Proteins Flashcards
What atoms do all proteins contain
- Carbon
- Hydrogen
- Oxygen
- Nitrogen
What atom do MOST proteins contain
Sulfur
What atoms do SOME proteins contain
- Zinc
- Copper
- Iron
- Phosphorus
How many calories per gram do proteins contain and what is the nitrogen content
4 calories per gram
16% nitrogen
What are the four basic parts of amino acids
- Side Chain (R group)
- Amine group
- Hydrogen atom
- Carboxyl group
how long can amino acids be stored in the body and how often do they need to be supplied
- They are not stored in the body
2. Need to be supplied in the diet daily
what bond joins amino acids
peptide bonds
what is produced when two amino acids joined
dipeptide bonds and water
Describe the primary structure of proteins
- linear arrangement of amino acids
2. a sequence
- How many structures are in the secondary structure
- What are these structures?
- What dictates which is formed?
- 3
- Beta pleated sheets, alpha helix, random coil
- the hydrogen bonds and pattern of backbone
What are the 2 tertiary structures and their functions
- Fibrous: structure, they are elongated molecules formed from repeating alpha helixes or beta pleated sheets and they are INSOLUBLE
- Globular: transport, hydrophobic amino acids residues and hydrophilic residues, straight runs of secondary structure
SOLUBLE
What makes up the quaternary structure
more than 2 tertiary structures
how does protein stability compare to carbs and lipids?
proteins change drastically when exposed to heat, air, osmotic pressure, or ph while carbs and lipids don’t change that much
Define protein confirmation and denaturation
Denaturation: unfolding of protein molecule, changes shape without changing primary structure
Confirmation: normal structure and activity of protein
2 physical denaturations of proteins and examples
- heat: heating egg which then cannot go back to original form
- air: when exposed to air proteins change and cannot return to original state
2 ways proteins are chemically denatured
- pH: pickle food
2. osmotic pressure: using salt to change structure of protein
define reversible and irreversible protein denaturation
- Reversible: protein can return to its original confirmation and biological activity
- irreversible: protein cannot go back to original state or activity
Define Complete and Incomplete protein quality and give sources of each
- Complete: contains all essential amino acids in approximately the right proportions EX: meat and fish
- Incomplete: lacks certain amino acids
EX: nuts, seeds
Define Protein complementation
completing the amino acid pattern by consuming complementing proteins, one contains what the other is lacking
BEANS AND RICE
5 functions of protein in food
- water binding
- reduction
- hydrolysis
- texturize
- emulsify
what is protein hydrolysis and what is the necessary input
- breaking down the peptide bond
2. water
