Mitochondria Overview

These flashcards cover key vocabulary terms related to mitochondria, their structure, functions, and metabolic processes.

Mitochondria

Organelles known as the powerhouses of the cell, responsible for producing ATP.

Matrix

The innermost compartment of the mitochondrion containing enzymes, ribosomes, and DNA.

Cristae

Infoldings of the inner mitochondrial membrane that increase surface area for ATP synthesis.

Outer membrane

The lipid bilayer that encloses the mitochondrion.

Inner membrane

The membrane that contains proteins for the electron transport chain and ATP synthase.

Intermembrane space

The space between the outer and inner membranes of the mitochondrion.

Oxidative phosphorylation

The metabolic pathway where ATP is formed as electrons are transferred through the electron transport chain.

Endosymbiont hypothesis

The theory that mitochondria originated from free-living bacteria that were engulfed by a primitive eukaryotic cell.

Mitochondrial genome

The circular DNA found in mitochondria that codes for some mitochondrial proteins.

Porins

Proteins that form pores in the outer mitochondrial membrane.

ATP synthase

An enzyme that synthesizes ATP from ADP and inorganic phosphate using a proton gradient.

Citric acid cycle

A series of enzymatic reactions in the mitochondrial matrix that generates NADH and FADH2.

Glycolysis

The breakdown of glucose to pyruvate, producing ATP and NADH, typically occurring in the cytoplasm.

Pyruvate

A three-carbon molecule that is a key intermediate in several metabolic pathways.

NADH

A reduced form of nicotinamide adenine dinucleotide that carries electrons to the electron transport chain.

FADH2

A reduced form of flavin adenine dinucleotide that also donates electrons to the electron transport chain.

Reactive oxygen species (ROS)

Chemically reactive molecules containing oxygen, which can damage cellular components.

Chemiosmosis

The process of ATP formation driven by the proton gradient across a membrane.

Drp1

A protein involved in mitochondrial fission.

Mfn1 and Mfn2

Proteins involved in mitochondrial fusion.

Mitochondrial biogenesis

The process by which new mitochondria are formed in the cell.

Mitochondrial dynamics

The balance between mitochondrial fission and fusion that affects mitochondrial function.

Ubiquinone

A mobile electron carrier in the mitochondrial electron transport chain.

Complex I

NADH dehydrogenase, the first enzyme complex in the electron transport chain.

Complex II

Succinate dehydrogenase, which feeds electrons from FADH2 to the electron transport chain.

Complex III

Cytochrome bc1 complex, transferring electrons from ubiquinol to cytochrome c.

Complex IV

Cytochrome c oxidase, which transfers electrons to oxygen, forming water.

ATP/ADP antiporter

A transporter that exchanges ATP out of the mitochondrion for ADP.

Mitochondrial protein import

The process by which mitochondria import proteins synthesized in the cytosol.

Import machinery

Proteins that facilitate the transport of proteins into mitochondria.

Cardiolipin

A unique phospholipid found in the inner mitochondrial membrane.

Cytochrome c

A heme protein involved in the electron transport chain.

Oxidative phosphorylation efficiency

The ability of mitochondria to produce ATP using the proton-motive force.

Proton gradient

The concentration difference of protons across the inner mitochondrial membrane.

Electrons transport chain

A series of complexes that transfer electrons and pump protons to create a gradient.

Calcium ion homeostasis

The regulation of calcium levels in the mitochondria, important for cellular signaling.

Metabolic pathways

Biochemical routes that convert substrates into products, utilizing enzymes.

Mitochondrial diseases

Disorders caused by dysfunction in mitochondria, often affecting energy production.

mitoribosomes

Ribosomes within mitochondria that synthesize some mitochondrial proteins.

Endosymbiosis

The theory explaining the origin of mitochondria as derived from engulfed prokaryotes.

Mitochondrial membranes

The outer and inner membranes that define the organelle's structure and function.

Fatty acid oxidation

The process of breaking down fatty acids to generate acetyl-CoA for energy.

Thermogenesis

The process of heat production in organisms, occurring in brown adipose tissue.

Metabolic coupling

The interconnection of metabolic pathways to facilitate energy transfer.

Metabolites

Small molecules produced during metabolic reactions.

Apoptosis

Programmed cell death, regulated by mitochondria.

Signal transduction

The process by which cells respond to external signals through biochemical pathways.

Integration of pathways

The coordination of different metabolic pathways in mitochondria.

Electron carriers

Molecules that transport electrons through the electron transport chain.

Redox potential

The tendency of a molecule to gain or lose electrons.

Substrate-level phosphorylation

The direct synthesis of ATP from ADP and a substrate.

Nutrient oxidation

The breakdown of nutrients to release energy stored in chemical bonds.

Energy metabolism

The set of biochemical processes that convert food into energy.