Protein Flashcards
Why is protein important?
Mediate most of the actions of life –> critical to all life processes.
What is dependent upon protein:
Structure and activity; growth, development, and continued maintenance of systemic tissues.
Protein synthesis:
The body’s need for protein met trough food –> protein synthesis in the liver
How many proteins must be synthesized to varry out the body’s activities?
50 000 different proteins.
What is the most abundant protein in the body?
Collagen –> found in all connective tissues.
What is enzymes?
Proteins that serve as chemical catalyst –> speeding up chemical reactions.
What can transport proteins do?
Shuttle chemical elements, such as oxygen (haemoglobin) or store minerals, such as iron (ferritin)
Why is antibodies important?
To maintain a healthy immune system.
What is the main role of protein?
Tissue building
What are protein made up of?
Amino acids
Amino acid structure:
Amino group (NH2), acid group (COOH), central carbon (C), side chain
Protein differ from:
Carbohydrates and fats –> presence of the amino groups.
What does Amino Acids have?
Amino group, carboxyl group and R-group attached to the same carbon.
What is Dipeptides
2.enzym: Aspartame (artifical sweetener)
What is Tripeptides?
3.enzym: Glutathione (natural antioxidant)
Short polypeptides?
Peptide hormones (glucagon)
Neurotransmitters (Substance)
Large polypeptides?
Proteins
Large proteins?
Dystrophin
How does proteins differ?
Number, order or sequencing.
How are the 20 amino acids categorized?
Required to be present in the diet or can be synthesized in the liver for other amino acids.
How are amino acids termed?
Essential (indispensable) and non-essential (dispensable) amino acids.
Protein structure: 4 levels
Primary, secondary, tertiary (3D) and quaternary
Sequence of aa in peptide chain
Primary structure
Folding/coiling of peptide chain: alfa - helix or beta-pleated sheet.
Secondary structure
Peptide chain folds upon itself
Tertiary (3D) structure
Folded peptide chains join together
Quanternary structure.
What happens when protein is eaten as part of the diet.
It is not absorbed directly, but must be broken down into component amino acids.
What is stage 1
Digestion in the mouth
Where does digestion begins?
In the mouth with the moistening effect of saliva and the chewing by the teeth.
What is secreted by parietal cells in the smomach lining?
Hydrochloric acid (HCl)
Why is HCl secreted?
To denature the protein and provide an environment for digestion.
What does chief cells in the stomach lining produce?
An inactive enzyme, pepsinogen.
What does the acidic environment converts the pepsinogen to ?
The active protease (proteincleaving enzyme), pepsin.
What breaks the polypeptide chain at numerous sites?
Pepsin
Where does the breakdown of the polypeptides takes place?
In a small intestine
What is absorbed by the small intestine?
Amino acids and short peptides
Where is proteins transported when proteins are degraded to amino acids and absorbed into the bloodstream.
To the liver which is the site of amino acid synthesis.
Why is a small percentage of amino acids broken down?
To provide energy
Why are protein intake, maintenance, metabolism and losses are carefully regulated?
Because protein is so important.
What is the name of the procedure where body proteins are degraded to amino acids and re-synthesized?
Protein turnover
What is the average protein turnover in adult?
300-400 g per day
What do we call food with high protein concentration?
“Protein foods”
What is protein rich foods?
Meat, fish, milk, cheese, eggs and legumes.
What do we call amino acid that are rapidly catabolised and the nitrogen is excreted as urea in the urine.
Surplus amino acids.
What is defined as the protein source’s ability to support growth?
Protein quality
What do we call a protein that has all the essential amino acids present in proper proportions to substain growth?
A complete protein
What do we call a protein that has all the essential amino acids present in proper proportions to substain growth?
A complete protein (high biological value)
Example of a protein that are incomplete?
Plant based
What do we call a protein that has high biological value?
Complete protein
What do we call a protein that has low biological value?
Incomplete proteins
What effects on calcium metabolism?
High-protein diets.
What happens when protein increases in the diet.
Bone loss
What effects on calcium metabolism
High-protein diets.
What can excessive intake lead to?
Lead to deterioration of renal function in patients with chronic renal disease (stages 1-4)
Who are at high risk of protein malnutrition (muscle loss)?
People that are chronically ill and elderly people.
What is a serious concern for childern in developing countries.
Protein-energy malnutrition.
Matrix protein of skin, bones and teeth
Collagen
Oxygen transport
Haemoglobin
Iron storage
Ferritin
Catalyzes the breakdown of starch to sugar in the mouth
Salivary amylase
Digest protein in the stomach
Pepsin
A hormone that regulates uptake and storage of glucose
Insulin
Found in salvia that neutralize foreign substance
IgA antibodies
How much percent should calories come from fat?
30-33%
How much percent saturated fat intake should be?
<10%
Fat around the organs
Visceral fat
What do not contain nitrogen?
Water, fat and carbohydrates
