Chapter 7 Flashcards
Energy metabolism is?
Metabolic rate?
What are the 2 processes?
- The sum of the processes by which animals acquire energy, channel energy into useful functions, and dissipate energy from their bodies.
- Also could be all the chemical reactions in the body
- How fast chemical reactions happen
- Anabolic- the building of. synthetic reactions
- Catabolic- breakdown of. destruction reactions
Why Animals Need Energy
Animals are organized/ordered systems
The ____ law of thermodynamics
- If an isolated system undergoes internal change, the direction of the change is always toward greater _____
- Applies to isolated systems. What is one?
- Order can be maintained or increased only if the system is not isolated
- second
- disorder
- does not exchange anything with its surroundings
What is energy?
The capacity to do mechanical work or the capacity to increase order
What are the 4 different forms of energy?
- Chemical energy- ATP
- Electrical energy- membrane voltage potential; movement of ions (amp)
- Mechanical energy- holding head up
- Heat (molecular kinetic energy)
The different energy forms are not equally capable of performing work
Physiological work is ?
Chemical energy is ___
Animals can not use heat to perform any physiological work
- Anything an animal does to increase order
- Totipotent (can do all kinds of mechanical work)
- Electrical and mechanical energy are not
High-grade energy transformations are _____
Efficiency= ?
Only ___ of the chemical energy in glucose is found in ATP
Only ___ of the energy in ATP can be used during muscle contraction
- inefficient
- output/input
- 70%
- 25-30%
Animals use energy for what 3 functions?
- Biosynthesis
- Maintenance
- Generation of external work
Metabolic rate is?
Consumption is?
Metabolic rates measured in calories/unit of time, or watts ( 1W = 1 J/sec)
Why is metabolic rate important?
What are 2 methods of measure MR?
- rate of energy consumption
- energy converted to external work and heat
- One of most important determinants of the amount of food needed
- Total heat production gives a quantitative measure of its physiological mechanisms
- Measures the drain the animal puts on the ecosystem
- Direct and indirect Calorimetry
Energy measurement
1Kcal=1 Calorie -or- Joule: 0.239 Cal
1000 calories = 1Kcal
What is a calorie?
energy to raise 1g H2O by 1°C, also = to 4.186J
What are the 2 ways to measure metabolic rate?
What is thermoneutral zone?
- Standard Metabolic Rate
* Resting metabolic rate of an ectotherm at a particular temperature (cold blooded) - Basal Metabolic Rate
* Resting metabolic rate of an endotherm in the thermoneutral zone (warm blooded) - A range of temperatures where the animal does not have to increase MR to maintain normal body temp
Direct Calorimetry: diectly measures the rate at which heat leaves the animal
Lavoisier’s method (picture)
If the animal moves_____, this energy is rapidly degraded to heat
Issues:
- hard to surround an animal in ice
- If all external energy is not converted to heat (it is stored), that energy must also be measured
- horizontally
Indirect calorimetry measures something other than the rate at which heat leaves the animal
1 way is respiratory gas exchange
- If a mole of glucose (C6H12O6) is burned, 6 mol of O2 and 6 mol CO2 will be produced
- Heat will also be released (heat of combustion, 2820 kJ/mol)
- If you measure the amount of O2 consumed, or CO2 produced, you can calculate the amount of heat produced
- Note that the amount of heat produced depends on the food consumed
If you know that an animal is only using glucose and it is consuming 10 ml of O2/min:
10 ml/min x 21.1J/ml=
211 J/min
Indirect Calorimetry another way to measure
Foodstuff is determined by indices of cellular function
- Moles of CO2 produced per unit of time
- Moles of O2 consumed per unit of time
Respiratory exchange ratio (R, respiratory organs) or respiratory quotient (RQ, cellular level)
1. If R=1, you have evidence that animal is metabolizing carbohydrates. why?
Representative conversion factors are often used (20.2J/ml O2
- Carbohydrates have a mole to mole ratio.
Indirect Calorimetry: another way
Material balance?
Widely used in agricultural production research
Subtract output from input
Complications: Growth (stored energy) or atrophy
Suited to long-term experiments
Measure organic material entering and leaving the body
Factors that Affect Metabolic Rate
Greatest factors? (more so ectoderms)
Other factors
- Ingestion of food
- Age
- Gender
- Time of day
- Body size
- Reproductive condition
- Hormonal state
- Psychological stress
- Water salinity (marine)
Physical activity
Temperature
Factors that Affect Metabolic Rate
Specific dynamic action
- Happens after absorption of nutrients
- Protein processing results in a much higher SDA
Diet-induced thermogenesis
- A long-term increase in metabolic rate following persistent overeating
Factors that Affect Metabolic Rate
Body size
While a larger animal eats more than a smaller one, the ratio between the amount eaten and body size is much greater for the smaller animal
i.e. Energy needs are not proportional to body size
body weight goes up then metabolic rate goes up
When do smaller mammals have higher/ faster metabolic rate?
whats the difference?
- Weight-specific metabolic rate
- it’s divided by the weight of the animal
Log-log graphs are more useful. Why?
- Can look a grater range of weights of animal
- Easier to read.
Why is metabolic rate important?
- You can predict features of the respiratory and cardiovascular systems
- It can be used for the study of ecology
