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How do proteins support movement, transport, and chemical reactions in cells?

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A herd of African elephants stands at the edge of the Chobe River in Botswana, drinking water with a backdrop of dry hills and scattered green trees. — life A herd of African elephants (*Loxodonta africana*) drinking from the Chobe River, Botswana.

Proteins are essential to cellular function, acting as the primary agents for movement, transport, and chemical regulation within the cell.

Chemical Reactions

Proteins known as enzymes function as biological catalysts, significantly increasing the rate of specific biochemical reactions without being consumed in the process. By lowering the activation energy required for reactions, enzymes enable vital processes—such as the breakdown of nutrients or the synthesis of cellular components—to occur at speeds necessary for life. Their activity is highly specific and can be regulated by allosteric effectors, which bind to the protein to change its shape and modulate reaction rates.123

Movement

Cellular movement is driven by specialized contractile proteins, most notably actin and myosin. These proteins form filaments that slide past one another to generate force, a process powered by the hydrolysis of ATP. Beyond muscle contraction, these motor proteins facilitate cytoplasmic streaming and structural changes that allow cells to move, change shape, and divide.546

Transport

Proteins embedded in the cell membrane act as gatekeepers for the cell. They facilitate the movement of large or charged molecules—such as glucose and various ions—that cannot pass through the lipid bilayer alone. While some proteins act as passive channels or facilitators, others function as active pumps, utilizing energy from ATP to transport substances against their concentration gradients.782