chapter 8 bio

what is the most important Potential E?

Chemical E which is E stored in a bond

Two types of energy

Potential Energy: Stored Energy Kinetic Energy: Energy in motion

to produce ATP E you need ____

Redox reaction

catabolic pathways

- works with exergonic-energy realeaseing pathway -Metabolic pathways that release energy by breaking down complex molecules into simpler compounds.

how can the active lower Ea through 4 mechanisms

-correct orientation of substrate -strain substrate bonds -provide a favorable microenviornment -covalently bond to the substrate

The Cycle of Enzyme-Substrate Interactions

1) Substrates enters the active site 2) both of them change shape, promote reactions 3) Product is released, enzyme is ready

two laws of thermodynamics

1. CONSERVATION E LAW: " E neither created/ destroyed - CONSTANT E "E in universe is constant (same) 2. ENTROPY LAW: Randomness/disordered "E will transform from high order E to low ordered E" aka low Entropy is high order E / high entropy is low order E

cooperativity

A kind of allosteric regulation whereby a shape change in one subunit of a protein caused by substrate binding is transmitted to all the other subunits, facilitating binding of additional substrate molecules to those subunits. --is allosteric because binding by a substrate to one active site affects catalysis in a different active site

Are most chemical reactions at equilibrium in living cells? A)yes B)no C)only the exergonic reactions D)all reactions except those powered by ATP hydrolysis

B) NO At equilibrium, the free energy change is zero, and no work can be done. A cell at equilibrium is dead!

metabolic pathway

Begins with a specific molecule, which is then altered in a series of defined steps, resulting in a certain product. Each step is catalyzed by a specific enzyme

When ATP turns into ADP,

E was released but also electron got released- oxidation ADP to Atp means gain E and Electron - reduction

ATP/ADP

Energy is released when a phosphate group is removed

How Enzymes Lower the EA Barrier

Enzymes catalyze reactions by lowering the EA barrier Enzymes do not affect the change in free energy (∆G); instead, they hasten reactions that would occur eventually - Enzyme is never used up, after chem reaction with substrate happens they regain shape and is ready for another set. You only use enzyme by old age. -enzyme is specific by working with only 1 substrate (reactant)

Gives free energy

G is the thermodynamics criteria for determining the spontaneity of a reaction

chemical equilibrium

In a chemical reaction, the state in which the rate of the forward reaction equals the rate of the reverse reaction, so that the relative concentrations of the reactants and products do not change with time.

If this is an enzyme-catalyzed reaction, how can the rate of this reaction be increased beyond the maximum velocity in this figure? Increase the substrate concentrations. Increase the amount of enzyme. Increase the amount of energy. any of the above There is no way to increase the rate of the reaction any further.

Increase the amount of enzyme.

why do we need ATP

It is the energy needed for our cells to do work.

How do living organisms create macromolecules, organelles, cells, tissues, and complex higher-order structures? A) The laws of thermodynamics do not apply to living organisms. B) Living organisms create order by using energy from the sun. C)Living organisms create order locally, but the energy transformations generate waste heat that increases the entropy of the universe.

Living organisms create order locally, but the energy transformations generate waste heat that increases the entropy of the universe.

Firefly luciferase catalyzes the reaction luciferin ATP ↔ adenyl-luciferin pyrophosphate then the next reaction occurs spontaneously: adenyl-luciferin O2 → oxyluciferin H2O CO2 AMP light What is the role of luciferase? Luciferase makes the G of the reaction more negative. Luciferase lowers the transition energy of the reaction. Luciferase alters the equilibrium point of the reaction. Luciferase makes the reaction irreversible. all of the above

Luciferase lowers the transition energy of the reaction.

The oxidation of glucose to CO2 and H2O is highly exergonic: G = -636 kcal/mole. Why doesn't glucose spontaneously combust? The glucose molecules lack the activation energy at room temperature. There is too much CO2 in the air. CO2 has higher energy than glucose. The formation of six CO2 molecules from one glucose molecule decreases entropy. The water molecules quench the reaction.

The glucose molecules lack the activation energy at room temperature.

A reaction has a ∆G of 5.6 kcal/mol. Which of the following would most likely be true? A)The reaction could be coupled to power an endergonic reaction with a G of 8.8 kcal/mol. B)The reaction would result in a decrease in entropy (S) and an increase in the energy content (H) of the system. C)The reaction would result in an increase in entropy (S) and a decrease in the energy content (H) of the system. D)The reaction would result in products with a greater free-energy content than in the initial reactants.

The reaction would result in an increase in entropy (S) and a decrease in the energy content (H) of the system.

bioenergetics

The study of how organisms manage their energy resources.

active site

a region on an enzyme that binds to a protein or other substance during a reaction.

endergonic reaction

absorbs free energy from its surroundings and is nonespontaneous -anabolic -more energy on product than reactant

phosphorylation

add a phosphate group energy storing

only way to lose enzyme is

ageing

Enzymes

all are proteins, biological catalysts

Adenosine monophosphate (AMP) activates the enzyme phosphofructokinase (PFK) by binding at a site distinct from the substrate binding site. This is an example of cooperative activation. allosteric activation. activation by an enzyme cofactor. coupling exergonic and endergonic reactions.

allosteric activation

noncompetative inhibators

allosteric site, causing the enzyme to change shape and making the active site less effective Examples of inhibitors include toxins, poisons, pesticides, and antibiotics

redox reaction

an oxidation-reduction reaction ex; OIL - Oxidation is loss of Electrons (pos charged in ion molecule;e means it got oxidized) RIG- Reduction is gaining of electrons ( charge will be anion bc more e- than proton)

cofactors

are nonprotein enzyme helpers Cofactors may be inorganic (such as a metal in ionic form) or organic An organic cofactor is called a coenzyme which include vitamins

ATP to ADP and Vis versa

becomes adp by releasing energy or by doing work exergonic -adp becomes atp through cellular respiration which is a couple reaction

competative inhibition

bind to the active site of an enzyme, competing with the substrate

ATP hydolysis

break one phosphate bond to make ADP exergonic (release)

a chemical reaction is ?

breaking or forming of bonds

How do enzymes speed up chemical reactions?

by lowering the activation energy Ae

without photosynthesis ___ cannot exist

cellular respiration

all cells do 3 kinds of work

chemical transport mechanical

no input or output is an

closed or isolated system -unequal but eventually reach equilibrium , the energy is delta 0 no change

enzyme helpers are called

cofactors -inorganic like metals, zinc -organic like vitamins

Vioxx and other prescription nonsteroidal anti-inflammatory drugs (NSAIDs) are potent inhibitors of the cycloxygenase-2 (COX-2) enzyme. High substrate concentrations reduce the efficacy of inhibition by these drugs. These drugs are competitive inhibitors. noncompetitive inhibitors. allosteric regulators. prosthetic groups. feedback inhibitors.

competitive inhibitors.

three types of inhibition mechanism

competitive, non competitive allosteric inhibition and non competitive feedback inhibition

intermediates

compounds that form between the initial reactant, glucose, and the final product, pyruvate

anabolic pathways

endergonic ex photosynthesis. consumes energy to build complex molecules from simpler ones

To do work, cells manage energy resources by

energy coupling, the use of an exergonic process to drive an endergonic one

Endergonic

energy is absorbed or produced for ex photosynthesis 6O2+6H2O = C6H2O+6O2

Exergonic

energy is released for ex cellular respiration C6H2O+6O2= 6CO2 + 6H2O + 36 net ATP

free energy

energy that is available to do work when temperature and pressure are uniform as in a living cell

Protein shape can be denaturalized by ___ for ex___

environmental factors ex 1. Temperature. 98.6 F body - thermofilic can be 110 C 2. pH- Enzyme in stomach will try to maintain pH less than 2. pH lower than 2 enzyme in intestine will die. all enzymes have own favorable temp, pH and salt concentration of 3. Salt

cycle of enzyme and substrate interactions

enzyme has shape and the substrate which is a reactant is supposed to have same shape which can fit into the enzyme. Enzyme protein sends signal which attracts substrate. Substrate will bind to binding side called active site through induced fit. the other side that doesn't bind with the substrate is called an allosteric site or remote site. When they have reaction it makes an enzyme substrate complex which is an intermediate temporary product. While they combine together inside of the active side the chemical reaction happens and as a product they will make original enzyme will regain the shape and product produces a different one

open system that has input and output like living organisms never reach

equilibrium. the reaction will always be negative which is exergonic

In the energy diagram below, which of the lettered energy changes would be the same in both the enzyme-catalyzed and uncatalyzed reactions?

free energy part C

Non-competitive allosteric inhibition

inhibitor doesn't occupy active site it binds with allosteric site binds to surface and changes shape of active sit enzyme therefore the substrate cannot bind

chemical reaction

metabolism

Ea (activation E)

minimum required E to ignitiate Chemical Reaction. w/o Ea the enzyme substrate reaction will end

how do we know more energy on reactant ?

more complicated compound it means more energy stored because of covalent bond.

how do we know the energy is releasing?

more energy on reactant that means energy releasing, so catabolic or exergonic

exergonic reaction

net release of free energy and is spontaneous catabolic -more energy on reactant than product

a defining feature of life is that metabolism is ___

never at equilibrium

reactions in a closed system eventually reach equilibrium and do ____

no work

spontaneous processes

occur without energy input; they cannot use energy which output is heat energy they can happen quickly or slowly

organisms are...

open systems -energy and matter can be transferred between the system and its own surroundings

couple reactions

pairs of chemical reactions in which some of the energy released from the breakdown of one compound is used to create a bond in the formation of another compound - linked reactions , w/o each other cannot exist -joined by 2 reactions endergonic and exergonic

Which enzymes may translocate from the cytoplasm to associate with the cytoplasmic face of the plasma membrane in response to a signal? ion channels active transport proteins phospholipid hydrolases aTP synthases motor proteins

phospholipid hydrolases

feedback inhibition

process in which the end product or result stops or limits the process -Feedback inhibition prevents a cell from wasting chemical resources by synthesizing more product than is needed

what is chemical reaction?

rearrangements of bonds . breaking from reactants or forming on product. -breaking/forming bond

enzyme can make _____

regulation with substrate- inhibition the substrate reaction

dephosphorylation

removal of a phosphate group

enzymes are protein. To become a protein from polypeptide what do they have to have?

shape, structure

Enzymes

speed up reactions (biological catalysts) by lowering Ea (activation E)

induced fit

substrate brings chemical groups of the active site into positions that enhance their ability to catalyze the reaction

Anabolism

synthesis of protein from amino acids

When sodium chloride (table salt) crystals dissolve in water, the temperature of the solution decreases. This means that, for dissociation of Na+ and Cl- ions, A)the change in enthalpy (H) is negative. B)the change in enthalpy (H) is positive, but the change in entropy is greater. C)the reaction is endergonic, because it absorbs heat. D)the reaction must be coupled to an exergonic reaction. E)the reaction cannot occur spontaneously.

the change in enthalpy (H) is positive, but the change in entropy is greater.

The hydrolysis of ATP: ATP H2O → ADP Pi is exergonic, with a G of 7.3 kcal/mol under standard conditions. What is the source of the 7.3 kcal/mol released in this reaction? breaking the terminal phosphate bond in ATP the increase in entropy from breaking apart ATP both the energy released from breaking the terminal phosphate bond and the increase in entropy the difference between the potential energy in the bonds of ATP and the water molecule, minus the potential energy in the bonds of ADP and Pi

the difference between the potential energy in the bonds of ATP and the water molecule, minus the potential energy in the bonds of ADP and Pi

biolumenescence

the production of light by living things

noncompetitive feedback inhibition

the products of the reaction at the end of the pathway bind to a site other than the active site of an enzyme at or near the beginning of the pathway and block enzyme activity indirectly mostly with amino acid product - the own product binds with allosteric site and changes shape of active site usually for amino acid product

Metabolism

the totality of an organism's chemical reactions and is an emergent property of life that arises from interactions between molecules within the cell

Cells are not in equilibrium

they are open systems experiencing a constant flow of materials

enzymes dont affect the change in free energy instead

they hasten reactions that would occur eventually -only affect Ae

when entropy increase delta g decrease bc minus portion

when delta S decrease it means highly order

competitive inhibition

when molecules similar to a substrate compete for placement on the active site of an enzyme, Vmax is still possible is substrate concentration is highenough -inhibitor competes for the active site and bind first and inhibit the original substrate enzyme complex the reaction

More energy in the reactants the delta g

will be negative