Metabolism and Energetics
The products of glycolysis include which of the following?
A. ATP B. pyruvic acid C. NADH
Excess cholesterol leaves somatic cells and is absorbed by __________, which then transport the cholesterol back to the liver.
HDLs
How does neural tissue normally respond during the postabsorptive state?
In the postabsorptive state, the activities of neural tissue do not change in comparison to its activities in the absorptive state.
Which of the following has been implicated in plaque buildup and cardiovascular disease?
LDL
NAD
a coenzyme that removes hydrogen atoms
Metabolism refers to __________.
all the chemical reactions in the body
The attachment of an amine group in the synthesis of an amino acid is called __________.
amination
Lipoprotein lipase
an enzyme that breaks down complex lipids
High-density lipoproteins __________.
are sometimes called "good cholesterol"
Which of the following is an important energy source during periods of starvation, when glucose supplies are limited?
free fatty acids
Levels of which endocrine hormone are high during the postabsorptive state?
glucagon
Which of the following hormones exhibits its influence most during the postabsorptive state?
glucagon
The synthesis of glucose from noncarbohydrates is __________.
gluconeogenesis
Which process in the aerobic metabolism of glucose takes place in the cytosol?
glycolysis
The lipoprotein that transports cholesterol to the liver is __________.
high-density lipoprotein
The most important factors in good nutrition are to obtain nutrients __________.
in sufficient quantity and quality
Which of the following foods are DEFICIENT in dietary fiber?
milk and meat
The TCA, or Krebs, cycle takes place in the __________.
mitochondria
The breakdown of fatty acid molecules yields __________ the breakdown of similar carbohydrates.
more ATP than
Which of the following tissues contains NO reserves of carbohydrates, lipids, or proteins and can metabolize only glucose?
neural tissue
Which of the following carries lipids from the digestive tract to the circulatory system?
chylomicrons
The first step in a sequence of enzymatic reactions in the tricarboxylic acid cycle is the formation of __________.
citric acid
The direct transfer of energy through physical contact is called __________.
conduction
Glycolysis occurs in the __________.
cytoplasm
A cell with excess carbohydrates, lipids, and amino acids will break down carbohydrates to __________.
obtain energy
In terms of the movement of electrons, the gain of electrons is called reduction, whereas the loss is called __________.
oxidation
In glycolysis, six-carbon glucose molecules are broken down into two three-carbon molecules of __________.
pyruvic acid
If excess glucose still remains in the circulation after glycogen formation, the hepatocytes use glucose to __________.
synthesize triglycerides
What is the primary function of very low-density lipoproteins (VLDLs)?
transporting the triglycerides to peripheral tissues
Amino acids are deaminated and the amine group is ultimately excreted as __________.
urea
Neurons must be provided with a reliable supply of glucose because they are __________.
usually unable to metabolize other molecules
Which of the following is a fat-soluble vitamin necessary for synthesis of visual pigments?
vitamin A
The synthesis of lipids is called __________.
lipogenesis
Lipids circulate through the bloodstream as __________.
lipoproteins and free fatty acids
Which type of lipid is linked to cholesterol deposition in arterial walls and may require a change in diet to control?
low-density lipoproteins (LDLs)
NAD, a key coenzyme used in the process of producing ATP, is produced from which water-soluble vitamin?
niacin
The four processes involved in heat exchange with the environment are __________.
radiation, conduction, convection, and evaporation
LDLs are absorbed by cells through the process of __________.
receptor-mediated endocytosis
Glycolysis occurs __________.
whether or not oxygen is present
Glycolysis produces a net gain of __________ ATP molecules from each glucose molecule.
2
For each glucose molecule converted to two pyruvates, the anaerobic reaction sequence in glycolysis provides a net gain of __________.
2 ATP for the cell
In the beta-oxidation of an 18-carbon fatty acid molecule, the cell gains __________.
144 ATP
For each glucose molecule processed during aerobic cellular respiration, the cell gains __________.
36 molecules of ATP
The efficiency rate for the complete catabolism of glucose is about __________.
42 percent
The basal metabolic rate (BMR) is __________.
A. the minimum resting energy of an awake, alert person B. 70 cal/hr or 1680 cal/day in the average individual C. measured by monitoring respiratory activity
Why are minerals, vitamins, and water classified as essential nutrients?
The body cannot synthesize the nutrients in sufficient quantities.
48. Milk and eggs are complete proteins because they contain __________.
all the essential amino acids in sufficient quantities
What is the term for the direct transfer of heat energy through physical contact?
conduction
Which of the following is a nitrogen compound important in energy storage in muscle tissue?
creatine
The synthesis of glucose from nonglucose precursors is known as __________.
gluconeogenesis
During open-heart surgery, which of the following thermoregulatory changes will be induced on the patient's body?
hypothermia
Lucy, a 35-year-old woman, says she CANNOT lose the fat around her abdomen because it is brown fat. You correct her by saying that the only people with brown fat are __________.
infants
No kidding: The town of Nederland, Colorado, has a winter festival called Frozen Dead Guy Days. A man named Bredo Morstoel, a native Norwegian, was born in 1900 and died in 1989. After his death, his grandson had his body cryogenically frozen and stored it in a shed in Colorado until a future date when he supposedly will be resuscitated. Why will this thawing procedure NOT bring Mr. Morstoel back to life?
A. Freezing temperatures cause water to expand, which would burst cell membranes. B. Death had already occurred before the freezing process. C. The ratio of surface area to volume is low in Mr. Morstoel's body, meaning that ice crystals would have formed during the freezing process.
Why is it that lipids CANNOT provide large amounts of adenosine triphosphate (ATP) in a short period of time?
A. Lipid reserves are difficult to mobilize. B. Lipids are insoluble, and it is difficult for water-soluble enzymes to reach them. C. Most lipids are processed in mitochondria, and mitochondrial activity is limited by the availability of oxygen.
The factors that make protein catabolism an IMPRACTICAL source of quick energy include which of the following?
A. Proteins are more difficult to break apart. B. One of the by-products, ammonia, is a toxin that can damage cells. C. Proteins are important structural and functional cellular components.
Which of the following people would be in positive nitrogen balance?
A. Proteins are more difficult to break apart. B. One of the by-products, ammonia, is a toxin that can damage cells. C. Proteins are important structural and functional cellular components.
Why is hypervitaminosis involving water-soluble vitamins relatively UNCOMMON?
Excessive amounts are readily excreted in the urine.
Why can lipogenesis use almost any organic substrate?
Lipids, amino acids, and carbohydrates can be converted to acetyl-CoA.
All the chemical reactions that occur in an organism are called __________.
Metabolism
Which of the following are coenzymes that deliver hydrogen ions and electrons to the ETS in the inner mitochondrial membrane?
NADH and FADH2
Why is it that fatty acids and many amino acids CANNOT be converted to glucose?
Their catabolic pathways produce acetyl-CoA.
The minimum resting energy expenditure of an awake, alert person is the __________.
basal metabolic rate
The breakdown of fatty acid molecules into two carbon fragments is called __________.
beta-oxidation
The process in which fatty acids are broken down into two-carbon fragments is __________.
beta-oxidation
To examine the metabolic state of an individual, results may be expressed as __________.
calories per hour, calories per day, and calories per unit of body weight per day
The process that breaks down organic substrates, releasing energy that can be used to synthesize ATP or other high-energy compounds, is __________.
catabolism
The series of integral and peripheral proteins in the inner mitochondria that takes NADH, FADH2, and oxygen and produces ATP and water is the __________.
electron transport system
The removal of the amine group from an amino acid, resulting in the formation of an ammonium ion, is __________.
deamination
The enzyme lipoprotein lipase __________.
digests lipid complexes into free fatty acids and monoglycerides
Which of the following hormones does NOT have important functions during the postabsorptive state?
insulin
Before the large vitamin B12 molecule can be absorbed, it must be bound to __________.
intrinsic factor
The trace minerals found in extremely small quantities in the body include __________.
iron, zinc, copper, and manganese
Which of the following selections includes ONLY essential amino acids for a growing child?
leucine, lysine, valine, tryptophan, arginine
The period following a meal when nutrient absorption is underway is __________.
the absorptive state
Glycolysis
the breakdown of glucose to pyruvic acid
Evaporation
the change of water to a gas
Radiation
the emission of heat into cooler surroundings by a warm object
Conduction
the loss of heat through direct contact with a cooler object
An individual's basal metabolic rate ideally represents __________.
the minimum resting energy expenditure of an awake, alert person
Convection
the process in the human body by which the body releases heat into the surrounding air; the heat rises and is replaced by cooler air
beta-oxidation
the sequence of reactions that breaks fatty acids into 2-carbon fragments
Lipogenesis
the synthesis of fats from acetyl Co-A or dihydroxyacetone phosphate
Which of the following statements is FALSE concerning basal metabolic rate (BMR) and thermoregulation?
The average person has a BMR of 3000 calories per day.
Phoebe grew up in Alaska's interior and used to play with her friends at recess in temperatures of −20°F. In fact, her school was not canceled until the temperatures reached −50°F. Which of the following terms describes her adaptation to Alaska's frigid winter climate?
acclimatization
Most pathways of lipogenesis begin with __________.
acetyl coenzyme A
Amino groups can be removed from amino acids by __________.
both deamination and transamination
Catabolism __________.
both produces ATP and heat and breaks down organic molecules
Which of the following is NOT a mechanism for heat loss?
diminishing activity in the sympathetic vasomotor center
The synthesis of glucose from noncarbohydrates is called __________.
gluconeogenesis
Gluconeogenesis
the synthesis of glucose from noncarbohydrate precursors
Which of the following individuals does NOT need to modify his or her daily activities to help regulate cholesterol levels?
a 40-year-old woman who weighs 135 pounds, has a total cholesterol level of 150 mg/dL, and does not have a history of atherosclerosis
Under normal circumstances, if you eat three meals a day, the body will spend approximately 12 hours in the __________.
absorptive state
The breakdown of fatty acid molecules results in the production of __________.
acetyl coenzyme A
The transition between glycolysis and the TCA cycle involves a molecule called __________.
acetyl coenzyme A
In resting skeletal muscles, a significant portion of the metabolic demand is met through the __________.
catabolism of fatty acids
When blood glucose concentrations are elevated, the glucose molecules are __________.
catabolized for energy
A diet deficient in essential fatty acids would __________.
slow growth, alter the appearance of the skin, and cause a decrease in the production of prostaglandins
Although small quantities of lipids are normally stored in the liver, most of the synthesized triglycerides are bound to __________.
transport proteins