Introduction
This guide is an introduction to the processes underlying cellular
metabolism and respiration. Metabolism is the process by which living
organisms acquire energy from external sources and utilize it internally in
order to carry out necessary cellular activities. Respiration is a means of
acquiring energy through biological degradation of food molecules.
In reviewing these processes, we will learn how
eukaryotic animals convert
ingested food
into energy they can use to function. We will also learn about the essential
role of molecular oxygen in the respiratory and metabolic processes. These
concepts provide an understanding of how and why food and oxygen are such
critical resources to most living organisms.
In this introduction to the topic, we will introduce some of the key concepts in
the study of cellular metabolism and respiration. Before we jump into our
discussions of metabolism and respiration, we will first explore the ultimate
goals of metabolism: energy. We will discuss the main energy source of humans,
adenosine triphosphate (ATP), as well as other essential biomolecules. We
will next discuss some of the broad concepts behind metabolism and respiration.
In the SparkNotes on Cell Metabolism and Respiration following this
introduction, we will make a more detailed examination of the various reactions
that occur the delivery of a food source to a cell through its conversion into
an energy source: glycolysis, the
metabolism of glucose; the citric acid
cycle; and oxidative
phosphorylation and electron
transport.
