Chapter 7 - Energy Metabolism Flashcards
What is energy metabolism?
The sum of processes by which animals require energy, channel energy into useful functions, and dissipate energy from their bodies.
What are the end products of catabolism?
CO2, H2O, & NH3
What are the building blocks used in anabolism, and which organelle builds amino acids?
Amino acids Fatty acids Sugars Nitrogenous bases The ribosome builds amino acids
What is the 2nd Law of Thermodynamics?
If an isolated system undergoes internal change, the direction of the changes is always toward greater disorder.
Can animals be isolated systems, why or why not?
No, animals require energy from outside sources.
-they are constantly changing AND need the input and output from their external environments
Name the four different forms of energy.
- Chemical-bond energy
- Electrical energy
- Mechanical energy
- Kinetic energy
Describe chemical-bond energy.
Liberated/required when atoms are rearranged into new configurations
-considered to be totipotent, it is used for all physiological work
Describe electrical energy.
Possessed in a system by virtue of separation of positive and negative electrical charges
-considered to be useful in some ways
Describe mechanical energy.
Of organized motion in which many molecules move simultaneously in the same direction
-considered to be useful in some ways
Describe kinetic energy.
Random atomic-molecular motion
-cannot use heat to preform physiological work
Thinking back to the quicksand example, with a person sinking faster in quicksand the more they move. How does this relate to energy being lost as heat?
The more energy you use, the more energy that is being lost as heat, hence why people will sink faster in the quicksand.
What are the three types of physiological work an animal uses its chemical energy for?
- Biosynthesis: breaking down food
- Maintenance: maintaining homeostasis
- External Work: energy relates to environment
What is the relationship between Watts and calories?
1 calorie = 4.816 Joules
1 Joule/sec = 1 Watt
What is the difference between the direct method and indirect method for measuring metabolic rate?
The metabolic rate is the rate at which you consume energy.
Can be measured with indirect or direct methods
Direct methods:rate at which heat leave your body
Indirect methods: measures oxygen consumption and converts that into joules
What is a limiting factor in the usefulness of the indirect method?
Animals yield different quantities of oxygen, and their health status affects their metabolic rate. This is not always accurate.
What is the material balance method?
Chemical energy content of organic materials entering/exiting the body
What is a limitation of the material balance method when assessing chemical energy?
If an animal is increasing or decreasing its biomass, this affects or skews the results.
What are the two major factors that affect metabolic rates?
- Temperature of environment
2. Physical activity of organism
Explain Specific Dynamic Action (SDA) and its relation to feeling warm after eating a big meal.
If you have not eaten in a long period of time (fasting), and eat a large meal, your bodies SDA will increase. This simply means that the total excess metabolic heat production will be kicked into high gear because of the meal. Oxygen plays a role by measuring the content after food consumption which is an indirect measure. Proteins yield higher SDAs.
An alpine skier rides a ski lift to the top of a mountain and then skis down a ski run. A telemark skier skis up the same mountain and then down the same ski run. Assuming the skiers weigh the same amount, which statement best describes the amount of work they do?
A. Both skiers do the same amount of physiological work but the telemark skier does more external work.
B. Both skiers do the same amount of external work but the telemark skier does more physiological work.
C. Both skiers do the same amount of external work but the alpine skier does more physiological work.
D. The telemark skier does much more work going up the mountain but both skiers do about the same amount of work skiing down the mountain.
D.
Suppose you eat five cookies, each of which contains 100 calories. If the same amount of energy in the cookies was used to heat 50,000 g of water, the temperature of the water would increase by
A. 0.1°C.
B. 1.0°C.
C. 10°C.
D. 100°C.
C.
Suppose an animal is oxidizing food according to the following reaction:
C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + 2820 kJ/mol. What is the respiratory quotient?
A. 1
B. 6
C. 18
D. 2820
A.
Suppose that you compare the amount of food needed by four groups of lizards, each of which has an MR that is expected for its body size. There are 10 lizards weighing 10 g each, 5 lizards weighing 20 g each, 2 lizards weighing 50 g each, and a single 100-g lizard. Assuming equivalent digestions, similar food, and so on, which lizard group requires the most food?
A. The 10-g lizard group
B. The 20-g lizard group
C. The 100-g lizard
D. All lizard groups require the same amount of food.
A.
