Ch. 6 HMD 211

How many pounds are in a kilogram?

2.2

An optimal intake of protein for Americans is approximately __________.

46 grams per day for women and 56 grams per day for men.

The recommended daily protein intake for a healthy adult weighing 165 pounds is __________ grams.

60

Added protein has been showing up in more and more packaged foods. Which of the following statements is correct about the added protein in packaged foods?

Certain segments of the population may need to supplement with more protein. In this case, packaged foods with added protein may make sense for those who have dietary challenges, such as allergies and food sensitivities, or picky eaters who won't eat eggs or meat.

Protein synthesis is directed by the ______ in the nucleus of the cell.

DNA

Which of the following statements about high-protein diets is correct?

Excess dietary protein may cause the development of kidney stones.

T/F - Amino acids are bound together by a chemical bond known as an amino acid bond to form proteins.

False

T/F - Approximately 50 percent of every protein molecule is composed of nitrogen.

False

T/F - Chemical digestion of protein begins in the mouth with enzymes found in the saliva.

False

T/F - The digestion of polypeptides begins in the mouth with the enzyme pepsin.

False

__________ direct activity in the body and can be made of proteins or lipids.

Hormones

_____________ is a severe deficiency of dietary protein, resulting in swelling in the feet, legs, and stomach among other symptoms.

Kwashiorkor

Amino acids that enter the bloodstream from the small intestine travel to here.

Liver

How do we determine whether we are in protein balance?

Measuring the amount of nitrogen consumed with the amount of nitrogen excreted.

Enzymes that digest amino acid chains are produced here and delivered via a duct to the small intestine.

Pancreas

The active form of a digestive enzyme in the stomach that breaks polypeptide chains into smaller polypeptides.

Pepsin

Which of the following statements is FALSE regarding nitrogen balance?

Pregnant women usually consume less nitrogen than they excrete.

Which of the following statements regarding protein absorption is true?

Protein is absorbed as single amino acids or small peptide chains by the process of active transport.

Single amino acids, dipeptides, and tripeptides are absorbed in which organ?

Small intestine

Which organ... • Secretes HCI • HCI denatures protein • Forms pepsin from pepsinogen

Stomach

The body uses two types of amino acids: essential and nonessential. Which of the following statements about essential and nonessential amino acids is correct?

There are 11 nonessential amino acids.

___________ _____________ carry many substances through the blood or allow movement of substances in and out of cells.

Transport proteins

T/F - The side chain of an amino acid differentiates one amino acid from another.

True

The ______________ _____________ is also known as the carboxyl group.

acid group

The part of an amino acid that contains nitrogen is called the ___________ ______________.

amine group

_______________ ________________ _______________ are stockpiles found in the blood and other cells of the body that can be used to build new proteins.

amino acid pools

The 20 different ______________ _____________ are the building blocks used for protein synthesis.

amino acids

A molecule with four to nine amino acids joined together by peptide bonds is referred to as __________.

an oligopeptide

Proteins called __________ aid the immune system in its fight against bacteria, viruses, and other foreign substance by binding to them and helping to inactivate or destroy them.

antibodies

Proteins help control the acid-base balance in the body by acting as _____________.

buffers

A nonessential amino acid is made...

by transferring amino acids and side chains.

Amino acids found in the amino acid pool...

can be used for protein synthesis.

Substances that speed up reactions without being changed or used up are ________.

catalysts

Most enzymes are proteins, but some may utilize _________________ in the form of vitamins to help with reactions.

coenzymes

To use amino acids for energy, the nitrogen must first be removed from the amino acid. This process is called...

deamination.

_____________________ occurs when a protein is exposed to heat, acid, bases, or mechanical agitation resulting in unfolding of the protein, though the peptide bonds remain intact.

denaturation

The quality of a protein is determined by the...

digestibility of the protein and the types and amounts of amino acids.

A chain of two amino acids is referred to as a __________.

dipeptide

__________________ describes an amino acid chain made up of two amino acids joined together.

dipeptide

Consistently eating too many high-protein foods can lead to a higher risk for...

heart disease, kidney problems, and calcium loss from bones.

A protein that acts as a hormone is __________.

insulin

Nitrogen that has been removed during deamination...

is converted to urea and excreted through the urine.

The primary organ responsible for excreting nitrogen-containing waste is the __________.

kidneys

Deamination occurs mostly in the ___________.

liver

The organ that determines what happens to the amino acids after they enter the bloodstream is the _________.

liver

All amino acids contain carbon, hydrogen, oxygen, and _______.

nitrogen

The bond that is formed when two amino acids join together is called __________.

peptide bond

The chemical bonds that connect amino acids are called...

peptide bonds

Cleavage of proteins by pepsin in the stomach results in formation of __________________ ____________ which get broken down further in the small intestine.

polypeptide strands

Single amino acids that are absorbed in the small intestine travel to the liver via the__________ ___________.

portal vein

Growing children and adolescents are in _________ ____________ ___________.

positive nitrogen balance

The continual process of degrading and synthesizing protein is called ___________ ____________.

protein turnover

Inadequate intake of protein and/or calories is known as...

protein-energy malnutrition.

A medical condition that is a genetic defect caused by a change in the amino acid sequence is __________.

sickle cell anemia

Proteins are digested by enzymes in the __________.

stomach and small intestine

Ketosis is defined as __________.

the abnormal accumulation of ketones in the body as a result of excessive breakdown of fats caused by inadequate consumption of carbohydrates

What is denaturation?

the uncoiling of the protein molecule by hydrochloric acid in the stomach

An amino acid chain made up of three amino acids joined together is called a ________________.

tripeptide

When the amine group is removed, the carbon-containing component of amino acids can be....

used for energy.

How does your body use the protein once it has been ingested?

• If calorie intake is inadequate, amino acids can be used for production of energy. • The liver uses amino acids to create glucose. • Amino acids are used to create new proteins.

What secretions are needed to digest complex proteins into single amino acids for absorption?

• hydrochloric acid and pepsin in the stomach • saliva from the salivary glands in the mouth • proteases secreted from the pancreas and the small intestine

Which of the following amino acids are considered essential?

• lysine • methionine • threonine