Proteins Flashcards
how much of body weights proteins account for?
Protein 20%
Fat 10%
Water 65%
Minerals 4%
Carbs 1%
which chemist first discovered proteins in 1839?
Gerharld Mulder
what atoms make up a protein ?
Carbon
Hydrogen
Oxygen
Nitrogen
The presence of which atom distinguish proteins from carbs and fat?
Nitrogen
what are amino acids
the basic building blocks of proteins
what do amino acid contain?
- 1 amine group - NH2
- 1 carboxylic Group - COOH
- 1 unique side group (R-group)
How many amino acids out of the 100 in nature do the human body require?
20 amino acids for protein synthesis
what is a protein and what is it made of? With which term can protein be interchanged with?
Proteins are Macromolecular polypeptides = large molecule made of many peptide-bonded amino acids
Polypeptide
what is so particular about the structure of the amino acid chain folding of a protein ?
The amino acids fold in a 3D structure linked to the function of the protein (lock and key)
give an example on a non-protein building block amino acid
Citrulline is a non-protein building block amino acid that plays a role in the urea cycle
which amino acids make up glutathione?
Cysteine - conditionally essential
Glutamic Acid - non-essential
Glycine - conditionally essential
How many amino acids are essential AA and name them
9 essential AA - PVT TIM HiLL
Phenylalanine
Valine
Threonine
Tryptophan - serotonin and melatonin
Isoleucine
Methionine - methyl donor
Histidine
Leucine
Lysine
what is a complete protein?
A protein that contains all the 9 EAAs (like animal protein and certain vegetarian proteins)
Which EAA is considered conditionally essential by some experts and why?
Histidine because it is synthesised in small amount by gut bacteria in adults and it does not impair protein synthesis when it is missing from the diet.
what causes protein denaturation? and Why a acid forming diet is problematic?
When exposed to heat, variation in pH, alcohol, heavy metals (aluminium)
=> lose its 3D structure, the protein unfold and lose its biological activity and function. They unravel.
Acid forming diet is problematic because it changed the pH around the cells and can impact the functioning of proteins within the cells
Why are protein denatured through digestion?
To facilitate the process of proteolysis which allow the protein to unfold for digestion of amino acids with the help of Pepsin enzymes
what is pepsin ideal pH
2 in the stomach
Name 3 function of proteins?
- Structure of body tissues - collagen
- Mouvement - Actin and myosin
- Carrier molecule - Haemoglobin (bind to O2)
- Storage molecule - Ferritin (bind to iron)
- Fluid balance - Albumin (bind to calcium, zinc and B6, steroids and fatty acids)
- Enzymes for reaction in the body - amylase
- Hormones - insulin, thyroid hormone (tyrosine), dopamine (tyrosine), adrenaline (tyrosine), serotonin and melatonin (tryptophan)
- Hormone receptors - cell membrane proteins are receptors for hormones
- Immune functions - antibodies IgG (virus and bacteria), IgA (saliva, tears, mucous), IgM (first to appear in antigen exposure) and IgE (allergies)
- Clotting mechanism - clotting factors
- Alternative energy source
What are the 6 conditionally essential AA
- Arginine
- Cysteine - taurine
- Glutamine - most abundant AA in the body
- Glycine - glutathione
- Proline
- Tyrosine - Thyroid hormone, dopamine, noradrenaline, epinephrine
what is the best buffer amino acid to regulate the acid/base balance and why
Histidine because can easily pick up and let go of H+ ions
Cysteine as well
give 3 protein related causes of oedema
kidney disease - protein loss
liver disease - inadequate protein synthesis
protein malnutrition - ascites (water more in peritoneal cavity)
What are glycoproteins? name 3
Glycoprotein are a protein bound to a sugar
- Mucins = in mucous and saliva
- ABO blood type antigens
- LH and FSH and TSH
- Major Histocompatibility Complex - antigen presentation
Describe & explain the 3 step process of protein metabolism
Protein metabolism = when we need to use protein for fuel or to convert protein into fat storage
Excessive protein from food will be transformed into energy
3 steps:
1. DEAMINATION - removal of the amine group
2. UREA CYCLE - conversion of ammonia formed during deamination to urea for safe removal
3. TRANSAMINATION - redistribution of AAs
Explain the process of Deamination in protein metabolism
1st step of protein metabolism
Removal of the nitrogen-containing amine group
Takes place in the liver
Purpose = for individual amino acids to be used as energy source or stored as fat
After deamination, the remaining fragment of amino acid can be used to produce glucose or ketones