MOL100H23 lecture 14-cellular energetics 1

ATP (adenosine triphosphate)

The universal energy "currency" that provides energy for chemical reactions, movement, and heat production in cells.

Hydrolysis

The process of breaking down ATP into ADP (adenosine diphosphate) and inorganic phosphate, releasing energy.

Endergonic reactions

Reactions that require energy input to proceed.

Exergonic reactions

Reactions that release energy.

Heterotrophic organisms

Organisms that obtain nutrients (carbohydrates, fat, amino acids) from external sources to produce ATP.

Autotrophic organisms

Organisms that can generate nutrients from small compounds like carbon dioxide to produce ATP.

Glycolysis

The anaerobic process in which glucose is broken down into two molecules of pyruvate, generating ATP and NADH.

Anaerobic oxidation

The fermentation of pyruvate in the absence of oxygen, producing lactic acid or ethanol.

Mitochondria

Organelles responsible for ATP generation and biosynthesis of other molecules in eukaryotic cells.

Cristae

Infoldings of the inner membrane of mitochondria.

Matrix

The innermost compartment within the inner membrane of mitochondria.

Endosymbiosis

The theory that mitochondria originated from bacteria that were engulfed by a host cell.

Mitochondrial DNA (mtDNA)

Circular DNA molecules found in mitochondria that encode for proteins.

Glycosidic bonds

Bonds formed between carbohydrates to create polysaccharides.

Pyruvate kinase

An enzyme involved in glycolysis that is inhibited by ATP in the presence of high levels of ATP.

Allosteric regulation

Regulation of enzyme activity by binding of molecules at sites other than the active site.

Fermentation

The process of anaerobic oxidation of pyruvate to produce lactic acid or ethanol.

Glucose oxidation

The process of breaking down glucose to produce energy.

Glycolysis

The first step of glucose oxidation, which takes place in the cytosol and generates 2 ATP molecules.

Citric acid cycle

The second step of glucose oxidation, which occurs in the mitochondrial matrix and generates NADH and FADH2.

Electron transport chain

The third step of glucose oxidation, where NADH and FADH2 transfer electrons to generate ATP.

ATP synthesis

The fourth and final step of glucose oxidation, where ATP is produced.

Cytosol

The fluid portion of the cytoplasm where glycolysis takes place.

Mitochondrion

The organelle where the citric acid cycle, electron transport chain, and ATP synthesis occur.

Pyruvate

The product of glycolysis, which is imported into the mitochondrial matrix.

Acetyl CoA

A molecule formed from the processing of pyruvate, which enters the citric acid cycle.

NADH

A molecule generated during the citric acid cycle, which serves as an electron carrier.

FADH2

A molecule generated during the citric acid cycle, which also serves as an electron carrier.

Krebs cycle

Another name for the citric acid cycle.

Tricarbolic acid (TCA) cycle

Another name for the citric acid cycle.

Hans Adolf Krebs

The scientist who discovered the citric acid cycle.

Fatty acids

An additional source of acetyl-CoA that can be processed in the citric acid cycle.

Electron donor

A molecule that donates electrons to the electron transport chain.

Proton motive force

The energy generated by the electron transport chain, which drives ATP synthesis.

Prosthetic groups

Non-protein molecules that bind to protein complexes in the electron transport chain.

ATP synthase

The enzyme responsible for synthesizing ATP in the inner mitochondrial membrane.

ATP synthase

An enzyme located in the inner mitochondrial membrane that is responsible for the synthesis of ATP.

FO subcomplex

One of the two subcomplexes of ATP synthase, consisting of three types of subunits (a, b, and c).

c-ring

The arrangement of c units in ATP synthase, forming a ring structure.

F1 subcomplex

The other subcomplex of ATP synthase, composed of subunits α, β, γ, δ, and ε.

Proton flow

The movement of protons through ATP synthase, inducing rotation of the c-ring.

γ subunit

The subunit of ATP synthase that is connected to the c-ring and rotates together with it.

ADP/ATP binding sites

Sites in the β subunits of ATP synthase where ADP and ATP molecules can bind.

Conformations

Different states or conformations of the β subunits in ATP synthase, including O (open), L (loose), and T (tight).