Chapter 8

Question 1

metabolism

Answer 1

totality of an organism’s chemical reactions

Question 2

metabolic pathway

Answer 2

• begins with a specific molecule that is altered in a series of defined steps, resulting in a certain product
• each step catalyzed by a specific enzyme: balance supply and demand

Question 3

catabolic pathway

Answer 3

ex: cellular respiration

energy stored in organic molecules becomes available to do the work of the cell

Question 4

anabolic pathway

Answer 4

consume energy to build complicated molecules from simpler ones
ex: synthesis of an amino acid from simpler molecules and of proteins from amino acids

Question 5

energy

Answer 5

the capacity to cause change

Question 6

kinetic energy

Answer 6

energy associated with the relative motion of objects

Question 7

thermal energy

Answer 7

kinetic energy associated with the random movement of atoms or molecules
in transfer from one object to another is called heat

Question 8

potential energy

Answer 8

non-kinetic energy, based on location

Question 9

chemical energy

Answer 9

potential energy available for release in a chemical reaction

Question 10

thermodynamics

Answer 10

the study of energy transformations that occur in a collection of matter

Question 11

isolated vs open system

Answer 11

ability to exchange either energy/matter with surroundings

Question 12

1st law of thermodynamics

Answer 12

energy cannot be created or destroyed, only exchanged and transformed

Question 13

2nd law of thermodynamics

Answer 13

entropy of the universe is always increasing

Question 14

entropy

Answer 14

the measure of disorder

Question 15

spontaneous process

Answer 15

a process that leads to an increase in entropy and can proceed without an input of energy

Question 16

free energy

Answer 16

delta G; the portion of a system’s energy that can perform work when temperature and pressure are uniform
when spontaneous delta H must be negative or TdeltaS must be positive

Question 17

deta G=

Answer 17

delta H-Tx delta S

G(final)-G(initial)

Question 18

negative free energy vs positive

Answer 18

negative=spontaneous (decreases the free energy)

positive=nonspontaneous

Question 19

ATP

Answer 19

ribose+nitrogenous base (adenine)+triphosphate group

phosphate groups broken with hydrolysis

Question 20

hydrolysis in ATP

Answer 20

• when the terminal phosphate bond is broken by hydrolysis, inorganic phosphate leaves ATP and the molecule becomes ADP; exergonic rxn
• can perform three types of work 1) chemical, 2) transport, 3) mechanical

Question 21

endergonic rxn free energy

Answer 21

if delta G of an endergonic reaction is less than the amount of energy released by ATP hydrolysis, the two can be coupled so that together they are exergonic

Question 22

phosphorylated intermediate

Answer 22

recipient molecule with the phosphate group covalently bonded to it, promote crucial protein shape changes during cellular processes

Question 23

regeneration of ATP

Answer 23

by addition of phosphate to ADP, free energy required to phosphorylate ADP comes from exergonic breakdown reactions in cell=ATP cycle process is endergonic

Question 24

cellular respirations provides…

Answer 24

energy for ATP process

Question 25

how do plants produce ATP?

Answer 25

use light energy

Question 26

enzymes

Answer 26

macromolecule that acts as a catalyst

Question 27

catalyst

Answer 27

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

Question 28

activation energy

Answer 28

the energy reactants must absorb before a chemical reaction will start, often supplied by heat

Question 29

transition state

Answer 29

when the molecules have absorbed enough energy for the bonds to break, the reactants are unstable

Question 30

how does an enzyme catalyze a reaction?

Answer 30

by lowering activation energy barrier and enabling the reactant molecules to absorb enough energy to reach the transition state even at moderate temperatures
**cannot change free energy

Question 31

substrate

Answer 31

reactant an enzyme binds to the enzyme and where catalysis occurs

Question 32

induced fit

Answer 32

entry of substrate, change in the shape of the active site of the enzyme so the bind is more snug

Question 33

cofactors

Answer 33

nonprotein helper for catalytic activity, may be tightly bound to enzyme or loosely and reversibly
* inorganic=cofactor, organic=coenzyme

Question 34

inhibitors

Answer 34

inhibit active site of specific enzymes=preventing catalysis

Question 35

competitive inhibitors

Answer 35

reduces activity of enzyme by entering the active site in the place of the substrate (whose structure it mimics), overcome by increasing the concentration of substrate

Question 36

noncompetitive

Answer 36

impede enzymatic reactions by binding to another part of the enzyme and thus changes its shape

Question 37

allosteric regulation

Answer 37

where a protein’s function at one site is affected by the binding of a regulatory molecule to a separate site=either results in inhibition or stimulation
controls the rates of important reactions in metabolic pathways

Question 38

enzymes in allosteric regulation

Answer 38

usually have two or more subunits with individual active sites and oscillates between it

Question 39

activator

Answer 39

binds so only the active form is kept

Question 40

inhibitor

Answer 40

binds so only the inactive form is kept

Question 41

cooperativity

Answer 41

a type of allosteric regulation where 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

Question 42

feedback inhibition

Answer 42

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