Catalysts
________: Chemical substances that accelerate reaction rates without affecting the products of the reaction and without being altered or destroyed by the reaction.
Troponin
________ requires calcium to perform its function.
Metabolic processes
________ must occur at biologically acceptable temperatures, which are too low for life.
Anaerobes
________: Those that employ another molecule as the final electron acceptor.
Cellular metabolism
________: Refers to the collective chemical processes that occur within living cells to accomplish these activities.
Aerobes
________: Those that use molecular oxygen as the final electron acceptor.
hydrogen atom
A(n) ________ is attached to one subunit and a hydroxyl- (OH) unit is attached to another.
Heterotrophs
________: Organisms that can not synthesize their own food but must obtain nutrients from the environment, including animals, fungi, and many single- celled organisms.
Cellular respiration
________: The oxidation of fuel molecules to produce energy with molecular oxygen as the final electron acceptor.
Hans Krebs
________: A British biochemist who described three stages in the complete oxidation of fuel molecules to carbon dioxide and water.
Second law of thermodynamics
________: States that a closed system moves toward increasing disorder, or entropy, as energy is dissipated from the system.
Aerobic cellular respiration
________: Uses oxygen as the final electron acceptor and releases carbon dioxide and water from the complete oxidation of fuels.
Nicotinamide adenine dinucleotide
________ (NAD) contains the vitamin** nicotinic acid** (niacin)
law of thermodynamics
First ________: States that energy can not be created or destroyed.
Mechanisms
________ exist for critically regulating enzymes in both quantity and activity.
vertebrates
Among ________, amphibians and especially mammals produce mainly urea.
α ketoglutaric
It is highly toxic because it inhibits respiration by reacting with ________ acid to form glutamic acid, and effectively removes ________ from the Krebs cycle.
Triglycerides
________ (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.
Coenzymes
________: Contain groups derived from vitamins, most of which must be supplied in the diet.
Cytochromes
________ contain iron.
Endergonic
________: Reactions in cells that require the addition of free energy.
Reptiles
________ and birds, as well as many terrestrial invertebrates, produce mainly uric acid.
Enzymes
________: They reduce the amount of activation energy required for a reaction.
Cofactors
________: Small nonprotein groups which perform their enzymatic functions.
Terrestrial animals
________ can not get rid of ammonia so conveniently and must detoxify it by converting it to a relatively nontoxic compound; urea and uric acid.
Deamination
________: the amino group splits to form ammonia and a keto acid.
Condensation
________: Subunits of molecules are linked together by removal of water.
Oxidation reduction redox reaction
________: Involves a transfer of electrons from an electron donor (the reducing agent) to an electron acceptor (the oxidizing agent)
nitrogen atoms
Once ________ are removed, the carbon skeletons of amino acids can be completely oxidized, usually by way of pyruvic acid or acetic acid.
Acetyl CoA
________ is channeled into the Krebs cycle, where the acetyl group is completely oxidized to carbon dioxide.
Stage II
________: Also called glycolysis, most of the glucose is converted into two 3- carbon units (pyruvic acid) in the cell cytoplasm.
Carbonic anhydrase
________ contains zinc.
Transamination
________: the amino group is transferred to a keto acid to yield a new amino acid.
digestive tract
When animals eat proteins, most are digested in the ________, releasing their constituent amino acids, which are then absorbed.
Hydrolysis reaction
________: A molecule is cleaved by the addition of water at the cleavage site.
Feedback inhibition
________: The final end product of a particular metabolic pathway inhibits the first enzyme in the pathway.
Ribosomal RNA
________: A major component of ribosomes, provides the activation energy that enables amino acids to assemble into polypeptide chains during the process of translation.
Hydrolysis
________: Breaking with water.
central purpose of carbohydrate
The ________ and fat metabolism is to provide energy, much of which is needed to construct and maintain cellular structure and metabolic processes.
Stage III
________: The final oxidation of fuel molecules occurs, with a large yield of ATP.
enzyme acts
If a(n) ________ reversibly, either synthesis or degradation may result.
Fatty acids
________: Are degraded by sequential removal of 2- carbon units, which enter the Krebs cycle through acetyl- CoA.
Coenzyme
________ A contains the vitamin pantothenic acid.
Cellular metabolism
Refers to the collective chemical processes that occur within living cells to accomplish these activities
Potential energy
It is stored energy
Kinetic energy
Energy of motion
First law of thermodynamics
States that energy cannot be created or destroyed
Second law of thermodynamics
States that a closed system moves toward increasing disorder, or entropy, as energy is dissipated from the system
Free energy
The energy in a system available for doing work
Exergonic
Reactions in cells release free energy
Endergonic
Reactions in cells that require the addition of free energy
Activation energy
This must be supplied before the bond is stressed enough to break
Catalysts
Chemical substances that accelerate reaction rates without affecting the products of the reaction and without being altered or destroyed by the reaction
Enzymes
They reduce the amount of activation energy required for a reaction
Cofactors
Small nonprotein groups which perform their enzymatic functions
Coenzymes
Contain groups derived from vitamins, most of which must be supplied in the diet
Ribosomal RNA
A major component of ribosomes, provides the activation energy that enables amino acids to assemble into polypeptide chains during the process of translation
Substrate
The molecule whose reaction it catalyzes
Enzyme-substrate complex (ES complex)
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
Hydrolysis
Breaking with water
Hydrolysis reaction
A molecule is cleaved by the addition of water at the cleavage site
Condensation
Subunits of molecules are linked together by removal of water
Feedback inhibition
The final end product of a particular metabolic pathway inhibits the first enzyme in the pathway
Oxidation-reduction "redox" reaction
Involves a transfer of electrons from an electron donor (the reducing agent) to an electron acceptor (the oxidizing agent)
Heterotrophs
Organisms that cannot synthesize their own food but must obtain nutrients from the environment, including animals, fungi, and many single-celled organisms
Aerobes
Those that use molecular oxygen as the final electron acceptor
Anaerobes
Those that employ another molecule as the final electron acceptor
Cellular respiration
The oxidation of fuel molecules to produce energy with molecular oxygen as the final electron acceptor
Oxidation of fuel molecules
describes the removal of electrons from fuel molecules and not the direct combination of molecular oxygen with fuel molecules
Aerobic cellular respiration
Uses oxygen as the final electron acceptor and releases carbon dioxide and water from the complete oxidation of fuels
Hans Krebs
A British biochemist who described three stages in the complete oxidation of fuel molecules to carbon dioxide and water
Stage I
Food passing through the intestinal tract is digested into small molecules that can be absorbed into the circulation
Stage II
Also called glycolysis, most of the glucose is converted into two 3-carbon units (pyruvic acid) in the cell cytoplasm
Stage III
The final oxidation of fuel molecules occurs, with a large yield of ATP
Krebs cycle
Also known as citric acid cycle and tricarboxylic acid cycle
Triglycerides (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
Fatty acids
Are degraded by sequential removal of 2-carbon units, which enter the Krebs cycle through acetyl-CoA
Deamination
the amino group splits to form ammonia and a keto acid
Transamination
the amino group is transferred to a keto acid to yield a new amino acid