Biology: Chapter 7 – Flashcards

a series of chemical reactions including the break down of molecules, releasing energy that can be used to do the work of the cell.

-glucose, fatty acids, or amino acids are partially broken down and energy is released. (glucose->pyruvate is called glycolysis). (cytoplasm). -pyruvate is converted to acetyl-CoA, and carbon dioxide is produced. (cytoplasm). -acetyl-CoA is broken down and carbon dioxide is released. (called the citric acid cycle). (mitochondria). -electron carriers produced in stages 1-3 donate their electrons to the electron transport chain, which then transfers them along a series of membrane-associated proteins to the final electron acceptor where ATP is produced. (called oxidative phosphorylation). (mitochondria).

molecules that store and transfer energy in the form of 'high-energy' or 'excited' electrons. the two important ones are (NAD+/NADH) and (FADH/FADH2). (oxidized/reduced forms). the more electron carriers, the smaller the delta G.

-glycolysis takes place in the cytoplasm. -oxidative phosphorylation takes place in the mitochondria. (electron transport chain is associated with the inner mitochondrial membrane).

-oxidation is the loss of electrons or a decrease in electron density. -reduction is the gain of electrons or an increase in electron density.

atom that gains electrons. also called an oxidizing agent.

atom that gives electrons. also called a reducing agent.

the breakdown of carbohydrates yields ATP, electron carriers, water, and carbon dioxide.

oxygen.

a way of generating ATP where a phosphate group is transferred to ADP from an organic molecule, which acts as a phosphate donor or substrate. produces only a small amount of ATP in cellular respiration.

the oxidation of glucose, and synthesis of two molecules of ATP (substrate-level phosphorylation) and two molecules of NADH. a six-carbon sugar is split into two three-carbon pyruvates anaerobically (no oxygen is consumed).

-preparation phase where two phosphate groups are added to glucose (requires 2 ATP), creating fructose 1,6-bisphosphate. -the cleavage phase. the six-carbon fructose molecule is split into two three-carbon glyceraldehyde 3-phosphates. -pyruvate production phase. 'payoff phase' because two pyruvates, four ATP and two NADH are produced. (net of only two ATP b/c two were used in phase one).

the space between the folded inner membrane and outer membrane in mitochondria.

the space enclosed by the inner mitochondrial membrane. where pyruvate is converted to acetyl-CoA.

-occurs when pyruvate enters the mitochondrial matrix. -pyruvate is oxidized and splits off to form carbon dioxide. -electrons are donated to NAD+, reducing to NADH. -the acetyl group is transferred to coenzyme A (CoA). -results in two molecules of carbon dioxide, NADH and acetyl-CoA. (one molecule each per pyruvate).

also called the Krebs cycle. it is where the chemical energy stored in the bonds of acetyl-CoA is transferred to ATP by substrate-level phosphorylation and to NADH/FADH2. also takes place in the mitochondrial matrix.

-eight reactions, starting and ending with the molecule oxaloacetate. -results in the complete oxidation of the acetyl group in acetyl-CoA. -two carbons are released as carbon dioxide in reactions 3/4. (the CO2 we exhale). the oxidation of carbon to carbon dioxide reduces NAD+ to NADH. -reactions 6/8 also produce electron carriers. -reaction 5 produces GTP which then goes through substrate-level phosphorylation to create ATP. -whole cycle produces six NADH, two FADH2, and two ATP. (double because of two acetyl-CoAs).

some bacteria run the citric acid cycle in reverse. it requires an input of energy, but it creates many intermediate molecules that can then be used throughout the cell, as well as reducing carbon dioxide levels.

electrons are transported along a series of four large protein complexes that form the ETC that are embedded in the mitochondrial inner membrane. the ETC produces 28 ATP.

NADH enter through complex I, FADH2 enter through complex II. they then move on to complexes III and IV. in complexes I and II, coenzyme Q accepts the electrons, and in complex III, cytochrome c does. all of these reductions produce an accumulation of protons in the intermembrane space.

this is an electrochemical gradient, and is a source of potential energy. Protons flow down their gradients, through the enzyme ATP synthase, and convert their potential energy to stored ATP.

an enzyme composed of two subunits: Fo and F1. Fo is the channel through which the protons flow, and F1 is the catalytic unit that synthesizes ATP. Protons flow through Fo, causing it to rotate, and therefore make a conformation change to F1 which then starts to produce ATP.

he built an artificial system with a membrane, bacterial proton pump, and light-activated ATP synthase. his experiments showed the proton concentration gradient significantly increasing with the lights on (producing more ATP), and depleting with the lights off (less ATP). this proved that the proton gradient drives the synthesis of ATP.

yields 32 molecules of ATP. (2-glycolysis, 2-citric acid cycle, 28-ETC).

the process in which pyruvate is broken down in the absence of oxygen. no net gain/loss of NADH/NAD+.

this is essential for glycolysis to continue. in aerobic respiration, NADH -> NAD+ when it enters the electron transport chain. in anaerobic respiration, it happens when pyruvate is reduced.

occurs in animals and bacteria. electrons from NADH are transferred to pyruvate to produce lactic acid and NAD+ which is then used again in glycolysis. produces 2 ATP, 2 lactic acid, and 2 waters.

occurs in plants and fungi. pyruvate releases carbon dioxide to form acetaldehyde, which NADH donates electrons to, to form ethanol and NAD+. produces 2 ATP, 2 ethanol, and 2 waters.

-animals: glycogen -plants: starch

disaccharides are hydrolyzed to form monosaccharides which then serve as intermediates in cellular respiration.

the process by which fatty acids are broken down and two carbon units are removed from their ends. this doesn't produce ATP, but it does produce lots of NADH and FADH2 used in oxidative phosphorylation.

produces large amounts of ATP. they are useful and efficient, but cannot however be used by all cells in the body.

it is inhibited by its products, and activated by its substrates.

an allosteric enzyme that regulates glycolysis.

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