VMCB LEC

• nutrition is the process by which chemicals substances called nutrients are acquired from the environment and used in cellular activities
• micronutrients or trace elements required in small amounts involved in enzyme function and maintenance of protein structure
• macronutrients required in large amounts play principal role in cell structure and metabolism
• essential nutrients must be provided to an organism (Carbon, Nitrogen, Oxygen, Hydrogen, Phosphorus and Sulfur
• cytoplasmic cell membrane controls the passage of nutrients into the cell.

  • semi-permeable
  • selectively permeable
• gram-negative bacteria of outer membrane plays a role in regulating the passage of solutes and they are semi-permeable because they have no proteins in the outer membrane are known to pump solutes across it although some activity facilitate passage
• passive diffusion or simple diffusion is a process in which molecules from a high concentration to a low concentration move down their concentration gradient

  
• facilitated diffusion is the diffusion in and out of the cell of certain compounds

  • specific membrane proteins collectively known as permeases or carrier proteins or channel proteins and
  • they have no energy input
  • they are the transport of glucose, amino aid, ion and nucleotide transport

  
• active transport is metabolic energy is utilized for the transport of substances through carrier proteins embedded in the membrane

  • all types utilize carrier proteins
  • primary active transport and secondary active transport

  
• active transport of proton motive force (PMF) is the transfer of hydrogen molecule through a proton pump generates an electrochemical gradient of protons

  • it drives the conversion of ADP to ATP through ATP synthase
  • Chemiosmotic theory

  
• entry of nutrients into the cell

  A) passive transport

  B) diffusion

  C) facilitated diffusion

  D) active transport

  
• ATP-binding cassette (ABC) transporters is one of the largest and most diverse superfamily of proteins that can be found in all eukaryotic and prokaryotic organisms.

  
• primary active transport is the establishment of a proton motive force by proton extrusion associated with the passage of electrons through a membrane-bound transport chain or by hydrolysis of ATP by the membrane-bound ATPase
• secondary active transport

  • uniport- transport one solute at a time
  • symport- transports the solute and a co-transported solute at the same time in the same direction
  • antiport- transports the solute in (or out) and the con transported solute the opposite direction
• entry of nutrients into the cell

  
• group translocation is the process in which a molecule is chemically modified as it is brought into the cell

  • source of energy is phosphoenolpyruvate (pep)
  • uptake of certain sugars like glucose and mannose
  • phophotransferase system (PTS)
• UTILIZATION OF SUBSTRATES THAT CANNOT PASS THE CELL MEMBRANE

  
• characteristics of exoenzymes

  • inactive while inside the cell
  • upon release from the cell, they become active
• water which consists of 80% to 90% of a cell which influences growth beyond its role in a cellular metabolism and nutrition through osmotic pressure and hydrostatic pressure
• osmotic pressure is the force with which water moves through the cytoplasmic membrane from a solution containing a low concentration of dissolved substances (solute) to one containing a high solute concentration
• osmophiles

  • grow in solution of increased osmolarity
  • microorganisms adapted to environments w high pressure
  • they r able to live in environments high sugar
• halophiles

  • grow in solution of increased salt concentration
  • extremophile organism
  • salt-loving
• effects of solute on growth and metabolism

  
• sodium requirement of bacteria detected only for growth at the expense of certain specific carbon and energy sources
• marine bacteria assures the correct function of transport mechanism
• extreme halophiles a high concentration of sodium chloride is essential in order to maintain both the stability and the catalytic activity of enzymes
• hydrostatic pressure exerted on the cells by the movement of water resting on top of them
• barophiles

  • metabolize or function better at high pressure than at atmospheric pressure
  • organisms that need a high pressure environment in order to grow (deep sea environment)
• psychrophiles

  • cold loving bacteria
  • cardinal temp are 20 degrees for maximal growth and 15 degrees or lower for optimal growth or 0 degrees for minimum growth
  • found in cold area (polar regions, deep sea)
  • pseudomonas
• mesophiles

  • grow in moderate temperature
  • temp range: 20-45 degrees celsius
  • most microorganism are mesophiles
  • E. coli, streptococcus pneumoniae
• hyperthermophiles

  • loves in extremely hot environment
  • temp range: 80 degrees to 110 degrees
  • cell membranes contains high levels of saturated fatty acids
• effects of pH on bacterial growth

  
• oxygen and carbon dioxide are two principal gases that affect the growth of microbial cells
• aerobes

  • organisms that can survive and grow in an oxygenated environment
  • standard air atmosphere (21%)
• anaerobes

  • microorganisms which may be poisoned by oxygen
  • cannot grown in an air atmosphere
• anaerobes (cont)

  • aetolerant anaerobes can tolerate low concentrations of oxygen
  • strict anaerobes killed by grief of exposure of oxygen
• facultative anaerobes

  • do not require oxygen for growth although may use it for energy production if available
  • under anaerobic conditions they may obtain energy by a metabolic process called fermentation
• microaerophiles

  • can use oxygen
  • usually grown best at oxygen levels between 1% and 15%
  • limited tolerance to oxygen is due to high susceptibility to superoxide radicals and hydrogen peroxide
• toxic derivatives of oxygen

  
• BACTERIAL NUTRITION

  • nutrition substances used in biosynthesis and energy production
  • bacteria requires sources of carbon, nitrogen, phosphorous iron and a large of number of other molecules
  • CARBON, NITROGEN and WATER are the highest quantities