40. Animal Metabolism, Nutrition, and Digestion

Question 1

metabolic rate varies with an animal’s:

Answer 1

activity, internal body temperature, and size

Question 2

adenosine triphosphate (ATP)

Answer 2

the molecule that provides energy in a form that all cells can readily use to perform the work of the cell. ATP is the universal energy currency for all cells

Question 3

catabolism

Answer 3

the set of chemical reactions that break down molecules into smaller units and, in the process, produces ATP to meet the energy needs of the cell

Question 4

anabolic

Answer 4

the set of chemical reactions that build molecules from smaller units utilizing an input of energy, usually in the form of ATP. anabolic reactions result in net energy storage within cells and the organism

Question 5

anaerobic metabolism

Answer 5

energy metabolism in the absence of oxygen-provides rapid but short-term energy to the cell and organism

Question 6

aerobic metabolism

Answer 6

energy metabolism that uses oxygen gas to oxidize organic compounds, generating ATP; found in Bacteria, Archaea, and the mitochondria of eukaryotic organisms

Question 7

citric acid cycle

Answer 7

the third stage of cellular respiration, in which acetyl-CoA is broken down and more carbon dioxide is released

Question 8

electron transport chain

Answer 8

the system that transfers electrons along a series of membrane-associated proteins to a final electron acceptor, using the energy released as electrons move down the chain to produce ATP

Question 9

metabolic efficiency

Answer 9

the amount of energy captured in a usable form per amount of energy in the starting molecule

Question 10

what is the metabolic efficiency of aerobic respiration?

Answer 10

at least 34%-other 66% converted to heat and lost to the environment or used to warm the animal

Question 11

glucose that is not metabolized is stored as:

Answer 11

glycogen, primarily in the liver and muscles

Question 12

lipids such as triacylglycerol are broken down to:

Answer 12

glycerol and free fatty acids which enter glycolysis or the citric acid cycle to yield ATP by oxidative phosphorylation or stored as fat (adipose tissue)

Question 13

what do animals preferentially rely on for long-term energy supply?

Answer 13

fats

Question 14

carbohydrates are always spared for the:

Answer 14

brain and nervous system

Question 15

protein can also be an energy source but only broken down when…

Answer 15

fat and carbohydrate reserves are depleted

Question 16

metabolic rate

Answer 16

an animal’s overall rate of energy use

Question 17

how do you measure metabolic rate?

Answer 17

by measuring the animal’s rate of oxygen consumption, which reflects the rate of aerobic production of ATP

Question 18

the onset of activity requires immediate energy, which in animals, is provided by:

Answer 18

specialized energy stores in their tissues

Question 19

in vertebrate muscle cells, for example, what is a ready source of high-energy phosphates that is hydrolyzed to synthesize ATP directly from ADP at the onset of activity?

Answer 19

phosphocreatine

Question 20

although glycolysis produces relatively few ATP, it is relatively fast providing:

Answer 20

rapid short-term supply of energy for animals-good for short bursts of intensive activity

Question 21

what supplies energy for longer activity?

Answer 21

aerobic respiration in the mitochondria-intially the rate of oxygen consumption increases, then levels off

Question 22

once mitochondrial ATP production increases, the steady state production of ATP depends on:

Answer 22

adequate transport of oxygen to the tissue by the cardiovascular system as well as by diffusion of oxygen into mitochondria

Question 23

recovery metabolism

Answer 23

an animal’s elevated consumption of oxygen following activity-represents the continued metabolic energy required to re-establish the resting metabolic state of the cells

Question 24

what occurs during recovery metabolism?

Answer 24

the cells re-synthesize depleted ATP stores and metabolize the end products of fermentation, particularly lactic acid

Question 25

“oxygen debt”

Answer 25

the difference between an animal’s immediate energy need at the onset of activity and energy supplied by aerobic metabolism, it is “paid back” following exercise by the animal’s recovery metabolism

Question 26

heat storage seems to enable:

Answer 26

quick bursts of speed, has evolved as an adaptation among both predators and prey to achieve short, rapid sprints

Question 27

at rest, larger animals consume:

Answer 27

more energy and have higher metabolic rates than smaller ones

Question 28

resting metabolic rate increases with:

Answer 28

animal mass raised to the 3/4 power

Question 29

the average rate at which each gram of body tissue consumes energy is….

Answer 29

LESS in larger animals compared to smaller ones

Question 30

the larger the organism, the…

Answer 30

LOWER the metabolic rate PER GRAM of body tissue

Question 31

metabolic rate increases linearly with…

Answer 31

speed-larger animals expend less per unit mass than smaller ones

Question 32

an animal’s internal body temperature can affect the rate of chemical reactions which in turn determines how fast:

Answer 32

fuel molecules can be mobilized and broken down to supply energy for a cell

Question 33

endotherm

Answer 33

an animal that produces most of its own heat as by-products of metabolic reactions-generally maintain a constant body temperature that is higher than that of their environment

Question 34

ectotherm

Answer 34

an animal that obtains most of its heat from the environment-body temperatures regulated by changing their behaviour

Question 35

endotherms have a higher…

Answer 35

metabolic rate than ectotherms, endotherms are able to be active over a broader range of external temperatures than ectotherms

Question 36

the activity level and metabolic rate of ectotherms increase with…

Answer 36

increasing body temperatures

Question 37

ectotherms that are of similar body mass at temperature to an endotherm have metabolic rates that are:

Answer 37

25% of the endotherm

Question 38

even when the body temperatures are similar, ectotherms cannot sustain:

Answer 38

prolonged activity

Question 39

endotherms benefit from having an active lifestyle but requires:

Answer 39

lots of food to keep warm and be active

Question 40

although ectotherms cannot sustain activity for long periods, they can survive longer periods without….

Answer 40

food

Question 41

the control of core body temperature or thermoregulation is a form of:

Answer 41

homeostasis and requires the coordinated activities of the nervous, muscular, endocrine, circulatory, and digestive systems.