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Nutrition-Midterm 2--Chapter 6: The Proteins and Amino Acids
Terms in this set (64)
1. Describe the structure of proteins and explain why adequate amounts of all the essential amino acids are required for protein synthesis
How is protein different from all other macronutrients?
Remember about Macronutrients
All of them contain carbon and are essential. Fat provides the most energy per gram.
Structure of Amino Acids
Amino group, acid group, hydrogen, carbon center, R-group/side chain is what makes each amino acid unique
Why are adequate amounts of all the essential amino acids are required for protein synthesis?
There are 20 amino acids. 9 are essential. The rest the body can make from the essential acids. Form determines function.
Protein synthesis and structure depend on _____
the DNA in our cells. Each gene codes for a different protein. It drives the order in which the amino acids are linked together which determines what the protein is
amino acid sequence
Amino acid sequences determines...
the shape of the protein
Shape of the protein determines...
the function of the protein
Protein synthesis: process
DNA unstranding is activated. DNA makes mRNA. mRNA leaves the nucleus and interacts with the ribosome. Each amino acid matches up with a tRNA and the tRNA attaches it and bonds/links it. Many amino acids chain together making a protein strand of amino acids
Role of mRNA
carries the message so the protein can be made
2. Describe protein digestion, absorption, and metabolism
Digestion of protein: mouth
Digestion of protein: stomach
hydrochloric acids are released and denature the protein
changing the shape of the protein from a blob to a linear shape; unfolding it; because it loses its shape it no longer functions; can happen by stomach acid or by heat when cooking
Digestion of protein: small intestine
MAJOR SITE OF DIGESTION. Acid is neutralized, enzymes are relased from pancreas and small intestine. Proteins are broken down into dipeptides, tripeptides, and single amino acids instead of polypeptides
What neutralizes the hydrochloric acid once it reaches the small intestine?
bicarbonate from the pancreas
Digestion of protein: intestinal shell
di/tri peptides are broken down into single amino acids. Single amino acids are absorbed
How are amino acids moved into the bloodstream to be absorbed by it?
the portal vein
What form does protein have to be in to be absorbed by the bloodstream?
single amino acids
Fate of amino acid in cell; metabolism of protein (4) (BEAN)
a protein, used as
for use in another compound, changes into a
When protein is used as energy what happens to it?
deanimation--the nitrogen is taken off
3. List and describe the roles of protein in the body and explain Nitrogen balance
What are the roles of protein in the body? (CRAFTS BEG)
help reactions catalyze/regulation, antibodies, acid-base and fluid balance, transport, structure, blood clotting, energy, growth
What is nitrogen balance?
protein excretion vs. protein intake
Positive nitrogen balance
when you're adding body tissue/growing; babies, pregnant women, body builders
Neutral nitrogen balance
regular healthy people
Negative nitrogen balance
losing body tissue; people in the hospital, austronaughts
Protein is wasted when... (IE, EP, EA, FA)
insuffient energy intake; in a starved state the body starts eating itself. Excess protein intake; protein is turned to fat or burned. Excess single amino acid; so don't take a single amino acid supplement. Too few essential amino acids
What happens to protein when you ingest more than you need?
Made into fat, burned, or excreted
What happens to protein when you don't have enough calories to meet energy needs?
Body starts breaking down muscle cells for energy
What happens to protein when you have extra single amino acids from a supplement?
Can prevent absorption of essential amino acids because the supplement is competing with them
4. Characterize foods in terms of protein amount and quality and also identify proteins that are complementary
Protein Amount: Grains (g/cup or oz)
Protein Amount: Vegetables (g/cup or oz)
Protein Amount: Fruits (g/cup or oz)
Protein Amount: Milk (g/cup or oz)
Protein Amount: Meat (g/cup or oz)
High quality protein
animal proteins--meat and dairy. Amino acid pattern and digestibility makes them absorb the best
Mid range protein
Low quality protein
grains/vegetables due to low absorption
grain+nut or legume
Examples of complementary proteins
tortilla and beans. rice and lentils. pita bread and hummus. bread and pita butter.
Can a vegetarian/vegan meet amino acid needs?
Yes, try to use complementary proteins
What is AMDR for grain, vegetable, fruit, milk, meat for 2,000 calorie diet?
8 oz grains. 4 cups vegetables. 2 cup fruits. 3 cup milk. 6 1/2 oz meat.
AMDR for protein (Lauren to future me)
10-35% of calories
What is AMDR for carbohydrates? (mom to grandma)
45-65% of calories
What is AMDR for fat? (me to future me)
20-35% of calories
DRI for protein
0.8 g/kg bodyweight. 2.2 pounds = 1 kilogram.
5. State the AMDR for protein. Calculate an individual's recommended protein intake--DRI.
6. Describe the consequences of consuming too much or too little protein.
Muscle is _____% by weight protein
Too Little Protein: Consequences (MINK DEG)
Malnutrition, impaired immune system, impaired nutrient absorption, impaired brain/kidney function, weakness, decreased growth, edema (retaining fluid). Diseases: Marasmus (skinny), Kwashiorkor (swollen stomach)
Too much protein: Consequences (HKBC)
heart disease, kidney disease, bone loss, cancer
7. Describe celiac disease, including what happens in the digestive tract, the consequences, how it is diagnosed, and what foods need to be avoided
What is Celiac disease?
an autoimmune response to gluten protein in wheat, barley, and rye. NOT AN ALLERGY
Result of the autoimmune response (in digestive tract)
villi in small intestine are flattened and destroyed, reducing nutrient absorption--malabsorption, inflammation, destruction of cells
Symptoms of Celiac disease
nausea, vomiting diarrhea, indigestion, weight loss, reduced growth in children
Complications of Celiac disease
Stomach cancer, low absorption, osteoporosis, anemia, low blood sugar, liver disease
Diagnosis of Celiac disease
blood test and duodenum intestinal biopsy (test a little piece of the intestine)
Treatment: foods to avoid forever
wheat, barley, rye, gluten, any products made with these
8. Identify the strengths and limitations of vegetarian and meat-containing diets. Identify nutrients of particular concern.
Vegetarian Diets: Possible benefits and pitfalls
Any diet can be fine so long as you're getting enough nutrients. Benefits: less obesity/chronic disease, high fiber/fruits/veggies, less saturated fats. Pitfalls: Low energy, nutrients of concern
Nutrients of concern for vegetarians (3PB12DCaZnFe)
Protein, omega 3, Vitamin B12, Vitamin D, Calcium, Zinc, Iron
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