Chapter 25: Metabolism and Energetics

Question 1

the term metabolism refers to all of the…

Answer 1

chemical reactions that occur in the body

Question 2

the source that cells rely on to provide energy and to create new intracellular components is the…

Answer 2

nutrient pool

Question 3

the periodic breakdown and replacement of the organic components of a cell is called…

Answer 3

metabolic turnover

Question 4

the process that breaks down organic substrates, releasing energy that can be used to synthesize ATP or other high-energy compounds, is…

Answer 4

catabolism

Question 5

acetyl-CoA cannot be used to make glucose because the…

Answer 5

decarboxylation step between pyruvic acid and acetyl-CoA cannot be reversed

Question 6

in glycolysis, six-carbon glucose molecules are broken down into 2 three-carbon molecules of…

Answer 6

pyruvic acid

Question 7

the first step in a sequence of enzymatic reactions in the citric acid cycle is the formation of…

Answer 7

citric acid

Question 8

for each glucose molecule converted to 2 pyruvates, the anaerobic reaction sequence in glycolysis provides a net gain of…

Answer 8

2 ATP for the cell

Question 9

the complete catabolism of a glucose molecule yields a net of ___________ molecules of ATP.

Answer 9

36

Question 10

lipids cannot provide large amounts of ATP in a short period of time because…

Answer 10

1. lipid reserves are difficult to mobilize
2. lipids are insoluble and it is difficult for water-soluble enzymes to reach them
3. most lipid are processed in mitochondria, and mitochondrial activity is limited by the availability of oxygen

Question 11

lipogenesis is an effective lipid metabolic pathway because lipids, as well as carbohydrates and amino acids, can be converted into…

Answer 11

acetyl-CoA

Question 12

most lipids circulate through the bloodstream as…

Answer 12

lipoproteins

Question 13

lipids are needed throughout the body because all cells require lipids to…

Answer 13

maintain their cell membranes

Question 14

protein catabolism is an impractical primary energy source because…

Answer 14

1. proteins are more difficult to break apart than are carbohydrates or lipid
2. one of the by-products or protein catabolism, ammonium ions, is toxic to cells
3. proteins are important structural and functional cellular components

Question 15

the first step in amino acid catabolism is the removal of the…

Answer 15

amino group

Question 16

an important energy reserve that can be broken down when a cell cannot obtain enough glucose from intersitial fluid is…

Answer 16

glycogen

Question 17

the metabolic pattern characterized by nutrient absorption, anabolism, and insulin dominance is the…

Answer 17

absorptive state

Question 18

a balanced diet contains all of the ingredients necessary to…

Answer 18

maintain homeostasis

Question 19

the metabolic pattern characterized by catabolism of internal energy reserves, elevated levels of ketone bodies in the blood, and a focus on maintaining homeostatic blood glucose levels is the…

Answer 19

postabsorptive state

Question 20

foods that provide all essential amino acids in sufficient quantities…

Answer 20

complete proteins

Question 21

inorganic ions released through dissociation of electrolytes and involved in a number of physiological functions are known as…

Answer 21

minerals

Question 22

minerals, vitamins, and water are classified as essential nutrients because…

Answer 22

the body cannot synthesize the nutrients in sufficient quantities

Question 23

examples of trace minerals found in small quantities in the body include…

Answer 23

iron, zinc, copper, and manganese

Question 24

hypervitaminosis involving water-soluble vitamins is relatively uncommon because…

Answer 24

excessive amounts are readily excreted in the urine

Question 25

to examine the metabolic rate of an individual, results may be expressed as...

Answer 25

1. calories per hour 2. calories per day 3. calories per unit of body weight per day

Question 26

an individual's basal metabolic rate ideally represents...

Answer 26

the minimum resting energy expenditure of an awake, alert person

Question 27

if your daily intake exceeds your total energy demands, you will store the excess energy primarily as...

Answer 27

triglycerides in adipose tissue

Question 28

the four processes involved in heat exchange with the environment are...

Answer 28

radiation, conduction, convection, and evaporation

Question 29

the primary mechanism for increasing heat loss in the body include...

Answer 29

vasomotor and respiratory

Question 30

the major metabolic pathways that provide most of the ATP used by typical cells are...

Answer 30

glycolysis and aerobic respiration

Question 31

a cells with excess carbohydrates, lipids, and amino acids will break down carbohydrates to...

Answer 31

obtain energy

Question 32

fatty acids and many amino acids cannot be converted to glucose because...

Answer 32

their catabolic pathways produce acetyl-CoA

Question 33

lipogenesis can use almost any organic substrate because...

Answer 33

lipids, amino acids, and carbohydrates can be converted to acetyl-CoA

Question 34

when more nitrogen is absorbed than excreted, an individual is said to be in a state of...

Answer 34

positive nitrogen balance

Question 35

the catabolism of lipids results in the release of...

Answer 35

9.46 C/g

Question 36

the catabolism of carbohydrates and proteins results in the release of...

Answer 36

4.18 C/g and 4.32 C/g, respectively

Question 37

the process that produces more than 90 percent of the ATP used by body cells is...

Answer 37

oxidative phosphoylation

Question 38

examples of essential fatty acids that cannot by synthesized by the body but must be included in the diet are...

Answer 38

linoleic and linolenic acids

Question 39

most lipids circulate through the bloodstream as...

Answer 39

lipoproteins

Question 40

the primary function of very-low-density lipoproteins is....

Answer 40

transporting triglycerides to peripheral tissues

Question 41

LDLs are absorbed by cells through the process of...

Answer 41

receptor-mediated endocytosis

Question 42

in the beta-oxidation of an 18-carbon fatty acid molecule, the cell gains...

Answer 42

144 ATP

Question 43

most of the lipids absorbed by the digestive tract are immediately transferred to the...

Answer 43

venous circulation via the lymphatic duct

Question 44

after a meal, the absorptive state continues for about...

Answer 44

4 hours

Question 45

when the amount of nitrogen you absorb from the diet is equal to the amount you lose in urin and feces, you are in...

Answer 45

nitrogen balance

Question 46

an important energy source during periods of starvation, when glucose supplies are limited, is...

Answer 46

free fatty acids

Question 47

hypervitaminosis usually involves one of the fat-soluble vitamins because...

Answer 47

is retained and stored in the body

Question 48

milk and eggs are complete proteins because they contain...

Answer 48

all the essential amino acids in sufficient quantities

Question 49

a nitrogen compound important in energy storage in muscle tissue is...

Answer 49

creatine