Certain nutrients are considered "essential" in the diets of some animals because
these animals are not able to synthesize these nutrients
To maintain adequate nutrition, animals require dietary access to certain amino acids. An amino acid that is referred to as "nonessential" would be best described as one that
can be made by the animal's body from other substances
Which pair correctly associates a physiological process with the appropriate vitamin?
normal vision and vitamin A
The fat-soluble vitamins include
vitamin A
A general rule relating the capacity of a specific animal's digestive system to provide adequate access to substrates for biosynthesis of cellular components, as well as fuel molecules needed for ATP production, is that the animal should have access to
a diet that matches the "food pyramid" for the species
Excessive iron absorption and accumulation to toxic levels is associated with
the genetic disorder known as hemochromatosis
Fat digestion yields fatty acids and glycerol, whereas protein digestion yields amino acids; both digestive processes
add a water molecule to break bonds (hydrolysis)
Ingested dietary substances must cross cell membranes to be used by the body, a process known as
absorption
In marine sponges, intracellular digestion of peptides is usually immediately preceded by
endocytosis
An advantage of a complete digestive system over a gastrovascular cavity is that the complete system
allows for specialized regions with specialized functions
Because the foods eaten by animals are often composed largely of macromolecules, this requires the animals to have mechanisms for
enzymatic hydrolysis
The large surface area in the gut directly facilitates
absorption
In the digestive system, peristalsis is
smooth muscle contractions that move food along the esophagus
After ingestion by humans, the first category of macromolecules to be chemically digested by enzymes in the mouth is
carbohydrates
Salivary amylase digests
starches
Digestive secretions with a pH of 2 are characteristic of the
stomach
Pepsin is a digestive enzym that
begins the hydrolysis of proteins in the stomach
Upon activation by stomach acidity, the secretions of the parietal cells
initiate the digestion of protein in the stomach.
The bile salts
emulsify fats in the duodenum
Complex nutrients are digested and then absorbed into the lymph or bloodstream as
monomers
An enzyme with high activity in an acidic environment is
pepsin
The absorption of fats differs from that of carbohydrates in that the
most absorbed fat first enters the lymphatic system, whereas carbohydrates directly enter the blood
For a nondiabetic person, the glucose concentration in this part of the vasculature varies more than in any other part.
hepatic portal vessel
Glandular secretions that are released initially as inactive precursors of digestive enzymes are the
protein-digesting enzymes
Because adult lampreys attach onto the surface of large fish for long periods of time to feed on body fluids, they can accomplish nutritional balance without need for a
stomach
Constipation can result from the consumption of a substance that
promotes water reabsorption in the large intestine
Historically inaccurate diagnosis of acid reflux disorders and gastric ulcers has been improved by
the diagnosis and treatment of H. pylori infection
A hiatal hernia that disrupts the functional relationship between the smooth muscle in the esophagus and that in the stomach would be most likely to increase the frequency of
gastric reflux
The cells that secrete the acidic components of stomach juices are
the parietal cells of the stomach
Stomach cells are moderately well adapted to the acidity and protein-digesting activities in the stomach by having
a thick, mucous secretion and active mitosis of epithelial cells