of water by 1ºC
← 40% released as heat. 60% released as ATP (metabolic reactions)
▪ Calories = 1000 calories▪ Metabolic rate is the speed at which cellular reactions that release energy occur.
o Carbohydrates
▪ Short-term energy storage
▪Glycogen in animals, cellulose in plants, starch in both
o Fats and oils
▪ Concentrate source of energy
▪ Contains over twice as many Calories per unitweight as do carbohydrates or proteins (9 Cal in fats/ 4 Cal in carbs)
▪ Fat deposits provide isolation
• Essential nutrients: Any nutrient that cannot be synthetized by thebody
o Essential fatty acids are raw materials used to synthesize molecules involved in psychological activities, cell division, fetal development, and the immune response
oEssential amino acids form the building blocks of protein that synthetize new proteins.
o Minerals help in bone and tooth formation and maintenance, pH of body fluids and osmoticstrength maintenance, enzyme activation, hemoglobin, thyroid hormones, teeth, bones, and enzyme’s composition, normal blood glucose level maintenance
o Vitamins are vital for normal cellfunction, growth and development, and for proper functioning of enzymes during metabolic reactions
▪ Water-soluble vitamins: Vitamin C and B (+9 compounds), which are dissolved in thewatery blood plasma and filtered out by the kidneys. They act as coenzymes to promote chemical reactions that supply energy or synthesize biological molecules.
▪ Fat-soluble vitamins:...
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