Unit 3: Cellular Energetics

What is the meaning of glycolysis? What occurs in this step of cellular respiration?

-"sugar splitting" -occurs in cytosol, breaks 1 glucose into 2 pyruvate

Oxidative phosphorylation

-1) electron transport chain: electron transport & pumping of protons (H+), which create an H+ gradient across the membrane -2) chemiomsosis: ATP synthesis powered by the flow of H+ back across the membrane

Glycolysis is thought to have evolved very early in the evolution of life on Earth. Provide three pieces of evidence that justify this hypothesis.

-1) glycolysis is the most widespread metabolic process -2) cytosolic location, cytosol is in every cell -3) pathway doesn't need any membrane bound organelles

Use two key difference to explain how chemiosmosis is different in photosynthesis & cellular respiration.

-1) in chloroplasts the high-energy electrons dropped down the transport chain come from water, while in the mitochondria they are extracted from organic molecules (which are thus oxidized) -2) chloroplasts don't need molecules from food to make ATP -mitochondria use chemiosmosis to transfer chemical energy from food molecules to ATP -chloroplasts transform lighter energy into chemical energy in ATP

Describe four ways that chemiosmosis is similar in photosynthesis & cellular respiration.

-1) in photosynthesis and cellular respiration, an ETC assembled in a membrane pumps protons across the membrane as electrons are passed through a series of carriers that are progressively more electronegative -2) in photosynthesis and cellular respiration, ATP synthase complex couples the diffusion of hydrogen ions down their gradient to the phosphorylation of ADP -3) inner membrane of the mitochondrion pumps protons from the mitochondrial matrix out to the intermembrane space, which then serves as a reservoir of hydrogen ions, thylakoid membrane of the chloroplast pumps protons from the stroma into the thylakoid space, which functions as the H+ reservoir -4) in mitochondrion, protons diffuse down their concentration gradient from the intermembrane space through ATP synthase to the matrix, driving ATP synthesis, in chloroplast, ATP is synthesized as the hydrogen ions diffuse from the thylakoid space back to the stroma through ATP synthase complexes, whose catalytic knobs are on the stroma side of the membrane

Electron transport involves a series of electron carriers. 1) Where are these found in eukaryotic cells? ____________________________ 2) Where are these found in respiring prokaryotic cells? _______________

-1) inner membrane of mitochondria -2) plasma membrane

Explain the 3 steps in the conversion of pyruvate to acetyl CoA.

-1) pyruvate's carboxyl group (-COO-), which is already fully oxidized & thus has little chemical energy, is removed & given off as a molecule of CO2 -2) the remaining 2-carbon fragment is oxidized, forming acetate (CH3COO-), the extracted electrons are transferred to NAD+, storing energy in the form of NADH -3) coenzyme A (CoA), a sulfur-containing compound derived from a B vitamin, is attached via its sulfur atom to the acetate, forming acetyl CoA (which has high potential energy)

List three places in the light reactions where a proton-motive force is generated.

-1) water is split by PSII on the side of the membrane facing the thylakoid space -2) as plastoquinone (Pq) transfers electrons to the cytochrome complex, 4 protons are translocatedacross the membrane into the thylakoid space -3) a hydrogen ion is removed from the stroma when it is take up by NADP+

The Calvin cycle produces one net G3P. That means the Calvin cycle must be turned three times. Each turn will require a starting molecule of RuBP, a 5-carbon compound. This means we start with _____ carbons distributed in 3 RuBPs. After fixing 3 molecules of CO2 using the enzyme _________________, the Calvin cycle forms _____ G3Ps with a total of _____ carbons. At this point the net gain of carbons is _______. or one net G3P.

-15 -rubisco -6 -18 -3

Add the ATPs formed by the substrate-level phosphorylation in glycolysis & the citric acid cycle to the ATPs formed by chemiosmosis. Each NADH can form a maximum of _________ ATP molecules. Each FADH2, which donates electrons that activate only two proton pumps, make ______________ ATP molecules.

-3 -3

Some of the types of energy in the electromagnetic spectrum will be familiar, such as X-rays, microwaves, and radio waves. The most important part of the spectrum in photosynthesis is visible light. What are the colors of the visible spectrum?

-380 nm to 750 nm -violet, indigo, blue, green, yellow, red

Why can extremes of pH or very high temperatures affect enzyme activity?

-3D structures of proteins are sensitive to their environment -as a consequence, each enzyme works better under some conditions than other conditions, because these optimal conditions favor the most active shape for their enzyme molecule

Use both chemical symbols & words to write out the formula for photosynthesis.

-6CO2 + 6H2O + light energy --> C6H12O6 + 6O2 -CO2 reacts with water and energy from the sun to produce glucose and O2 -photosynthesis is another example of a redox reaction where CO2 is reduced to glucose and water is oxidized to O2 -electrons increase in potential energy as they move from water to sugar (endergonic)

The net production of one G3P requires __________ molecules of ATP & _________________ molecules of NADPH.

-9 -6

To summarize, note that the light reactions store chemical energy in _________ & ________________, which shuttle the energy to the carbohydrate-producing ____________ cycle.

-ATP -NADPH -Calvin

Explain the important events that occur in the carbon fixation stage of the Calvin cycle.

-Calvin cycle incorporates each CO2 molecule, one at a time by attaching a 5-carbon sugar called RuBP -enzyme that catalyses this first step is rubisco -product of the reaction is a 6-csarbon intermediate that is short lived bc it so energetically unstable that it immediately splits in half forming 2 molecules of 3-phophoglycerate

Describe how Engelmann was able to form an action spectrum long before the invention of a spectrophotometer.

-Englemann illuminated a filament of algae through different wavelengths of light, then aerobic bacteria were used to see where they would clump the most (clump= O2 released)

In this reduction stage, the low-energy acid 1, 3-biphophoglcerate is reduced by electrons from NADPH to form the 3-carbon sugar _______________________.

-G3P

The carbohydrate produced directly from the Calvin cycle isn't glucose, but the 3-carbon compound _______________. Each turn of the Calvin cycle fixes 1 molecule of CO2; therefore it will take ____ turns of the Calvin cycle to net one G3P.

-G3P -3

Explain the overall concept of how ATP synthase uses the flow of hydrogen ions to produce ATP.

-H+ ions flow down their gradient and enter binding sites within a rotor, changing the shape of each subunit so that the rotor spins within the membrane, before leaving the rotor and passing through a second half channel into the mitochondrial matrix -the spinning of the rotor causes an internal rod to spin, activating catalytic sites in the knob that produce ATP

Oxygen stabilize the electrons by combing with two hydrogen ions to form what compound?

-H2O (water)

In cellular respiration, electrons are not transferred directly from glucose to oxygen. Following the movement of hydrogen allows you to follow the flow of electrons. What electron carrier is transferred to first?

-NAD+

Are NAD+ and NADH: -oxidized or reduced? -higher energy or lower energy?

-NAD+ is oxidized, lower energy -NADH is reduced, higher energy

The step that converts pyruvate to acetyl CoA at the top of the diagram occurs twice per glucose. This oxidation of pyruvate accounts for two additional reduced __________ molecules & two molecules of CO2.

-NADH

What are the two electron carrier molecules that feed electrons into the electron transport system?

-NADH -FADH2

In phase 2, the reduction state, what molecule will donate electrons, & therefore is the source of reducing power? ____________

-NADPH

Cyclic Electron Flow is thought to be similar to the first forms of photosynthesis to evolve. In cyclic electron flow no water is split, there is no production of ________________________, & there is no release of _____________________.

-NADPH -oxygen

Photosystem II (PSII) has at its reaction center a special pair of chlorophyll a molecules called P680. What is the explanation for this name?

-P680 is best at absorbing light that has a wavelength of 680 nm (red)

What is the name of the chlorophyll a reaction center of PS I?

-P700

Formula of a redox reaction: Xe- + Y --> X + Ye- Draw an arrow showing which components (X or Y) is oxidized & which is reduced. ______________ is the reducing agent in this reaction, & ____________ is the oxidizing agent.

-Xe- -Y

What is a catalyst?

-a chemical agent that speeds up a reaction without being consumed by the reaction

Use the image to help answer questions about the citric acid cycle. a) How many NADHs are formed? b) How many total carbons are lost as pyruvate is oxidized? c) The carbons are lost in which molecule? d) How many FADH2 are formed? e) How many ATPs are formed? f) How many times does the citric acid cycle occur for each molecule of glucose?

-a) 3 -b) 2 -c) CO2 -d) 1 -e) 1 -f) twice

These questions deal with linear electron flow. a) What is the source of energy that excites the electron in PSII? b) What compound is the source of electrons for linear electron flow? c) What is the source of O2 in the atmosphere? d) As electrons fall from PSII to PSI, the cytochrome complex uses the energy to pump ____________ ions. This builds a proton gradient that is used in chemiosmosis to produce what molecule? ______________ e) In PSI, NADP+ reductase catalyses the transfer of the excited electron & H+ to NADP+ to form __________________.

-a) light -b) H2O -c) H2O -d) hydrogen, ATP -e) NADPH

There are two types of reactions in metabolic pathways: anabolic & catabolic a. Which reactions release energy? b. Which reactions consume energy? c. Which reactions build up larger molecules? d. Which reactions break down molecules? e. Which reactions are considered "uphill"? f. What type of reaction in photosynthesis? g. What type of reaction is cellular respiration? h. Which reactions require enzymes to catalyze reactions?

-a. catabolic -b. anabolic -c. anabolic -d. catabolic -e. anabolic -f. anabolic -g. catabolic -h. catabolic & anabolic

List the three main kinds of work that a cell does. Give an example of each.

-a. chemical work: the pushing of endergonic reactions that wouldn't occur spontaneously (ex: synthesis of polymers from monomers) -b. transport work: the pumping of substances across membranes against the direction of spontaneous movement (ex: sodium potassium pump) -c. mechanical work: such as the beating of cilia, the contraction of muscle cells, & the movement of chromosomes during cellular reproduction

Many factors can affect the rate of enzyme action. a. initial concentration of substrate b. pH c. temperature

-a. initial concentration of substrate: more substrate = more frequently collide with enzyme (however the enzyme can become the limiting factor) -b. pH: straying to far away from the optimum pH will disrupt bonds in enzymes -c. temperature: straying to far the the optimum T will disrupt bonds in enzymes

Label Ea on the graph "Progress of the reaction", both with & without an enzyme. a. What effect does an enzyme have on Ea? b. Label ∆G. Is it positive or negative? c. How is ∆G affected by the enzyme?

-a. it lowers the Ea -b. ∆G is negative -c. ∆G isn't affected by the enzyme, the enzyme only affects Ea

a. When the terminal phosphate bond is broken, a molecule of inorganic phosphate Pi is formed, & energy is ____________________. b. For this reaction: ATP --> ADP + Pi, ∆G= __________________. c. Is this reaction endergonic or exergonic ?

-a. released -b. -7.3 kcal/mol -c. exergonic

Label this figure while you define the following terms: a. substrate b. enzyme c. active site d. products

-a. substrate: reactant that binds to the enzyme -b. enzyme: biological molecules that catalyses chemical reactions, lowers the Ea -c. active site: enzyme's catalytic site where the substance fits & where chemical reactions take place -d. products: material resulting from a chemical reaction

Study the "Feedback inhibition in isoleucine synthesis" a. What is the substrate molecule that initiates this metabolic pathway? b. What is the inhibitor molecule? c. What type of inhibitor is it? d. When does it have the most significant regulatory effect? e. What is this type of metabolic control called?

-a. threonine -b. isoleucine -c. noncompetitive -d. when it binds to an allosteric site -e. feedback inhibition

Enzymes use a variety of mechanism to lower activation energy. Describe four of these mechanisms.

-a. when there are 2 or more reactants, the active site provides a template on which the substrates can come together in the proper orientation for a reaction to occur between them -b. as the active site of an enzyme clutches the bound substrates, the enzyme may stretch the substrate molecules toward their transition-state form, stressing & bending critical chemical bonds that must be broken during the reaction (Ea is proportional to the difficulty of breaking bonds) -c. the active site may also provide a microenvironment that is more conductive to a particular type of reaction that the solution itself would be without the enzyme -d. direct participation of the active site in the chemical reaction is another mechanism of catalysis

Explain the relationship between absorption spectrum & an action spectrum.

-absorption: provide clues to the relative effectiveness of different wavelengths for driving photosynthesis -action: profiles the relative effectiveness of different wavelengths of radiation in driving the process -action spectrum shows that the chlorophylls in the absorption spectrum are most important bc they correlate closest to the action spectrum

What is activation energy (Ea) ?

-amount of energy that reactants must absorb before a chemical reaction can start

Define the terms autotroph & heterotroph.

-autotroph: "self-feeders", sustain themselves without eating anything derived from other living beings -heterotroph: unable to make their own food, they live on compounds produced by other organisms

Explain why oxygen is considered the ultimate electron acceptor.

-bc it is very electronegative

Explain the difference between an allosteric activator & an allosteric inhibitor.

-binding of activator to regulatory site stabilizes the shape that has functional active sites -binding of inhibitor stabilizes the inactive form of the enzyme

Label the ATP molecule. Use an arrow to show which bond is likely to break. a. By which process will that bond break? b. Explain the name ATP by listing all the molecules that make it up.

-bond it most likely to break on the third phosphate group -a. hydrolysis -b. adenosine triphosphate: sugar ribose with nitrogenous base adenine & a chain of 3 phosphate groups bonded to it

What is the role of the electron transport chain following H+ gradient across the inner mitochondrial membrane?

-certain members of the electron transport chain accept and release protons (H+) along with electrons. (aq solutions inside/outside the cell full of H+) -at certain steps along the chain, electron transfers cause H+ to be taken up and released into the surrounding solution -in eukaryotic cells, the electron carriers are spatially arranged in the inner mitochondrial membrane in such a way that H+ is accepted from the mitochondrial matrix and deposited in the intermembrane space -H+ gradient that results is referred to as a proton-motive force, emphasizing the capacity of the gradient to perform work -force drives H+ back across the membrane through the H+channels provided by ATP synthases

Energonic

-chemical reaction that requires an input of energy

Exergonic

-chemical reactions that release energy

Two key terms are chemiosmosis and proton-motive force. Relate both of these terms to these processes of oxidative phosphorylation.

-chemiosmosis: an energy-coupling mechanism that uses energy stored in the form of an H+ gradient across a membrane to drive cellular work -proton-motive: potential energy stored in the form of a proton electrochemical gradient, generated by the pumping of hydrogen ions (H+) across a biological membrane during chemiosmosis -relate: electron transport chain pumps protons from the mitochondrial matrix into the intermembrane space, during chemiosmosis, the protons flow back down their gradient via ATP synthase, which is built into the membrane nearby, the ATP synthase harnesses the proton-motive force to phosphorylate ADP, forming ATP, together, electron transport and chemiosmosis make up oxidative phosphorylation

Distinguish between cofactors and coenzymes. Give examples of each.

-cofactors: non-protein, small inorganic compounds & ions that is required for the proper functioning of an enzyme, can be permanently bound to the active site or may bind loosely and reversibly, along with the substrate, during catalysis (ex: Mg, K, Ca, Zn, Fe, Cu) -coenzymes: organic molecule serving as a cofactor (ex: vitamins) -differences: cofactors are inorganic while coenzymes are organic

Anabolic pathway

-consume energy to build complicated molecules from simpler ones

What is free energy? What is its symbol?

-def: is the portion of a system's energy that can preform work when the temperature & pressure are uniform throughout the system -∆G

What are coenzymes?

-def: organic molecule serving as a cofactor -NAD+ is a coenzyme

Substrate-level phosphorylation

-direct transfer of phosphate from an organic substrate to ADP to form ATP

Photosynthesis is __________________.

-endergonic

Is photosynthesis endergonic or exergonic? What is the energy source that drives it?

-endergonic -plants get 686 kcal/mol from the environment by capturing light & converting its energy into chemical energy

Oxidative phosphorylation involves two components: the ETC & ATP synthesis. Notice that each member of the ETC is lower free _______________ than the preceding member of the chain, but higher in ___________________. The molecule at zero free energy & the highest in electronegativity.

-energy -electronegativity

According to the first law of thermodynamics, what can and cannot happen to energy?

-energy can be transferred & transformed -can't be created or destroyed

Describe what happens when NAD+ is reduced. What enzyme type is involved?

-enzymatic transfer of 2 electrons & 1 proton (H+) from an organic molecule in food to NAD+ reduces the NAD+ to NADH; second proton (H+) is released -enzyme: dehydrogenase

Explain how protein structure is involved in enzyme specificity.

-enzymes are proteins, and proteins are macromolecules with unique 3D configuration -specificity of an enzyme results from its shape, which is a consequence of its amino acid sequence -specificity of an enzyme is attributed to a compatible fit between the shape of its active site and the shape of the substrate

Is cellular respiration an endergonic or exergonic reaction? What is ∆G for this reaction?

-exergonic -C6H12O6 + 6O2 --> 6CO2 + 6H2O -∆G = -686 kcal/mol

Explain the difference between fermentation & aerobic respiration.

-fermentation: partial degradation of sugars or other organic fuel that occurs without oxygen -aerobic: oxygen is consumed as a reactant along with the organic fuel -difference: fermentation doesn't need oxygen while aerobic does

Alcohol fermentation starts with glucose & yields ethanol. Explain this process, & be sure to describe how NAD+ is recycled.

-first, CO2 released from the pyruvate is converted to the two-carbon compound acetaldehyde, which is reduced by NADH to ethanol -this regenerates the supply of NAD+ needed for the continuation of glycolysis -then, pyruvate is converted to ethanol, releasing CO2 and oxidizing NADH in the process to form more NAD+

Explain what has happened to each of the six carbons found in the original glucose molecule?

-glucose --> pyruvate --> acetyl CoA --> CO2 -pyruvate is broken into 3CO2, including the CO2 released during the conversion of pyruvate to acetyl CoA

Although it is not an enzyme, hemoglobin shows cooperative in binding O2. Explain how hemoglobin works in the gills of a fish.

-hemoglobin is made up of four subunits, each of which has an oxygen-binding site. -binding of an oxygen molecule to one binding site increases the affinity for oxygen of the remaining binding sites -thus, where oxygen is at high levels, such as in the lungs or gills, hemoglobin's affinity for oxygen increases as more binding sites are filled

The second law of thermodynamics is sometimes called the "you always lose rule". Why is that an apt expression?

-it is an apt expression bc during energy transfer some energy becomes unavailable to do work

Contrast kinetic energy with potential energy.

-kinetic: energy of relative motion of objects -potential: energy matter posses bc of location/structure -difference: potential is the energy of what can be & kinetic is the energy of what is

Three turns of the Calvin cycle nets one G3P because the other five must be recycled to three RuBps. Explain how regeneration of RuBP is accomplished.

-last step of carbon cycle rearranges carbon skeletons of 5 molecules of G3P are rearranged into 3 molecules of RuBP -this reconfiguration requires the energy of 3 ATP molecules

Explain what occurs in the light reactions stage of photosynthesis. Be sure to use NADP+ & photophoasphorlation in your discussion.

-light reactions convert solar energy to chemical energy, occur in thylakoid membrane -water is split providing a source of electrons & protons (H+), & give off O2 as a by product -light absorbed by chlorophyll drives a transfer of the electrons & hydrogen ions from water to an acceptor called NADP+ -photophosphorylation: light reactions generate ATP, using chemiosmosis to power the addition of a phosphate group to ADP -end of the light reactions, light energy is converted into chemical energy store in ATP and NADPH

When compounds lose electrons, they ________________ energy; when compounds gain electrons, they _______________ energy.

-lose -gain

Feedback inhibition

-method of metabolic control in which the end product of a metabolic pathway acts as an inhibitor of an enzyme within that pathway

If you couldn't regenerate ATP by phosphorylating ADP, how much ATP would you need to consume each day?

-nearly my body weight in ATP

Explain the Calvin cycle, utilizing the term carbon fixation in your discussion.

-occur in stroma -carbon fixation: cycle beings by incorporation CO2 from the air into organic molecules already present in the chloroplast -Calvin cycle then reduces the fixed carbon into carbohydrates by adding electrons provided by NADPH, chemical energy is supplied by ATP -end result of the Calvin cycle is carbohydrate molecules called G3P which consist of 3 carbons -G3P molecules used to produce glucose

Where does glycolysis occur in the cell? Is oxygen required?

-occurs in cytosol -no oxygen required

Both cellular respiration & photosynthesis are redox reactions. What is the difference between oxidation & reduction?

-oxidation: loss of electrons from one substance -reduction: addition of electrons to another substance

Fermentation allows for the production of ATP without using either ________________ or any ________________________________.

-oxygen -electron transport chain

What strongly electronegative atom, pulling electrons down the electron transport chain , is the final electron acceptor?

-oxygen (O2)

Using 18 O as the basis of you discussion, explain how we know that the oxygen released in photosynthesis comes from water.

-oxygen-18 is used as a tracer to follow the fate of oxygen atoms during photosynthesis -experiments show that the O2 from plants was labelled with 18 O only if water was the source of the tracer -if O2 was introduced to the plant in the form of CO2 the label didn't turn up in the released O2

Name a human enzyme that functions well in pH 2. Where is it found?

-pepsin, found in stomach

In many cellular reactions, a phosphate group is transferred from ATP to some other molecule in order to make the second molecule less stable. What term is now used to describe the second molecule?

-phosphorylated intermediate

Why is the total count about 30 or 32 ATP molecules rather than a specific number?

-phosphorylation & the redox reactions aren't directly coupled with each other, so the ratio of the number of NADH molecules to the number of ATP molecules in not a whole number -ATP yield varies slightly depending on the type of shuttle used to transport electrons from the cytosol into the mitochondrion -variable that reduces the yield of ATP is the use of proton-motive forced generated by the redox reactions of respiration to drive other kinds of work

What is meant by a spontaneous process?

-process that occurs without an overall input of energy, a process that is "energetically favorable"

For aerobic respiration to continue, the cell must be supplied with oxygen-the ultimate electron acceptor. What is the electron acceptor in fermentation?

-pyruvate

Lactic acid fermentation stars with glucose & yields lactate. Explain this process, & be sure to describe how NAD+ is recycled.

-pyruvate is reduced directly by NADH to form lactate as a final product with no release of CO2 -reduction of pyruvate by NADH leads to the formation of NAD+, & lactate is formed as a waste product

Explain why pyruvate is a key juncture in metabolism.

-pyruvate is reduced directly by NADH to form lactate as a final product with no release of CO2 -reduction of pyruvate by NADH leads to the formation of NAD+, and lactate is formed as a waste product

A photosystem is composed of a protein complex called a _____________________-_____________________ complex surrounded by several __________________-____________________ complexes.

-reaction-center -light-harvesting

Role & components of a photosystem.

-reaction-center complex: an excited electron from the special pair of chlorophyll molecules is transferred to a primary electron acceptor -light-harvesting complex: a pigment molecule absorbs a Photon from light energy and passes the energy from pigment molecule to pigment molecule until it reaches the reaction center complex -primary electron acceptor: accepts electrons and becomes reduced, prevents the potential energy from being lost as light and heat

Catabolic pathway

-release energy by breaking down complex molecules into simpler compounds

The enzyme responsible for carbon fixation in the Calvin cycle, & possibly the most abundant & most important protein on Earth is _____________________.

-rubisco

Many toxins and poisons cause irreversible enzyme inhibition. Select one and explain why its so deadly.

-sarin: binds to the active site of acetylcholinesterase (enzyme important to nervous system), blocks the enzyme's ability to hydrolyze neurotransmitter

Notice the colors & corresponding wavelengths. Explain the relationship between wavelength & energy.

-shorter wavelength=higher energy (ex. purple) -lower wavelength= lower energy (ex: red)

What is the function of the electron transport chain in cellular respiration?

-shuttles electrons down a series of redox reactions that release energy used to make ATP

How is allosteric regulation somewhat like noncompetitive inhibition? How might it be different?

-similar bc it can inhibit enzyme activity -different bc it can stimulate enzyme activity

Label a chloroplast

-storma is the dense fluid -thylakoids are a membrane system made up of sacs

What is energy coupling?

-the use of an exergonic process to drive an endergonic one

Three types of phosphorylation are covered in text, & two of these occur in cellular respiration. Explain how the electron transport chain is utilized in oxidative phosphorylation.

-this mode of ATP synthesis is powered by redox reactions of the ETC -oxidative: powered by redox reactions of electron transport chain -substrate: enzyme transfer phosphate group from a substrate molecule to ADP

Light reactions & the Calvin cycle

-thylakoids (green) are sights of light reactions -Calvin cycle occurs in storma (gray) -light reactions use solar energy to make ATP & NADPH, which supply chemical energy & reducing power, to the Calvin cycle -Calvin cycle incorporates CO2 into organic molecules, which are converted to sugar

What type of energy does water behind a dam have? A mole of glucose?

-water dam: potential energy bc of altitude above sea level -glucose: potential energy but more specifically chemical energy that is available for release in a chemical reaction

What is allosteric regulation?

-when a protein's function at one site is affected by the binding of a regulatory molecule to a separate site -results in inhibition or stimulation of enzyme's activity

What is meant by induced fit?

-when the substrate enters the active site, it forms weak bonds with the enzyme, inducing a change in the shape of the protein. -this change allows additional weak bonds to form, causing the active site to enfold the substrate and hold it in place

When ∆G is negative it is _____________________________. When ∆G is positive it is ______________________________.

-∆G = spontaneous +∆G = non-spontaneous

If energy is release, ∆G must be _______________.

-∆G is negative (∆G < 0)

Once we know the value of ∆G for a process, we can use it to predict whether it will be spontaneous. For an exergonic reaction, is ∆G negative or positive?

-∆G is negative (∆G < 0), bc exergonic reaction release energy, thus loosing free energy

Pyruvate oxidized to acetyl CoA yields __________________________.

2C sugar + NADH +CO2

Give the formula (with names) for the catabolic degradation of glucose by cellular respiration.

C6H12O6 + 6O2 --> 6CO2 + 6H2O + energy(ATP+heat) glucose + oxygen gas --> carbon dioxide + water

Calvin cycle formula

CO2 + ATP + NADPH --> C6H12O6 + ADP + NADP

Light reaction formula

H2O + sunlight --> NADPH + ATP + O2