protein Flashcards
What elements are proteins made of?
carbon, hydrogen, oxygen, and nitrogen atoms.
Some also contain sulfur atoms.
How are proteins arranged?
amino acids linked in a chain.
What are the two main groups in an amino acid?
basic (amino) group (-NH₂)
acidic (carboxyl) group (-COOH).
What is the distinguishing feature of amino acids?
amine group, which is the body’s source of nitrogen.
What are the building units that make up proteins?
Amino acids
How many amino acids are used to make up the chemical structure of proteins?
20
How many amino acids are typically linked together in a protein?
100
What is a peptide bond?
bond that connects the acid end of one amino acid with the amino group of another, forming a link in a protein chain.
What is the amino acid sequence for hemoglobin?
V-H-L-T-P-G-G.
What is the amino acid sequence for sickle-cell hemoglobin?
V-H-L-T-P-V-G.
What causes the difference between hemoglobin and sickle-cell hemoglobin?
The difference is caused by a single amino acid substitution: glycine (G) is replaced by valine (V).
What does “indispensable amino acid” mean?
required in the diet because the body cannot synthesize them.
How many indispensable amino acids are there?
9:
Histidine
Isoleucine
Leucine
Lysine
Methionine
Phenylalanine
Threonine
Tryptophan
Valine
What are dispensable amino acids?
they are essential for the body, can be made from essential amino acids, so not required in the diet
How many dispensable amino acids are there? AAAGS
5:
Alanine
Aspartic Acid
Asparagine
Glutamic Acid
Serine
What are conditionally indispensable amino acids?
normally dispensable but become indispensable in certain nutritional, disease stages, or developmental conditions.
What is an example of a conditionally indispensable amino acid?
In phenylketonuria (PKU), phenylalanine cannot be converted to tyrosine, making tyrosine conditionally indispensable.
What defines a high-quality protein?
provides all 9 indispensable amino acids in amounts adequate to maintain nitrogen balance and support growth.
What defines a low-quality protein?
lacks sufficient quantities of one or more indispensable amino acids for optimal protein synthesis.
Can low-quality proteins support life and growth?
can support life but not normal growth. Other proteins are needed to support normal growth.
What are some plant sources of low-quality protein?
Legumes
Peas
Beans
Grains
Nuts
What are some animal sources of high-quality protein?
Chicken
Pork
Beef
Eggs
Lamb/veal
Turkey/Duck/Wild Game
All seafood
How can a complete protein be made from low-quality protein foods?
combining two low-quality protein foods in the same meal.
Give an example of a combination that creates a complete protein.
Rice and beans, or macaroni and cheese
Can the body combine proteins eaten in separate meals to form a complete protein?
Yes, the body can combine proteins eaten a few hours apart to form a complete protein.
Give an example of combining proteins from different meals.
Cereal and milk
What is nitrogen balance?
the balance of reactions in which protein substances are broken down and rebuilt.
What happens in nitrogen balance for healthy individuals?
When nitrogen consumed equals the amount of nitrogen excreted
What is positive nitrogen balance?
when more nitrogen is absorbed than excreted by the body.
What are some conditions that can cause positive nitrogen balance?
Rapid growth
Pregnancy
Lactation
Illness
Infants
Tissue repair
Recovering from protein-energy malnutrition (PEM)
Athletic training
Medications
What is negative nitrogen balance?
when the body excretes more nitrogen than it absorbs.
What are some conditions that can cause negative nitrogen balance?
Rapid weight loss
Illness/Infection
Fever
Starvation/diet
Emotional stress
Burns
Injuries
Inadequate protein intake
Inadequate energy intake
what are the Primary Roles of Protein In the Body?
- Growth and Maintenance
- Repair
- Enzymes and Hormones
- Regulation of Fluid Balance
- Resistance to disease: Antibodies
- Transportation
- Energy
When is the body’s need for protein increased?
during periods of growth (infancy, childhood, adolescence, and pregnancy) and during recovery from illness, surgery, burns, fever, or SRP (scaling and root planing).
Why is protein important during growth and maintenance?
is needed to build new tissue during growth and healing, and it is in every cell, including connective tissue, teeth, bone matrix, eye lens, and muscles.
What body parts can indicate protein deficiencies during an examination?
Hair and fingernails are constantly growing and can indicate possible protein deficiencies during an extraoral examination (EOE).
Why must body proteins be continuously replaced?
constantly being broken down, so they need to be replaced to maintain bodily functions and structure.
What are some activities or situations that can require protein replacement due to breakdown?
Lifting weights
Floss injury (floss clefts)
Palatal trauma from eating hard or rough-textured foods (chips, pretzels, nuts)
What essential compounds are proteins part of?
enzymes, hormones, and other body secretions.
What is collagen, and what role does it play in the body?
protein found in connective tissue that helps support body structures like skin, bones, teeth, and tendons.
What is the enzyme for carbohydrate digestion in the oral cavity?
amylase
What protein stimulates the release of insulin?
glucagon
How do proteins regulate fluid balance in the body?
Proteins dissolved in water attract water molecules. For example, blood albumin draws water from interstitial fluid or cells to maintain blood volume.
What happens during protein deficiency in relation to fluid balanc
causes a loss of osmotic balance, leading to an accumulation of interstitial fluid (edema).
are antibiotics proteins?
yes
What happens to the immune system with low protein levels?
weaken the immune response, making it harder to fight bacteria and other harmful organisms.
How do proteins help with fat transportation in the body?
enable insoluble fats to be transported through the blood.
What other substances do proteins help transport in the body?
lipids, vitamins, minerals, and oxygen
Is energy a main function of protein?
No, but it is used when carbohydrate and fat stores have been used and body needs energy
or
when Indispensable amino acids are not available to create new proteins
What happens to protein-rich food in the mouth?
mashed into smaller parts as it is chewed in the mouth, then swallowed.
What breaks apart protein molecules in the stomach?
Hydrochloric acid and pepsin
What process occurs in the small intestine during protein digestion?
Hydrolysis, where enzymes like trypsin and chymotrypsin break proteins down into single amino acids
What is the final product of protein digestion?
single amino acids.
What happens to digested proteins after they pass through the intestinal villi?
carried by the blood to the liver.
What does the liver do with amino acids?
use them for protein synthesis and can remove the amine group to use carbon chains for fuel.
what are the symptoms of protein deficiency?
Anemia
Lowered resistance to infection
Edema
Brittle and slow-growing hair and nails
Scaly appearance to skin with sores that will not heal
who is at risk of protein deficiency?
- elderly individuals (cost of food, inability to prepare meals, depression)
- individuals with low income
- strict vegetarians or vegans
- individuals with lack of education or who are unwilling to shop wisely
- patients who are chronically ill or hospitalized
What is sarcopenia?
is the progressive loss of muscle mass and strength with aging, often considered a normal condition for elderly individuals.
What are the benefits of high-quality protein intake for muscle health?
helps promote and maintain muscle mass, maintaining mobility and body weight and preventing sarcopenia and osteoporosis
What is Protein Energy Malnutrition (PEM)?
When people are deprived of protein, energy or both.
Can PEM be chronic or acute?
either or
Where is PEM most prevalent globally?
Africa, Central America, South America, East and Southeast Asia
Where in the U.S. is PEM commonly found?
homeless people, inner cities and rural areas
What is marasmus?
severe malnutrition caused by near or total starvation due to a lack of calories and high-quality protein.
What are the main dietary causes of marasmus?
caused by a diet low in calories, where protein is used for energy instead of building and repairing tissues or maintaining immune function.
When does marasmus often occur?
often occurs during periods of physiological stress
What are the key characteristics of marasmus?
is characterized by muscle wasting and the absence of subcutaneous fat.
What causes kwashiorkor?
Caused from a lack of high-quality protein in the diet but adequate caloric intake
Who is most affected by kwashiorkor?
Affects mainly children
What is a common physical sign of kwashiorkor?
Appear pot-bellied
What type of nitrogen balance is associated with kwashiorkor?
Negative nitrogen balance
Where is kwashiorkor and marasmus commonly seen?
Seen in developing countries or those with food security issues
Can we predict what a protein supplement will do in the body?
No; the body uses it based on its needs at the time of consumption.
Will protein supplements automatically build body mass?
No
Who has higher protein needs, athletes or non-athletes?
Athletes
How can excess amino acids be used by the body?
used for energy during intense physical activity when carbohydrates are lacking.
How much protein should be consumed per meal to optimize skeletal muscle synthesis?
20g-30g of protein per meal
How can older adults and those trying to lose weight benefit from protein distribution?
by distributing protein intake throughout the day and especially not omitting protein at breakfast
How does malnutrition affect healing and infections?
Malnourished patients take longer to heal, regain strength, and are at higher risk for frequent infections. Adequate infection control procedures are important for these patients.
What resources can be suggested for older patients with an inadequate diet?
Suggest Meals on Wheels or community senior centers
How can dietary protein be supplemented in meals?
by adding skim milk powder to milk, soup, or mashed potatoes, and by incorporating cheeses into food.
How can a high-protein breakfast assist with weight management?
can help prevent body fat gain and increase satiety (feeling of fullness)
What are some good high-protein, low-fat food choices?
fish, skinless chicken, low-fat dairy products, and lean beef and pork.
What happens when protein intake exceeds 200% of the RDA?
increases the work of the liver and kidneys, potentially stressing these organs.
How does protein deficiency affect oral health?
can affect the synthesis of oral tissues and structures, making them weaker.
How does protein deficiency impact the immune system?
increases susceptibility to oral and other types of infections.
What is the effect of protein deficiency on wound healing?
can impede wound healing, slowing recovery after dental procedures.
How does the chemical structure of proteins differ from the structures of carbohydrates?
proteins contain nitrogen atoms in their building blocks (amino acids), while carbohydrates only contain carbon, hydrogen, and oxygen atoms
What factors affect the quality of dietary protein? What is a high quality protein?
9 indispensable amino acids of adequate amounts to maintain nitrogen balance and permit growth
If one is insufficient then it is a low quality protein
How would a protein deficiency affect dental health?
Affect the synthesis of oral tissues and structures
Increases susceptibility to oral and other types of infections.
Impede wound healing
Discuss the difference between Marasmus and Kwashiorkor?
marasmus: due to a lack of calories and high-quality protein
kwashiorkor: lack of high-quality protein in the diet but adequate caloric intake
