respiration is a vital and complex process that occurs in every living
organism. It is simply the oxidative breakdown of complex organic molecules
such as glucose and starch into energy in the form of ATP (adenosine
triphosphate) along with carbon dioxide and water (Postharvest physiology textbook). Energy that is formed through
the process of cellular respiration aids in an organism’s metabolism, growth
and development of cells and tissues (Why
resp?). With the diverse range of animal and plant species, the process of
cellular respiration remains conservative as all organisms predominantly use
glucose and similar components to produce large amounts of energy (Why resp?).
understand how energy is acquired to maintain biological processes within an
organism, it is important to measure the metabolic rate. The metabolic rate is rate
of respiration through the consumption of oxygen and release of carbon dioxide
over the mass (e.g. grams) of an organism (Textbook).
The determination of an organism’s energy consumption is based upon the
respiratory quotient (R.Q.). The respiratory quotient is the ratio of CO2
produced to the amount of O2 consumed (Varients). The respiratory quotient indicates the oxidation of the
mixture of carbohydrates, fats and proteins involved in the metabolic substrate
used in tissues.
respiration quotient values for each substrate i.e. carbohydrates, lipids and
proteins can be found through its appropriate chemical equation (Biology: approach). In the case of
carbohydrates, a typical sugar such as glucose has an R.Q. value of 1.0 (Essential A2). Lipids have an R.Q.
value as low as 0.7 as it has less oxygen relative to the amount of carbon,
therefore for complete oxidation of lipids more oxygen is consumed (Essential A2). As for proteins, each
amino acid has unique properties that determine its structure hence the R.Q.
values will range from 0.9 to values as high as 1.2 (Essential A2). In this paper, the experimental animal being
studied is an insect in its larvae form known as the yellow mealworm, Tenebrio molitor. The diet of these wild
mealworms mainly consists of wheat storage protein gliadins however, they eat a
variety of foods ranging from fungus, seeds and vegetables (Dipeptidyl).
conducted at the Guy’s Hospital Medical School in London, England on rats is
indicative of the effect of diet on metabolic rate and respiratory quotient.
The adult male rats were given three different feeding treatments that consisted
of different carbohydrates. This treatment contained sucrose, glucose and
fructose. The duration of the metabolic rate was measured for 150-180 minutes
(Different Effects). The researchers concluded that there was an increase in
the metabolic rate and respiratory quotient after the feeding of the
carbohydrates. Sucrose being the greatest, then glucose and lastly fructose
purpose of this lab experiment is to examine how various diet influences the
metabolic rate in mealworms, Tenebrio
molitor and to determine whether the different diets result in distinct