Metabolism chapter 6 AP BIO

metabolism

• the totality of an organism’s chemical reactions

metabolic pathway

• A _______ begins with a specific molecule and ends with a product

• Each step is catalyzed by a specific enzyme

catabolic pathways

release energy by breaking down complex molecules into simpler compounds

cellular respiration

_______ the breakdown of glucose in the presence of oxygen, is an example of a pathway of catabolism

anabolic pathways

• consume energy to build complex molecules from simpler ones

anabolism

The synthesis of protein from amino acids is an example of:

energy

• the capacity to cause change

work

Energy exists in various forms, some of which can perform:

kinetic energy

____ is energy associated with motion

thermal energy

_______ is kinetic energy associated with random movement of atoms or molecules

heat

___is thermal energy in transfer from one object to another

potential energy

___ is energy that matter possesses because of its location or structure

chemical energy

___is potential energy available for release in a chemical reaction

• Energy can be converted from one form to another 

thermodynamics

• is the study of energy transformations

isolated system

An ______, such as that approximated by liquid in a thermos, is isolated from its surroundings

open

• In an_____ system, energy and matter can be transferred between the system and its surroundings

• Organisms are _____ systems

1st law

According to the____of thermodynamics, the energy of the universe is constant

1st law

_______ is also called the principle of conservation of energy

cannot

Energy can be transferred and transformed, but it _____ be created or destroyed

heat

During every energy transfer or transformation, some energy is unusable and is often lost as:

2nd law

Every energy transfer or transformation increases the entropy of the universe

entropy

___ is a measure of disorder, or randomness

spontaneous processes

____ occur without energy input

spontaneous

•  is another way to say energetically favorable – it does not imply that the process will be fast (example:  rusting is spontaneous)

energy

For a process to occur without _____ input, it must increase the entropy of the universe

free energy

A living system’s _____ is energy that can do work when temperature and pressure are uniform, as in a living cell

free energy

The change in ______ (∆G) during a chemical reaction is the difference between the free energy of the final state and the free energy of the initial state

negative

Only processes with a ______ ∆G are spontaneous

work

Spontaneous processes can be harnessed to perform:

instability

Free energy is a measure of a system’s _____ its tendency to change to a more stable state

decreases

During a spontaneous change, free energy _____ and the stability of a system increases

equilibrium

At _____, forward and reverse reactions occur at the same rate; it is a state of maximum stability

toward

A process is spontaneous and can perform work only when it is moving _____ equilibrium

exergonic

An ______ reaction proceeds with a net release of free energy and is spontaneous

exergonic

∆G is negative because the chemical mixture is losing energy (G decreases)

maximum

The magnitude of ∆G represents the _____amount of work the reaction can perform in an exergonic rxn.

endergonic

An _____ reaction absorbs free energy from its surroundings and is nonspontaneous; ∆G is positive

quantity

The magnitude of ∆G is the _____of energy required to drive the reaction in an endergonic rxn.

chemical transport mechanical

three types of cell work:

energy coupling

To do work, cells manage energy resources by _____, the use of an exergonic process to drive an endergonic one

ATP

Most energy coupling in cells is mediated by:

ATP

is composed of ribose (a sugar), adenine (a nitrogenous base), and three phosphate groups

hydrolysis

The bonds between the phosphate groups of ATP can be broken by:

terminal

Energy is released from ATP when the ____ phosphate bond is broken

lower

This release of energy comes from the chemical change to a state of ______ free energy, not from the phosphate bonds themselves

ATP

The three types of cellular work (mechanical, transport, and chemical) are powered by the hydrolysis of:

endergonic

In the cell, the energy from the exergonic reaction of ATP hydrolysis can be used to drive an _____reaction

exergonic

• Overall, the coupled reactions are____:

phosphorylation:

ATP drives endergonic reactions by _______, transferring a phosphate group to some other molecule, such as a reactant

intermediate

The recipient molecule is now called a phosphorylated _____

shape

ATP hydrolysis leads to a change in a protein’s _____ and often its ability to bind to another molecule

renewable

ATP is a _____resource that is regenerated by addition of a phosphate group to adenosine diphosphate (ADP)

catabolic

• The energy to phosphorylate ADP comes from _____ reactions in the cell

catalyst

A ____ is a chemical agent that speeds up a reaction without being consumed by the reaction

enzyme

An _____ is a catalytic protein

sucrose

Hydrolysis of _____ by the enzyme sucrase is an example of an enzyme-catalyzed reaction

chemical

Every ______reaction between molecules involves bond breaking and bond forming

activation energy

The initial energy needed to start a chemical reaction is called the free energy of activation, or _________ (E_A)

thermal

Activation energy is often supplied in the form of ______ energy that the reactant molecules absorb from their surroundings

lowering

Enzymes catalyze reactions by _______ the E_A barrier

do not

Enzymes______ affect the change in free energy (∆G); instead, they hasten reactions that would occur eventually

substrate

The reactant that an enzyme acts on is called the enzyme’s:

enzyme substrate complex

The enzyme binds to its substrate, forming an:

active site

The ______ is the region on the enzyme where the substrate binds

specificity

Enzyme _______ results from the complementary fit between the shape of its active site and the substrate shape

chemical

Enzymes change shape due to______ interactions with the substrate

induced fit

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

active site

In an enzymatic reaction, the substrate binds to the ______ of the enzyme

orienting

The active site ____ substrates correctly lowers Ea barrier

straining

The active site ____substrate bonds lowers Ea

favorable

The active site Providing a _____ microenvironment lowers Ea

covalently

The active site ____ bonding to the substrate lowers Ea

ph, temperature, chemicals

enzymes activity can be affected by these 3 factors:

temperature, Ph

Each enzyme has an optimal ____ and _____ in which it can function

active shape

Optimal conditions favor the most ______ for the enzyme molecule

tertiary structure

Denaturation occurs if the pH, temperature, etc. are altered to the point that the weak interactions holding the_______ of the enzyme are destroyed.

unravels

as an enzyme denatures, it _____ and cannot function properly

cofactors

• are nonprotein enzyme helpers

coenzyme

• An organic cofactor is called a ____

• ____ include vitamins

competitive inhibitors

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

noncompetitive inhibitions

• bind to another part of an enzyme, causing the enzyme to change shape and making the active site less effective

inhibitors

• Examples of ______ include toxins, poisons, pesticides, and antibiotics

genes

• Chemical chaos would result if a cell’s metabolic pathways were not tightly regulated

• A cell does this by switching on or off the______ that encode specific enzymes or by regulating the activity of enzymes

allosteric regulation

___ may either inhibit or stimulate an enzyme’s activity

Allosteric regulation

___ occurs when a regulatory molecule binds to a protein at one site and affects the protein’s function at another site

polypeptide

Most allosterically regulated enzymes are made from multiple _____ subunits

inactive

Each enzyme has active and_____ forms

activator

The binding of an _____ stabilizes the active form of the enzyme

inhibitor

The binding of an _____ stabilizes the inactive form of the enzyme

feedback inhibition

In _______ the end product of a metabolic pathway shuts down the pathway

feedback inhibition

___ prevents a cell from wasting chemical resources by synthesizing more product than is needed

exergonic

catabolic rxns are:

endergonic

anabolic rxns are:

anabolic

this rxn consumes energy

catabolic

this rxn releases energy

anabolic

this rxn builds up larger molecules

catabolic

this rxn breaks down molecules

anabolic

this rxn is considered uphill

anabolic

photosynthesis is an _____ rxn

catabolic

this rxn requires enzymes to catalyze reactions: