Chapter 25 MC
Phoebe grew up in Alaska's interior and played with her friends at recess in temperatures just above 20 degrees Fahrenheit. In fact, administrators would not close her school until temperatures reached 5 degrees Fahrenheit. Which of the following terms describes her adaptation to Alaska's frigid winter climate?
acclimatization
When blood glucose concentrations are elevated, the glucose molecules can be __________.
catabolized for energy, used to build energy reserves, and used for growth and tissue repair
The first step in the sequence of enzymatic reactions in the tricarboxylic acid cycle is the formation of __________.
citric acid
What is the term for the direct transfer of heat energy through physical contact?
conduction
When the body is relying on internal energy reserves to continue meeting its energy demands, it is in the ________ state.
postabsorptive
Although small quantities of lipids are normally stored in the liver, most of the synthesized triglycerides are exported and bound to __________.
proteins
All nutrients can be used by the mitochondria to provide energy. In what form are these nutrients "fed" into the mitochondria?
two-carbon fragments
Catabolizing fatty acids by beta-oxidation results in the formation of what product?
Acetyl-CoA
Inadequate exposure to sunlight could result in decreased amounts of vitamin ________ in the body.
D
What is the term for an amino acid that either cannot be synthesized or is not synthesized in adequate amounts in the body?
Essential amino acid
Excess cholesterol leaves somatic cells and is absorbed by __________, which then transport the cholesterol back to the liver.
HDLs
The vitamin that is essential for the production of several clotting factors is vitamin
K
What lipoproteins transport cholesterol to cells of the body?
LDL
NAD, a key coenzyme used in the process of producing ATP, is produced from which water-soluble vitamin?
Niacin
Why are minerals, vitamins, and water classified as essential nutrients?
The body cannot syntesize these nutrients in sufficient quantities
The attachment of an amine group in the synthesis of an amino acid is called __________.
amination
Which of the following people would not likely be in positive nitrogen balance?
an elderly grandmother
Cells in our body are constantly building new molecules to replace worn-out structures. This process is what part of cellular metabolism?
anabolism
Which lipoprotein carries dietary triglycerides to the liver?
chylomicrons
The first steps of catabolism generally take place in the
cytosol
The removal of amino group from a protein to prepare it to enter the citric acid cycle is termed
deamination
Most of the ATP from metabolism is produced in the
electron transport system.
The mechanism of heat loss that involves the skin and alveoli of the lung is _______.
evaporation
A high uric acid level (above 7.4 mg/dl) can lead to the painful condition known as
gout
Part complete About 40 percent of the energy content of nutrients is captured as ATP. The remainder is lost as __________.
heat
The trace minerals found in extremely small quantities in the body include __________.
iron, zinc, copper, and manganese
What happens to oxygen when it functions as the final electron acceptor in the electron transport chain?
it becomes part of a water molecule
What is a complete protein?
it contains all the essential amino acids.
The synthesis of lipids is called __________.
lipogenesis
Lipids circulate through the bloodstream as __________.
lipoproteins and free fatty acids
All the chemical reactions that occur in an organism are called ________.
metabolism
Which of the following foods are deficient in dietary fiber?
milk and meat
The formation of GTP from GDP in the citric acid cycle is an example of
substrate-level phosphorylation.
If excess glucose remains in the blood circulation after glycogen formation, the hepatocytes use the glucose to __________.
synthesize triglycerides
The period following a meal when nutrient absorption is underway is __________.
the absorptive state
The carbon dioxide released by the lungs into the atmosphere was very likely produced within __________.
the citric acid cycle
The production of ATP provides energy to support anabolism as well as other cell functions. Which of the following is NOT supported by energy from ATP?
the diffusion of molecules across the plasma membrane
An individual's basal metabolic rate ideally represents ________.
the minimum resting energy expenditure of an awake, alert person
Which vitamin is required for the synthesis of visual pigments?
vitamin A
What is the vitamin that functions as a coenzyme in the deamination process?
vitamin B6
The element that is necessary for the proper function of the enzyme carbonic anhydrase is
zinc
Which part of the cell is most heavily involved in energetics?
mitochondria
A cell with excess carbohydrates, lipids, and amino acids will break down carbohydrates in order to __________.
obtain energy
Metabolism refers to __________.
all the anabolic and catabolic reactions in the body
Milk and eggs are complete proteins because they contain __________.
all the essential amino acids in sufficient quantities
The flow and transformation of energy is called __________.
energetics
Frank has diabetes mellitus and his blood pH has dropped. What is the most likely cause of his acidosis?
excess ketone formation
In the nutrient pool, which chemical is best suited for storage of energy content?
fatty acids
On a tour of African countries, Mark contracts a bad case of traveler's diarrhea. Because he can't eat very much, his body starts to use energy sources other than carbohydrates. This would result in all of the following, except
glycogenesis
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 nitrogen-containing compound that is important for energy storage in muscle tissue?
creatine
Catabolism of protein is not a practical source of quick energy because of all of the following except that
most individuals have little protein to spare before harming vital organs.
For each glucose molecule converted to two pyruvates, the anaerobic reaction sequence in glycolysis provides a net gain of __________.
two ATP for the cell
An element that is a component of hemoglobin, myoglobin, and cytochromes is
iron
Glycolysis produces how many pyruvate molecules and how many ATP molecules? (Figure 25-2)
2 pyruvate molecules with a net gain of 2 ATP molecules
For each glucose molecule processed during aerobic cellular respiration, the cell gains __________.
32 molecules of ATP
The basal metabolic rate (BMR) is ________.
70 cal/hr or 1680 cal/day in the average individual
The vitamin that plays a role in maintaining epithelia and is required for the synthesis of visual pigments is vitamin
A
What is meant by the term balanced diet?
A balanced diet supplies all ingredients to maintain homeostasis.
During open-heart surgery, which of the following thermoregulatory changes is induced in the patient's body?
Hypothermia
Where in the cell does the electron transport chain occur?
Inner mitochondrial membrane
Where in the cell does the citric acid cycle occur?
Mitochondrial matrix
Why is it that lipids cannot provide large amounts of adenosine triphosphate (ATP) in a short period of time?
Most lipids are processed in mitochondria, and mitochondrial activity depends on the availability of oxygen.Lipids are insoluble in water, and it is thus difficult for water-soluble enzymes to reach them.Lipid reserves are difficult to mobilize.
The two most important coenzymes for glycolysis and the citric acid cycle are
NAD and FAD
Which of the following tissues contains no reserves of carbohydrates, lipids, or proteins and can metabolize only glucose?
Neural tissue
All of the following occur during glycolysis, except
a molecule of carbon dioxide is produced.
Eating disorders are common among girls and young women. They result from a psychological problem that causes inadequate or excessive food consumption. Two major eating disorders are anorexia nervosa and
bulimia
The end products of aerobic respiration are
carbon dioxide, water, and ATP
The process that breaks down organic substrates, releasing energy that can be used to synthesize ATP or other high-energy compounds, is ____________.
catabolism
In resting skeletal muscles, a significant portion of their metabolic demand is met through the __________.
catabolism of fatty acids
What happens to a glucose molecule as a result of the reactions of glycolysis?
formation of the two molecules of pyruvic acid
Which of the following is an important energy source during periods of starvation, when glucose supplies are limited?
free fatty acids
The process of synthesizing glucose from noncarbohydrates is called
gluconeogenesis
Although other nutrients can feed into the citric acid cycle, ________ yields energy the quickest.
glucose
Which of the following is not one of the N compounds (nitrogen-containing compounds) in the body?
glucose
Which process in the aerobic metabolism of glucose takes place in the cytosol?
glycolysis
________ carry excess cholesterol from peripheral tissues to the liver.
high-density lipoproteins (HDLs)
The most important factor of good nutrition is obtaining nutrients __________.
in sufficient quantities and qualities
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 brown fat is present primarily in __________.
infats
Before the large vitamin B12 molecule can be absorbed, it must be bound to __________.
intrinsic factor
What chemical in the catabolism of glucose enters the mitochondria?
pyruvate
During the catabolism of glucose, some energy is captured by __________ molecules, while the rest of the energy is lost mainly as ________.
reduced; heat
What is the primary role of the citric acid cycle in the production of ATP?
removal of electrons from substrates
The function of the citric acid cycle is to
remove hydrogen atoms from organic molecules and transfer them to coenzymes.
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
Reactions within ________ provide most of the energy needed by a typical cell.
the mitochondria
Which of the following is NOT a mineral required by the body?
thiamine
In order to determine the LDL level in a patient's blood, it is necessary to measure
total cholesterol level, HDL level, and triglyceride level.
The conversion of ammonia into a less toxic substance produces
urea
What is the total ATP production just from the acetyl-CoA fragments of an 18-carbon fatty acid?
120
What is the primary focus of nutritional processing in the postabsorptive state?
Maintaining blood glucose levels
The factors that make protein catabolism an impractical source of quick energy include which of the following?
Proteins have more important uses as structural and functional cellular components.One of the by-products, ammonia, is a toxin that can damage cells.Proteins are difficult to break apart.
The minimum resting energy expenditure of an awake, alert person is the __________.
basal metabolic rate
The process in which fatty acids are broken down into two-carbon fragments is __________.
beta-oxidation
If the cells are catabolizing amino acids for energy, what is the first step in amino acid catabolism?
deamination
Which of the following is NOT a way your body generates or conserves heat?
decreased metabolic rate
Fatty acids that are necessary for proper health but cannot be synthesized by the body are called ________ fatty acids.
essential
Which of the following enables infants to produce or conserve heat?
lipolysis of brown fat
In terms of the movement of electrons, the gain of electrons is called reduction, whereas the loss of electrons is called __________.
oxidation
Why is hypervitaminosis involving water-soluble vitamins relatively uncommon?
excessive amounts of these vitamins are readily excreted in the urine
The lipoproteins that carry absorbed lipids from the intestinal tract to the bloodstream are
chylomicrons
When considering the chemicals in the nutrient pool, which chemical is LEAST likely to be broken down to supply energy for the cell?
amino acids
Which nutrient in the nutrient pool is most often used to replace structural and functional components of the cell?
amino acids
Which process in the metabolism of glucose does not require oxygen?
glycolysis
The lipoprotein that transports cholesterol to the liver is __________.
high-density lipoprotein
