Nutrition: Unit 2: Chapter 6:

Most proteins are absorbed as single amino acids. Give some examples of proteins that are absorbed intact.

Whole proteins are absorbed intact, like antibodies from breast milk or in the case of food allergies.

Define nonessential amino acids.

they are called nonessentials because they can be made by the body, therefore they don't need to be consumed in the diet.

Most enzymes are made up of _____. Without enzymes, reactions would occur so slowly that you couldn't survive.

proteins

What do catabolic enzymes do?

Catabolic enzymes break compounds apart.

What are the "building blocks" of proteins?

The proteins are made up of amino acids.

The body is made up of over _____ different proteins. At birth, the exact code for each of these proteins is stored in ____ and filed away in DNA.

100,000, genes.

All proteins consist of some combinations of ____ unique amino acids and are classified according to the number of amino acids. A chain with more than 50 amino acids is called a ______?

20, protein.

Define the terms amino acid pools and protein turnover. How do amino acid pools contribute to protein turnover?

Amino acid pool: its an accumulation of amino acids in the blood and cells. Amino acids are pulled from the pools and used to build new proteins. Protein turnover: is the process of degrading and synthesizing protein.

After a protein is digested and the amino acids are absorbed, what can the cells use those amino acids for?

Amino acids can be used to synthesize new proteins, or can be converted to ATP, glucose, or fat.

When amino acids are absorbed, they reach the liver first. What are some possible ways the liver might metabolize these amino acids?

Amino acids might be used as an energy source or if the individual doesn't get an adequate diet the amino acids can be converted to glucose through the process called gluconeogenesis.

Define a catalyst.

Catalysts are substances that aid and speed up reactions without being changed, damaged, or used up in the process.

_____ is the most abundant protein in the body and is found in all connective tissue, including the bones, tendons, and ligaments that support and connect joints and other body parts. This fibrous protein is also responsible for the skin's elasticity and forms the scar tissue necessary to repair injuries.

Collagen

Why might a lack of protein cause edema?

Edema occurs because the interstitial spaces between the cells becomes bloated and the body tissue swells.

Describe what happens in the stomach to digest proteins.

HCI and pepsinogen are released. once the bolus enters the stomach HCI converts the pepsinogen to an active enzyme called pepsin. the strands are propelled into the small intestines as part of the chyme.

Proteins can be unfolded or denatured by ____, _____, ______,_____, or _______.

Heat, acids, bases, salts, or mechanical agitation.

Some proteins are chemical messengers such as _____?

Hormones

Of the 20 amino acids the body combines to make proteins, _____ of them are classified as essential amino acids. Why do we call them essential amino acids?

Nine, They are called essential because they cant be made by the body or cannot be made in sufficient quantities to sustain the body's needs.

Describe the four levels of structure of every protein.

Primary Structure: first stage after transcription. the amino acids have been linked together with a peptide bond to form a simple linear chain. Secondary structure: The hydrogen ions of amino acids linked together with the amine group, causing the straight chain to fold and twist. Tertiary structure: Side chains of the amino acids, most often containing sulfur, form bridges, causing the protein to form even stronger bonds than the second. These form loops, bends, and folds in the molecule. Quaternary structure: forms when two or more polypeptide chains cluster together, forming a final ball like structure.

Can proteins provide energy to the body? Are they the primary source? Why or why not?

Proteins can be used as an energy source, but you don't want to use proteins as a primary energy source. Proteins have so many more important roles that the proteins need to be used for.

Explain how proteins play a role in fluid balance.

Proteins help with moving fluids and keeping water dispersed evenly inside and outside of cells, which helps maintain a state of fluid balance.

Discuss some of the essential roles proteins play in the human body.

Proteins play a role in every cellular activity, from building, repairing and maintaining cells to storage, transport, and utilization of the nutrients.

It is the _____ of the protein that determines its function in the body. Anything that alters the bonds between the side chains will alter the protein's ______ and thus its function.

Shape, shape.

Each amino acid contains a central carbon C surrounded by four parts. what are these 4 parts?

The 4 parts are carboxyl or acid group, amine group, and side chain.

What happens if amino acids in the amino acid pool aren't used for protein synthesis?

The amino acids that aren't used are broken down inot component parts. These component parts are used for other purposes, such as energy production, or stored in another form.

How does protein affect satiety?

The satiety when eating a high- protein meal comes from dietary protein suppressing the release of ghrelin.

Describe what happens in the mouth to digest proteins.

The teeth tear and shred the food, breaking it into smaller pieces.

What are the three steps of protein synthesis?

The three steps of protein synthesis are; transcription, translation, and elongation.

Describe what happens in the small intestine to digest proteins.

Trypsin, chymotrypsin, and carboxypeptidase are released. Trypsin and chymotrypsin continue to break down peptide bonds in the center of the polypeptide chain.

Proteins act as ____ and minimize the changes in acid-base levels by picking up or donating hydrogen ions in the blood.

buffers

Define conditionally essential amino acids.

conditionally essential means the nonessentials like tyrosine and glycine, that become essential when the body cannot make them.

Protein is the only food component that provides the ____ the body needs for important processes, such as the synthesis of neurotransmitters.

nitrogen

Proteins can alter the ____ of the body fluids.

pH

All of the 20 amino acids that the body uses to make proteins contain the same four parts. what makes each amino acid unique?

the side chain is what makes each amino acid unique.