Ch 8: Metabolism

Question 1

What is metabolism?

Answer 1

the totality of an organism’s chemical reactions (emergent property)

Question 2

What is a metabolic pathway?

Answer 2

a specific molecule is altered in a series of steps to produce a product

Question 3

What is a catabolic pathway?

Answer 3

releases energy by breaking down complex molecules into simpler compounds (“dowhill”)

Question 4

What is a anabolic pathway?

Answer 4

consume energy to build complex molecules from simpler ones (“uphill”)

Question 5

What is bioenergetics?

Answer 5

the study of how energy flows through living organisms

Question 6

What is energy?

Answer 6

the capacity to cause change

Question 7

What is kinetic energy?

Answer 7

energy associated with motion

Question 8

What is thermal energy?

Answer 8

the kinetic energy associated with random movement of atoms or molecules

Question 9

What is heat?

Answer 9

thermal energy in transfer from one object to another

Question 10

What is potential energy?

Answer 10

energy that matter possesses because its location or structure

Question 11

What is chemical energy?

Answer 11

potential energy available for release in a chemical reaction9

Question 12

What is thermodynamics?

Answer 12

the study of energy transformations in a collection of matter

Question 13

What is an isolated system?

Answer 13

a system that is unable to exchange energy or matter with its surroundings, will eventually reach equilibrium and then do no work

Question 14

What is an open system?

Answer 14

a system where energy and matter can be transferred between the system and its surroundings, ex. organisms

Question 15

What is the first law of thermodynamics (the principle of conservation of energy)?

Answer 15

the energy of the universe is constant, energy can be transferred and transformed, but it cannot be created or destroyed

Question 16

What is the second law of thermodynamics?

Answer 16

every energy transfer or transformation increases the entropy of the universe

Question 17

What is entropy?

Answer 17

a measure of molecular disorder, or randomness

Question 18

What is a spontaneous process?

Answer 18

a process that occurs without energy input; they can happen quickly or slowly (energetically favorable), ex. rusting car

Question 19

What is free energy?

Answer 19

the portion of a system’s energy that can do work when temperature and pressure are uniform throughout the system, as in a living cell

Question 20

If ΔG is negative

Answer 20

the process is spontaneous

Question 21

If ΔG is zero or positive

Answer 21

the process is nonspontaneous

Question 22

What is an exergonic reaction?

Answer 22

(“energy outward”) proceeds with a net release of free energy to the surroundings, products store less energy than the reactants

Question 23

What is an endergonic reaction?

Answer 23

(“energy inward”) absorbs free energy from the surroundings, products store more energy than the reactants

Question 24

Whats is energy coupling?

Answer 24

the use of an exergonic process to drive an endergonic

Question 25

What is ATP composed of?

Answer 25

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

Question 26

What is the recipient molecule in ATP?

Answer 26

phosphorylated intermediate

Question 27

How is ATP regenerated?

Answer 27

by an addition of a phosphate group to adenosine diphosphate (ADP)

Question 28

What is a catalyst?

Answer 28

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

Question 29

What is an enzyme?

Answer 29

a macromolecule (typically protein) that acts as a catalyst to speed up a specific reaction

Question 30

What is activation energy?

Answer 30

the initial energy needed to break the bonds of the reactants

Question 31

What is catalysis

Answer 31

the process by which a catalyst speeds up a reaction without itself being consumed (lowers activation energy)

Question 32

What is a substrate?

Answer 32

the reactant that an enzyme acts on

Question 33

What is an enzyme-substrate complex?

Answer 33

when an enzyme binds to its substrate

Question 34

What is an active site?

Answer 34

the region on the enzyme, often a pocket or groove, that binds to the substrate

Question 35

What is an induced fit?

Answer 35

when the substrate enters the active site, the enzymes changes shape slightly, tightening around the substrate like a handshake

Question 36

How does enzymes lower activation energy?

Answer 36

substrates may be oriented to facilitate the reaction, substrates may be stretched to make the bonds to easier to break, the active site may provide a microenvironment, and amino acids in the active site may participate in the reaction

Question 37

What are cofactors?

Answer 37

nonprotein helpers that bind to the enzyme permanently, or reversibly with the substrate

Question 38

What are coenzymes?

Answer 38

organic cofactors

Question 39

What are competitive inhibitors?

Answer 39

closely resemble the substrate, and can bind to the enzyme's active site, as a result enzyme productivity is reduced

Question 40

What is allosteric regulation?

Answer 40

occurs when a regulatory molecule binds to a protein at one site and affects the protein's function at another site, this type of regulation may either inhibit or stimulate enzyme activity

Question 41

What is cooperativity?

Answer 41

substrate binding to one active site triggers a shape change in the enzyme that stabilizes the active form for all other sites

Question 42

What is feedback inhibition?

Answer 42

the end product of a metabolic pathway shuts down the pathway, and prevents a cell from wasting chemical resources by synthesizing product