Protein Flashcards
What type of bonds do proteins form?
peptide bonds
What are some examples of proteins?
canola seed, canola meal, soybean, dry distillers grains, corn gluten meal, and urea.
What are amino acids?
building blocks for protein
What do amino acids consist of?
amino group, carboxyl group, hydrogen, and side chain
nonpolar=
hydrophobic
polar=
hydrophilic
What is a protein?
biopolymer made up of repeating units of amino acids linked to each other by a peptide bond
what type of bond contains 2 amino acids?
dipeptide
what type of bond contains 3 amino acids?
tripeptide
what type of bond contains 2-20 amino acids?
oligopeptides
what type of bond contains 20 or more amino acids?
polypeptides
what is an essential/indispensable amino acid?
an amino acid that cannot be synthesized, therefore must be supplied in the diet.
how many essential amino acids are there?
8-10 depending on the species and physiological state
What are 4 common essential amino acids?
Lysine, Methionine, Valine, Tryptophan
what is methionine?
sulfur containing acid
most limiting amino acid
**if there is enough methionine, it can synthesize cysteine.
Lysine+Methionine-
cysteine
What is a nonessential/dispensible amino acid?
amino acids that the body can synthesize.
if you do not have enough of these, it can increase your need for essential amino acids.
there are 10-12 NEAA
Name 4 non-essential amino acids
Cysteine
Alanine
Glutamine
Proline
What is a conditionally essential amino acid?
Their synthesis can be limited under certain conditions.
Ex- Glutamine, Tyrosine
Name 3 conditionally essential amino acids
tyrosine, cysteine, glutamine
How to read the Liebigs Barrel
shortest stave=1st limiting amino acid
What is biological value?
the ability of a specific dietary protein to supply amino acids in the relative amounts required for protein synthesis by body tissues.
It is influenced by essential amino acids. It is fixed
How is protein synthesized?
DNA-Transcription-Translation-Phenotype
What is transcription?
converts DNA to mRNA
What is translation?
converts info in mRNA to a polypeptide chain.
what is cell signaling of protein synthesis?
cell first receives signals
up or down regulation
-turning of protein on or off
what is a gene?
a region of DNA that encodes a functional RNA or protein product
What is a complete protein
contains all AA you need
what is an incomplete protein?
doesn’t have all required AA for protein synthesis
What is a high quality protein?
complete protein
contains adequate amount of AA
what is a low qualtity protein?
lacks one or more essential amino acid
What is nutritive value determined by?
digestibility
primary structure in nutritive value
amino acid polypeptide chain
What is nutritive value related to?
folding of protein
What is the product of altering protein quality?
genetic modification and engineering
GMO’s
contains protein with more lysine and tryptophan
Protein Structure
"form follows function" order of AA in chain length of polypeptide chain interactions within chain, between chains, with other components -folding, interfolding, coiling
order of structures
primary, secondary, tertiary, quaternary
What is the primary structure?
the sequence of amino acids in a single polypeptide chain
- it is critical to protein function
- impacts nutritive value through EAA composition and chemical and physical properties
what is the secondary structure?
folding of a protein as a result of hydrogen bonds that form between carboxyl and amino groups in the peptide backbone
common patterns: alpha-helix and beta-folded sheets
what is the tertiary structure?
3-dimensional folding and coiling of polypeptide chain into globular structure caused by hydrogen bonds, ionic bonds, disulfide bonds, hydrophobic interactions
what is the quaternary structure?
interactive interfolding of several polypeptide chains to form a single functional protein function determined by: shape, components
what does hemoglobin transport?
oxygen
what are some diseases of improper folding?
sickle cell anemia, cystic fibrosis, cancers, alzheimers
what is denaturation?
change (unfolding and unraveling) in protein tertiary and quaternary structure caused by physical agitation, heat, acid, and alcohol
what are some biological functions of proteins?
structural and mechanical roles, catalysis, cell signaling and immune function, fluid balance and pH regulation, transport, source of energy
what are examples of structural role in biological functions?
collagen, keratin
what are examples of mechanical role in biological functions?
motor proteins (make muscles work)
what is catalysis?
proteins that speed up (catalyze) chemical reactions without being used up or destroyed in the process
ex: amylase, lactase, cellulase, sucrase
What do hormones have to do with cell signaling?
chemical messengers that are made in one part of the body but act on cells in other parts of the body
ex: insulin, testosterone, estrogen
immune function
immunoglobulins, antibodies
y-shaped proteins that attack and inactivate bacteria and viruses that cause infection
ex of immunoglobulins: igg, iga, igm
what is fluid balance?
movement of fluid between intravascular and interstitial space dependent on:
pumping action of heart, osmotic pressure, albumin
what is an edema?
disruption of body fluid balance
fluid build up in the limbs
transport proteins
transport substances across cell membranes, transport substances in blood
ex: hemoglobin (transports oxygen) and lipoproteins (transports lipids)
