Mmg Energy And Bioenergetics

Front 1

What are key points to defining/explaining bioenergetics?

Back 1

-how cells use biochemical reactions (metabolism) to obtain energy
-associated with breaking of covalent bonds which releases energy
-released energy is trapped of dissipated as heat
-available energy is free energy (G) in kJ

Front 2

When delta G is negative what is it?
Positive?

Back 2

-exergonic
-endergonic

Front 3

What is activation energy?

Back 3

-the energy required to bring reactants to the reactive state
*catalyst in chemical reactions
*enzymes in cellular reactions

Front 4

What is an enzyme for?

Back 4

-increases speed or rate of reaction
-NOT altered in reaction

Front 5

Describe an enzyme.

Back 5

-usually a protein (except catalytic RNA)
-specific for a given substrate becuase of its tertiary/quaternary structure

Front 6

What is the reduction potential?

Back 6

-a measurement in volts of tendency to become oxidized or reduced
*the greater reduction potential between reactants, the greater the energy released!

Front 7

What does NAD+ stand for?

Back 7

-Nicotinamine adenine dinucleotide

Front 8

What is NAD?

Back 8

-an electron carrier that's freely diffusable in a cell
-When oxidized, it accepts and transports electrons and hydrogens
-when reduced, donates them
-NAD/NADH-energy generating catabolic pathways
-NADP/NADPH-anabolic pathways

Front 9

How does NAD work as a coenzyme?

Back 9

-it is regenerated after acting as a coenzyme in a two-part reaction

Front 10

How is energy from redox reations retained?
When is it released?

Back 10

-put in high-energy phosphate bonds (can be easily released for anabolic reactions)
-hydrolysis of phosphate bond

Front 11

Which bond releases more energy when phosphate is hydrolized?

Back 11

-anhydride bonds (unstable) release more than ester bonds

Front 12

What are the three levels of phosphorylation?

Back 12

-Substrate level
-Oxidative
-Photophosphorylation

Front 13

What happens in substrate level phosphorylation?

Back 13

-ATP is synthesized in steps in catabolism of organic molecule through transfer from phosphorylated intermediates

Front 14

What happens in oxidative AND photophosphorylation?

Back 14

-ATP is synthesized by membrane bound ATP synthase coupled to the protonmotive force

Front 15

How much ATP is produced in aerobic respiration?
Anaerobic?
Fermentation?

Back 15

-36 to 38
-2 to 36
-2

Front 16

What are the three pathways for respiration from start to finish?

Back 16

-glycolysis
-synthesis of acetyl CoA and Krebs cycle
-Aerobic electron transport chain

Front 17

What do you get from gycolysis in terms of ATP and NADH?

Back 17

-2 of each molecule
*look up for detailed reactions

Front 18

Why is more ATP generated through respiration compared to fermentation?

Back 18

-organic molecule is completely oxidized to CO2
-greater difference in reduction potentials between donor and terminal electron acceptor (O2): occurs in aerobic bacteria, eukaryotic mitochondria

Front 19

Draw the sythesis of acetyl-CoA

Back 19

.

Front 20

Draw Krebs cycle

Back 20

.

Front 21

What couples ATP synthesis to redox reations in respiration?

Back 21

-through a membrane-bound electron transport chain

Front 22

What are 5 electron carriers?

Back 22

1) NADH dehydrogenase
2) Flavoproteins
3) Iron-sulfur proteins
4) Cytochromes-heme
5) Quinones-nonprotein
*see E and B lecture for diagrams

Front 23

What is chemiosmosis?

Back 23

-coupling of protonmotive force to ATP synthesis which using F1/F0 ATP synthase

Front 24

How does chemiosmosis work?

Back 24

-H+ ions flow down electrochemical gradient (propelled by prton motive force) through ATP synthases that phosphorylate ADP to ATP

Front 25

How many molecules at ATP are formed from one molecule of glucose?

Back 25

-34

Front 26

What creates the proton gradient in chemiosmosis?
What's this called?

Back 26

-created by oxidation of components of electron transport chain
-called oxidative phosphorylation

Front 27

What do inhibitors do in chemiosmosis? Which ones?

Back 27

-block electron flow
-CO, CN (inhibit cytochromes)

Front 28

What do uncouplers do in chemiosmosis?
Which one?

Back 28

-prevent ATP synthesis without affecting electron flow
-dinitrophenol

Front 29

What are three random facts about fermentation?

Back 29

-regeneration of NAD+ for use in ATP production during glycolysis
-allows ATP sythesis in the absence of respiration
-byproducts are not useful to microbes (waste products) but are for humans!

Front 30

What fermentation product does each one make from pyruvic acid?
Propionibacterium
Bacillus/Lacto/strepto
Saccharomyces
Clostridium
E. acetobacter

Back 30

-CO2 propionic acid (swiss cheese)
-lactic acid
-CO2 ethanol
-acetone, isopropanol
-acetic acid

Front 31

In photosynthetic anabolism, what do organisms do first?
Then what?

Back 31

-synthesize organic molecules from inorganic CO2
-many capture light energy to get carbohydrates from CO2 and water (AKA photosynthesis)

Front 32

How do organisms catch light energy?

Back 32

-use pigment molecules (most importantly chlorophylls)
-varying length adn structure of chlorophylls and their tails cause different wavelengths to be absorbed

Front 33

What are chlorophylls composed of?

Back 33

-hydrocarbon tail attached to light-absorbing active site centered around manesium ion

Front 34

What are photosystems?

Back 34

-light harvesting matrices that contain chlorophyll molecules and found embedded in cellular membranes called thylakoids

Front 35

How are thylakoids formed in prokaryotes?
Eukaryotes?

Back 35

-invagination of cytoplasmic membrane
-formed from infoldings of inner membrane of chloroplasts

Front 36

What are the two types of photosystems?

Back 36

-PS I
-PS II

Front 37

What is used to generate ATP in photophosphorylation?

Back 37

-proton motive force

Front 38

What are two types of photophosphorylation?

Back 38

-cyclic
-noncyclic

Front 39

What are light independent reactions?

Back 39

-do not require light directly but use ATP and NADPH generated by light dependent reactions

Front 40

What is the key reaction for light independent reactions?

Back 40

-carbon fixation by Calvin Benson cycle

Front 41

Describe carbon fixation using the Calvin Benson cycle

Back 41

-for every 3 CO2 that enter cycle, one molecule of glyceraldehyde 3-phosphate leaves
-for every two of these, onle molecule of glucose 6-phosphate in anabolically synthesized by glycolysis

Front 42

What do anabolic reacions require and why?

Back 42

-energy and source of metabolites because it is a synthesis reaction

Front 43

How do anabolic reactions compare to catabolic pathways?

Back 43

-often the reversal of them

Front 44

What are amphibolic reactions?

Back 44

-can prceed in either direction

Front 45

What three pathways provide the basic precursers to which all macromolecules and structures are made? How many?

Back 45

-Glycolysis, the Krebs Cycle, and the pentose phosphate pathway
-12 precursers

Front 46

See simplified view of central metabolism in E and B lecture.

Back 46

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