Biology: Exam 2

Front 1

first law of thermodynamics

Back 1

energy cannot be created or destroyed

Front 2

2nd law of thermodynamics

Back 2

every reaction must increase disorder (entropy)

Front 3

nonspontaneous

Back 3

increase order -> requiring energy input

Front 4

free total energy

Back 4

portion of energy that can do wrk or be useful

Front 5

standard conditions

Back 5

1 atm, 25C, 1M of products and reactants

Front 6

ATP Adenosine triphosphate

Back 6

nucleotide w/ three terminal phosophates;
intermediate coupling exergonic and endergonic

Front 7

phosphorylation

Back 7

target reactant forms a covalent bond with phosphate;
phosphate = ionic and strongly hydrophillic, so changes structure

Front 8

endergonic + ATP

Back 8

phosphorylation makes exergonic

Front 9

enzyme effects on free energy

Back 9

activation energy lowered; does not change free energy

Front 10

analog

Back 10

compound similar to a substrate; but eventually the induced fit fails and catalysis never occurs

Front 11

catalysis mechanisms

Back 11

1. template for orientation
2. distortion
3. favorable environment
4. accepts or donates a proton/ shares electrons

Front 12

enzyme: optimal pH

Back 12

near neutrality (7)

Front 13

cofactors

Back 13

ions that participate in the enzyme-substrate binding

Front 14

coenzyme

Back 14

organic cofactor

Front 15

competitive inhibitor

Back 15

analog of the substrate that also binds to the active site

Front 16

noncompetitive inhibitor

Back 16

bind to a regulator or allosteric site; causing conformational changes

Front 17

cooperativity

Back 17

binding of a substrate at an intial active site causing confomation changes that transfer to the other subunits and increase their affinity for the substrate

Front 18

cellular respiration

Back 18

oxidation of organic molecules through catabolic pathways occuring largely in the mitochondria to produce ATP, CO2, and H2O

Front 19

glycolysis

Back 19

initial breakdown in the cytoplasm of the 6-carbon glucose molecule to two 3-C pyruvate

Front 20

citric acid cycle

Back 20

completion of glucose catabolism in mitochondia matrix as mostly electron transfer potential of e- carriers

Front 21

oxidative phosporylation

Back 21

conversion of e- transfer energy to chemical bond energy of ATP

Front 22

reducing agent

Back 22

donates the electrons

Front 23

oxidizing agent

Back 23

accepts the e-

Front 24

NAD+

Back 24

most ubiquitous electron carrier;
often acts as a coenzyme for dehydrogenases

Front 25

dehydrogenase

Back 25

family of enzymes that catalyze electron and proton transfer

Front 26

reduction of NAD+

Back 26

transfer of 2 e- and one proton to for NADH and one H+

Front 27

hexokinase

Back 27

immediately phosphorylates glucose;
renders it impermeant

Front 28

phophofructokinase (PFK)

Back 28

key regulatory enzyme; regulated by ATP
creates 2-three C isomers

Front 29

substrate level phosphorylation

Back 29

direct phosphorylation of ADP by transfer of a high energy phosphate bond from an organic substrate

Front 30

glycolysis: net energy yield

Back 30

2 ATP and 2 NADH

Front 31

citric acid cycle

Back 31

complete oxidation of pyruvate to acetyl coenzyme!; occurs in mitochondria

Front 32

citric acid cycle steps

Back 32

1. decarboxylate pyruvate
2. oxidize 2-C intermediate to acetate; reduces NAD+
3. forms thio ester bond between acetate and sulfur-containing coenzyme A

Front 33

citric acid cycle: net energy yield

Back 33

2 ATP; 3 NADH; FADH2

Front 34

oxidative phosphorylation

Back 34

conversion of electron transfer potential to ATP synthesis (mitochondrial membrane)

Front 35

electron transport chain

Back 35

electrons are transferred sequentially from low electron affinity compounds to greater e- affinity -> final acceptor O2

Front 36

ATP synthase

Back 36

hydrogen ion electrochemical gradient powers ADP phosphorylation

Front 37

chemiosmosis

Back 37

coupling of the h+ gradient w/ ATP synthesis

Front 38

oxidative phosporylation: net energy yield

Back 38

36-38 ATP

Front 39

fermentation

Back 39

used in anaerobic conditions;

Front 40

lactic acid fermentation

Back 40

regeneration of NAD+ substrate by oxidizing NADH -> reducing pyruvate to lactate

Front 41

alcohol fermentaion

Back 41

pyruvate is decarboxylated and reduced to ethanol -> oxidizing NADH

Front 42

phototrophs

Back 42

utilize photons to synthesize organic material and O2

Front 43

chloroplast

Back 43

site of trapping photon energy for organic synthesis

Front 44

photosynthesis

Back 44

reductive carboxylation for synthesis organic substrates
(mitochondria respiration = opposite)

Front 45

light reactions

Back 45

conversion of photon energy to reduction potential of NADPH + H+; ATP
uses oxidation of H2O

Front 46

Calvin cycle

Back 46

synthesis of organic compounds using ATP and NADPH + H+;
uses reduction of CO2

Front 47

carbon fixation

Back 47

initial incorporation of carbon from CO2 into an organic compound

Front 48

chloroplast envelope

Back 48

two outer membranes;
encloses the STROMA

Front 49

thylakoid

Back 49

flattened, connected membrane sacs

Front 50

granum

Back 50

stacks of thylakoid; connected by lamallae

Front 51

carbon fixation: location

Back 51

stroma

Front 52

light reactions: location

Back 52

thylakoid membrane

Front 53

types of pigment

Back 53

chlorophyll (a & b): main pigment
carotenoids
phycoerythrin
phycocyanin

Front 54

excited electon: options

Back 54

1. decay: heat and fluoresce
2. pass energy to neighboring pigment
3. pass excited electron to an acceptor molecule

Front 55

light harvesting complexes

Back 55

photon energy is transferred w/ increasing wavelength to special pairs of chlorophyll molecules in reaction center

Front 56

primary electron acceptor

Back 56

non-pigment electron acceptor

Front 57

reaction center

Back 57

pair of chlorophyll molecules; pass high energy e- to acceptor

Front 58

P680

Back 58

photosystem II

Front 59

P700

Back 59

photosystem I

Front 60

plastoquinone and ferrodoxin

Back 60

mobile elements, carry the high energy e- out of reaction centers and into transport chain

Front 61

electron binding affinity of chlorophyll P680

Back 61

greater than 02 -> why photon is needed to release e-; donor is HO

Front 62

electron binding affinity of chlorophyll P700

Back 62

less than P680

Front 63

O2 production

Back 63

4 photons needed

Front 64

noncyclic electron flow

Back 64

2H2O + 2 NADP+ + 8photons -> O2 + 2(NADPH + H+) + 2ATP

Front 65

cyclic electron flow - why necessary?

Back 65

produces ATP -> Calvin cycle requires a 3:2 NADPH to ATP

Front 66

cyclic electron flow

Back 66

PS 1: does not reduce NADP+ but contributes to additional H+ gradient,
producing only ATP

Front 67

carbon fixation: energy requirements

Back 67

driven by light reactions

Front 68

RuBP

Back 68

5-carbon compound; accepts CO2 -> immediately breaks into 2-three carbon compounds

Front 69

RuBP carboxylase

Back 69

AKA rubisco; aids in carboxylation and hydrolysis of RuBP
(most abundant protein)

Front 70

G3P

Back 70

product of Calvin cycle; transported to the stroma -> synthesize sugars, fats, amino acids

Front 71

synthesis of glucose: energy needs

Back 71

18 ATP; 12 NADPH

Front 72

photorespiration

Back 72

RuBP carboxylase adds O2 instead of CO2 to RuBP; occurs on hot days (low CO2 levels)
harmful to plant

Front 73

C4 cycle

Back 73

carboxylates PEP eventually to malate; malate transported to Calvin cycle
allows for concentrate CO2 levels

Front 74

PEP

Back 74

has a high affinity for CO2

Front 75

bundle-sheath cells

Back 75

contain RuBP carboxylase in C4 plants

Front 76

mesophyll

Back 76

contain enzymes for CO2 fixation; surround bundle-sheath

Front 77

CAM plants

Back 77

synthesize organic molecules at night to avoid heat.