Chapter 6 Protein

Proteins go from the small intestine to the _____ , where if catabolism of amino acids takes place, ____ is released, but because it is toxic, the liver transforms it into urea, which is transported to the kidneys and excreted in urine.

liver; ammonia

Proteins are broken down and brought into enterocytes of the intestinal lining as _____.

mostly individual amino acids

Kwashiorkor and marasmus are

the two types of protein-energy malnutrition

The functions of proteins include

transportation, fluid balance maintenance, acting as enzymes, immune function, providing structure, being hormones, healing of wounds, & regeneration of tissues

Denaturation

Can be caused by heat, acid, high salt concentrations, alcohol, and mechanical agitation Occurs when the complicated folded structure of a protein unravels, and it becomes just a long strand of amino acids again Causes a loss of that protein's function

Risks of continued excessive protein intake include:

Continued excessive protein intake can restrict other essential nutrients, compromising vitamin and mineral absorption. Continued high intake of red meat and processed meat is associated with a significant increase in colon cancer risk. Continued excessive protein intake may accelerate bone loss because under some conditions the acids in protein block absorption of calcium in the gut. Continued excessive protein intake are linked to a higher risk for kidney stones, kidney disease, and liver malfunction.

Important steps in protein digestion.

HCl denatures proteins Pepsin breaks proteins down into smaller and smaller fragments Pancreatic chymotrypsin and trypsin break proteins into even smaller pieces Enzymes from the cells lining the small intestine take short peptides to individual amino acids

What is true about proteins?

Protein makes up ~20% of the human body It is estimated that more than 100,000 different proteins exist within the human body Protein is present in every single cell of the body

How can vegetarians and vegans meet their daily protein requirements?

Soy and quinoa are plant sources of complete proteins Use the PDCAAS results to determine the quality of the protein being consumed Consume tofu, soy, quinoa, or pistachios as they are all good sources of lysine, an amino acid it can be difficult to get enough of for vegetarians/vegans Consume complementary protein sources within the same day

Proteins we consume must be broken down so that we can form the non-essential amino acids and build the proteins that we need. This process is ________.

a protein metabolic pathway

Which isn't correct regarding the steps in protein production? a) modification: adding carbohydrates to one end and lipids to the other end of the protein b) transcription: copying of the double-stranded DNA into the single-stranded, messenger RNA (mRNA) c) folding: specific amino acid sequences contain the information needed to spontaneously fold a string of amino acids into a particular shape d)translation: RNA instructs the cells and add amino acids to the growing protein chain in a very specific order

a) modification: adding carbohydrates to one end and lipids to the other end of the protein

Once they are no longer needed, what happens to proteins?

amino acids are liberated as proteins are broken down

The parts of an amino acid include

an amino group and a carboxylic acid group NH2 and COOH with a middle C atom an R group that makes each amino acid type different

A biological catalyst (lowering the amount of energy and time it takes for a chemical reaction to happen) that can be reused many times is called ______

an enzyme

Antibodies

are secreted to surround and destroy invaders like bacteria, and trigger other factors in the immune system to seek and destroy unwanted intruders as well.

(Weight in lbs. ÷ 2.2 lb/kg) × 0.8 g/kg What does the formula above tell us?

body mass index (BMI)

Which is NOT true of proteins? a) Incomplete proteins do not have all of the amino acids we need to ingest in sufficient quantity. b) Two incomplete proteins can be combined to create a complete protein. c) Complete proteins have all of the amino acids we need to ingest in sufficient quantity. d) Plant proteins are complete and animal proteins are incomplete.

d) Plant proteins are complete and animal proteins are incomplete.

Which is NOT true of complementary proteins? a) complementary proteins can be combined to create a complete protein b)hummus & pita bread, red beans & rice, macaroni & cheese are examples of complimentary proteins c) plant proteins, other than soy, are not complete proteins d) any two fruits can be combined to create a complete protein

d) any two fruits can be combined to create a complete protein

Which is NOT true of essential, non-essential and conditionally essential amino acids? a) conditionally essential amino acids are only needed in certain conditions in some individuals b) essential amino acids must be consumed c)non-essential amino acids are not needed to be consumed d) non-essential amino acids cannot be made in the body, but are not required by the body

d) non-essential amino acids cannot be made in the body, but are not required by the body

Which is NOT correct regarding the levels of protein structure? a) primary structure - the chain of amino acids b) secondary structure - the initial α helix and the β pleated sheet folding c) tertiary structure - the three dimensional structure d) quaternary structure - joining of more than one protein molecule e) quinary structure - the joining of multiple protein molecules

e) quinary structure - the joining of multiple protein molecules

When are protein supplements such as shakes or bars beneficial?

for endurance or strength athletes without much time who need an exercise-recovery snack