BIOL125_Ch7 Text Notes

BIOL125_Ch7 Text Notes - BIOL 125(Microbiology Text Notes...

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BIOL 125 (Microbiology) Text Notes Chapter 7: Elements of Microbial Nutrition, Ecology, and Growth 1. MICROBIAL NUTRITION a. Adaptation – changes in structure and function that improve an organism’s survival in a given environment. b. Nutrition – a process by which chemical substances called nutrients are acquired from the environment and used in cellular activities such as metabolism and growth. c. Essential Nutrient – any substance, whether an element or molecule, that must be provided to an organism. i. Two categories of essential nutrients: macronutrients and micronutrients. 1) Macronutrients – required in relatively large quantities and play principle roles in cell structure and metabolism. This includes compounds containing carbon, hydrogen, and oxygen. 2) Micronutrients – are also known as trace elements and are present in small amounts. They are involved in enzyme function and maintenance of protein structure. These include manganese, zinc, and nickel. d. Most organic nutrients are molecules that contain a basic framework of carbon and hydrogen. Natural organic molecules are almost always the products of living things. e. Inorganic Nutrient – composed of an element or elements other than carbon and hydrogen. f. Chemical Analysis of Cell Contents (No notes from this section) g. Sources of Essential Nutients i. Carbon Sources. 1) Heterotroph – an organism that must obtain its carbon in an organic form. 2) Autotroph – an organism that uses inorganic CO 2 as its carbon source. ii. Nitrogen Sources. 1) Nitrogen-containing molecules are the primary source for heterotrophs, but it first must first be degraded into their basic building blocks (proteins into amino acids; nucleic acids into nucleotides). 2) Some bacteria and algae utilize inorganic nitrogen sources such as nitrate (NO 3 ), nitrite (NO 2 ), or ammonia (NH 3 ). 3) A small number of prokaryotes can utilize N 2 . Inorganic nitrogen must first be converted to NH 3 , the only form that can be directly combined with carbon to synthesize amino acids and other compounds. iii. Oxygen Sources. 1) Oxygen is a major component of macromolecules such as carbohydrates, lipids, nucleic File: a58fa11a2d45de9d012c47598153db5e88eac3f6.doc Updated 8/14/09
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Text Notes Chapter 7 Page 2 acids, and proteins. 2) Oxygen is also a component of water and inorganic salts such as sulfates, phosphates, and nitrates. iv. Hydrogen Sources. 1) Hydrogen is a major element in all organic and several inorganic compounds, including water, salts, and certain naturally occurring gases (ex. hydrogen sulfide, methane, and hydrogen). v. Phosphorus (Phosphate) Sources. 1) The main inorganic source of phosphorus is phosphate, derived from phosphoric acid. 2)
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BIOL125_Ch7 Text Notes - BIOL 125(Microbiology Text Notes...

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