Lesson 6: Proteins Flashcards
What are the building blocks of proteins?
amino acids
What are the 3 parts of an amino acid?
- amino group
- acid group
- side group
What does the amino group contain?
a nitrogen atom
True or False: All amino acids have different amino and acid groups.
False. They all have identical amino and acid groups
How many different amino acids are there in the side chain?
20
Which part of the amino acid varies?
It’s side group
Alanine, Valine, Leucine, Isoleucine, Glycine, Cysteine, Phenylalanine, Tryptophan, Methionine & Proline are what type of amino acids?
Non-Polar Amino Acids
Aspartic Acid and Glutamic Acid are what type of amino acids?
Negatively Charged (Acidic) Polar amino acids
Lysine, Arginine, Histidine are what type of amino acids?
Positively Charged (Basic) Polar Amino Acids
Serine, Threonine, Tyrosine, Asparagine and Glutamine are what type of amino acids?
Uncharged Polar amino acids
Which 9 amino acids are essential and must come from the diet?
Histidine Isoleucine Leucine Lysine Methionine Phenylalanine Threonine Tryptophan Valine
Which amino acids are able to hydrogen bond?
Polar and uncharged amino acids
Why don’t non-polar amino acids hydrogen bond?
They lack oxygen
What is the name of the covalent bond that linked the amino acids?
Peptide bond
What do we call a long chain of amino acids?
Polypeptide bond
What do we call a completed polypeptide?
a protein
What determines protein shape?
The sequence of amino acids along the chain
What can cause a protein to denature?
A change in temperature
A change in pH
What does a denatured protein in food do?
Changes texture and consistency
What does denatured protein do in the body?
It is no longer functional
What happens to protein in milk or vinegar when pH turns more acidic?
Milk or vinegar will curdle
What happens to eggs when we cook them slowly?
Slow cooking & constant whisking causes egg and egg white to denature slowly
What are the effects of whipping on protein?
It can mechanically denature the proteins (like in an eggwhite for example)
What does slow cooking do to collagen?
It denatures it and reduces the toughness of the collagen (like in meat).
What is meat toughness a function of?
Resistance to chewing
What is the name of the protein that melts into gelatin when slow cooked?
Collagen
What are the functions of proteins?
Provide structural support and movement Work as enzymes Work as hormones Maintain fluid balance Regulate pH of fluids Crucial component of cell membranes Source of energy Antibodies are proteins
What is the foundation of bone?
Highly woven collagen fibers
What are the two key structural proteins?
Collagen and Keratin
Are enzymes and hormones proteins?
Yes, enzymes work in a lock and key mechanism and insulin is a type of protein that helps the cells uptake blood glucose.
What is plasma protein necessary for?
Maintaining the right amount of fluids within your tissues
How do proteins in the plasma function to draw fluid back into the capillaries to prevent swelling?
Through hydrogen bonding.
What happens if protein levels drop?
Escaped plasma proteins will Hbond with water molecules in the interstitial fluid, so the H-bonded water is not drawn back into the capillaries. Result is accumulation of fluid in tissues.
What is the accumulation of fluid in tissues called?
Edema
What pH do blood and tissue fluids need to function properly?
A pH of 7.35 to 7.45
What do we call the condition in which body fluids become too acidic (pH < 7.35) ?
Acidosis
What do we call the condition in which body fluids become too basic (pH > 7.45) ?
Alkalosis
What does the Sodium Potassium pump do?
Works to pump ions in and out of cells
How many amino acids do you need to build protein?
All 20
What are 2 functions of HCL in the stomach?
Denatures food protein
Activates pepsin
What is pepsin?
a stomach enzyme that will cut the denatured proteins into smaller polypeptides (gastric enzymes that hydrolyzes protein).
What are the end products of protein digestion?
Amino acids
The liver keeps some amino acids for it’s needs. What happens to the rest of them?
They get released into the general circulation
What do we call the recycling of protein?
Protein turnover
What is hemoglobin?
the protein found in red blood cells (RBCs)
What does hemoglobin do?
Delivers oxygen to the cells of the body
What is the recycling of protein important for?
Nitrogen Balance
What percentage of protein is nitrogen?
16%
Nitrogen Equilibrium: _______ + ______ = ________
Intake + retention = losses
When do we have positive nitrogen balance?
During pregnancy lactation resistance exercise recovery from illness growing children
When do we have negative nitrogen balance?
Starvation
Trauma emotional/other
What happens during negative nitrogen balance?
The body breaks down muscle protein and other body protein for energy
What happens if carbohydrates and lipids are lacking in the body?
The body will sacrifice body protein to get energy
What does this process require?
Deamination
What is deamination?
The removal of the amino (NH2) group from a compound such as an amino acid
What happens if you eat too much protein?
Your liver will deaminate it, and you will store it as fat
What happens when the immune system responds to protein in food as though it was some harmful pathogen?
Food allergies and celiac disease occur
What is an allergy?
hypersensitive responses to substances that have no effect on most people
Which allergies are the most common?
Pollen and food allergies cause by certain proteins found in certain plant families
What are pollen allergies caused by?
an immune hyper-sensitive response to protein on the surface of pollen grains
What are food allergies caused by?
an immune hyper-sensitive response to protein in certain foods
What is celiac disease?
An autoimmune disorder that affects the small intestine
What is damage to the villi in celiac disease caused by?
a hyper-sensitive immune response to gluten
What is gluten?
a protein found in wheat and related grains
What is non-celiac gluten sensitivity (NCGS)?
“The clinical state of individuals who develop symptoms when they consume gluten-containing foods and feel better on a gluten-free (GF) diet but do NOT have a celiac disease”
When does protein intake increase?
Pregnancy Breast feeding Infancy and childhood Recovery from serious illnesses Blood losses Burns
Are all proteins equal?
No, only 9 of the amino acids are essential and so foods may be high in protein but low in the essential amino acids
Are all 9 essential amino acids required in the same amount?
No
What is protein quality influenced by?
Amino acid composition
Protein digestibility
What is a high quality/complete protein?
Contains all essential amino acids in adequate amounts
Well absorbed
What is a low quality/incomplete protein?
Lacks 1 or more essential amino acids
Poorly absorbed
What are some high quality protein foods?
Animal protein
Eggs (include all 9 essential amino acids we require)
Plant protein (plant lack at least 2 amino acids)
What is protein complementation?
the process of mixing incomplete plant-based protein sources to provide all essential amino acids without adding animal proteins
