Chapter 7 - Energy Metabolism

Question 1

What is energy metabolism?

Answer 1

The sum of processes by which animals require energy, channel energy into useful functions, and dissipate energy from their bodies.

Question 2

What are the end products of catabolism?

Answer 2

CO2, H2O, & NH3

Question 3

What are the building blocks used in anabolism, and which organelle builds amino acids?

Answer 3

Amino acids
Fatty acids
Sugars
Nitrogenous bases
The ribosome builds amino acids

Question 4

What is the 2nd Law of Thermodynamics?

Answer 4

If an isolated system undergoes internal change, the direction of the changes is always toward greater disorder.

Question 5

Can animals be isolated systems, why or why not?

Answer 5

No, animals require energy from outside sources.

-they are constantly changing AND need the input and output from their external environments

Question 6

Name the four different forms of energy.

Answer 6

1. Chemical-bond energy
2. Electrical energy
3. Mechanical energy
4. Kinetic energy

Question 7

Describe chemical-bond energy.

Answer 7

Liberated/required when atoms are rearranged into new configurations
-considered to be totipotent, it is used for all physiological work

Question 8

Describe electrical energy.

Answer 8

Possessed in a system by virtue of separation of positive and negative electrical charges
-considered to be useful in some ways

Question 9

Describe mechanical energy.

Answer 9

Of organized motion in which many molecules move simultaneously in the same direction
-considered to be useful in some ways

Question 10

Describe kinetic energy.

Answer 10

Random atomic-molecular motion

-cannot use heat to preform physiological work

Question 11

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?

Answer 11

The more energy you use, the more energy that is being lost as heat, hence why people will sink faster in the quicksand.

Question 12

What are the three types of physiological work an animal uses its chemical energy for?

Answer 12

1. Biosynthesis: breaking down food
2. Maintenance: maintaining homeostasis
3. External Work: energy relates to environment

Question 13

What is the relationship between Watts and calories?

Answer 13

1 calorie = 4.816 Joules

1 Joule/sec = 1 Watt

Question 14

What is the difference between the direct method and indirect method for measuring metabolic rate?

Answer 14

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

Question 15

What is a limiting factor in the usefulness of the indirect method?

Answer 15

Animals yield different quantities of oxygen, and their health status affects their metabolic rate. This is not always accurate.

Question 16

What is the material balance method?

Answer 16

Chemical energy content of organic materials entering/exiting the body

Question 17

What is a limitation of the material balance method when assessing chemical energy?

Answer 17

If an animal is increasing or decreasing its biomass, this affects or skews the results.

Question 18

What are the two major factors that affect metabolic rates?

Answer 18

1. Temperature of environment

2. Physical activity of organism

Question 19

Explain Specific Dynamic Action (SDA) and its relation to feeling warm after eating a big meal.

Answer 19

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.

Question 20

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.

Answer 20

D.

Question 21

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.

Answer 21

C.

Question 22

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

Answer 22

A.

Question 23

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.

Answer 23

A.