Chapter 25: Metabolism and Energetics Flashcards Preview

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Flashcards in Chapter 25: Metabolism and Energetics Deck (49)
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1
Q

the term metabolism refers to all of the…

A

chemical reactions that occur in the body

2
Q

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

A

nutrient pool

3
Q

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

A

metabolic turnover

4
Q

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

A

catabolism

5
Q

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

A

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

6
Q

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

A

pyruvic acid

7
Q

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

A

citric acid

8
Q

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

A

2 ATP for the cell

9
Q

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

A

36

10
Q

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

A
  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
11
Q

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

A

acetyl-CoA

12
Q

most lipids circulate through the bloodstream as…

A

lipoproteins

13
Q

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

A

maintain their cell membranes

14
Q

protein catabolism is an impractical primary energy source because…

A
  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
15
Q

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

A

amino group

16
Q

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

A

glycogen

17
Q

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

A

absorptive state

18
Q

a balanced diet contains all of the ingredients necessary to…

A

maintain homeostasis

19
Q

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…

A

postabsorptive state

20
Q

foods that provide all essential amino acids in sufficient quantities…

A

complete proteins

21
Q

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

A

minerals

22
Q

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

A

the body cannot synthesize the nutrients in sufficient quantities

23
Q

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

A

iron, zinc, copper, and manganese

24
Q

hypervitaminosis involving water-soluble vitamins is relatively uncommon because…

A

excessive amounts are readily excreted in the urine

25
Q

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

A
  1. calories per hour
  2. calories per day
  3. calories per unit of body weight per day
26
Q

an individual’s basal metabolic rate ideally represents…

A

the minimum resting energy expenditure of an awake, alert person

27
Q

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

A

triglycerides in adipose tissue

28
Q

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

A

radiation, conduction, convection, and evaporation

29
Q

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

A

vasomotor and respiratory

30
Q

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

A

glycolysis and aerobic respiration

31
Q

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

A

obtain energy

32
Q

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

A

their catabolic pathways produce acetyl-CoA

33
Q

lipogenesis can use almost any organic substrate because…

A

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

34
Q

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

A

positive nitrogen balance

35
Q

the catabolism of lipids results in the release of…

A

9.46 C/g

36
Q

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

A

4.18 C/g and 4.32 C/g, respectively

37
Q

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

A

oxidative phosphoylation

38
Q

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

A

linoleic and linolenic acids

39
Q

most lipids circulate through the bloodstream as…

A

lipoproteins

40
Q

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

A

transporting triglycerides to peripheral tissues

41
Q

LDLs are absorbed by cells through the process of…

A

receptor-mediated endocytosis

42
Q

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

A

144 ATP

43
Q

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

A

venous circulation via the lymphatic duct

44
Q

after a meal, the absorptive state continues for about…

A

4 hours

45
Q

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

A

nitrogen balance

46
Q

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

A

free fatty acids

47
Q

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

A

is retained and stored in the body

48
Q

milk and eggs are complete proteins because they contain…

A

all the essential amino acids in sufficient quantities

49
Q

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

A

creatine