Question

Cellular Respiration Questions

questsion 1.

Energy output. The Gibb’s free energy value for glucose is -2870kJ/mol or -686kcal/mol. If the one molecule of ATP releases 30.5 kJ/mol or 7.3 kcal/mol, calculate the theoretical efficiency (showing your work) for cellular respiration and for anaerobic respiration.

Explain the difference between metabolic rate and basal metabolic rate (BMR).

What happens to BMR with age?

I would highly appreciate if it was in a text form not handwritten.( I have difficulty reading handwritten)

Thank you very much.

Answer 1

The metabolic rate represents the number of calories needed to fuel ventilation, blood circulation and temperature regulation. Calories are also required to digest and absorb consumed food and fuel the activities of daily life. Or put another way, metabolic rate is an estimate of how many calories you would burn if you were to do nothing but rest for 24 hours. It represents the minimum amount of energy required to keep your body functioning.

BMR is defined as Basal Metabolic Rate. BMR is synonymous with Basal Energy Expenditure or BEE. BMR measurements are typically taken in a darkened room upon waking after 8 hours of sleep, 12 hours of fasting to ensure that the digestive system is inactive, and with the subject resting in a reclined position.

RMR can be defined as Resting Metabolic Rate. RMR is synonymous with Resting Energy Expenditure or REE. RMR measurements are typically taken under less restricted conditions than BMR and do not require that the subject spend the night sleeping in the test facility prior to testing.

Both BMR and RMR are measured by gas analysis through either direct or indirect calorimetry, although a rough estimation of RMR can be acquired through an equation using age, sex, height and weight. This equation is the Mifflin-St.Jeor equation.

The Mifflin-St Jeor equations are:

Male: BMR = 10×weight + 6.25×height - 5×age + 5
Female: BMR = 10×weight + 6.25×height - 5×age - 161

Age is one of the most important factors of changes in energy metabolism. The basal metabolic rate decreases almost linearly with age. Skeletal musculature is a fundamental organ that consumes the largest part of the energy in the normal human body. The total volume of skeletal muscle can be estimated by 24-hours creatinine excretion. The volume of skeletal musculature decreases and the percentage of fat tissue increases with age. It is shown that the decrease in muscle mass relative to the total body may be wholly responsible for the age-related decreases in basal metabolic rate. Energy consumption by physical activity also decreases with atrophic changes of skeletal muscle. Thus, energy requirement in the elderly decreases. With the decrease of energy intake, intake of essential nutrients also decreases. If energy intake, on the other hand, exceeds individual energy needs, fat accumulates in the body. Body fat tends to accumulate in the abdomen in the elderly. Fat tissue in the abdominal cavity is connected directly with the liver through the portal vein. Accumulation of abdominal fat causes disturbance in glucose and lipid metabolism. It is shown that glucose tolerance decreases with age.