Proteins Flashcards
What are proteins?
Protein is a macronutrient made from amino acids and contains nitrogen and maybe some sulphur.
Multiple amino acids become….?
polypeptides
Protein provides building- material for body tissues. What are these?
Muscles, enzymes, hormones, connective tissue (CT), antibodies, and RBC’s
What are the major functions of proteins int he body?
Structure (bones, teeth, skin), enzyme production, movement (via muscles), communication (protein hormones and cell-signaling hormones), immunity, and regulation of pH
Amino acids are the building blocks of ______.
protein
Protein is broken down by enzymes and absorbed by teh body as _______.
amino aicds
How many different amino acids do we need to make all of the proteins required by the body?
20 different amino aicds
How many essential amino acids are there? Why are they essential?
9 essential
They are essential because the body cannot produce them. They must instead, be consumed.
How many non-essential amino acids are there? Why are they non-essential?
11 non-essential
The body can produce them and they are not necessary in our diets.
What are the essential amino acids (there are nine)?
Histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, valine
What are the non-essential amino acids (there are eleven)?
alanine, arginine, asparagine, aspartic acid, cysteine, gluatmic acid, glutamine, glycine, proline, serine, tyrosine
How much protein do you need?
Enough to supply adequate amounts of essential amino acids, and enough for additional nitrogen to synthesize nonessential amino acids
**How many grams per 20 pounds of body weight should someone have a day?
8 grams
**know this for exam
How many grams of protein a day should the average sedentary man have?
56-91 grams
How many grams per day should the average sedentary woman have?
46-75 grams
How much protein should pregnant women have a day?
25% more than the average daily requirement
Protein at 25-30% of calories has been shown to boost metabolism by up to how many calories per day?
80-100 calories
What is the most important contribution of protein to weight loss?
Its ability to reduce appetite and cause a spontaneous reduction in calorie intake
True or False. Protein is much more satiating than both fat and carbs
True
What are the best sources of proteins?
Meats, fish, eggs and dairy products.
How is sickle-cell anemia caused?
Disease caued by a single error in the amino acid sequence of hemoglobin.
It causes red blood cells to become misshapen.
What is denaturation (irreversible)?
Alteration of a protein’s 3-dimensional structure by heat, agitation, acid, chemicals, enzymes or heavy metals such as lead or mercury
What can a fever above 105 degrees F do?
Denature enzymes and proteins in the body, and can cause death
When proteins enter the stomach, what hormone is secreted?
Hormone gastrin
What does the hormone gastrin do?
Stimulates production and release of gastric juice (HCl, pepsinogen, mucus, IF)
What does HCl do to proteins in the stomach?
It denatures it.
What does pepsin (a protease) do to proteins in the stomach?
It breaks peptide bonds between amino acids in the protein, producing shorter polypeptides
What hormones are secreted by the duodenum?
Secretin and cholecystokinin (CCK)
What does the pancreas release in response to hormones secreted by the duodenum?
Bicarbonate in pancreatic juice, which neutralizes acid and inactivates pepsin
______ are converted into active proteases
proenzymes
Name the four proenzymes that the pancreas produces.
Trypsinogen, chymotripsinogen, proelastase, and procarboxypeptidase
Name the active enzymes cleaved by enzymes in duodenal enterocytes.
Trypsin, chymotripsin, elastase, carboxypeptidase
_____ break proteins down to tri-peptides, di-peptides, and free amino acids
proteases
Where are dipeptides and tripeptides transported? What happens here?
They are transported into the enterocytes. Here, di-peptides and tri-peptides are converted into free amino acids.
Name the three types of digestion a protein undergoes (in order).
- Luminal digestion (oligopeptides)
- Membrane digestion
- Cytoplasmic digestion (free amino acids)
Where does absorption of amino acids take place?
The duoedenum and the jejunum.
Amino acids must be transported into the _______
brush border (enterocytes)
What is a complete protein source?
Contains adequate relative amounts of all essential amino acids
What is an incomplete protein source?
Contains very low amounts of one or more essential amino acids
What are sources of complete protein?
Meat, poultry, fish, eggs, dairy products
Plant protein: soy
What is protein complementation?
Combining foods with incomplete proteins to provide adequate amounts of essential amino acids
What are some examples of complementary proteins?
Beans and corn tortillas, PB & whole bread, Rice and beans, tofu with rice, hummus with pita bread, chickpeas and rice
What organ in the body is the main site for protein synthesis?
The liver
What are the roles of the liver?
Detoxify drugs & alcohol, degradation of hormones, produces cholesterol and proteins including blood proteins
What is done with excess protein?
It is stored as fat, broken down for energy and used to make carbs or fat
What are the most common protein allergy foods?
Wheat, milk, eggs, peanuts, fish, shellfish, soy
What is kwashiorkor caused by (protein deficiency disease?
Occurs mainly in children whose diet lacks high-quality protein
What is marasmus caused by (protein deficiency disease)?
A diet low in both protein and calories
What are lacto-ovo vegetarians?
No meats, poultry, fish but include eggs and dairy
What is a lactovegetarian?
Plant and dairy products only
What are some of the health benefits of vegetarian diets?
Heart disease, stroke, hypertension, diabetes, colon cancer
How can you speed up your metabolism and get rid of belly fat?
- Skip the sugar
- Ditch flour
- Start the day off with protein
- Have protein with every meal
Organic milk cows are often milked while pregnant, producing milk that’s full of what?
Hormones
The average glass of milk has how many types of hormones in it?
60
True or False. Clinical research shows that dairy products have little or no benefit for bones.
True
Amino acids can be converted to glucose via?
Gluconeogenesis
What is protein turnover?
Balance between protein degradation and protein synthesis
What is an amino acid pool?
In the body, amino acids are that are immediately available to cells for protein synthesis and other purposes
