Metabolism

Question 1

Which type of energy can be used to do all forms of physiological work?

Answer 1

Chemical Energy

Question 2

What types of energy can do only SOME physiological work?

What type can’t do any physiological work?

Answer 2

Mechanical and electrical energy can only do SOME physiological work

Heat cannot do any

Question 3

How does chemical energy enter the body?

Answer 3

Ingestion of food

BUT only some of it is absorbed

Question 4

In what ways can energy leave the body? How are these lost?

Answer 4

Chemical energy

• fecal mater
• organic matter after death

Mechanical energy
-work done by muscle action

Heat energy
- due to inefficiencies

Question 5

What is metabolism?

Answer 5

The energy required to perform all the chemical reactions in an animal.

All of the reactions, including those that release energy and use energy

Question 6

What is anabolism?

Answer 6

The biosynthetic or constructive part of metabolism; those chemical reactions involved in biosynthesis.

Growing & building the body.

Ex. The synthesis of glycogen from glucose

Question 7

What is catabolism?

Answer 7

In a cell, those metabolic reactions that result in the breakdown of complex molecules into simpler compounds, often with the release of energy.

Ex. Breaking down

The process of digesting food.

Question 8

During aerobic metabolism, how much energy is produced to make ATP and how much is released as heat?

Answer 8

40% ATP

60% heat
- heat is always the dominant component of metabolic rate

Question 9

What is metabolic rate?

Answer 9

The rate at which an animal converts chemical energy to heat + external work

NOTE: energy of external work also usually ends up as heat

Question 10

What does an animal’s metabolic rate tell us?

Answer 10

How much food an animal needs

Quantitative measures of the total activity of all its physiological mechanisms.
(its intensity of living)

Measures the drain the animal places on the physiologically useful energy supplies of its ecosystem

Question 11

What are the direct and indirect measures of metabolic rate?

Answer 11

Direct:
Heat

Indirect:
Food Intake
O2 Consumption
CO2 Production

Question 12

What is the most common form of measuring metabolic rate?

Answer 12

Respirometry

Question 13

What is the Material Balance Method?

Answer 13

Measuring the chemical energy content of organic matter that enters and leave the body

Subtract energy in excretion from the energy in the intake and you can estimate the animal’s metabolic rate

Mostly used in agricultural production research

Question 14

What is respirometry?

Answer 14

The measure of gas exchange of an organism with its environment.

Either O2 consumption or CO2 production

Question 15

What would make measuring an animal’s metabolic rate inaccurate?

Answer 15

Gaining / Losing weight

Shedding fur / feathers

Question 16

What produces the most heat per O2 consumption? Lowest?

Answer 16

Carbohydrates are the most.

Proteins are the least

Question 17

What produces the most heat per CO2 consumption? Lowest?

Answer 17

Lipids are the most.

Carbohydrates are the least

Question 18

Why can’t metabolic rate calculations be exactly accurate?

Answer 18

Because food is made up of different specific mixtures of carbs, lipids, and proteins, and each of those cause heat production to vary.

Question 19

What factors have large effects on an animal’s metabolic rate?

Answer 19

Physical activity levels

Environmental temperature

Question 20

What factors have small effects on an animal’s metabolic rate?

Answer 20

Ingestion of a meal
Body size
Age 
Gender
Environmental O2 Levels
Hormonal status
Time of day

Question 21

What is specific dynamic action?

Answer 21

This is when an animal’s metabolic rate goes up for a while after it has eaten when it has not eaten for a while, even if everything else is kept constant.

Question 22

What is the thermal neutral zone?

Answer 22

The range of environmental temperatures in which homeopathic species have a minimal metabolic rate.

Question 23

What is basal metabolic rate and when does it occur?

Answer 23

This is the lowest metabolic rate for an endotherm.

This occurs when the animal is in the thermoneutral zone, is fasting, and is resting.

Question 24

What is the difference between the lower critical temperature and the upper critical temperature?

Answer 24

These are the bounds of the thermoneutral zone.

Beyond the lower critical temperature MR is increased due to shivering.

Beyond the upper critical temperature MR is increased due to active heat loss.

Question 25

What is standard metabolic rate and when does it occur?

Answer 25

This is the minimum metabolic rate needed to sustain the life of an ectotherm at a certain temperature.

This occurs when the animal is fasting, and is resting.

Question 26

What has the lower metabolic rate: endotherms or ectortherms?

Answer 26

Ectotherms have a lower metabolic rate because they don’t have to spend energy regulating their temperature.

Question 27

What is metabolic scaling?

Answer 27

The study of the relationship between metabolic rate and body size

Question 28

Why does it cost more to be small?

Answer 28

Because there is a higher surface area to volume ratio for smaller animals, there is also higher heat loss for these.