Portage Microbiology Module 2

cellular metabolism

a controlled set of biochemical reactions that occur in living organisms in order to maintain life

enzyme

a protein, or group of proteins, that catalyze (speed up) chemical reactions/is not consumed during the reaction and can be used repeatedly by the cell

cofactor

a small chemical component, usually metal ions, that assist enzymes during the catalysis reactions/serve as regulators of chemical reactions: in their absence, enzymes are inactive while in its presence enzymes are active

catabolism

the process of breaking down larger molecules into useful energy sources

anabolism

the building up or biosynthesis of macromolecules from smaller molecular units into larger complexes

anabolism

used during growth and repair phases of the cell

ATP

most widely used form of energy in the cells

donate/accept

ATP has energy to _________ while ADP can ___________ energy (phosphate group) to become ATP

phototrophs

acquire energy from photons of light to generate ATP from ADP

chemotrophs

acquire energy from preformed (already existing) chemicals found in the environment

organotrophs

removing electrons from organic molecules such as glucose

lithotrophs

remove electrons from inorganic molecules such as elemental sulfur

carbon

in order to carry out metabolic processes, microbes must also have a source of...

heterotroph

a microorganism that derives its carbon from organic molecules such as sugars

autotroph

organisms that derive their carbon from inorganic molecules, most often from carbon dioxide (CO2)

phosphorylation

the addition of a phosphate group

photophosphorylation

light energy is used to power the formation of ATP from ADP

substrate-level phosphorylation

the phosphoryl (PO3) group of a chemical compound is transferred and donated (added) directly to ADP

phosphorylated reactive intermediate

in substrate-level phosphorylation, the chemical compound losing the phosphate group is referred to as the...

oxidative phosphorylation

used by chemotrophs, the energy released by the chemical oxidation of nutrients is used to reform ATP

glycolysis

the breakdown of a single molecule of glucose

reactants

molecules present and involved at the beginning of a chemical reaction

2NAD/2ATP

reactants with glucose in glycolysis

phosphorylation of glucose

prevents glucose from diffusing out of the cell as well serving as the signal molecule to the cell that glycolysis is about to begin

products of glycolysis

2 pyruvate molecules, 2 NADH molecules and 4 ATP

NAD/NADH

plays a vital role in generating and maintaining energy for the cell

fermentation/respiration

two main strategies utilized by cells to replenish the supply of NAD+

fermentation

an anaerobic process in which NADH is converted back to NAD+ while pyruvate is converted to a waste byproduct, commonly lactic acid or ethanol, to be eliminated from the cell

respiration

a more efficient aerobic process used by microorganisms to produce energy

tricarboxylic acid (TCA) cycle

central pathway of respiration/requires an additional coenzyme similar to NAD called flavin adenine dinucleotide (FAD)

products of TCA

2 ATP in total (one for each pyruvate processed) and an abundance of reduced electron carriers: NADH and FADH2

primary function of the TCA cycle

production of these reduced electron carriers (NADH and FADH2)/the transfer of these electrons will fuel the generation of ATP via the electron transport system

electron transport chain

a continuation of cellular respiration and can proceed either aerobically or anaerobically

anaerobic respiration

less efficient and yields fewer ATP molecules than aerobic respiration

mitochondria

as electrons are transferred from NADH/FADH2 to terminal electron acceptors (O2; aerobic respiration), energy is released and captured by electron acceptor proteins located in the inner membrane of....

protons

electrons are then passed down a chain of electron acceptors (thus the name) causing ___________ (H+; positive charge) to be pumped out of the membrane, causing a strong differential across the mitochondrial membrane,

proton motive force

drives H+ back through the ATP synthase complex, also located in the membrane, resulting in the production of up to 34 molecules of ATP

polysaccharides

typically molecules that are too large to be transported directly across the plasma membrane. Instead microbes must secrete enzymes capable of degrading the polymer into small, more manageable subunits

direct contact

________________ w/ a polysaccharide is often required by the microorganism to ensure maximal absorption

proteins

must also be broken into smaller subunits or individual amino acids by enzymes

protease

an enzyme that catabolizes protein

amino acid

a rich source of nutrients as they are a source not only of carbon and energy but also nitrogen and sulfur

lipids

rich in energy, often having many reduced carbon molecules

lipase

separate the fatty acid chains from the glycerol backbone

lipid backbone

processed for carbon and energy

fatty acid chain

degraded via the β-oxidation pathway

β-oxidation pathway

a highly efficient process that overlaps with both the TCA and electron transport chain cycles/for each lipid-derived carbon atom 48 molecules of ATP are yielded, compared to the 38 molecules of ATP produced from glucose

photosynthesis

the process of capturing sunlight and converting it into the usable energy sources ATP and NADPH

chloroplasts

site of photosynthesis, double membrane-enclosed organelles specific to algae and plants

chlorophyll

photosynthetic pigment

photophosphorylation

also known as the 'light reactions', is the process of converting light energy into chemical energy to be used by the cell in the forms of ATP and NADPH

membrane

light reactions always occur in the __________________, as one of the main functions is to generate a proton concentration gradient to generate ATP, a function very similar to the electron transport systems proton motor force

Calvin cycle

also referred to as the 'dark reactions', involves the ability of a microorganism to use the ATP and NADPH generated in the light reactions to convert carbon dioxide (CO2) and water (H2O) into organic carbon compounds and useful carbohydrates

carbon fixation

to convert carbon dioxide (CO2) and water (H2O) into organic carbon compounds and useful carbohydrates

primary function of Calvin cycle

to produce the three-carbon compound glyceraldehyde 3-phosphate (G3P), which, through a series of steps, eventually leads to the generation of glucose

end byproducts

__________________ of the Calvin cycle supplies the molecules required during the light reactions, just as the end products of the light reactions enables the dark reactions to occur

six

in order for sufficient resupply, the Calvin cycle requires _______ 'turns' (or repetitions) to generate one molecule of glucose

homeostasis

in order to maintain ________________, the optimal level of activity for a stable environment, enzymes are very specific and will only effectively catalyze a specific chemical reaction

catalase

accelerates the decomposition of hydrogen peroxide (H2O2) into water and oxygen/without it, a cell would be unprotected from oxidative damage by reactive oxygen species (ROS) and could not survive

hydrolase

catalyze hydrolysis—the cleavage or breaking apart of chemical bonds by the addition of water. (i.e.) A-B + H2O → A-OH + B-H

isomerase

promote intramolecular rearrangements by altering bonds and/or confirmations within the same molecule producing a different molecule having the same molecular formula, also known as an isomer. (i.e.) A-B→ B-A

ligase

cause covalent bonds to be formed between molecules. (i.e.) A + B → A-B

lyase

cause the cleavage (break) of bonds by means other than via hydrolysis or oxidation. (i.e.) A-B → A + B

oxidoreductase

catalyze the transfer of electrons from the reductant (electron donor) to the oxidant (electron acceptor). (i.e.) A— + B →A + B—

transferase

acts to transfer a specific functional group from one molecule to another. (i.e.) Ab + C → A + Cb

active site

specificity of an enzyme is heavily influenced by its ________________, a unique chemical structure bound only by select target molecules