MCB 2000 Chapter Notes - Chapter 7: Turbidity, Exponential Growth, Generation Time
Document Summary
Microbial nutrition: nutrition is a process of acquiring chemical substances from the environment, the absorbed nutrients are used, the chemical elements absolutely needed - essential nutrients. 50% of microbial dry weight is c. Nitrogen: 14% of microbial dry weight is n. Required for protein, dna, rna, atp synthesis: microorganisms derive n by: Breaking down proteins into amino acids (reuse of amino acids) N2 nitrogen fixers: free-living, symbionts with plants. Energy and carbon source from organic molecules: saprobes derive nutrients from dead organic material. Opportunistic pathogene a saprobe infecting the compromised host: parasites derive nutrients from living organisms. The movement of molecules across the cell membranes: diffusion movement of molecules from an area of higher concentration to the area of lower concentration, used for transport of small molecules (o2) Facilitated diffusion: substance to be transported -combines with the plasma membrane protein transporter, this changes the shape of the transporter substance is moved across the membrane and released, no energy needed.
