Chemical Energy

Front 1

overal reaction of chemical reactions

Back 1

may either release energy or absorb energy

Front 2

exergonic reactions

Back 2

release more energy than they absorb

Front 3

endergonic reactions

Back 3

absorb more energy than they release

Front 4

What is the connection between exergonic reactions and endergonic reactions?

Back 4

Key feature of metabloism is the coupling of exergonic and endergonic reactions; energy released from an exergonic reaction often is used to drive an endergonic one

Front 5

When do exergonic reactions occur?

Back 5

Exergonic reactions occur as nutrients, such as glucose, are broken down; energy released as may be trapped in covalen bonds of adenosine triphosphate ATP

Front 6

What happens to the energy trapped by ATP molecules?

Back 6

The energy transferred to ATP molecules is used to drive endergonic reactions needed to build body structres (muscles, bones)

Front 7

What does the energy in ATP do?

Back 7

The energy in ATP is also used to do the mechanical work involved in the contraction of muscle or the movement of substances into or out of cells.

Front 8

Activation energy

Back 8

the collision energy needed to break the chemical bonds of the reactants; atoms, ions, & molecules move due to kinetic energy

Front 9

How does initial energy (activation energy) work?

Back 9

reactants must absorb enough energy for their chemical bonds to become unstable and their valence electrons to form new combinations--as new bonds form, energy is released to the surroundings

Front 10

What influences the chance that a collision will occur and cause a chemical reaction?

Back 10

the concentration of particles and the temperature

Front 11

How does concentration influence chemical reactions?

Back 11

the more particles of matter present in a confined space, the greater the chance that they will collide; pressur on the space increase which forces the particlea closer together so that they collide more often

Front 12

How does temperature influence chemical reactions?

Back 12

as temperature rises, particles of matter move more rapidly; higher temp causes particles to collide more forcibly

Front 13

True or false?
Body temperature and the concentrations of molecules in body fluids are far too low for most chemical reactions to occur rapidly enough to maintain life.

Back 13

True

Front 14

How is the problem of low body temperature and low concentration solved?

Back 14

By utilizing catalysts

Front 15

catalysts

Back 15

chemical compounds that speed up chemical reactions by lowering the activation energy needed for a reaction to occur

Front 16

How does a catalyst work in a chemical reaction?

Back 16

a catalyst does not alter the difference in poteneial energy between the reactants and the products. It lowers the amount of energy needed to start the reaction.

Front 17

True or false?
An enzyme catalyst can only be used once.

Back 17

False. The catalyst is unchanged at the end of the reaction. A single catalyst molecule can assist one chemical reation after another.

Front 18

Name an enzyme catalyst.

Back 18

Lactose (milk sugar)