Bioenergética do metabolismo celular: ATP e exercício físico
DOI:
https://doi.org/10.33233/rbfe.v8i4.3595Abstract
A constância do meio interno (homeostase) é crucial para a vida. A habilidade dos organismos vivos em realizar trabalho (função) depende do suprimento contínuo de energia, o qual é garantido pelo fluxo energético do meio externo para nutrientes dentro da célula. O fluxo ajustado de matéria prima (de energia) entre a célula e o meio, seguido por consumo da célula e eliminação de produtos para o meio celular caracteriza o estado estacionário. A liberação de energia de nutrientes é acompanhada pela maquinaria bioquímica da célula através de reações químicas acopladas e associadas seqüencialmente (vias metabólicas). Essas vias permitem a liberação gradual de energia livre, estocada em ligações químicas entre átomos dentro de moléculas biológicas (carboidratos, lipídios e proteínas), em adequados pacotes energéticos os quais são usados para fosforilar o ADP í ATP. Dessa maneira, a forma de utilização universal de energia celular é conservada em ligações fosfatos da molécula de ATP, a qual é considerada a moeda energética celular. As duas vias metabólicas, aeróbia e anaeróbia, diferem em complexidade. Quantomais complexa a estrutura química da molécula orgânica, mais longo é o tempo para degradá-la e mais alta é a produção de ATP. Logo, o organismo prioriza uma ou outra via metabólica de acordo com a demanda energética específica, a qual é estabelecida pelo modo, intensidade, volume e freqüência da atividade física.
Palavras-chave: exercício físico, ATP, metabolismo, energia livre, bioquímica do exercício.
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