metabolic pathways

Question 1

an organisms metabolism transforms matter and energy

Answer 1

true

Question 2

total chemical reactions of an organism

Answer 2

metabolism

Question 3

begins with a specific molecule and ends with a producs and each step is catalyzed by a specific enzyme

Answer 3

metabolic pathway

Question 4

releases energy by breaking down complex molecules into simpler compounds

Answer 4

catabolic pathways

Question 5

examples of catabolic pathways

Answer 5

Hydrolysis
– Cellular respiration = breakdown of glucose in presence
of oxygen
– “downhill” rxn

Question 6

consume energy to build
complex molecules from simpler ones

Answer 6

anabolic pathways

Question 7

examples of anabolic pathways

Answer 7

Dehydration/synthesis rxn
* synthesis of protein from AA
* “uphill” rxn
“do u wanna build a snowman”

Question 8

Chemical rxns occur when

Answer 8

One substance is combined with another
* Atoms are rearranged in molecules
* Or small molecules combine to form larger molecules

Question 9

chemical reactions occur when

Answer 9

One substance is broken down into another substance
* Molecules are split into atoms or smaller molecules

Question 10

Chemical bonds are broken and new bonds form , happpens in most chemical reactions

Answer 10

coupled reaction

Question 11

when the foward and reverse reactions proceed at the same rate , and the quantities of reactants and products remain constant

Answer 11

chemical equillibrium

Question 12

capacity to do work (or supply heat)

Answer 12

energy

Question 13

amount of enrgy to do work

Answer 13

freee energy

Question 14

stored potential, in position

Answer 14

potential energy

Question 15

active in motion , motion, measured as temp

Answer 15

kinetic energy

Question 16

kinetic energy associated w/random movement of atoms or molecules

Answer 16

thermal energy

Question 17

potential E available for release in a chemical rxn

Answer 17

chemical energy

Question 18

An object’s position determines its ability to store energy

Answer 18

potential energy / chemical energy

Question 19

For electrons, farther away from a nucleus it is = more potential
energy it has
* Electrons in an outer shell (farther from the + charged nucleus)
have more potential energy than electrons in an inner shell

Answer 19

true

Question 20

Principle of Conservation of E
– It cannot be created or destroyed, but it
can be transferred or transformed

Answer 20

first law of thermodynamics

Question 21

Entropy always increases
– Chemical rxns result in products w/
* More disorder (entropy)
* Less usable energy

Answer 21

second law of thermodynamics

Question 22

Physical and chemical processes proceed in the
direction that results in lower potential energy and
increased disorder

Answer 22

SPONTANEOUS

Question 23

They proceed w/o any continuous external influence
– No added E is needeD

Answer 23

Chemical reaction is spontaneous

Question 24

Spontaneity of a rxn is determined by two factors

Answer 24

amount of potential energy and the degree of order

Question 25

Products have less potential E than the reactants

Answer 25

. The amount of potential E

Question 26

Products are less ordered (higher dis-order) than the reactants * Disorder = Entropy (∆S)

Answer 26

The degree of order

Question 27

the potential E of the molecule (heat content)

Answer 27

Enthalpy

Question 28

Energy that can do work when temp. and pressure are uniform, as in a living cell. Only processes with a -∆G = spontaneous Spontaneous processes can be harnessed to perform work

Answer 28

Gibbs Free-Energy Change (G)

Question 29

Determines whether a rxn is spontaneous or requires added energy to proceed

Answer 29

Gibbs Free Energy Change (G)

Question 30

G = H −TS

Answer 30

G = Gibbs free energy change * H = change in enthalpy – measure of chemical potential E * S = change in entropy – measure of disorder * T = temp in degrees Kelvin

Question 31

G < 0 = spontaneous rxn; E released products have less potential e than reactants

Answer 31

exergonic rxn

Question 32

G > 0 = rxn that requires E input to occur and is not spontaneous; E absorbed products have higher potential e than reactants

Answer 32

endergonic rxn

Question 33

G = 0

Answer 33

rxn that is @equilibrium

Question 34

a cell does 3 main kinds of work

Answer 34

chemical transport mechanical

Question 35

chemical

Answer 35

energonic rxns

Question 36

transport

Answer 36

molecules up their concetration gradient

Question 37

mechanical

Answer 37

moving structures, usu by motor proteins

Question 38

to do work, cells manage energy resources by energy coupling

Answer 38

use of an exergonic process to drive an endergonic one

Question 39

* Most energy coupling in cells is mediated by

Answer 39

ATP

Question 40

is the cell’s energy shuttle; cellular currency

Answer 40

atp

Question 41

atp is composed of

Answer 41

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

Question 42

All 3 types of cellular work (mechanical, transport, and chemical) are powered by hydrolysis of

Answer 42

atp

Question 43

The energy from exergonic rxn of ATP hydrolysis can be used to drive an endergonic rxn

Answer 43

true

Question 44

When a protein is phosphorylated, exergonic phosphorylation rxn is paired with an endergonic rxn

Answer 44

Energetic coupling

Question 45

ATP drives endergonic rxns by ______, transferring a phosphate group to some other molecule (reactant); transfer E

Answer 45

phosphorylation

Question 46

How electron transfers are related to energy

Answer 46

Electrons can be transferred completely or simply shift their position in covalent bonds

Question 47

Each electron transferred is usually accompanied

Answer 47

by a proton (H+)

Question 48

Reduced molecule (one that gets reduced)

Answer 48

Gains a proton and has higher potential energy

Question 49

Oxidized molecule (one that gets oxidized)

Answer 49

oses a proton and has lower potential energy

Question 50

Reduction often “adds H’s

Answer 50

Oxidation often “removes H’s”

Question 51

Nicotinamide adenine dinucleotide (NAD+) gets reduced to form NADH

Answer 51

true

Question 52

NADH

Answer 52

Readily donates electrons to other molecules – Is called an electron carrier – Has reducing power

Question 53

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

Answer 53

substrate

Question 54

The enzyme binds to its substrate =

Answer 54

enzyme-substrate complex

Question 55

region on the enzyme where the substrate binds

Answer 55

Active site

Question 56

Enzymes speed up metabolic reactions by lowering energy barriers

Answer 56

yes

Question 57

speed up a rxns w/o being consumed by the rxn

Answer 57

catalyst

Question 58

is a catalytic protein

Answer 58

enzyme

Question 59

Enzymes do not affect change in free energy (∆G)

Answer 59

only speeds up rxns that would occur eventually

Question 60

rxns occur when

Answer 60

Reactants have enough kinetic energy to reach the transition state – Kinetic energy of molecules is a function of their temp

Question 61

How Enzymes Lower the EA Barrier

Answer 61

Enzymes catalyze rxns by lowering the energy of activation (EA) barrier

Question 62

interactions betwn the enzyme and the substrate stabilize the transition state

Answer 62

Lower the activation E required for the rxn to proceed

Question 63

The rate of an enzyme-catalyzed reaction depends on

Answer 63

[Substrate] – Enzyme’s intrinsic affinity for the substrate – Temp. – pH

Question 64

Enzymes can be saturated

Question 65

* The rate of a rxn is limited by the amount of:

Answer 65

– Substrate present – Enzyme available

Question 66

All enzymes show this type of saturation kinetics

Answer 66

Active sites cannot accept substrates any faster

Question 67

Enzymes are regulated by molecules that are not part of the enzyme itself

Answer 67

cofactors & coenzymes

Question 68

Cofactors

Answer 68

norganic ions – i.e. metal ions (Zn2+, Mg2+, Fe2+) – Reversibly interact with enzymes

Question 69

Coenzymes

Answer 69

are organic molecules – That interact with enzymes – i.e. electron carriers NADH or FADH2; vitamins

Question 70

Competitive inhibitors

Answer 70

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

Question 71

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

Answer 71

Noncompetitive inhibitors

Question 72

Some inhibitors are toxins, poisons, pesticides, and antibiotics

Answer 72

true

Question 73

Regulation needed to prevent chemical CHAOS

Answer 73

Allosteric regulators can speed up or slow down enzyme activity