Lecture 5- Protein Flashcards
Essential amino acids
- cannot be produced by out bodies
- must be obtained from food
- 9/20 are essential
What are proteins?
Large complex molecules compised of amino acids
- contains C, H, O, N
- primary source of nitrogen in our diet
- 20 dif amino acids
- cannot be readily storedfor energy
Nonrssential amino acid
- Can be madeby our bodies through transamination
- the carbon skeleton can come from carbs or fat derived metabolites
Protein synthesis
- protein are made up of long chain of amino acids
- nonessential and essential amino acids
- the structure if each protein is dictated by the DNA of a gene
How proteins are made?
Transcription: use if genetic information in DNA to make RNA
- mRNA copies the genetic information and carries it to the ribisome
- tRNA recognize the three nucleotide mRNA sequence and adds thr corresponding amino acid to the polyprptide chain
Translation: conversion of genetic information in RNA to assemble amino acids in the proper sequence to synthesis a protein on the ribosome
Protein structure
- primary: sequential order of amino acids
- secondary: sprial shape due to chemical bonding between the amino acids
- tertiary and quaternary: further folding into a unique 3-D shape that may be globularor fibrous
Loss of function in a protein
protein lose shape(denaturation) when subjected to:
- heat
- acids and bases
- heavy metals
- alcohol
Functions of bodily proteins:
- cell growth, repair, and mainenamce
- enzymes
- hormones
- fluid and electrolyte balance
- pH balance
- antibodies to protect against disease
- energy source
- transport and storage
Protein: fluid and electrolyte balance
- responsible for fluid balance between tissues and blood vessels
- proteins keep fluid in vessels amd are solutes
- H2O travels where solutes are located and concentrated
- proteins also regulate ion movement, which can also lead to edema
Protein as an energy source
- carbs and fat are the body’s primary source of energy
- small amounts of protein are used for energy
- most protein is saved for special functions that carb and fats cannot fulfill
- when carbs an fat intake is low, protei is broken down and used for energy
How much protein shoul we eat?
Proper protein inyake depends on:
- activity level
- age
- health status
Recommended intakes
- 10-35% of total energy intake should be from protein (AMDR)
- 0.8g/kg body weight/ day/ adults (RDA)
People who require more protein:
- children
- adolescents
- pregnant or lactating women
- athletes (endurance runners and strength athletes)
• 1.2-1.7g/kg
Complete protein
- lean meat
- low fat or far free dairy
- soy products
Complementaty protein
Two protein sources that together supply all nine essential amino acids
- legumes
- nuts
- whole grains
Incomplete proteins
Does not contain all essential amino acids in sufficient quantities
- growth and health are compromised
- considered a “low quality” protein
