Chapter 4: Cellular Metabolism

________: Chemical substances that accelerate reaction rates without affecting the products of the reaction and without being altered or destroyed by the reaction.

________ requires calcium to perform its function.

________ must occur at biologically acceptable temperatures, which are too low for life.

________: Those that employ another molecule as the final electron acceptor.

________: Refers to the collective chemical processes that occur within living cells to accomplish these activities.

________: Those that use molecular oxygen as the final electron acceptor.

A(n) ________ is attached to one subunit and a hydroxyl- (OH) unit is attached to another.

________: Organisms that can not synthesize their own food but must obtain nutrients from the environment, including animals, fungi, and many single- celled organisms.

________: The oxidation of fuel molecules to produce energy with molecular oxygen as the final electron acceptor.

________: A British biochemist who described three stages in the complete oxidation of fuel molecules to carbon dioxide and water.

________: States that a closed system moves toward increasing disorder, or entropy, as energy is dissipated from the system.

________: Uses oxygen as the final electron acceptor and releases carbon dioxide and water from the complete oxidation of fuels.

________ (NAD) contains the vitamin** nicotinic acid** (niacin)

First ________: States that energy can not be created or destroyed.

________ exist for critically regulating enzymes in both quantity and activity.

Among ________, amphibians and especially mammals produce mainly urea.

It is highly toxic because it inhibits respiration by reacting with ________ acid to form glutamic acid, and effectively removes ________ from the Krebs cycle.

________ (neutral fats): Are especially rich depots of metabolic energy because the fatty acids of which they are composed are highly reduced and free of water.

________: Contain groups derived from vitamins, most of which must be supplied in the diet.

________ contain iron.

________: Reactions in cells that require the addition of free energy.

________ and birds, as well as many terrestrial invertebrates, produce mainly uric acid.

________: They reduce the amount of activation energy required for a reaction.

________: Small nonprotein groups which perform their enzymatic functions.

________ can not get rid of ammonia so conveniently and must detoxify it by converting it to a relatively nontoxic compound; urea and uric acid.

________: the amino group splits to form ammonia and a keto acid.

________: Subunits of molecules are linked together by removal of water.

________: Involves a transfer of electrons from an electron donor (the reducing agent) to an electron acceptor (the oxidizing agent)

Once ________ are removed, the carbon skeletons of amino acids can be completely oxidized, usually by way of pyruvic acid or acetic acid.

________ is channeled into the Krebs cycle, where the acetyl group is completely oxidized to carbon dioxide.

________: Also called glycolysis, most of the glucose is converted into two 3- carbon units (pyruvic acid) in the cell cytoplasm.

________ contains zinc.

________: the amino group is transferred to a keto acid to yield a new amino acid.

When animals eat proteins, most are digested in the ________, releasing their constituent amino acids, which are then absorbed.

________: A molecule is cleaved by the addition of water at the cleavage site.

________: The final end product of a particular metabolic pathway inhibits the first enzyme in the pathway.

________: A major component of ribosomes, provides the activation energy that enables amino acids to assemble into polypeptide chains during the process of translation.

________: Breaking with water.

The ________ and fat metabolism is to provide energy, much of which is needed to construct and maintain cellular structure and metabolic processes.

________: The final oxidation of fuel molecules occurs, with a large yield of ATP.

If a(n) ________ reversibly, either synthesis or degradation may result.

________: Are degraded by sequential removal of 2- carbon units, which enter the Krebs cycle through acetyl- CoA.

________ A contains the vitamin pantothenic acid.

Refers to the collective chemical processes that occur within living cells to accomplish these activities

It is stored energy

Energy of motion

States that energy cannot be created or destroyed

States that a closed system moves toward increasing disorder, or entropy, as energy is dissipated from the system

The energy in a system available for doing work

Reactions in cells release free energy

Reactions in cells that require the addition of free energy

This must be supplied before the bond is stressed enough to break

Chemical substances that accelerate reaction rates without affecting the products of the reaction and without being altered or destroyed by the reaction

They reduce the amount of activation energy required for a reaction

Small nonprotein groups which perform their enzymatic functions

Contain groups derived from vitamins, most of which must be supplied in the diet

A major component of ribosomes, provides the activation energy that enables amino acids to assemble into polypeptide chains during the process of translation

The molecule whose reaction it catalyzes

Formed during the binding of enzyme to substrate, in which the substrate is secured by covalent bonds to one or more points in the active site of the enzyme

Breaking with water

A molecule is cleaved by the addition of water at the cleavage site

Subunits of molecules are linked together by removal of water

The final end product of a particular metabolic pathway inhibits the first enzyme in the pathway

Involves a transfer of electrons from an electron donor (the reducing agent) to an electron acceptor (the oxidizing agent)

Organisms that cannot synthesize their own food but must obtain nutrients from the environment, including animals, fungi, and many single-celled organisms

Those that use molecular oxygen as the final electron acceptor

Those that employ another molecule as the final electron acceptor

The oxidation of fuel molecules to produce energy with molecular oxygen as the final electron acceptor

describes the removal of electrons from fuel molecules and not the direct combination of molecular oxygen with fuel molecules

Uses oxygen as the final electron acceptor and releases carbon dioxide and water from the complete oxidation of fuels

A British biochemist who described three stages in the complete oxidation of fuel molecules to carbon dioxide and water

Food passing through the intestinal tract is digested into small molecules that can be absorbed into the circulation

Also called glycolysis, most of the glucose is converted into two 3-carbon units (pyruvic acid) in the cell cytoplasm

The final oxidation of fuel molecules occurs, with a large yield of ATP

Also known as citric acid cycle and tricarboxylic acid cycle

Are especially rich depots of metabolic energy because the fatty acids of which they are composed are highly reduced and free of water

Are degraded by sequential removal of 2-carbon units, which enter the Krebs cycle through acetyl-CoA

the amino group splits to form ammonia and a keto acid

the amino group is transferred to a keto acid to yield a new amino acid