AP Bio: Cell Resp

heterotroph

organisms that obtain energy from the food it consumes; also called a consumer

electron carrier

a compound that can accept a pair of high-energy electrons and transfer them along with most of their energy to another molecule

NADP+

one of the carrier molecules that transfers high energy electrons from chlorophyll to other molecules- when reduced becomes NADPH

ATP

adenosine triphosphate; a nucleotide that serves as the energy currency for the cell

ADP

adenosine diphosophate; after ATP has lost a phosphate group in its less energized form

cellular respiration

process that releases energy by breaking down glucose and other food molecules in the presence of oxygen

glycolysis

the first step in releasing the energy of glucose, in which a molecule of glucose is broken into two molecules of pyruvic acid

Krebs cycle

second stage of cellular respiration in which pyruvic acid is broken down into carbon dioxide in a series of energy-extracting reactions

Electron Transport Chain

a series of proteins in which the high-energy electrons from the Krebs cycle are used to convert ADP into ATP

aerobic

process that requires oxygen

anaerobic

process that does not require oxygen

fermentation

process by which cells release energy in the absence of oxygen

lactic acid fermentation

Type of fermentation which produces lactic acid as a byproduct. formula: pyruvic acid + NADH--> lactic acid + NAD+ Produced during vigorous exercise as your muscles run out of oxygen

alcohol fermentation

type of fermentation which produces ethyl alcohol and carbon dioxide as wastes Formula: pyruvic acid + NADH--> alcohol + CO2 + NAD+ (used by yeasts and microorganisms)

NAD+

one of two energy carrier molecules used during cellular respiration; when reduced becomes NADH

FAD

one of two energy carrier molecules used during cellular respiration; when reduced becomes FADH2

ATP synthase

Enzyme that grabs a low energy ADP and attaches a phosphate forming high energy ATP during the third stage (electron transport chain) of cellular respiration

cellular respiration formula

C6H12O6 + O2 --> CO2 + H2O + ATP

reduction

gain of electrons

oxidation

loss of electrons

redox reaction

A chemical reaction involving the transfer of one or more electrons from one reactant to another; also called oxidation-reduction reaction.

substrate-level phosphorylation

The formation of ATP by directly transferring a phosphate group to ADP from an intermediate substrate in catabolism.

oxidative phosphorylation

The production of ATP using energy derived from the redox reactions of an electron transport chain; the third major stage of cellular respiration.

chemiosmosis

A process for synthesizing ATP that involves the movement of hydrogen ions (protons) across a selectively permeable membrane, driven by an electrochemical gradient created by the electron transport chain. During chemiosmosis, ATP synthase catalyzes the reaction by allowing protons to flow back into the mitochondrial matrix, using their kinetic energy to convert ADP and inorganic phosphate into ATP, thus producing energy for cellular functions.

Decoupling Oxidative Phosphorylation

process by which the electron transport chain generates heat instead of ATP

Pyruvate

Three-carbon compound that forms as an end product of glycolysis.

proton-motive force

The potential energy stored in the form of an electrochemical gradient, generated by the pumping of hydrogen ions across biological membranes during chemiosmosis.

reducing agent

Donates electrons and becomes oxidized.

oxidizing agent

Accepts electrons and becomes reduced.

uncoupling proteins

These allow for protons to reenter the matrix without energy being captured as ATP by disconnecting ATP synthase. Energy is released as heat (non shivering thermogenesis)

What molecule is oxidized in cellular respiration?

Glucose (C6H12O6) is oxidized during cellular respiration.

energy payoff phase

The phase of glycolysis where 4 ATP is produced, resulting in a net gain of 2 ATP for the cell.

oxaloacetate

A four-carbon molecule that combines with acetyl-CoA to enter the Krebs cycle, playing a crucial role in cellular respiration.

location of glycolysis

cytoplasm of the cell.

location of Krebs cycle

mitochondrial matrix

location of electron transport chain

inner membrane of the mitochondria.

Pyruvate Dehydrogenase

A multi-enzyme complex crucial for cellular respiration that converts pyruvate, the end product of glycolysis, into acetyl-CoA. This reaction is essential as acetyl-CoA enters the Krebs cycle, and is coupled with the release of carbon dioxide and the reduction of NAD+ to NADH.

Alcohol Fermentation

An anaerobic process wherein sugars such as glucose are converted into ethanol and carbon dioxide by yeast and some bacteria. This metabolic pathway yields energy in the absence of oxygen, producing ethanol as a byproduct, and is utilized in the production of alcoholic beverages and bread.

Lactic Acid Fermentation

A metabolic process that occurs in the absence of oxygen, where glucose is partially broken down to lactic acid, allowing for ATP production in situations such as intense exercise when oxygen is scarce. This process occurs in muscle cells and certain bacteria, and is also responsible for the sourness in yogurt.

Deamination

A biochemical process where an amino group (NH2) is removed from an amino acid or other organic compound. Deamination is critical for the metabolism of proteins, as it converts amino acids into intermediates that can enter the Krebs cycle while releasing ammonia, which is excreted as urea.

Beta Oxidation

A catabolic process that takes place in the mitochondria, where fatty acids are broken down into two-carbon fragments called acetyl-CoA. This process is a key source of energy during prolonged fasting or intense exercise, allowing fats to be used as an efficient fuel source.

Negative Feedback Inhibition

A regulatory mechanism in cellular metabolism where the accumulation of a product inhibits the activity of an enzyme involved in its synthesis. This process helps to maintain homeostasis within the cell, preventing the overproduction of metabolites and ensuring metabolic balance.