Ch 8 study guide

Question 1

*Give cellular examples of potential and kinetic energy

Answer 1

POTENTIAL = Chemical energy & free energy

*potential energy stored in the bonds connecting atoms in molecules

*A raised weight., Water that is behind a dam, A car that is parked at the top of a hill

KINETIC = Heat & Light

*A speeding bullet, a walking person, and the rapid movement of molecules in the air

Question 2

Define and understand the 2 laws of thermodynamics

Answer 2

The first law, also known as Law of Conservation of Energy, states that energy cannot be created or destroyed in an isolated system. The second law of thermodynamics states that the entropy of any isolated system always increases.

Question 3

Catabolic pathway

Answer 3

Release energy by breaking down complex molecules to simpiler compounds

Question 4

Anabolic pathway

Answer 4

Consume energy to build complicated molecules from simplier ones

Question 5

Synthesis pathway

Answer 5

Anabolic

Question 6

breakdown pathway

Answer 6

Catabolic

Question 7

kinetic energy

Answer 7

Energy which a body possesses by virtue of being in motion.

Question 8

potential energy

Answer 8

The energy held by an object because of its position relative to other objects

Question 9

What is the difference between exergonic and endergonic reactions?

Answer 9

Exergonic reactions release energy; endergonic reactions absorb it In exergonic reaction the free energy of the products is lower than that of the reactants; meanwhile in endergonic the free energy of the products is higher than that of the reactants. … Most chemical reactions are reversible

Question 10

What is the free energy of reactants vs products

Answer 10

The standard free energy change (∆Gº’) of a chemical reaction is the amount of energy released in the conversion of reactants to products under standard conditions.

Question 11

What type of cellular reactions require energy to take place?

Answer 11

Metabolism is all the chemical reaction that take place in a living organism.

Question 12

Where is the potential energy stored in an ATP molecule?

Answer 12

Energy is stored in the covalent bonds between phosphates, with the greatest amount of energy (approximately 7 kcal/mole) in the bond between the second and third phosphate groups.

Question 13

Why is an investment of activation energy necessary to initiate a spontaneous reaction?

Answer 13

Molecules are stable. In order to be reactive, they must be unstable. Therefore, energy must be added to molecule in order for them to reach the transition state where their bonds can be broken.

Question 14

What effect do enzymes have on activation energy and free energy wtihin a reaction?

Answer 14

enzymes lower the activation energy for chemical reactions. Enzymes decrease the Gibbs free energy of activation, but they have no effect on the free energy of reaction. Enzymes work by lowering the activation energy ( Ea or ΔG✳ ) for a reaction. This increases the reaction rate. The free energy of the product is the same as it would be without the enzyme.

Question 15

What does it mean “Enzymes are highly specific?”

Answer 15

Enzymes are highly selective catalysts, meaning that each enzyme only speeds up a specific reaction. ..

Question 16

Name the nonspecific factors that affect enzyme activity?

Answer 16

Temperature PH Enzyme concentration Substrate concentration

Question 17

Describe how enzymes and substrates interact?

Answer 17

The enzyme ‘s active site binds to the substrate. … When an enzyme binds its substrate it forms an enzyme-substrate complex. Enzymes promote chemical reactions by bringing substrates together in an optimal orientation, thus creating an ideal chemical environment for the reaction to occur.

Question 18

What is the difference between competitive and non competitive inhibition?

Answer 18

The competitive inhibitor binds to the active site and prevents the substrate from binding there. The noncompetitive inhibitor binds to a different site on the enzyme; it doesn’t block substrate binding, but it causes other changes in the enzyme so that it can no longer catalyze the reaction efficiently.

Question 19

How can allosteric regualtion activate and inhibit enzymes?

Answer 19

The allosteric inhibitor binds to an enzyme at a site other than the active site. The shape of the active site is altered so that the enzyme can no longer bind to its substrate