AP BIO / UNIT 2 - CELLULAR RESPIRATION

Cellular respiration and fermentation

cellular respiration

cellular respiration

most efficient catabolic pathway, also called aerobic respiration (even though utilizes both aerobic and anaerobic)

oxidative reaction

A reaction that causes the loss of electrons

reductive reaction

A reaction that causes a gain in electrons

ATP (adenosine triphosphate)

the molecule that drives most cellular work, energy source

ADP

a building block for ATP that is already found in the mitochondria

oxidative phosphorylation

Final step of cellular respiration, occurs in the mitochondrial membrane, made up of two parts (electron transport, and chemiosmosis), produces almost 90% of the ATP made from respiration

electron transport chain

Another name for oxidative phosphorylation

cristae

The inner folded membrane of the mitochondria where oxidative phosphorylation occurs

aerobic respiration

consumes organic molecules and oxygen, and yields ATP

citric acid cycle (aka Krebs cycle)

Second step of cellular respiration, occurs in the mitochondrial matrix, finishes the breakdown of the glucose, makes a majority of the electron carriers used in the ETC, makes a majority of the CO_2, reaction called substrate-level phosphorylation

ATP synthase

functions in chemiosmosis, uses energy of hydrogen to make ATP

matrix

the cytosol-like center of the mitochondria where the citric acid cycle occurs

high energy phosphate bond phosphorylation

the last bond between phosphates that creates ATP from ADP

when broken, releases energy for cellular processes

NAD⁺ / NADH (nicotinamide adenine dinucldeotuide)

one of the two electron carriers used in cellular respiration, it carriers 2 electrons and 1 hydrogen

FAD / FADH₂

one of the two electron carriers used in cellular respiration, it carriers 2 electrons and 2 hydrogen

anaerobic respiration

consumes compounds other than oxygen

glycolysis

First step of cellular respiration, occurs in the cytosol, starts the breakdown of glucose, reaction called substrate-level phosphorylation

pyruvic acid (aka pyruvate)

Product of glucose (through glycolysis), and either goes through fermentation or continues through the citric acid cycle as acetyl CoA

acetyl CoA (acetyl coenzyme A)

the reactant used in the Krebs cycle, made from pyruvate (made by the link reaction/pyruvate oxidation)

lactic acid

used to make cheese and yogurt, made from pyruvate (lactic acid fermentation), causes the muscle burn during intense physical activity

chemiosmotic gradient phosphorylation

the flow of H+ across the mitochondria membrane

ton of H+ in the intermembrane space that flow into the matrix

alcoholic fermentation

pyruvate is converted into ethanol, 2 steps:

1 - releases CO₂ from the pyruvate, and converts it to acetaldehyde (two-carbon compound)

2 - the acetaldehyde is reduced by NADH to ethanol (recycles NAD⁺)

lactic acid fermentation

pyruvate is reduced by NADH to form lactate (ionized form of lactic acid)

catabolism

A reaction that breaks down things

anabolism

A reaction that builds up things

aerobic respiration formula

C₆H₁₂O₂ + 6O₂ → 6CO₂ + 6H₂O + 38 ATP

3 (main) steps of cellular respiration

glycolysis, citric acid cycle, oxidative phosphorylation

what is used in glycolysis

glucose

what is produced in glycolysis

2 (net) ATP, 2 pyruvate, 2 NADH

what is used in the citric acid cycle

2 acetyl Co A

what is produced in the citric acid cycle

4 CO₂, 6 NADH, 2 FADH₂, 2 ATP

what is used in oxidative phosphorylation

6 O₂ (brought in), 10 NADH, 2 FADH₂

what is produced in oxidative phosphorylation

34 ATP, 6 H₂O

Link reaction (aka pyruvate oxidation)

The process between glycolysis and the citric acid cycle where the pyruvate is oxidized into acetyl CoA

what is used in the link reaction

2 pyruvate

what is produced in the link reaction

2 acetyl CoA, 2 CO₂, 2 NADH

role of electron carriers in cellular respiration (ex: NAD⁺)

to carry what is stripped from the glucose as it’s breaking down (2 electrons + 1 *or 2* proton*s*), and bring them to the last step to contribute to the products

fermentation process

glycolysis combined with reactions that regenerate NAD⁺ by transferring electrons from NADH to pyruvate/pyruvate derivatives (allows NAD⁺ to be reused)

necessity of fermentation

allows glycolysis to produce ATP, and then recycles the NADH back into NAD⁺ to continue the production of ATP when there’s little O₂

pyruvate in alcohol fermentation vs lactic acid fermentation

used to make either alcohol or lactic acid, and goes through 2 steps or 1,

ATP production in each stage

2 (net) in glycolysis, 2 in the citric acid cycle, and 34 in oxidative phosphorylation (a range of ATP is made, 38 is the higher end)

how ATP is recycled

when the high energy phosphate bond is broken in the ATP for energy, it goes back to ADP

the ADP repeats the cycle to continue making ATP

how much ATP is produced overall

around 38

what is added to NAD⁺, FAD, ½O₂, and why

2 electrons each, because the hydrogen molecules being added have a positive charge

fermentation

catabolic process, partial degradation of sugars and other organic fuels without oxygen (anaerobic process)

substrate-level phosphorylation

when an enzyme transfers a phosphate group from a substrate molecule to ADP in order to make ATP

oxidative phosphorylation (level of ATP production)

addition of an inorganic phosphate to ADP in order to make ATP

chemiosmosis

powers ATP synthesis with the flow of H⁺ back across the membrane (by moving energy stored in the hydrogen)

electron transport (step of oxidative phosphorylation)

transportation of electrons and pumping of protons, which creates an H⁺ gradient outside the membrane