Muscles 3/3 (Textbook) Ch14 Animal Energetics

Question 1

Understand the nature of nutrients, and the roles they play in physiology.

Answer 1

Nutrients are substances obtained from food that are vital for growth, metabolism, and for maintaining health and life.
There are six major classes of nutrients: carbohydrates, proteins, fats (lipids), vitamins, minerals, and water.

Question 2

Discuss how animals find food and use feeding structures to ingest food.

Question 3

Discuss the basic features of a mammalian digestive system, and the evolutionary variants seen in metazoans.

Question 4

Describe the regulation of the various digestive system compartments.

Question 5

Discuss the pathways by which specific nutrients are assimilated.

Question 6

Discuss the relationship between digestion and metabolism.

Question 7

How is energy partitioned in an animal’s diet?

Question 8

What are the major nutrients in a diet, and what enzymes metabolize them into the forms in which they are transported into the digestive epithelium?

Question 9

How is it that many animals obtain nutrition from eating cellulose, yet lack the enzymes to break it down?

Question 10

Contrast the digestive systems of a sponge and a hydra.

Question 11

Contrast the teeth of a dog and a beaver.

Question 12

Are bird beaks and mammalian teeth living tissue?

Question 13

How do the physical properties of nutrients affect their uptake and transport within the body?

Question 14

What is the main function of each region of the digestive tract?

Question 15

What are four ways vertebrates increase the surface area of the intestine?

Question 16

Where are carbohydrates broken down and absorbed?

Question 17

Where are proteins broken down and absorbed?

Question 18

Where are lipids broken down and absorbed?

Question 19

What is the postprandial period?

Question 20

Why do animals produce ketone bodies during starvation?

Question 21

What is a BMI?

Question 22

What might happen if a nectar-eating bird consumed fruit?

Question 23

What is meant by a scaling coefficient ?

Question 24

What is the metabolic theory of ecology?

Question 25

LO 1 A diet is rich in chemical energy, but not all of this energy is available to the animal. How is energy partitioned in a diet?

Question 26

LO 1 How does specific dynamic action benefit an animal?

Question 27

LO 2 How do animals use neurosensory systems to detect food in a complex environment?

Question 28

LO 2 What role might genetic variation play in the evolution and development of bird beak shape variation?

Question 29

LO 3 Summarize the basic organization of the vertebrate GI tract. What is the function of each compartment?

Question 30

LO 3 Discuss the variation in the nature of fermentation chambers.

Question 31

LO 4 What roles do glands play in the process of digestion?

Question 32

LO 4 How do animals control the secretions along the gastrointestinal tract?

Question 33

LO 5 Compare the different pathways for digestion and uptake of the three main classes of macromolecules: lipids, carbohydrates, and proteins.

Question 34

LO 5 How might an animal alter its ability to import monosaccharides from the gastrointestinal tract?

Question 35

LO 6 Discuss the fate of glucose during a meal, after a meal, and two days after an animal’s meal.

Question 36

LO 6 What factors might alter the relationship between body mass, body temperature, and metabolic rate?

Question 37

Discuss situations where digestion and reproduction may be antagonistic processes.

Question 38

An animal that feeds on a large meal undergoes numerous changes that affect its other physiological systems. Discuss how the digestive process impinges on other systems.

Question 39

When wild animals are domesticated, the years of artificial selection can alter the digestive physiology of the animal. Choose an example of a domesticated animal and consider how its digestive physiology might differ from that of its wild ancestors, given the differences in diet and selective pressures.

Question 40

Why is digestion a metabolically expensive process?

Question 41

Follow the path of glucose from the nectar reservoir of a plant to the muscle of a hummingbird. What steps control the rate of this process?

Question 42

What differences in digestive physiology systems would you expect when comparing birds that eat nectar (easy to digest, high energy per gram), seeds (difficult to digest, high energy per gram), or fruit (easy to digest, low energy per gram)?

Question 43

The harsh chemical and enzymatic conditions in the gastrointestinal tract break down nutrients. How do animals protect themselves from their own digestive secretions?

Question 44

For the following calculations, assume the following:

The generic daily caloric requirements are 2,500 kcal for men, and 2,000 for women.
The caloric expenditures for someone with an average lifestyle are attributed to basal metabolic rate (about 70 percent of total), specific dynamic action (10 percent), and physical activity (20 percent).
There are 9,000 kcal in 1 kg of fat, and 4,000 kcal in 1 kg of protein or carbohydrate.
There are about 7,000 kcal in 1 kg of body mass.
A pint of beer has about 200 kcal.
You burn about 500 kcal by jogging for 1 h at 10 km/h (though it depends on your weight and the running speed).

QUESTIONS:
(a)Assuming that your metabolic rate during sleep is equal to your basal metabolic rate (it’s actually lower), how many calories did you expend while sleeping for 8 hours? Translate those calories into units of body mass. Did you lose that much weight while you slept? How do respiration and urine production factor into this analysis?
(b)Assuming no change in basal metabolic rate or SDA, how long would it take to lose 1 kg of body mass (a) by reducing caloric intake by 500 kcal per day or (b) by doubling your physical activity each day?
(c)If you jogged to your local pub, how far would you have to go to ensure you expended enough calories to maintain caloric balance if you plan to consume two pints of beer?

Question 45

You conduct an experiment to assess the rates of uptake of glucose by bird intestines. One approach is to prepare rings of intestine. You cut across the intestine to create nearly equal-sized pieces, and incubate each ring in a solution of radiolabeled glucose (various concentrations) for 10 minutes. You remove the rings, quickly rinse in fresh saline, and assess the radioactivity in the ring as an index of glucose uptake. You report your raw data in the form of the following table, with the goal of calculating the apparent affinity for glucose () and the maximum rate of transport (, which is analagous to for an enzyme).

*The following are horizontal rows of a chart:
Ring
1
2
3
4
5
6
7
8
9

Mass (g)
0.12
0.11
0.13
0.10
0.11
0.13
0.09
0.15
0.13

Glucose concentration (mM)
0
0.01
0.02
0.04
0.1
0.2
0.4
0.7
1.0

Glucose uptake (nmol/min/ring)
0
10
30
70
140
230
180
320
330

QUESTIONS:
(a)How and why do you correct for the mass of the intestine?
(b)Plot the data to estimate the and for the intestine preparation. (Hint: What is the independent (X) variable? What variable is the dependent (Y) variable?)
(c)Use the linear transformations of the Michaelis-Menton equation (see Chapter 3) to calculate the actual and values.

Question 46

Why can an animal consume large amounts of water-soluble vitamins without issue but not fat-soluble vitamins?

Answer 46

An animal can consume copious amounts of water-soluble vitamins with little ill effect because any excess is readily excreted in the urine. Fat-soluble vitamins can be problematic, however, because they are stored in lipid depot tissues and can be released in a toxic pulse when fats are mobilized.

Question 47

What is coprophagy?

Answer 47

Rabbits, for example, eat their own feces as a way of regaining vitamins lost in undigestible material. While coprophagy increases the risk for parasites and disease, it provides important nutritional advantages to some animals, including a second opportunity to extract nutrients from the vegetation they eat.

Question 48

What are metazoans?

Answer 48

Metazoans are a broad group of animals that are multicellular and heterotrophic, distinguished from single-celled organisms and plants.