(exam 1) ch 5 microbial metabolism Flashcards
what is metabolism?
is the buildup and breakdown of nutrients within a cell
why is metabolism necessary for life?
Provides energy and creates substances that sustain life
what are catabolic pathways?
pathways that break down macromolecules into simple component parts, releasing energy in the process (breaking down)
what are anabolic pathways?
pathways that build up macromolecules by combining simpler molecules, using energy in the process (build up)
what are some examples of positive effects of bacterial metabolism?
Nitrogen cycle, food production, sewage treatment
what are some examples of negative effects of bacterial metabolism?
Disease and food spoilage
The ability of bacteria to grow and thrive in certain environments is directly related to what?
their specific metabolism
Differences in metabolism between bacterial species are based on differences in what?
the enzymes expressed by bacteria (Type and amount of expressed enzymes is based in the bacterial genome)
what are enzymes?
biological catalysts
what do enzymes act on?
specific substances called substrates
what do enzymes do?
Assist with chemical reactions without being altered; they drastically speed up chemical reactions by lowering the activation energy
what contacts the enzyme’s active site and what does it form?
contacts the substrate to form an enzyme-substrate complex
is the enzyme changed in the reaction?
Enzyme is unchanged and can react with other substrates
how do the enzyme and substrate fit together?
lock and key mechanism; Enzymes are specific to certain substrates; Certain compounds may be substrates for several enzymes
how is enzyme activity affected by temperature?
Rate of reaction decreases above enzymes optimal temperature due to denaturation (Optimal temp for most pathogens is 35-40oC) it can become inactive or denatures
how is enzyme activity affected by pH?
Denaturation can occur above or below optimal pH
what is an example of an enzyme inhibitor?
Inhibitors Antibacterial drugs (e.g. sulfanimide)
what are metabolic pathways?
Series of enzymatically catalyzed chemical reactions; Extract energy from organic compounds and ATP is generated from this energy as it is passed (in the form of electrons) between carrier molecules
what are two examples of metabolic pathways
oxidation (electrons removed) / reduction (electrons gained) reactions
what does ATP stand for?
Adenosine triphosphate (ATP)
what is ATP?
“Energy carrier” of living cells; Possesses unstable bonds that can easily be formed/broken to store/provide energy for the cell
what is the primary energy source of most microorganisms?
Most microorganisms use carbs (glucose) as their primary energy source
what is Carbohydrate Catabolism?
Breakdown of carb molecules to produce energy (Glucose is the most common energy source)
what is chemiosmosis?
movement of ions across a semipermeable membrane bound structure, down their electrochemical gradient
what is an example of chemiosmosis?
An example of this would be the formation of adenosine triphosphate by the movement of hydrogen ions across a membrane during cellular respiration or photosynthesis.
how much ATP is made from cellular respiration (aerobic respiration) ?
38 ATP
how much ATP is made from anaerobic respiration?
less than 38 ATP but more than 2
how much ATP does fermentation make?
2 ATP
how are lipids degraded?
degraded by extracellular lipases
when lipids are degraded what is the result?
fatty acids and glycerol
how are proteins degraded?
degraded by extracellular proteases and peptidases
when proteins are degraded what is the result?
amino acids
to produce ATP organisms need what three things?
1) energy source or electron donor
2) electron carriers during oxidation reduction reactions
3) final electron acceptor
how do biochemical tests work?
tests identify bacteria by detecting enzymes
what is the fermentation test?
bacteria that catabolize carbohydrates or protein produce acid, causing a pH indicator to change color
what is the Oxidase test?
identifies bacteria that have cytochrome c oxidase
what is the energy source for a chemoheterotroph?
chemical
what is the carbon source for a chemoheterotroph?
organic compounds
what is an example of a chemoheterotroph?
fermentative bacteria, animals, protozoa, fungi, and bacteria
what nutritional type are bacteria considered?
chemoheterotroph
what is most energy given off as?
heat
what is energy in ATP typically used for?
1) transport across plasma membranes - active transport
2) movement - flagella
3) most used in production of new compounds
what are Amphibolic pathways?
(shown as double arrows) function in both anabolism and catabolism
