Lecture 5- Protein Flashcards Preview

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Flashcards in Lecture 5- Protein Deck (23):

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


Essential amino acids

- cannot be produced by out bodies
- must be obtained from food
- 9/20 are essential


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


Completr protein

Contains sufficient amounts of all nine amino acids
- considered a "high quality" protein


Nitrogen balance

Positive nitrogen balance: times of growth

Negative nitrogen balance: times if protein loss


Risks of too much protein:

High cholesterol and heart disease
- diets high in protein from animal sources are associated with high cholesterol an sat fats

Possiblr bone loss
- high protein diets may cause excess calcium excretion leading to bone loss
• protein metabolism produces uric acid, decreasing body pH and potentially harming bone

Hormonal changes
- protein ingestion can alter gut hormone secretion
- circulating levels of insulin and other hormones

- excess calories from any source can cause weight gain and obesity


Protein- energy malnutrition

A disorder caused by inadequate intake of protein an energy



Disease resulting from severly inadequate intake of protein, energy, and other nutrients

- severe wasting of muscle tissue
- stunted physical growth
- stunted brain development
- anemia



Disease resulting from extremely liw protein intake

- some weight loss and muscle wasting
- edema resulting in distention of the belly("swollen belly")
- protein imbalance in blood
- retarded growth and development



Breaking down protein into amino acids



-Nitrogen must be removed for utilization of amino acids
- after amine removal, left with carbon skeleton= keto acid