NTR 401 Exam 1 NCSU

Zymogen can be defined as

A protein that can become an active enzyme through proteolysis at a location outside the cells where it is synthesized.

The absorptive cells lining the gastrointestinal tract are called:

Enterocytes

The hormonal feedback loop between the last segment of the small intestine and the pyloric sphincter, involving substance GLP-1, is:

Ileal brake

All of the following factors stimulate or increase thirst EXCEPT:

Increased blood volume presumably detected by cardiac stretch receptors

The most common digestive problem associated with carbohydrates is hypolactasia, which is

a reduced ability to digest the galactose-glucose bond of milk sugar

Phytate (phytic acid) is a

derivative of the sugar alcohol, inositol phosphate, that chelates minerals in the diet and reduces their absorption

The "Adequate Macronutrient Distribution Range" is:

the percentage of daily calories from each energy source that provides a reduced risk for chronic disease

Substance that is needed in a metabolic reaction or tissue structure that cannot be synthesized in humans may be generally referred to as

indispensable nutrient

UL refers to which of the following statements?

"Tolerable Upper Intake Limit" is a nutrient intake above which the risk for harm begins to increase

"Reference height and weight" refers to:

Average height and weight of American men and women with a "healthy" BMI, used to provide a representative nutrient intake for a population for nutrients that should be consumed in quantities based on body weight

Diverse populations around the world consume sodium at levels greater than the Upper Tolerable Intake Level set in the DRIs. One explanation for this "sodium appetite" is that humans choose a sodium intake that does not trigger an excessive secretion of the hormone

Renin

Biological scientists study the regulation of food intake in terms of the gut-brain and adipose-brain hormonal axes. In contrast, nutritionists who take a more holistic view of human ecology, sociology, psychology and public health in their research, frequently refer to the ___________________, which can include the concept of _________________ to explain the current prevalence of obesity.

the socioecological model; neuroeconomics

The DRI value that is most likely to be applicable to 100% of the population, i.e. not overlap the normal distribution, is

UL

The physiological principle that allows the kidney to excrete urine that can be either more or less dilute than the blood plasma it originates from is

countercurrent sodium pumping in the loop of Henle creates a high concentration of salt in the interior of the kidney, and the collecting ducts have variable permeability to water.

Which of the following components does NOT have an important role in the breakdown and absorption of fats in the intestine?

Salivary lipase

The dietary component that is the precursor of monoacylglycerol and 2 molecules of free fatty acid in the gut is called

triglyceride

According to the Institute of Medicine's Dietary Reference Intake guidelines, a nutritionist using the RDA to plan meals for a population must take into account several sources of variation that allow calculation of the percentage of the population that would meet their requirements. Among the following, the LEAST IMPORTANT source of uncertainty would be:

Organic foods have different nutrient content than conventionally grown foods, as is usually noted on the labels or in the nutrient database.

The best way to change the dietary intake of a free-living population for a given nutrient is to:

Educate people about food choices or modify the nutrient profile of foods most commonly eaten.

Which factors were LEAST likely to be considered important in determining the age and gender categories for Dietary Reference Intakes?

Different racial and ethnic groups may have different nutrient requirements.

The brain initiates or reduces food-seeking behavior by integrating various signals, including all of the following EXCEPT:

pH of the blood

The process of digestion serves ALL of the following functions EXCEPT:

moves food components from the gut into the blood stream (this would be absorption)

As soon as food is eaten, the hormone gastrin

stimulates hydrochloric acid secretion by the stomach's pariental cells.

All of the following are considered to be exocrine glands associated with the gastrointestinal tract EXCEPT:

adrenal glands

An enzyme that breaks the alpha 1-4 bonds of straight chain glucose polymers is

amylase

A transport enzyme that couples the sodium gradient from the gut lumen to the inside of the enterocytes to the uptake of a monosaccharide is

SGLT-1

Where is the Vitamin D receptor located in the intestinal epithelial cell?

On the cell, on top of the box with the double arrows labeled "VDR calcitriol"

Where is the Ca channel TRPV6 located?

in the cell membrane, enabling transport from the intestinal lumen into the cell

Where is paracellular transport occurring in the diagram?

Through the cell, from the intestinal lumen

Where is calbindin D9k located in the diagram?

It is binding to Ca, right below the TRPV6 Ca channel

Where is Calcium ATPase located in the diagram?

at the bottom of the cell, where Ca is flowing out as ATP loses a phosphate to become ADP

Hormone produced in the stomach that signals hunger so as to elicit food-seeking behavior

Ghrelin

Hormone produced in the adipose tissue that signals the brain to reduce food intake

Leptin

Hormone produced in the small intestine that signals the brain to cease food intake

Cholecystokinin (CCK)

Hormone produced in the liver that signals the intestine to reduce iron absorption

Hepcidin

Paracellular transport

Movement from the intestinal lumen to interstitial space by passing through leaky junctions between neighboring enterocytes

Primary active transport

Nutrient can be moved against a concentration gradient because a transport enzyme hydrolyzes a high energy bond from ATP or a related molecule

Facilitated Diffusion

Nutrient moves through a channel or pore in a membrane in the direction of high to low concentraton

Passive diffusion

Random motion of small molecules allows them to enter and leave small spaces between other molecules, such as water passing through a lipid membrane

Secondary active transport

A transporter couples movement of one nutrient across a membrane against its concentration gradient to the simultaneous movement of a second molecule down an energetically greater concentration gradient

When a person changes from a consistent diet that is omnivorous and high in processed food to vegetarian diet high in fiber from fruits and vegetables, researchers studying this person would be LEAST likely to find changes in the data coming from _____________ analysis.

genomic

When we compare the physiological mechanisms for absorption of calcium and zinc, we find:

increase in synthesis of a specific calcium-binding cytosolic protein (Calbindin-D) _________ calcium absorption; and synthesis of a specific zinc-binding cytosolic protein (metallothionein) ___________ zinc absorption

increases; decreases

Calbindin-D increases Ca absorption.

Metallothionein decreases Zn absorption.

Food labeling changed to the protein digestibility-corrected amino acid score (PDCAAS) method of measuring protein quality in the early 1990's from older methods like Biological Value and Protein Efficiency Ratio. Which of the following statements best reflects the concept behind the PDCAAS?

The quality of a protein food is only as high as its limiting amino acid.