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cytochrome c
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A branching phylogenetic tree diagram shows evolutionary relationships among various organisms, from Neurospora mold to humans, based on differences in cytochrome c gene sequences. Each branch is labeled with nucleotide substitution values and illustrated with animal or organism icons along the tree. Diagram comparing two phylogenetic trees based on molecular changes: one tree shows evolutionary relationships among four species using myoglobin changes, and the other compares humans, rhesus monkeys, and horses using cytochrome c changes, with arrows and numbers indicating the amount of molecular change between branches. A line graph compares the evolutionary rates of three proteins-fibrinopeptides (very fast), hemoglobin (intermediate), and cytochrome c (slow)-by showing amino acid changes per 100 residues over millions of years since divergence from a common ancestor, with geological time periods and major organism groups labeled along the axes.
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cytochrome c

chemical compound
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A branching phylogenetic tree diagram shows evolutionary relationships among various organisms, from Neurospora mold to humans, based on differences in cytochrome c gene sequences. Each branch is labeled with nucleotide substitution values and illustrated with animal or organism icons along the tree.
phylogeny Phylogeny based on differences in the protein sequence of cytochrome c.

Cytochromes are a group of hemoprotein cell components crucial for energy transfer within cells. These proteins contain an iron-bearing heme group that facilitates reversible oxidation and reduction reactions, acting as electron carriers, primarily within the mitochondria.1

Cytochromes are classified into three main types (a, b, and c) based on their light-absorption spectra. Cytochrome c is the most stable and abundant, making it the most extensively studied.1

In cellular respiration, cytochromes are part of the electron-transport chain. This chain involves a series of proteins embedded in the mitochondrial membrane that pass electrons, releasing energy at each step. This energy is used to synthesize adenosine triphosphate (ATP), the cell's energy currency. Cytochrome c specifically transfers electrons to the third complex of this chain, cytochrome oxidase.2

Cytochrome c also plays a role in apoptosis, or programmed cell death. When released from the mitochondria, it can trigger a cascade of events leading to cell self-destruction.3

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3 Britannica Sources
  1. cytochrome
  2. cell - The electron-transport chain
  3. apoptosis

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