Lecture 5/6 Metabolism Flashcards
Microbial metabolism
the sum of all chemical reactions in a cell - separated into two components which are catabolism and anabolism
catabolism
set of chemical reactions that degrade compounds and release energy that cells capture to make ATP
the processes also produce precursor metabolites used in biosynthesis (anabolic processes)
Anabolism/biosynthesis
set of chemical reactions that cells use to synthesize and assemble the subunits of macromolecules using ATP for energy
what are the subunits of macromolecules
amino acids, nucleotides, monosaccharides, fatty acids
what is the relationship between catabolism and anabolism?
precursor metabolites are compounds produced during catabolism that can either be further degraded or be used in anabolism to make subunits of macromolecules
precursor metabolites
chemicals that can either be further broken down to generate energy (via catabolism) or used to make certain subunits of of macromolecules (via anabolism)
photosynthetic organisms
harvest energy of sun and use it to power the synthesis of organic compounds from CO2
chemoorganotrophs
obtain energy by degrading organic compounds; they then use some of that energy to make other organic compounds - they take the potential energy of certain chemical bonds and use it to create other ones
describe the three types of metabolic pathways (figure 6.4)
linear
branched
cyclical
how do cells regulate certain processes and ensure that certain molecules are produced in precise quantities
if a metabolic step is blocked, certain products downstream of that block will not be made
starting compound - intermediate -end product
what are the essential components of a metabolic pathway
enzymes, ATP, chemical energy source, terminal electron acceptor, electron carriers
what is an enzyme
usually a protein that functions as a biological catalyst which speeds up the conversion of one substance to another - a specific enzyme facilitates each step of a metabolic pathway
how does an enzyme catalyze a chemical reaction?
by lowering the activation energy of the reaction
how do chemoorganotrophs make ATP
they use two different processes to make ATP
substrate-level phosphorylation
oxidative phosphoryaltion
substrate-level phosphorylation
energy released in a n exergonic reaction is used to power the addition of Pi to ADP
oxidative phosphorylation
the energy of a proton motive force drives the reaction
proton motive force
form of energy generated as an electron transport chain moves protons across a membrane to create a chemiosmotic gradient
proton motive force
form of energy generated as an electron transport chain moves protons across a membrane to create a chemiosmotic gradient
energy that results from the electrochemical gradient established by the electron transport chain
photophosphorylation
how photosynthetic organisms can generate ATP - uses sun’s radiant energy and an electron transport chain to create a proton motive force
when do cells produce and use ATP or ADP
cells produce ATP by adding a phosphate during exergonic reactions of catabolism and then use it to power endergonic reactions of anabolism
how do cells obtain the energy used to make ATP
they remove electrons from glucose or another low electron affinity chemical and donate them to a molecule such as O2 that has a higher electron affinity - energy is released in this process
what is the source of energy in the process of making ATP
the chemical that serves as the electron donor
terminal electron acceptor
chemical that is ultimately reduced as a consequence of fermentation or respiration - it accepts the electrons that are donated by the energy source. in this exergonic reaction energy is released to make ATP
Name 3 examples of chemoorganotrophic metabolism
glucose as energy source and pyruvate as electron acceptor
glucose as energy source and O2 as electron acceptor
glucose as energy source and NO3- as acceptor
