LECTURE 28: basics of metabolism

anabolic

energy-requiring pathways that use ATP and other useful energy and smaller molecules to make larger, more complex molecules.

ATP, AMP

pyrophosphate formed as a byproduct of _____-->______

Stage II

small molecules are run through metabolic pathways to get key intermediates such as acetyl CoA and pyruvate

coenzymes

the B vitamins function as _________, which facilitate catalysis.

more, more

the _________ reduced a carbon atom is, the _________ free energy is released upon oxidation

energy status

the __________ __________ of the cell is often an important regulator of enzyme activity. energy charge and phosphorylation potential can be used to asses this.

CO2, H2O

the carbon atoms in fuels are oxidized to yield ________, and electrons are ultimately accepted by oxygen to form _________.

ATP

the energy currency of life

substrate-level phosphorylation

the energy of oxidation is initially trapped as a high-phosphoryl-transfer-potential compound and then used to form ATP

mitochondria

the harvesting of energy from a proton gradient to generate ATP occurs inside the __________.

exergonic, phosphoanhydride

the hydrolysis of ATP is __________ because the triphosphate unit has 2 ______________ bonds that are unstable.

out

the oxidation of fuels pumps protons ________ of the proton gradient

transcription

the quantity of enzyme present can be regulated at the level of gene _________.

phosphoryl-transfer potential

the standard free energy of hydrolysis. a means of comparing the tendency of organic molecules to transfer a phosphoryl group to an acceptor molecule

thioester

transfer of the acyl group is highly exergonic because the ____________ is unstable.

group-transfer

_______________ reactions transfer a functional group from one molecule to another. seen a lot with ATP

phosphoanhydride

_________________ bonds are very unstable

stoichiometric

___________________ coenzymes are used up. new source outside of the enzyme will regenerate them

CoA

acyl carrier derived from vitamin B5. activated carrier of acyl groups, such as acetyl group.

creatine phosphate

an energy reserve in our muscle. has high energy bond between N and P. transfers phosphate onto ADP that we generate, making more ATP that we can use

NAD+

carries activated electrons derived from the oxidation of fuels. oxidant. removes 2 H from carbons.

lower

compounds with a _________ phosphoryl-transfer potential than ATP are phosphorylated by ATP during metabolism

higher

compounds with a _________ phosphoryl-transfer potential than ATP are used to power ATP synthesis

flux

controlling the __________ of substrates between compartments is used to regulate metabolism

ion gradients

couple endergonic reactions with exergonic reactions by providing an important form of cellular energy that can be coupled to ATP synthesis.

nicotinamide

derived from niacin. electron acceptor and donor in NAD+

Stage I

digestion. large molecules in food (lipids, proteins, etc.) are broken down to small monomeric units. favorable reaction

catabolism

during _______, NAD is used to make NADH, which generates ATP with oxidative phosphorylation

NAD(P)H

electron carrier derived from niacin (vit B3)

FAD(H2)

electron carrier derived from riboflavin (vit B2). contains 2 reactive sites. is a catalytic coenzyme. generates/breaks double bonds

oxidation

ATP can be formed by the ____________ of carbon fuels

A

ATP forms when protons flow through an ATP-synthesizing enzyme A. true B. false

oxidative phosphorylation

ATP generation as a result of oxidation of fuels producing a proton gradient which drives ADP phosphorylation

high

ATP has a ________ phosphoryl-transfer potential because of resonance stabilization, electrostatic repulsion, increase in entropy, and stabilization by hydration.

E

ATP has a high phosphoryl group transfer potential because: A. it is chemically unstable B. it has a high rate of spontaneous hydrolysis at physiological pH and temperature C. it exhibits resonance stabilization prior to hydrolysis D. it has 3 phosphate groups E. cleavage of either of its 2 phosphoanhydride bonds proceeds with a large negative delta G of hydrolysis

The processes are coupled to the dephosphorylation of ATP = the endergonic reaction forming glucose‑6‑phosphate de novo (from scratch) anabolism of nucleotides myosin action during muscle contraction One reason that ATP is a source of energy is that the products of ATP hydrolysis have less free energy than the reactants because: electrostatic repulsion in ATP resonance stabilization of free phosphate

ATP is a source of free energy that drives unfavorable reactions. Which of the processes are coupled to the dephosphorylation of ATP? ion transport with the concentration gradient the endergonic reaction forming glucose‑6‑phosphate de novo (from scratch) anabolism of nucleotides reversible isomerization of glucose‑6‑phosphate to fructose‑6‑phosphate during glucose catabolism myosin action during muscle contraction One reason that ATP is a source of energy is that the products of ATP hydrolysis have less free energy than the reactants. Why? electrostatic repulsion in ATP formation of ion pairs involving ATP hydrogen bonding between free phosphate and water resonance stabilization of free phosphate

phosphate

ATP wants to get rid of ______________ very badly so that it will be more stable.

Thioesters: the sulfur-carbon bond is hydrolyzed acetyl-CoA Reduced Cofactors: These compounds accept electrons during the oxidation of substrates. Energy is released when they are oxidized. ubiquinol Phosphorylated compounds these compounds yield HPO2−4 upon hydrolysis guanosine triphosphate Thioesters contain a A carbon atom is double bonded to an oxygen atom and single bonded to an S atom and an R group. The S atom is also bounded to an R group. group. The bond between the carbonyl carbon atom and the sulfur atom is broken during hydrolysis, and free energy is released. Coenzyme A is a thioester. Cofactors, such as NAD+, FAD, and ubiquinone (coenzyme Q), accept electrons and hydrogen, forming the reduced cofactors NADH, FADH2, and ubiquinol, respectively, that store free energy from the oxidation of substrates. Phosphorylated compounds contain phosphate groups. Large amounts of free energy are generated by hydrolysis, which results in the cleavage of HPO2−4. Phosphocreatine, guanosine triphosphate (GTP), phosphoenolpyruvate, and 1,3-bisphosphoglycerate contain phosphate groups.

Adenosine triphosphate (ATP) is the main energy currency used in cells. ATP hydrolysis is coupled with unfavorable reactions, making the net change in energy for the set of reactions less than 0, which is favorable. Although ATP is the main energy currency, other molecules can fulfill this role and take part in coupled reactions. Determine whether each of the phrases or examples describes a thioester, reduced cofactor, or phosphorylated compound. Answer Bank: These compounds accept electrons during the oxidation of substrates. Energy is released when they are oxidized. these compounds yield HPO2−4 upon hydrolysis the sulfur-carbon bond is hydrolyzed ubiquinol acetyl-CoA guanosine triphosphate

ribose adenine phosphate ATP is the abbreviation for adenosine triphosphate. The name indicates that ATP consists of adenosine joined to three phosphate groups. Adenosine consists of the base adenine bound to a ribose ring. Adenine is a purine base and contains two fused rings. NAD is the abbreviation for nicotinamide adenine dinucleotide. NAD contains two nitrogenous bases, nicotinamide and adenine, joined by two phosphate groups. Nicotinamide is a pyridine base with an amide group. As their names suggest, both ATP and NAD contain adenine, ribose, and phosphate. Only NAD contains nicotinamide. Neither molecule contains deoxyribose, which is a component of DNA nucleotides

Although ATP is the main energy currency in cells, other molecules, such as NAD, play a central role in some metabolic pathways by transferring electrons. The oxidized form of NAD is NAD+, and the reduced form is NADH. Identify the components of NAD+ and ATP Answer Bank: adenine nicotinamide ribose phosphate deoxyribose Select the components that are common to both ATP and NAD. nicotinamide deoxyribose ribose adenine phosphate

3

energy from foodstuffs is extracted in ____ stages.

In oxidation-reduction reactions, there is a transfer of electrons between molecules. The reducing agent is often NADH or FADH2. In isomerization reactions, the atoms of a molecule are rearranged. These reactions often prepare molecules for further reactions, such as oxidation-reduction reactions or decarboxylation reactions. Group transfer reactions involve the transfer of a functional group from one molecule to another. Often the group being transferred is a phosphoryl group. These reactions can generate high-energy molecules, such as ATP and GTP.

Classify each metabolic reaction as an oxidation-reduction reaction, isomerization reaction, or group transfer reaction.

True: If something is oxidized, it is formally losing electrons. If there are no changes in the oxidation state of the reactants or products of a particular reaction, that reaction is not a redox reaction. Oxidizing agents can convert into CO2. A reducing agent gets oxidized as it reacts. False: In the redox reaction Fe3+ + Co2+ ⟶ Fe2++ Co3+ is the reducing agent and Co2+ is the oxidizing agent. If something is reduced, it is formally losing electrons. An oxidation-reduction, also called redox reaction, is a type of chemical reaction that involves the transfer of electrons between two chemical species. In an oxidation-reduction reaction, one species is oxidized and the other is reduced. The chemical species that loses electrons is oxidized. This species is called the reducing agent, because the other species in the redox reaction accepts the lost electrons. Conversely, the species that accepts the lost electrons is reduced. This species is called the oxidizing agent, since the other species in the redox reaction is oxidized. The oxidation state of the reducing agent increases, because it loses electrons. The oxidation state of the oxidizing agent decreases, because it gains electrons. A redox reaction can be identified by these changes in oxidation state. In the reaction Fe3++Co2+⟶Fe2++Co3+, iron decreases in oxidation state from +3 to +2 and cobalt increases in oxidation state from +2 to +3. Since the oxidation state of iron decreases and the oxidation of cobalt increases, iron is the oxidizing agent and cobalt is the reducing agent. Carbon monoxide, CO, has a triple bond between the carbon and oxygen atoms. In CO, the oxidation state of carbon is +2. Carbon dioxide, CO2, has double bonds between carbon and the two oxygen atoms. In CO2, the oxidation state of carbon is +4. The oxidation state of carbon increases when CO is converted to CO2, so CO loses electrons and is oxidized by an oxidizing agent.

Classify the statements about redox reactions as true or false. Answer Bank: If something is oxidized, it is formally losing electrons. In the redox reaction Fe3+ + Co2+ ⟶ Fe2++ Co3+ is the reducing agent and Co2+ is the oxidizing agent. If there are no changes in the oxidation state of the reactants or products of a particular reaction, that reaction is not a redox reaction. If something is reduced, it is formally losing electrons. Oxidizing agents can convert into CO2. A reducing agent gets oxidized as it reacts.

NTP hydrolysis

DNA, RNA, and protein synthesis, as well as activation of amino acids and activation of Ub by E1, are driven by _________ _________.

In the second stage, monomers are broken down, and a small amount of ATP is produced In the third stage, fuel molecules are completely oxidized to CO2, and most of the ATP needed for cellular processes is produced. In animals, foodstuffs are completely oxidized in three stages. ATP is produced in two out of three of the stages. The first stage of the oxidation of foodstuffs does not produce ATP. In the first stage, digestion breaks down macromolecules into their monomeric forms. Thus, this stage involves the breakdown of proteins, polysaccharides, and lipids into amino acids, simple sugars, and fatty acids, respectively. The monomers are absorbed by the intestinal cells and distributed to the rest of the body. The second stage of the oxidation of foodstuffs produces a small amount of ATP. In the second stage, the monomers are converted to simple molecules that can be completely oxidized to CO2. The majority of the monomers produced in the first stage of energy extraction are converted to acetyl CoA. The third stage of the oxidation of foodstuffs produces the majority of the ATP used by the cell. In the third stage of energy generation, acetyl CoA is oxidized to CO2 in the citric acid cycle. Electrons from acetyl CoA are transferred to the electron carriers NAD+ and FAD. The reduced electron carriers donate electrons to O2 through the electron transport chain. The energy released from the transfer of electrons to O2 is used to generate a proton gradient, which in turn is used to synthesize ATP.

Energy extraction and the complete oxidation of foodstuffs requires three stages. The energy extracted from fuels is converted to ATP. Select the statements that are true for the different stages required for energy extraction and complete oxidation of foodstuffs. In the third stage, fuel molecules are completely oxidized to CO2, and a small amount of ATP is produced. In the third stage, fuel molecules are completely oxidized to CO2, and most of the ATP needed for cellular processes is produced. In the first and second stages the majority of ATP needed for cellular processes is produced. In the third stage, fuel molecules are completely oxidized to CO2, and no ATP is produced. In the second stage, monomers are broken down, and a small amount of ATP is produced. In the first stage, macromolecules are converted to monomers, and a small amount of ATP is produced.

Ethanol / Acetaldehyde Lactate / Pyruvate Succinct / Fumarate Oxalosuccinate / Isocitrate Maleate / Oxaloacetate The most reduced molecules are ethanol, lactate, succinate, isocitrate, and malate. Reductive biosynthesis is common in many metabolic pathways. Reduction involves a decrease in the oxidation state of a molecule. Reduction causes molecules to gain electrons and often involves the addition of a hydrogen atom with two electrons. Hydroxyl carbons are more reduced than carbonyl carbons. A single carbon-carbon bond is more reduced than a double carbon-carbon bond. Reduction of acetaldehyde yields ethanol. Lactate forms from the reduction of pyruvate. Fumarate becomes succinate after two carbons become reduced. Reduction of oxalosuccinate produces isocitrate. One round of reduction yields malate from oxaloacetate.

Examine the pairs of molecules and identify the more reduced molecule in each pair. Ethanol / Acetaldehyde Lactate / Pyruvate Succinct / Fumarate Oxalosuccinate / Isocitrate Maleate / Oxaloacetate

From which B vitamin is the coenzyme FAD/FADH2 derived? riboflavin From which B vitamin is the coenzyme NAD+/NADH derived? niacin

From which B vitamin is the coenzyme FAD/FADH2 derived? folic acid riboflavin pantiothenic acid cobalamin From which B vitamin is the coenzyme NAD+/NADH derived? niacin thiamin pyridoxamine biotin

ADP, ATP

GAP + NAD+ + HPO42- --> 1,3-BPG + ________ --> 3-phosphoglyceric acid + ________

biosynthesis of more complex molecules active transport cellular movement Cells require a constant input of energy for movement (locomotion and cellular movement), active transport of substances, and the biosynthesis of more complex molecules. ATP hydrolysis is exergonic; it does not require an input of free energy.

How do cells use energy? biosynthesis of more complex molecules active transport cellular movement ATP hydrolysis

charge repulsion increase in entropy stabilization by hydration Consider hydrolysation, the reaction when a nucleoside triphosphate, NTP, transfers its phosphoryl group to water. This results in the formation of a nucleoside diphosphate and an orthophosphate. Phosphoanhydride bonds that hold together phosphoryl groups in NTP are high‑energy bonds because a large amount of energy is released upon their hydrolysis. The amount of energy released in this reaction determines the phosphoryl‑transfer potential of the NTP. Charge repulsion accounts for the high phosphoryl‑transfer potential of NTPs. A molecule of NTP carries four negative charges on its three phosphate groups. These charges repel each other due to their close proximity. Hydrolysation of NTP reduces the number of charges and reduces charge repulsion. Resonance stabilization accounts for the high phosphoryl‑transfer potential of NTPs. An orthophosphate product of the hydrolysation reaction has a higher number of resonance forms than the gamma phosphoryl group in the NTP molecule. This delocalization of charges in orthophosphate reduces the energy of the molecule and stabilizes it. Increase in entropy accounts for the high phosphoryl‑transfer potential of NTPs. NTP hydrolysation produces two molecules from a single NTP molecule. Concentration of water molecules is effectively the same at the end of the reaction. Therefore, entropy or "disorder" of the products is greater than that of the reagents. Stabilization by hydration accounts for the high phosphoryl‑transfer potential of NTPs. Binding of water stabilizes the products of the hydrolysation reaction. This makes synthesis of the NTP molecules less favorable. Decrease in entropy and low standard free energy of hydrolysis do not account for the high phosphoryl‑transfer potential of the NTPs. NTP hydrolysation increases entropy. Standard free energy of NTP hydrolysis is high.

Identify factors that account for the high phosphoryl‑transfer potential of the nucleoside triphosphates, NTPs. decrease in entropy charge repulsion low standard free energy of hydrolysis increase in entropy stabilization by hydration

rearrangement or isomerization or elimination The reactant and the product contain the same number and kind of atoms, but arranged or connected differently.

Identify the most appropriate biochemical reaction type for the given reaction. oxidation-reduction reaction group transfer free radical reaction cleavage or formation of a C−C bond rearrangement or isomerization or elimination

Anabolic process: uses NADPH as the electron carrier requires energy inputs, such as ATP synthesizes macromolecules Catabolic process: breaks down macromolecules uses NAD+ as the electron carrier transforms fuels into cellular energy, such as ATP or ion gradients Metabolic processes can be divided into two general types of reactions: anabolic and catabolic. Anabolic processes, or biosynthetic reactions, involve the synthesis of macromolecules and use cellular energy in the form of ATP. Most anabolic processes are reductive reactions that require an electron donor. This reductive nature is because the final macromolecules have more energy‑containing bonds than the preceding simple molecules and are therefore more reduced. NADPH is the most common electron donor used for reductive biosynthetic reactions. A catabolic process breaks down fuels, such as fats and carbohydrates, to generate ATP. These processes are often oxidation reactions that transfer electrons from fuels to electron carriers such as NAD+, and ultimately to oxygen. The energy released from these oxidation reactions is used to generate ATP. NAD+ is used as an electron carrier mainly in catabolic processes, whereas NADPH is used as an electron donor in anabolic processes.

Match each characteristic to the appropriate process. Anabolic process or Catabolic process Answer Bank: breaks down macromolecules uses NAD+ as the electron carrier synthesizes macromolecules transforms fuels into cellular energy, such as ATP or ion gradients uses NADPH as the electron carrier requires energy inputs, such as ATP

formation of bonds between small organic molecules to form larger organic molecules Biosynthesis reactions are anabolic reactions in which small molecules are joined to form larger organic molecules. Biosynthesis reactions are facilitated by enzymes and use chemical energy, often in the form of adenosine triphosphate (ATP). Examples of biosynthesis reactions include amino acids being joined to form proteins, fatty acids being joined to form triglycerides, monosaccharides being joined to form polysaccharides, and nucleotides being joined to form nucleic acids. Catabolic reactions are the opposite of biosynthesis reactions. In catabolic reactions, large molecules are broken down into smaller materials. Catabolic reactions in the body occur when proteins, triglycerides, polysaccharides, and nucleic acids are broken down into their respective building blocks. The chemical pathways that form ATP all involve catabolic reactions. The exchange of bonds in organic molecules to form different organic molecules describes a rearrangement reaction, rather than a biosynthesis reaction.

Select the statement that best describes a biosynthesis reaction. exchange of bonds within organic molecules to form different organic molecules breakdown of proteins to form amino acids formation of bonds between small organic molecules to form larger organic molecules bonds in a large organic molecule are broken to form smaller organic molecules

ion gradients across membranes.

The energy for the phosphorylation of ADP to ATP can come from either molecules with a higher phosphoryl‑transfer potential or from energy released due to the interaction between molecules. ion gradients across membranes. the energy derived directly from electron carriers giving up electrons. heat.

metabolism

The reactions of energy extraction and energy use

The reaction ATP + H2O ⇌ ADP + Pi proceeds to the right The reaction ATP + glycerol ⇌ glycerol 3 − phosphate + ADP proceeds to the right The reaction ATP + pyruvate ⇌ phosphoenolpyruvate + ADP proceeds to the left The reaction ATP + glucose ⇌ glucose 6 − phosphate + ADP proceeds to the right The standard free energy of hydrolysis, Δ𝐺∘′, is the amount of energy released when a phosphorylated molecule transfers a phosphoryl group to water. The sign on Δ𝐺∘′ indicates the spontaneity of the reaction. A negative value indicates a spontaneous reaction, which is thermodynamically favorable. Conversely, a positive value indicates an unfavorable reaction. The first reaction is the hydrolysis of ATP. According to the table, Δ𝐺∘′ for ATP hydrolysis is −30.5 kJ mol−1. Since Δ𝐺∘′ is negative, the reaction proceeds to the right. When you compare the standard free energies of hydrolysis for two phosphorylated compounds, you are comparing their phosphoryl‑transfer potentials. That is, the greater the magnitude of Δ𝐺∘′, the more likely the compound is to transfer a phosphoryl group. When reactions are coupled, you can determine the direction of a reaction by identifying which side of a reaction equation has the compound with the higher phosphoryl‑transfer potential. The second reaction involves the hydrolysis of ATP and the formation of glycerol 3‑phosphate. If you consider the phosphoryl‑transfer potentials, the Δ𝐺∘′ for ATP hydrolysis, −30.5 kJ mol−1, is more negative than the Δ𝐺∘′ for glycerol 3‑phosphate hydrolysis, −9.2 kJ mol−1. Therefore, ATP is more likely than glycerol 3-phosphate to transfer its phosphoryl group, and the reaction will proceed to the right. Another way to determine the direction of a reaction is to add the standard free energy values of the two reactions. The third reaction is the hydrolysis of ATP and the formation of phosphoenolpyruvate. The Δ𝐺∘′ for ATP hydrolysis is −30.5 kJ mol−1. If Δ𝐺∘′ for the hydrolysis of phosphoenolpyruvate is −61.9 kJ mol−1, then Δ𝐺∘′ for the formation of phosphoenolpyruvate is +61.9 kJ mol−1. Therefore, the standard free energy change for the net reaction is 31.4 kJ mol−1, and the reaction proceeds to the left. Δ𝐺∘′=(−30.5 kJ mol−1)+(61.9 kJ mol−1)=31.4 kJ mol−1 The fourth reaction is the hydrolysis of ATP coupled to the formation of glucose 6‑phosphate. The standard free energy change for the hydrolysis of glucose 6‑phosphate, −13.8 kJ mol−1, is less negative than the standard free energy change for ATP hydrolysis, −30.5 kJ mol−1. Because ATP has the higher phosphoryl‑transfer potential, the reaction will proceed to the right.

The table lists the standard free energies of hydrolysis (Δ𝐺∘′) of some phosphorylated compounds. Compound | 𝐤𝐉 𝐦𝐨𝐥−1 | 𝐤𝐜𝐚𝐥 𝐦𝐨𝐥−1 Phosphoenolpyruvate (PEP) | −61.9 | −14.8 1,3‑Bisphosphoglycerate (1,3‑BPG) | −49.4 | −11.8 Creatine phosphate | −43.1 | −10.3 ATP (to ADP) | −30.5 | −7.3 Glucose 1‑phosphate |−20.9 | −5.0 Pyrophosphate (PPi) | −19.3 | −4.6 Glucose 6‑phosphate | −13.8 | −3.3 Glycerol 3‑phosphate | −9.2 | −2.2 What is the direction of each of the following reactions when the reactants are initially present in equimolar amounts? The reaction ATP + H2O ⇌ ADP + Pi ________ The reaction ATP + glycerol ⇌ glycerol 3 − phosphate + ADP __________ The reaction ATP + pyruvate ⇌ phosphoenolpyruvate + ADP __________ The reaction ATP + glucose ⇌ glucose 6 − phosphate + ADP _______________

hormones

_____________ coordinate metabolic activity, often by instigating the covalent modification of allosteric enzymes.

catalytic

______________ coenzymes link with the enzyme and are immediately regenerated before a new cycle happens

hydrolytic

______________ reactions involve the cleavage of bonds by the addition of water. catalyzed by hydrolases or hydratases. create 2 different peptides.

isomerization

______________ reactions involve the rearrangement of atoms to form isomers. catalyzed by isomerases. often prepare the molecule for redox reaction.

regulating substrate accessibility controlling the amount of enzymes present altering the catalytic activity of enzymes Cellular metabolic processes produce and utilize energy and synthesize and degrade macromolecules. Metabolism is tightly regulated to support the proper function of a cell. Transcriptional regulation controls the amount of enzyme present. The cell conserves the resources needed to synthesize an enzyme if the enzyme is not necessary. A cell can increase the transcription of an enzyme when environmental cues signal a need for it. Altering the catalytic activity of an enzyme, such as by feedback inhibition, allows a cell to rapidly respond to metabolic needs. Inhibition reduces catalytic activity, whereas stimulation increases activity. Compartmentalization regulates substrate accessibility. Regulating substrate availability prevents the futile cycling of anabolic and catabolic processes. A cell does not regulate its metabolism by changing the concentrations of substrates. Metabolic substrates generally exist in a dynamic steady state, meaning that a substrate is generally provided at the same rate that it is used. Substrate concentration does not change significantly. Enzymes are not regulated indirectly by restricting access to cofactors. Direct regulation enables a cell to rapidly change enzymatic activity to meet metabolic demands.

Which strategies do cells use to regulate metabolic processes? regulating substrate accessibility changing the concentration of substrates controlling the amount of enzymes present restricting access to enzyme cofactors altering the catalytic activity of enzymes

Hydrolysis of ATP: ATP+H2O⟶ADP+Pi Hydrolysis of ADP: ADP+H2O⟶AMP+Pi Hydrolysis is a reaction in which a large molecule is split into two smaller molecules upon the addition of water, H2O. When hydrolyzed, ATP, which has three phosphate groups, is split into ADP which has two phosphate groups, and inorganic phosphate (Pi). ATP+H2O⟶ADP+Pi The hydrolysis of ADP, which has two phosphate groups, yields adenosine monophosphate, AMP, which has one phosphate group, and inorganic phosphate. ADP+H2O⟶AMP+Pi

Write equations for the hydrolysis of ATP and ADP. Use abbreviations such as ATP for adenosine triphosphate and Pi to represent inorganic phosphate. hydrolysis of ATP: ⟶ ______________ hydrolysis of ADP: ⟶ _____________

ATP hydrolysis

_____ _________ is often used to drive unfavorable reactions

catabolic

_______ pathways combust carbon fuels to synthesize ATP. these are energy-yielding degrading pathways.

reduced, reductive biosynthesis

__________ NADH (NADPH) carries activated electrons in the same manner as NADH, but is used almost exclusively for _____________ ______________.

phosphate

__________ is the anabolic tag in NADPH

lyase

__________ reactions either add or remove functional groups, often involving formation of/removal of double bonds. 1. carbon bonds cleaved by means other than hydrolysis or oxidation, with 2 substrates yielding one product, or vice versa 2. functional groups removed from single bonds to form double bonds

redox

__________ reactions involve electron transfer. oxidation of molecules results in production of reduced cofactors. catalyzed by oxidoreductases usually with the name dehydrogenase in the enzyme.

catalytic activity

____________ ___________ is regulated allosterically or by covalent modification

ligation

____________ reactions involve the formation of covalent bonds using ATP. catalyzed by ligases.

reduced

fats are a more efficient food source than glucose because fats are more _________.

ATP, AMP

harder reactions use _______-->_______

activated carrier

harvest the energy of very favorable reactions and put it on something to then drive unenergetically favorable reactions.

A

in cells, NAD(P)H serves as a carrier of which of the following? A. electrons B. acetyl groups C. hydroxyl groups D. methyl groups E. phosphoryl groups

homeostasis

in metabolic pathways, we want to maintain ___________. we can do this by controlling amounts of enzymes, catalytic activity, and accessibility of substrates.

specific, thermodynamically

in order to construct a metabolic pathway, 2 criteria must be met: 1. the individual reactions must be _________. 2. the pathway in total must be ___________________ favorable.

ATP, ADP

inorganic phosphate formed as a byproduct of ________-->_________

Stage III

key intermediates are taken to mitochondria where oxidative phosphorylation and citric acid cycle generates lots of ATP

activated carriers, enzymatic reactions, regulatory strategies

metabolic pathways all have common ________ ___________, ___________ ___________, and ___________ ____________.

highly

metabolic pathways are ___________ regulated

metabolic pathways

molecules are degraded or synthesized stepwise in a series of reactions termed ___________

nucleotide triphosphates

other ________ _________ can be used to drive some biosynthetic reactions. these are called "ATP equivalents"

B

which of the following best characterizes NADH and NADPH? A. NADH and NADPH are interchangeable used for both ATP generation and biosynthesis B. NADH is primarily used for ATP generation whereas NADPH is primarily used for biosynthesis C. NADPH is primarily used for ATP generation whereas NADH is primarily used for biosynthesis D. both ATP generation and biosynthesis preferentially use NADH over NADPH

E

which of the following can be used as a metabolic control mechanism? A. enzyme compartmentalization B. action of hormones C. covalent modification of an enzyme D. regulation of enzyme degradation E. all of the above

A

which of the following supplies the necessary free energy to help drive DNA (and RNA) synthesis? A. release and subsequent splitting of two phosphate groups from a dNTP molecule B. release of a single phosphate group from a dNTP molecule C. release of a triphosphate group from a dNTP molecule D. release of a single phosphate group from a dNDP molecule