Dietary Fiber and Health Benefits Quiz

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Questions and Answers

Which type of dietary fiber helps reduce the risk of heart disease and obesity?

Lignins

Beta-glucan (correct)

Cellulose

Hemicellulose

What is the primary function of glycogen in animals?

Source of protein

Storage form of glucose (correct)

Structural component of cells

Digestive enzyme

Which food is high in soluble fiber and helps reduce constipation?

Citrus fruits (correct)

Spinach

Brown rice

Whole-grain bread

What enzyme is deficient in individuals with lactose intolerance?

Lactase Signup and view all the answers

Which of the following foods contains cellulose?

Whole grains Signup and view all the answers

What condition results from lactose maldigestion?

Nausea and cramps Signup and view all the answers

What does muscle glycogen primarily provide?

Energy for muscle contraction Signup and view all the answers

Which type of dietary fiber is primarily found in oats and reduces the risk of diabetes mellitus?

Beta-glucan Signup and view all the answers

What is the primary structural difference between proteins and carbohydrates or lipids?

Proteins contain nitrogen in addition to carbon, hydrogen, and oxygen. Signup and view all the answers

How many amino acids are typically linked together to form a protein?

More than 50. Signup and view all the answers

Which of the following correctly describes a dipeptide?

A peptide with 2 amino acids. Signup and view all the answers

What components make up the anatomy of an amino acid?

An amine group, a carboxylic acid group, and a side chain. Signup and view all the answers

What is the process by which peptide bonds are formed?

Through condensation. Signup and view all the answers

What breaks peptide bonds during the process of digestion?

Hydrolysis. Signup and view all the answers

What are essential amino acids?

Amino acids that must be consumed in the diet. Signup and view all the answers

Which of the following best describes polypeptides?

They consist of more than 10 amino acids. Signup and view all the answers

Why can't excess dietary protein be stored in the body?

The body does not store nitrogen from protein. Signup and view all the answers

Which amino acids become conditionally essential?

Nonessential amino acids that cannot be synthesized under certain conditions. Signup and view all the answers

What is the correct order of the four levels of protein structure?

Primary, Secondary, Tertiary, Quaternary Signup and view all the answers

Which of the following can cause denaturation of proteins?

Basic pH levels Signup and view all the answers

What initiates protein digestion in the stomach?

The release of HCl stimulated by gastrin Signup and view all the answers

What happens to a protein's primary structure during denaturation?

It remains unchanged. Signup and view all the answers

Which hormone stimulates the release of proteases in the small intestine?

CCK Signup and view all the answers

How many essential amino acids must be consumed in the diet?

9 Signup and view all the answers

What does the protein digestibility corrected amino acid score (PDCAAS) take into account?

The digestibility of the protein and the amino acid score Signup and view all the answers

Which of the following food sources is considered a complete protein?

Quinoa Signup and view all the answers

How is biological value defined?

The rate at which nitrogen from absorbed protein is converted into body protein Signup and view all the answers

Which of the following statements accurately describes incomplete proteins?

They are low in one or more essential amino acids Signup and view all the answers

Which food combinations illustrate the concept of complementary proteins?

Rice and beans Signup and view all the answers

What is the general protein content provided by a 3-ounce serving of cooked meat, poultry, or fish?

21 to 25 grams Signup and view all the answers

Why is eating a wide variety of foods recommended for meeting protein needs?

It ensures adequate intake of all essential amino acids Signup and view all the answers

What is NOT a characteristic of complete proteins?

They are primarily sourced from plants Signup and view all the answers

What happens to amino acids when the amino acid pool reaches capacity?

They undergo deamination and are converted into urea. Signup and view all the answers

How does the body utilize amino acids when carbohydrate intake is low?

They are converted into glucose. Signup and view all the answers

What role do amino acid pools play in the body?

They provide a ready supply of amino acids for protein synthesis. Signup and view all the answers

What is a consequence of high blood ammonia levels?

Potential liver damage. Signup and view all the answers

What is the process called that involves breaking down and synthesizing proteins in the body?

Protein turnover Signup and view all the answers

Which function is NOT typically associated with proteins in the body?

Regulating body temperature Signup and view all the answers

What can excess protein be converted into when not needed by the body?

Triglycerides Signup and view all the answers

Which statement best describes the function of hormones in relation to proteins?

They regulate cell actions. Signup and view all the answers

Study Notes

Dietary Fiber and Its Health Benefits

Insoluble fiber such as cellulose, hemicellulose and lignin, found in foods such as whole grains and legumes, can reduce the risk of constipation, diverticulosis, and certain cancers.
Soluble fiber such as pectin and beta-glucans, found in fruits like citrus and prunes, can lower the risk of constipation, heart disease, diabetes mellitus, and obesity.

Polysaccharides

Glycogen: is the storage form of glucose in animals and is stored in the liver and muscles.
Liver glycogen helps to regulate blood glucose levels. However, muscle glycogen is broken down for energy use in the muscle.
Animals do not have glycogen, while animal products do not contain glycogen.

Lactose Intolerance

Lactose maldigestion is the inability to digest lactose due to low levels of the lactase enzyme.
Lactose intolerance occurs when symptoms of lactose maldigestion cause nausea, cramps, bloating, flatulence, and diarrhea.
Most individuals can continue to consume milk, cheese, and yogurt without side effects.

Essential, Nonessential and Conditionally Essential Amino Acids

Essential amino acids must be consumed in the diet. There are 9 essential amino acids.
Nonessential amino acids can be synthesized in the body. There are 11 nonessential amino acids.
Conditionally essential amino acids are nonessential, but can become essential if the body can no longer produce them. Tyrosine and glycine are examples of conditionally essential amino acids.

The Organization and Shape of Proteins Affect Their Function

Primary structure: amino acids are linked together in a linear chain
Secondary structure: the protein is folded and twisted
Tertiary structure: the protein as its three-dimensional (3D) globular shape
Quaternary structure: two or more polypeptide chains bond together to form a single protein

Denaturation of Proteins Changes Their Shape

Denaturation is the unfolding of a protein and is caused by heat, acids, bases, salts, and mechanical agitation.
Altering the shape of the protein alters its function. The primary structure of the protein is not impacted by denaturation.

Digesting and Absorbing Protein

Protein digestion begins in the stomach where the bolus enters.
Gastrin is released in response to food entering the stomach, which stimulates the release of HCl.
HCl denatures the protein and converts pepsinogen to pepsin.
Pepsin breaks polypeptides into shorter chains.
Polypeptides enter the small intestine and are broken down into smaller peptides.
CCK is released and stimulates the release of proteases by the pancreas.

Differences between Proteins, Carbohydrates and Lipids

Protein is made up of chains of amino acids.
The production of proteins is determined by a person's DNA.
The body cannot store excess dietary protein.
Proteins contain nitrogen in addition to carbon, hydrogen, and oxygen.
Some protein foods contain sulfur which is not found in carbohydrates or lipids.

Amino Acids

There are 20 amino acids that are used to make proteins.
Proteins are classified by the number of amino acids in a chain.
Peptides : fewer than 50 amino acids
- Dipeptides: 2 amino acids
- Tripeptides: 3 amino acids
- Polypeptides: more than 10 amino acids
Proteins: greater than 50 amino acids (typically 100-10,000 amino acids)
Every amino acid contains an amine group (NH2), a carboxylic acid group (COOH), and a side chain (R group).
The side chains make each amino acid unique and influence the function of the individual amino acid.
Peptide bonds form when the carbon of the acidic group of on amino acid joins to the nitrogen of the amine group of a second amino acid.
Peptide bonds are formed through condensation and broken through hydrolysis.

Amino Acid Metabolism

The body breaks down and makes proteins daily to maintain body structures and organs.
Amino acid pools provide a ready supply of amino acids to the body, to make proteins on demand or to help the body heal.
Protein turnover is the process of degrading and synthesizing proteins. Adults turn over around 200 grams of protein daily.

Deamination

Deamination is the removal of an amine group from an amino acid.
Ammonia is formed during deamination.
The liver converts ammonia to urea, which is subsequently excreted in urine.
Conditions, like liver disease, can result in high blood ammonia levels.

Protein Metabolism

If the body consumes too few carbohydrates, the body will convert glucogenic amino acids into glucose.
Excess protein can be converted to fatty acids and stored as triglycerides in adipose tissue.
If the body consumes too few kilocalories, protein will be oxidized for energy.

Function of Protein in the Body

Structural support & movement
Catalysts: Enzymes speed up reactions
Chemical Messengers: Hormones regulate cell actions
Fluid Balance: Albumin regulates fluid balance.
Acid-Base Balance: Proteins help to maintain the acid-base balance.

Protein Quality

Amino acid score: the composition of essential amino acids in a protein compared to the standard (usually egg protein).
Protein digestibility corrected amino acid score (PDCAAS): includes the digestibility of the protein and the amino acid score. Used by the FDA to determine the %DV of protein in a serving.
Biological value: how quickly nitrogen from absorbed protein is synthesized into body protein.

Food Sources of Protein

All 9 essential amino acids are found in complete proteins which are usually found in animal products. Exceptions include soy, quinoa, buckwheat, and hemp seed.
Incomplete proteins have a deficiency in at least one essential amino acid, referred to as the limiting amino acid. Incomplete proteins are generally from plant sources (except gelatin).
Complementary proteins are created by combining an incomplete protein with a food that supplies the limiting amino acid. For example, combining grains and legumes.
Significant amounts of proteins can be found in eggs, meat, fish, soy, and dairy.
A 3-ounce serving of meat, poultry, or fish provides 21 to 25 grams of protein.
Eating a variety of food is the best way to meet protein needs.
Protein supplements are generally unnecessary and often not recommended.

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Description

Test your knowledge on dietary fiber, its types, and health benefits along with insights into polysaccharides and lactose intolerance. This quiz covers essential concepts related to nutrition and health.