(Biol 211) Chap 9- Cellular Respiration: Harvesting Chemical Energy

Front 1

Energy flow and chemical recycling in ecosystem:

Back 1

Front 2

Fermentation:

Back 2

a partial degradation of sugars that occur without the use of oxygen

Front 3

Aerobic respiration:

Back 3

oxygen is consumed as a reactant along with the organic fuel

Front 4

aer =

Back 4

air

Front 5

bios =

Back 5

life

Front 6

anerobic respiration:

Back 6

processing harvests chemicals without using any oxygen.

Front 7

an =

Back 7

without

Front 8

cellular respiration:

Back 8

include both aerobic and anerobic processes, but is often used to refer to the aerobic process.

Front 9

overall process of aerobic respiration:

Back 9

Front 10

cellular respiration in the degradation of the sugar glucose:

Back 10

- breakdown of glucose is exergonic having a free energy change of -686kcal (-2,870kJ) per mole of glucose decomposed.

- recall that a -delta G indicates that the products of the chemical reaction can happen spontaneously.

Front 11

what is the fuel that cells most often use?

Back 11

glucose

Front 12

Redox reactions:

Back 12

electron transfer reactions

Front 13

Oxidation:

Back 13

- the loss of electrons from one substance

- reducing agent

Front 14

reduction:

Back 14

- addition of electrons to another substance

- oxidizing agent

Front 15

The redox reaction of respiration:

Back 15

- the oxidation of glucose transfers electrons to the lower energy state, liberating energy that becomes available for ATP synthesis.

Front 16

NAD+

Back 16

(nicotinamide adenine dinucelotide)

- an electron acceptor

- functions as an oxidizing agent during respiration

Front 17

How does NAD+ trap electrons from glucose and other organic molecules?

Back 17

enzymes called dehydrogenases remove a pari of hydrogen atoms (2 electrons & 2 protons) from the substrante therefore oxidizing it. The enzyme delivers the 2 electrons along with 1 proton to the coenzyme NAD+. The other proton is released as hydrogen ion (H+) into the surrounding solution.

Front 18

NAD+ as an electron shuttle:

Back 18

Front 19

What does each NADH molecule formed during respiration represent?

Back 19

stored energy that can be tapped to make ATP when the electrons complete their "fall" down an energy gradient from NADH to odygen.

Front 20

Electron Transport Chain:

Back 20

- consists of a number of molecules, mostly proteins, built into the inner membrane of mitochondria of eukaryotic cells and the plasma membrane of aerobically respiring prokaryotes.

- oxygen pulls electrons down the chain into an energy-yielding tumble analogous to gravity pulling objects downhill.

Front 21

during cellular respiration, most electrons travel the following "downhill" route:

Back 21

glucose --> NADH --> electron transport chain --> oxygen.

Front 22

Respiration is a cumulative function of what three metabolic stages?

Back 22

Front 23

An overview of cellular respiration:

Back 23

Front 24

Glycolysis:

Back 24

occurs in the cytosol, begins the degradation process by breaking glucose into two molecules of a compound called pyruvate.

"sugar splitting"

- occurs whether or not oxygen is present. (however, if oxygen is present, the chemical energy stored in pyruvate and NADH can be extracted by the citric acid cycle and oxidative phosphorylation.

Front 25

Citric Acid Cycle:

Back 25

takes place within the mitochondrial matrix of eukaryotic cells or simply the cytosol of prokaryotes,

completes the breakdown of glucose by oxidizing a derivative of pyruvate to carbon dioxide.

Front 26

Oxidative Phosphorylation:

Back 26

- ATP synthesis from energy released at each step of the chain, it is powered by the redox reactions of the electron transport chain.

- occurs in teh inner membrane of the mitochondrion

- accounts for almost 90% of the ATP generated by respiration.

Front 27

Substrate-level Phosphorylation:

Back 27

- the production of smaller amounts of ATP in teh reactions of glycolysis & the citric acid cycle.

- occurs when an enzyme transfers a phosphate group from a substrate molecule to ADP, rather than adding an inorganic phosphate to ADP.

Front 28

"substrate molecules" refer to what?

Back 28

to an organic molecule generated as an intermediate during the catabolism of glucose.

Front 29

compare and contrast aerobic and anaerobic respiration

Back 29

Front 30

The energy input and output of glycoolysis:

Back 30

Front 31

A closer look at glycolysis:

Back 31