Quiz 3: ch 6

a chemical reaction that requires an input for energy in order to proceed is termed _____, whereas one that releases energy is Called _____

endergonic exergonic

the energy released when a chemical bond is broken that is available to do work is called

free energy

Fermentation

Metabolic process that stops short of oxidizing glucose or other organic compounds completely, using an organic intermediate as a terminal electron acceptor.

Catabolism

Metabolic processes that harvest energy released during the breakdown of compounds such as glucose, using it to synthesize ATP.

Anabolism

Metabolic processes that synthesize and assemble the subunits of macromolecules, using energy of ATP; biosynthesis.

Substrate-Level Phosphorylation

Synthesis of ATP using the energy released in an exergonic (energy-releasing) chemical reaction during the breakdown of the energy source.

central metabolic pathway that splits glucose and gradually oxidizes it to from two molecules of pyruvate is ______

glycolysis

the primary pathway to convert glucose to pyruvate is

glycolysis

Photosynthetic organisms

harvest the energy of sunlight, using it to power the synthesis of organic compounds from CO2. By doing so, they convert the kinetic energy of photons (particles that travel at the speed of light) to the potential energy of chemical bonds.

the TCA cycle completes the _____ of glucose

oxidation

Enzyme

A molecule, usually a protein, that functions as a catalyst, speeding up a biological reaction.

when a cell processes glucose or other organic molecules through its central metabolic pathways, it does so to generate what three critical things?

ATP, reducing power, precursor metabolites

Terminal Electron Acceptor

Chemical that is ultimately reduced as a consequence of fermentation or respiration.

Proton Motive Force

Form of energy generated as an electron transport chain moves protons across a membrane to create a chemiosmotic gradient.

photosynthetic organisms use the light-dependent reactions to accomplish which two tasks?

Generate ATP via photophosphorylation; generate reducing power

Electron Transport Chain (ETC)

Group of membrane-embedded electron carriers that pass electrons from one to another, and, in the process, create a proton motive force.

Precursor Metabolites

Metabolic intermediates that can be either used to make the subunits of macromolecules or oxidized to generate ATP.

Cellular Respiration

Metabolic process that transfers electrons stripped from a chemical energy source to an electron transport chain, generating a proton motive force that is then used to synthesize ATP.

Oxidative Phosphorylation

Synthesis of ATP using the energy of a proton motive force created by harvesting chemical energy.

Photophosphorylation

Synthesis of ATP using the energy of a proton motive force created by harvesting radiant energy.

Adenosine Triphosphate (ATP)

The energy currency of cells. Hydrolysis of the bonds between its phosphate groups can be used to power endergonic (energy-consuming) reactions.

the critical site of an enzyme to which a substrate binds by weak forces is called the

active site

process that transfers electrons extracted from glucose via the central metabolic pathways to the electron transport chain, where they are used to generate a proton motive force that can be harvested to make ATP via oxidative phosphorylation

cellular respiration

in photosynthesis, the reactions that capture radiant energy and convert it to chemical energy in the form of ATP are called the ______ reactions

light, or light-dependent

a series of sequential chemical reactions in a cell that converts a starting compound to an end product is called a _____ ______

metabolic pathway

the sum total of all chemical reactions in a cell is called ______

metabolism

a cell will usually contain how many different enzyme?

more than a thousand

Chemoorganotrophs

obtain energy by degrading organic compounds; they then use some of that energy to make other organic compounds. In other words, they take the potential energy of certain chemical bonds and use it to create other ones. Because chemoorganotrophs depend on a constant source of organic compounds, they generally rely on the metabolic activities of photosynthetic organisms (figure 6.3). In some environments, however, chemolithoautotrophs play the most significant role in synthesizing organic compounds

the mechanism by which cellular respiration uses reducing power generated in glycolysis, the transition step, and the TCA cycle to synthesize ATP is the _____ phosphorylation

oxidative

forms of phosphorylation that require an electron transport chain for ATP production

oxidative phosphorylation and photophosphorylation

in photosynthesis, the protein complexes located within photosynthetic membranes that contain pigments and are responsible for capturing radiant energy are called

photosystems

when cells use glucose to make amino acids and other subunits for biosynthesis, certain intermediates of catabolism called ______ metabolites exit the "deconstruction line" of the breakdown process

precursor

what are the two fundamental tasks that all cells must accomplish to grow?

synthesize new parts and harvest energy to power reactions

in photosynthesis by cyanobacteria and chloroplasts, why is O2 generated?

the process strips electrons from H2O, generating O2

best summarizes prokaryotes as a group in terms of their metabolism

they are highly diverse with respect to compounds they use for energy but remarkably similar in their biosynthetic processes.

why do reduced electron carriers such as NADH, NADHP, and FADH2, represent reducing power?

they can easily transfer their electrons to another chemical that has a higher affinity for electrons

certain intermediates of catabolic pathways, called precursor metabolites, are important because

they serve as carbon skeletons from which subunits of macromolecules can be made

the metabolic pathway that oxidizes a 2-carbon acetyl group to release two molecules of CO2 and generates the most reducing power of all the central metabolic pathways is called the _______

tricarboxylic acid cycle (citrus acid cycle, Krebs cycle, or TCA cycle)