UNIT 7 Flashcards
Proteins and Amino Acids
Proteins
compounds composed of carbon, hydrogen, oxygen, and nitrogen and arranged as strands of amino acids. Some of these acids contain sulfur
What are working proteins?
These are the proteins that include the body’s enzymes, antibodies, transport vehicles, some hormones, and oxygen carriers.
What are structural proteins
These are the proteins in tendons and ligaments, scars, the fibres of muscles, the cores of bones and teeth, etc.
Amino acids
Amino = Nitrogen containing
these acids are the building blocks of proteins. each has an amine group at one end, an acid group at the other, and a distinctive side chain
amine group
the nitrogen-containing portion of an amino acid.
side chain
the unique chemical structure attached to the backbone of each amino acid that differentiates one amino acid from another.
Dispensable/ nonessential amino acids
amino acids that the body can synthesize in sufficient amounts to meet its need
indispensable/ essential amino acids
amino acids that either cannot be synthesize at all by the body or cannot be synthesize in amounts sufficient to meet physiological need.
conditionally indispensable/ essential amino acid
an amino acid that is normally nonessential but must be supplied by the diet in special circumstances when the need for it exceeds the body’s ability to produce it.
How does the body’s priority system work when choose which tissue protein to break down in times of emergency?
It starts with the most dispensable tissues first. Examples being the small proteins found in the blood and muscles.
It guards the structural proteins of the heart and other organs until there is no other options available.
How many amino acids can compose a protein?
A maximum of 20
Peptide Bond
a bond that connects one amino acid with another, forming a link in a protein chain.
collagen
a type of body protein from which connective tissues such as tendons, ligaments, scars, and the foundation of bones and teeth are made
enzymes
protein catalysts. A catalyst is a compound that facilitates a chemical reaction without itself being altered in the process.
Hemoglobin
the globular protein of red blood cells, whose iron atoms carry oxygen around the body via the bloodstream
What is meant by “ Inherited Amino Acid Sequences”
For each protein within the body, there exists a standard amino acid sequence that is specified by heredity
If a wrong amino acid is inserted into this standardized chain, there can be disastrous consequences on health
EX: Sickle Cell anemia
Describe the process of coiling and folding of a protein molecule
- A chain is a shape taken by a strand of amino acids
- This chain becomes coiled and spring shaped as their side chains variously attract and repel one another
- Due to this attraction and repulsion, the coil will fold over itself and adopt its functional shape
- At this point a protein may become functional, or may need to join with other proteins, or even add a carbohydrate, vitamin, or mineral to become functional
ex: Hemoglobin must bond with iron to become functional.
Denaturation
The irreversible change in a proteins shape, brought about by heat, acids, bases, alcohol, salts of heavy metals, or other agents.
Generally speaking
How does the body begin to process dietary protein?
The body first alters the protein by breaking it down into its constituent amino acids
The stomachs acid helps to uncoil the protein so that the stomachs protein digesting enzymes can attack the peptide bonds.
Doing this allows to body to rearrange them into specific human body proteins later.
polypeptides
Protein fragments of many (more than 10) amino acids bonded together
oligopeptide
A strand of amino acids that is between 4-10 acids long
dipeptides
protein fragments that are two amino acids long
tripeptides
protein fragments that are three amino acids long
What happens to the polypeptides and amino acids that fragmented off digested proteins as they enter the small intestine?
Enzymes from the pancreas and the intestine split this peptide strands into tripeptides, dipeptides, and amino acids
After this, absorptive cells split them further into their constituent elements. These amino acids are then absorbed into the blood stream.
What are the main organs in protein digestion?
Stomach: Starts the initial breakdown of protein into mostly polypeptides. This breakdown process is denaturation
Small Intestine Alkaline juice from the pancreas neutralizes the acid digesta released by the stomach. Once neutralized, protein digesting enzymes from the pancreas and intestine break down proteins into di and tripeptides, or single amino acids.
Enzymes on the surface of the small intestine split the di and tripeptides for absorption.
Protein turnover
The continuous breakdown and synthesis of body proteins involving the recycling of 300-400g of amino acids each day.
What is an enzyme?
An enzyme is a catalyst that serves to speed up reactions that would happen regardless, but at a reduced rate.
What are proenzymes
These are the protein digesting enzymes that are inactive.
These are secreted by the stomach and small intestine.
Hormones
Chemical messengers secreted by a number of body organs in response to conditions that require regulation.
Each hormone affects a specific organ or tissue and elicits a specific response.
Serotonin
a compound related in structure to (and made from) the amino acid trytophan. It serves as one of the brains principal neurotransmitters
antibodies
Large proteins of the blood, produced by the immune system in response to an invasion of the body by foriegn substances.
Antibodies combine with and activate the antigens.
Immunity
protection from or resistance to a disease or infection by development of antibodies and by the actions of cells and tissues in response to a threat.
Fluid and electrolyte balance
The distribution of fluid and dissolved particles among body compartments
Edema
Swelling of body tissue caused by leakage of fluid from blood vessels
Acids
compounds that release hydrogen’s in a watery solution
Bases
compounds that accept hydrogens from solutions
acid-base balance
equilibrium between acid and base concentrations in the body fluids
Buffers
compounds that help keep a solution’s acidity or alkalinity constant.
Acidosis
the condition of excess acid in the blood, indicated by an below-normal blood pH
Alkalosis
a condition of excess base in the blood, indicated by an above-normal blood pH
What role does protein play in managing blood pH
Protein buffers are the tools the blood has to remove excess acidity and alkalinity
What role does protein play in clotting of blood
Special blood proteins exist that respond to an injury such as an open cut.
These proteins from a stringy net that traps platelets to form a clot.
The clot (scab) plugs the wound and diverts blood flow back to normal
Urea
the principal nitrogen-excretion product of protein metabolism; generated mostly by removal of amine groups from unneeded amino acids or from amino acids being sacrificed to a need for energy.
What are the core similarities between the three energy yielding nutrients?
Carbohydrates offer energy
Fat offers concentrated energy
Protein offers energy plus nitrogen.
Legumes
Plants of the bean, pea, and lentil family that have roots with nodules containing special bacteria that can trap nitrogen from the air
High quality protein
Dietary proteins containing all the essential amino acids in relatively the same amounts as a human being requires.
Amino acid pools
amino acids dissolved in the body’s builds that provide cells with the ready raw materials from which to build new proteins or other molecules.
What is a limiting amino acid
an essential amino acid that is present in dietary protein in an insufficient amount, thereby limiting the body;s ability to build protein
Complementary proteins
Two or more proteins whose amino acid assortments complement each other in a way that the essential amino acids missing from one are supplied by the other.
Mutual supplementation
The strategy of combing two incomplete protein sources so that the amino acids in one food make up for those lacking in the other food.
Factors determining protein quality
Protein digestiblity
Essential Amino Acid completeness and adequacy
The balance of essential amino acids to each other.
What are PDCAAS
Protein digestibility - corrected amino acid acore
A tool to measure protein quality
What is gluten?
A combination of small proteins found in wheat, rye, and barley that helps give dough its elastic texture.
Nitrogen Balance
The amount of nitrogen consumed with the amount excreted in a given time frame.
How does a negative nitrogen balance occur?
Nitrogen is lost when a muscle of other protein is broken down and lost.
protein-energy under nutrition (PEU)
The worlds most widespread malnutrition problem
Includes : Maramus and kwashiorkor which are sub-variants of PEU
What are some factors that influence protein requirements in the body?
Age and physiological state
Lean body mass
Protein quality
Total energy intake
Personal health status
Individual variation
How many amino acids do human adults require
9
What is the end product of protein digestion in the stomach
Large and small polypeptides
Why are proteins important regulators of acid-base balance ?
It is because they function as both acids and bases
Is the presence of amino acids a consideration in determining the quality of dietary protein?
It is not
Remember the idea of complementary protein.
What is a peptide bond? Which digestive tract site is it broken down?
A peptide bond is a chemical bond connecting an acid group on one amino acid with the amine group of another.
It is broken down in the stomach and the small intestine.
True of false: Children and pregnant women have a positive nitrogen balance?
True
Will incomplete proteins not be absorbed because of the lack of EAAs?
The absorption of amino acids from the gastrointestinal tract does not require the presence of ALL EAA’s
