Chapter 25: Metabolism and Energetics Flashcards
the term metabolism refers to all of the…
chemical reactions that occur in the body
the source that cells rely on to provide energy and to create new intracellular components is the…
nutrient pool
the periodic breakdown and replacement of the organic components of a cell is called…
metabolic turnover
the process that breaks down organic substrates, releasing energy that can be used to synthesize ATP or other high-energy compounds, is…
catabolism
acetyl-CoA cannot be used to make glucose because the…
decarboxylation step between pyruvic acid and acetyl-CoA cannot be reversed
in glycolysis, six-carbon glucose molecules are broken down into 2 three-carbon molecules of…
pyruvic acid
the first step in a sequence of enzymatic reactions in the citric acid cycle is the formation of…
citric acid
for each glucose molecule converted to 2 pyruvates, the anaerobic reaction sequence in glycolysis provides a net gain of…
2 ATP for the cell
the complete catabolism of a glucose molecule yields a net of ___________ molecules of ATP.
36
lipids cannot provide large amounts of ATP in a short period of time because…
- lipid reserves are difficult to mobilize
- lipids are insoluble and it is difficult for water-soluble enzymes to reach them
- most lipid are processed in mitochondria, and mitochondrial activity is limited by the availability of oxygen
lipogenesis is an effective lipid metabolic pathway because lipids, as well as carbohydrates and amino acids, can be converted into…
acetyl-CoA
most lipids circulate through the bloodstream as…
lipoproteins
lipids are needed throughout the body because all cells require lipids to…
maintain their cell membranes
protein catabolism is an impractical primary energy source because…
- proteins are more difficult to break apart than are carbohydrates or lipid
- one of the by-products or protein catabolism, ammonium ions, is toxic to cells
- proteins are important structural and functional cellular components
the first step in amino acid catabolism is the removal of the…
amino group
an important energy reserve that can be broken down when a cell cannot obtain enough glucose from intersitial fluid is…
glycogen
the metabolic pattern characterized by nutrient absorption, anabolism, and insulin dominance is the…
absorptive state
a balanced diet contains all of the ingredients necessary to…
maintain homeostasis
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…
postabsorptive state
foods that provide all essential amino acids in sufficient quantities…
complete proteins
inorganic ions released through dissociation of electrolytes and involved in a number of physiological functions are known as…
minerals
minerals, vitamins, and water are classified as essential nutrients because…
the body cannot synthesize the nutrients in sufficient quantities
examples of trace minerals found in small quantities in the body include…
iron, zinc, copper, and manganese
hypervitaminosis involving water-soluble vitamins is relatively uncommon because…
excessive amounts are readily excreted in the urine
to examine the metabolic rate of an individual, results may be expressed as…
- calories per hour
- calories per day
- calories per unit of body weight per day
an individual’s basal metabolic rate ideally represents…
the minimum resting energy expenditure of an awake, alert person
if your daily intake exceeds your total energy demands, you will store the excess energy primarily as…
triglycerides in adipose tissue
the four processes involved in heat exchange with the environment are…
radiation, conduction, convection, and evaporation
the primary mechanism for increasing heat loss in the body include…
vasomotor and respiratory
the major metabolic pathways that provide most of the ATP used by typical cells are…
glycolysis and aerobic respiration
a cells with excess carbohydrates, lipids, and amino acids will break down carbohydrates to…
obtain energy
fatty acids and many amino acids cannot be converted to glucose because…
their catabolic pathways produce acetyl-CoA
lipogenesis can use almost any organic substrate because…
lipids, amino acids, and carbohydrates can be converted to acetyl-CoA
when more nitrogen is absorbed than excreted, an individual is said to be in a state of…
positive nitrogen balance
the catabolism of lipids results in the release of…
9.46 C/g
the catabolism of carbohydrates and proteins results in the release of…
4.18 C/g and 4.32 C/g, respectively
the process that produces more than 90 percent of the ATP used by body cells is…
oxidative phosphoylation
examples of essential fatty acids that cannot by synthesized by the body but must be included in the diet are…
linoleic and linolenic acids
most lipids circulate through the bloodstream as…
lipoproteins
the primary function of very-low-density lipoproteins is….
transporting triglycerides to peripheral tissues
LDLs are absorbed by cells through the process of…
receptor-mediated endocytosis
in the beta-oxidation of an 18-carbon fatty acid molecule, the cell gains…
144 ATP
most of the lipids absorbed by the digestive tract are immediately transferred to the…
venous circulation via the lymphatic duct
after a meal, the absorptive state continues for about…
4 hours
when the amount of nitrogen you absorb from the diet is equal to the amount you lose in urin and feces, you are in…
nitrogen balance
an important energy source during periods of starvation, when glucose supplies are limited, is…
free fatty acids
hypervitaminosis usually involves one of the fat-soluble vitamins because…
is retained and stored in the body
milk and eggs are complete proteins because they contain…
all the essential amino acids in sufficient quantities
a nitrogen compound important in energy storage in muscle tissue is…
creatine
