Module 2.1- Energy Metabolism Flashcards
Describe the difference between absorptive and post-absorptive phases of fuel metabolism. Define catabolism, anabolism and give examples of hormones involved with each of these. Define Basal Metabolic Rate (BMR)
What are the three kinds of fuels an animal body demands?
Amino Acids (protein), fatty acids (fats and acids) and glucose (carbohydrates)
Why do animal bodies require fuel?
For Homeostasis (the maintenance of the body) and because they are building blocks for growth and reproduction.
Is it likely that the supply of fuel matches the demand for it in an animals body?
Highly unlikely.
How does the animal body cope with the differences between supply and demand for fuels?
Energy (fuel) metabolism. The endocrine and homeostasis systems of the body assist in maintaining constant energy supply, dealing with excess and shortcomings in energy intake
Which body systems assist in maintaining the supply of energy needed by the body?
Endocrine and Homeostasis
What is anabolism?
Building up of tissues
What is catabolism?
Breaking down of tissues
What are the two steps of catabolism?
Hydrolysis of larger organic molecules (similar to what happens in the digestive tract) followed by oxidation of the smaller molecules to release energy for ATP production
What regulates metabolic function?
Substrate concentration
Enzyme activity
Enzyme concentration
Compartmentation (eg. glycolysis=cytosol, Krebs cycle=mitochondrial matrix)
Outline Carbohydrate (glucose) conversion as part of energy metabolism?
Carbohydrate compound is oxidised generating energy, CO2 and H2O and substrates for other metabolic reactions. Converted into Glycogen which can be readily stored and retrieved for conversion into ATP.
What is ATP?
adenosine triphosphate, the chemical compound which the body can use as energy.
What is Glycogen?
A product of the biochemical pathway of conversion of carbohydrate (glucose) into useable energy. Can be readily stored and retrieved.
How are Amino Acids transported in the body?
In the blood
What are Amino Acids used for?
Protein synthesis
Outline the chemical process of the conversion of Amino Acids to useable energy
Catabolised via Proteolysis
Amino acid (in blood) -> Protein (in cell, readily stored and retrieved in cell) -> CO2 + H2O + NH3 + energy (in cell)
2 NH3 then converted into urea in the liver.
How are Amino Acids stored in cells?
Converted via Proteolysis into proteins to be stored in the cell
Outline the chemical process of fat metabolism
Fats (triglycerides) broken down by lipoprotein lipase. Fatty acids are taken up by the liver (glycerol -> liver). Fatty acids are oxidised for energy + H2O + CO2.
Unused glycerol is combined with fatty acids and stored as fat droplets until they are ready to be released back into the blood
What happens when biomolecules exist in excess in the body?
They are stored as storage molecules (glycogen, triglycerides)
What can biomolecules be used for?
Synthesis of other molecules
What is released when molecules are broken down?
Energy is released
What is metabolic rate?
The rate at which energy is expended during internal and external work.
What is energy balance?
Energy input - energy output (heat + work)
What are some things that cause an animal to have a higher energy output than usual?
Growth, reproduction, lactation
What is the measurement for metabolic rate?
Kilojoules per hour (kJ/h)
How is metabolic rate often expressed?
The rate of heat production
What is metabolic rate influenced by?
Muscular activity, age, gender, size (body surface area), environmental temperature
What is basal metabolic rate (BMR)?
An animals resting metabolic rate
How is basal metabolic rate estimated?
By measuring oxygen consumption over time (Volume of O2 in ml per minute)
Why is basal metabolic rate estimated using the rate of oxygen consumption over time?
Because oxygen consumption correlates with the rate at which nutrients are being oxidised and thus correlates with the rate of heat and energy production
What is basal metabolic rate often scaled by?
Body mass
Why do we need to scale basal metabolic rate by body mass?
Because metabolic rate is proportional to body weight and body surface area. Scaling it by body mass allows for expression of metabolic level independent of these factors, allowing cross species comparison.
Does a horse produce more heat per day than a rat? Explain your answer
Yes, bigger homeotherms produce more heat per day than smaller homeotherms. Metabolic rate is positively correlated to body size
Is metabolic rate positively (increases as body size increases) or negatively (decreases as body size increases) correlated to body size?
Positively
Does a horse produce more heat per day per kilogram than a rat? Explain your answer.
No, the horse has a lower rate of heat production per unit of body weight than that of a rat. Metabolic rate per unit of body weight is negatively correlated to body size
Is metabolic rate per unit of body mass positively (increases as body size increases) or negatively (decreases as body size increases) correlated to body size?
Negatively
As mass increases what also increases?
Metabolic rate
What are the three states of energy balance?
positive, neutral and negative
What is the state of positive energy balance?
Energy input > (more than) Energy output
What is the state of negative energy balance?
Energy input < (less than( energy output
What is the state of neutral energy balance?
Energy input = energy output
What is the absorptive state?
Anabolic metabolism
When nutrients are being absorbed after consumption
What is post-absorptive state?
Catabolic metabolism
Fasting, when no nutrients are being absorbed. The time between feeding.
Which of the three forms of energy storage are limited and which are (virtually) unlimited in their ability to store energy in this form?
Fat = unlimited Proteins = limited Glycogen = limited
In which state (absorptive or post-absorptive) does energy storage occur?
Absorptive state
In which state (absorptive or post-absorptive) does conversion of stored macromolecules into energy occur?
Post-absorptive
What does glycogenesis convert, and into what?
Glucose -> glycogen
What does glycogenolysis convert, and into what?
Glycogen -> glucose
What does gluconeogenesis convert, and into what?
Amino acids -> glucose
What does protein synthesis convert, and into what?
Amino acids -> protein
What does protein degradation convert, and into what?
Proteins -> amino acids
What does fat synthesis (lipogenesis of triglyceride synthesis) convert, and into what?
Fatty acid and glycerol -> Triglycerides
What does fat breakdown (lypolysis or triglyceride degradation) convert, and into what?
Triglycerides -> Fatty acids and glycerol
What does glycogenesis (Glucose -> glycogen) do to blood glucose levels?
Decreases it
What does glycogenolysis (Glycogen -> glucose) do to blood glucose levels?
Increases it
What does gluconeogenesis (Amino acids -> glucose) do to blood glucose levels?
Increases it
What does protein synthesis (Amino acids -> protein) do to blood amino acid levels?
Decreases them
What does protein degradation (Proteins -> amino acids) do to blood amino acid levels?
Increases them
What does fat synthesis (lipogenesis of triglyceride synthesis) (Fatty acid and glycerol -> Triglycerides) do to blood fatty acid levels?
Decreases them
What does fat breakdown (lypolysis or triglyceride degradation) (Triglycerides -> Fatty acids and glycerol) do to blood fatty acid levels?
Increases them
