Chapter 6 Flashcards
How are proteins working molecules? x6
1)Enzymes
2)Antibodies
3)Transport Vehicles
4)Hormones
5)Cellular Pumps
6)Oxygen Carriers
How are proteins used for structure?x7
1)Tendons
2)Ligaments
3)Scars
4)Fibres of Muscles
5)Cores of bone and teeth
6)Filaments of hair
7)Materials of nails
What are proteins made of?
Carbon, Hydrogen, Oxygen
Nitrogen
Some AA contain sulpher
Proteins are composed of?
Amino Acids
What are AA made of?
Amine group (N)
Acid Group
Side Chain (centre)
What is the role of side chains?
Make AA differ in Size, Shape, Electrical Charge
-determine molecules shapes and behaviours
What are essential AA?
AA cannot be synthesized by the body and can only be replenished from foods.
What are Nonessential AA?
AA that can be synthesized by the body
-Made from carbs or fat for backbones and nitrogen from other sources
What are the 9 essential AA?
1) Histidine
2)Isoleucine
3)Leucine
4)Lysine
5) Methionine
6)Phenylalanine
7)Threonine
8)Tryptophan
9)Valine
What are the 11 Nonessential AA?
1)Alanine
2)Arginine
3)Asparagine
4)Aspartic Acid
5)Cysteine
6)Glutamine
7)Glycine
8)Proline
9)Serine
10)Tyrosine
11)Glutamic Acid
When do nonessential AA become conditionally essential?
In circumstances when the needs exceeds that body’s ability to produce it, it must be supplied by the diet.
T or F the body can recycle AA?
T: Can Breaks down proteins to reduce AA
What is average protein turnover per day?
300-400 g/day
When does the body recycle AA?
Recycle system provides access to amino acids for energy when needed
How do cells use AA for energy?
-Tissues can break down their proteins in times of fuel or glucose deprivation.
-Working proteins are sacrificed
How does the body decide what tissue proteins to dismantle?
Priority System
-Most dispensable proteins are used first (Blood and muscle)
-Structural proteins of certain organs are guarded until their use is forced by dire need. (heart and other organs)
What are peptide bonds?
Connects one AA to another
-Amine group of one to acid group of next
What rxn forms peptide bonds?
Condensation reaction
What are primary structures?
Linear sequence of AA connected by peptide bonds
What are secondary structures?
Polypeptide shapes (helix or b-pleated sheets)
How are secondary structures formed?
-Positively charged hydrogens attract nearby negatively charged oxygen
-Determined by weak electrical attractions within the chain
What are tertiary structures?
Polypeptide tangles
shapes gives characteristics
What determines tertiary structure?
-Side groups attract or repel each other
-Hydrophobic and Hydrophilic
-Disulphide Bridges
What are quarternary structures?
Multiple Polypeptide Interactions
-Interactions between 2 or more polypeptide
How does the shape of a protein affect it?
Proteins perform different tasks dictated by their shape
What is Collagen?
A protein from which connective tissues are made
-(tendons, ligaments, scars and foundations of bones and teeth)
-Acts like glue between cells
What is insulin?
Helps regulate blood sugar
What are enzymes?
Protein Catalysts
What is sickle-cell disease?
Inherited variation in AA sequence resulting in abnormal hemoglobin
What is the mutation that occurs in sickle-cell disease?
Replacement
Valine replaces glutamic acid
What is the result of sickle-cell disease?
Alters protein so that it is unable to carry oxygen
-Red blood cells collapse from the normal disk shape into crescent shape causing blood clotting, stroke and death
What is denaturation?
Irreversible change in a protein’s shape
-Can be caused by heat, acids, bases and alcohols
How is the denaturation of proteins important to digestion of food proteins?
-Stomach acids open up a protein’s structure
-Allows digestive enzymes to make contact with peptide bonds and cleave the,
Why is cooking important in terms of denaturing?
A protein that binds stuff together is denatured and allows for digestion.
In general what are the 3 steps of protein digestion?
1)Each protein performs a particular task in a specific type of tissue
2)Proteins eaten, must be broken down and absorbed
3)AA then arranged into specific human body proteins
How are stomach proteins protected from acids/enzymes?
Coating of mucus secreted by the stomach wall
What digests proteins?
Certain acid-tolerant proteins (enzymes) digest proteins from food that have been denatured by acid.
What is the mouth’s role in protein digestion?
Protein is crushed by chewing and moistened with saliva
What stomach enzyme is responsible for digestion proteins?
Pepsin
What type of proteins are received by the small intestine?
Polypeptides (small denatured pieces of protein from stomach)
What is the role of pepsin in the stomach?
Uncoil proteins into polypeptide strands
What digestion of proteins occurs in pancreas?
1)Neutralize Stomach Acid
2)Proteases (enzymes) break down until only protein left are dipeptides, tripeptides or single amino acids
What is the enzyme that digests proteins in the pancreas and small intestine?
Proteases
Why are single amino acids supplements bad?
Compete for absorption sites or overwhelm a carrier, resulting in possible deficiency in another AA
What are the claim to use AA supplements?
Easy to digest and protect digestive system from overworking
T or F the stomachs digestive enzymes can be denatured and absorbed when their jobs are done?
True
What absorbs AA in the small intestine?
The cells lining the small intestine absorb single AA in addition to splitting them into smaller pieces
T or F: Di-tripeptides can be absorbed into the bloodstream by the cells lining of small intestine?
False
They can be absorbed by the lining of small intestine but then are split into single amino acids by those cells
T or F: Few larger protein molecules can escape digestion processes all together and enter bloodstream intake?
True
What are the repercussions of large protein molecules entering blood stream without being digested? x2
1)May give info about the external environment
2)Stimulate an immune response and have a potential role in food allergies
Where are AA carried once in bloodstream?
Liver
Once in the liver what occurs to AA?
Used by liver or released back into blood to be taken up by other cells
What are AA used for in the liver? x3
-Protein Synthesis
-Energy
-Synthesize nonessential AA and released into bloodstream for cells
What are AA used for by cells? x3
-Make proteins for their own use
-Make proteins for other uses that are released into lymph or blood
-Energy
What are the 6 roles of proteins in the body?
1)Supporting growth and maintenance
2)Building enzymes, hormones and other compounds
3)Maintaining fluid and electrolyte balance
4)Maintaining Acid-Base Balance
5)Clotting of Blood
6)Providing Energy and Glucose
How are AA used to support growth and maintence?
1)AA must be continuously available to build the proteins of new tissue
2)Proteins helps replace worn-out cells and cell structures
What is protein turnover?
The continuous breakdown and synthesis of body proteins involving the recycling of AA (300/4–g/day)
T or F AA are only used for protein synthesis?
F: some AA are components of things
Tryptophan: Serotonin and Niacin
Tyrosine: Epinephrine and Norepinephrine and Melanin and thyroxine
What is used to make Antibodies?
AA
Produced by the immune system
large proteins of blood
How does proteins maintain fluid balance in cells?
-Protein Attracts Water: By maintaining stores of internal proteins cells retain the fluids they need (proteins cant cross barriers but water can)
-Keeps fluids in vessels so it is not flowing in-between spaces between cells
What is it called when the fluid balance system fails?
edema: The swelling of body tissue caused by the leakage of fluid from the blood vessels
-Seen in protein deficiency
How do proteins maintain acid-base balance?
Blood Proteins act as buffers to maintain bloods pH
-Pick up hydrogens when too acidic (act as base)
-Release hydrogens when too basic (act as acid)
What is Acidosis?
The condition of excess acid in blood
Below than normal pH
What is Alkalosis?
The condition of excess base in blood
Above normal pH
What are the effects of acidosis and alkalosis on proteins?
Proteins denatured- disturbs body processes
How do proteins effect blood clotting?
Some proteins provide netting on which blood clots are built
How do proteins provide energy and glucose?
When insufficient carb and fat- energy is provided
Gluconeogenesis (when fat cant provide glucose)
T or F all hormones are proteins?
False
What are the 3 ways a AA that arrives at a cell can be used?
- Used to build part of a growing proteins
- Altered to make another needed compound
- Dismantled to use its amine group to build another amino acid (remainder than used for energy)
What occurs to amino acids when the cell is starved for energy and lacks glucose and fatty acids?
-The amine group is removed, and the remainder is used for energy.
-The amine group is excreted in urine
What occurs when the body has surplus AA and energy? x2
1)Amino group is excreted
2)Remainder can be used for energy or converted to glucose or fat for storage
What is wasted AA?
AA not used to build protein or make other nitrogen-containing compounds
What are the 4 things that can occur that would result in a Wasted AA?
1)Body does not have enough energy from other sources
2)Has more protein than it needs
3)Has too much of any single AA, such as from a supplement
4)The diet supplies protein of low quality, with too few essential AA
What are 3 things that must be done to prevent wasting of dietary protein and permit synthesis of needed body protein?
1)Dietary protein must be adequate in quality
2)The diet must supply all of the essential AA in proper amounts
3)Enough energy-yielding carbs and fat must be present (protein sparing_
What does the body response to protein depend on? x3
1)Body’s state of health
2)Other nutrients and energy taken with the protein
3)Protein quality
How does state of health effect the body’s need for protein?
Malnutrition and infection may greatly increase need for protein
How does undernutrition effect the need for proteins?
Secretion of digestive enzymes slows as the tract’s lining degenerates
How does infection effect the need for proteins?
Extra protein is needed for enhanced immune function
What is protein quality and what is it influenced by? x2
Determines how well a diet supports the growth of a child and the health of adults.
-A protein digestibility
-A protein AA composoitin
T or F Digestibility of a protein varies food to food?
True: Animals easier than plants
-Animals: 90+%
-Legumes: 80-90%
-Grains and other plant food: 70-90%
What are high-quality proteins?
Dietary proteins containing all of the essential amino acids in relatively the same amounts that human beings require
What is the AA pool?
AA dissolved in the body’s fluids, providing cells with ready raw materials to build new proteins or other molecules.
What occurs if there are nonessential AA that the body requires?
If not available from food, the cell can synthesize it and continue to attach AA to the proteins strand being created
Where do cells acquire AA composition?
AA pool
Food
What occurs if the diet fails to supply enough of a essential AA?
-Cells begin to adjust activities
-Cells conserve restricted AA:
-limiting the breakdown of
their working proteins
-reducing their use of AA for
fuel
Why is limiting AA bad?
-Limits proteins synthesis
What occurs if the shortage of a AA is chronic?
Cell break down their protein-making machinery
-Cells will function less and with less efficiently
If protein synthesis is limited due to an essential AA shortage, what happens to that partially completed protein? x2
NOT KEPT:
-Dismantled and AA returned to circulation
or
-Stripped of their amine group and residue is used for other purposes
What are complementary proteins?
Two or more proteins whose AA assortments complement each other in such a way that the essential AA missing from one are supplied by the other.
-Dont need to be in the same meal
What is mutual supplementation?
The strategy of combining 2 incomplete protein sources so that the AA in one food makes up for those lacking in other
Why is protein quality important?
Concern about protein quality is generally not an issue when food is abundant.
-Quality can make the difference between health and disease in areas where protein is limited and adequate food energy is limited
What is the RDA for protein recommended by the DRI committee?
0.8g/kg body weight/day RDA
10-35% of total calories AMDR
T or F most people in Canada receive more protein than required?
True
What is Nitrogen Balance?
The amount of nitrogen consumed compared with the amount excreted in a given time period
In normal circumstance what is Nitrogen Balance?
At Equilibrium = Zero Balance
-Amount N in = Amount N out
What is positive Nitrogen Balance/Status
More Amount IN than out
(more synthesized than degraded)
-Growing Children
-Preggo
-Recovering from protein deficiency
What is negatuve Nitrogen Balance/Status
More Amount OUT than in
(degrades more than synthesized, body looses N when proteins are broken down)
-Starving/Stress
What is the most widespread malnutrition problem?
Protein-Energy Undernutrition (PEU, PEM)
What is Marasmus?
Chronic inadequate food intake
-Shrivelled and Lean all over
-Inadequate energy, vitamin, mineral and protein intake
What is Kwashiorkor?
Severe acute malnutrition
-Swollen Belly and Skin rash
-Too little energy and protein to support body functions
What age does Marasmus occurs the most?
Children 6-18 Months
-Food is a weak cereal drink with scant energy and protein of low-quality
How are the symptoms of Marasmus and Kwashiorkor differ?
Everything is similar except Marasmus severe wasting of body fat
What is a common cause of Kwashiorkor?
Baby is weaned off breast milk when the next child is born
-goes from high-quality breast milk to low quality cereal
Why is a swollen belly a common symptom of Kwashiorkor?
-Proteins and hormones previously maintained fluid balanced are diminished
-Fluids then leak out of the blood and accumulate in the belly and legs, causing edema
Sad
Why does the liver become fatty during Kwashiorkor?
Lack of protein carriers that transport fat out of liver, fatty liver looses ability to clear posions from body prolonging toxic effects
What are common PEU/PEM causes in Canada? x8
1)Poverty
2)Elderly
3)Unhoused children and adults
4)Anorexia
5)Infants (over diluted formula)
6)Toddlers: Replacing milk with un-enriched, protein-poor health food rice drinks, almond drinks
7)Wasting diseases such as AIDS and Cancer
8)Addiction to drugs or alc
PEU/PEM and Serious illness have a positive or negative relationship?
Positive
Treating PEU/PEM often reduces the severity of other illnesses.
What are symptoms of hungry children x3?
1)Do not learn as well
2)Not as Competitive
3)Ill more often
What is the DRI recommendation for max protein intake?
No more than 35% of calories from protein AMDR
Does overconsumption of protein pose health benefits?
No
Cause health risk to heart, kidneys and bones
What types of foods contribute to a abundance of high quality protein?
Meat, Milk/dairy, Soy
What types of foods contribute to small quantities of proteins but can add up?
Veggies and Grain
What vitamins are often found in proteins?
B12 and Iron
What vitamins are not often found in proteins?
Vit C and Folate
T or F Many protein rich foods are low in kcal-obesity?
False they are high in kcal-obesity
What are the advantages of legumes as protein sources?
Many B Vitamins
Iron
Calcium
What are the disadvantages of legumes as protein sources?
Vit A
Vit C
Vit B12
How to balance AA in legumes?
Balance AA in legumes using grain and veggies
Why may the use to too much soy products be bad?
Inhibits iron absorption
Improve by using small amounts of meat and or food rich in vit c
What are texturized veggie protein?
Soy protein is often used by vegetarians that look and taste like meat but fall short in nutrition content (processed)
Omnivore
Includes foods of both plant and animal
Lacto-ovo vegetarian
Includes dairy products and eggs but excludes animal flesh and sea food
Lacto- Vegetarian
Includes dairy products but excludes eggs, animal flesh and sea food
Ovo-Vegetarian
Includes eggs but no dairy, animal flesh and seafood
Pesco-vegetarian
Excludes animal flesh but eats seafood
Vegan
Only food from plant sources
Flexitarian
Primary plant-based foods but animal products are eaten occasionally
Reasons for Vegetariansim?
Preference
Convenience
Advertising
Availability
Economy
Emotional Comfort
Habot
Positive Associations
Social Pressure
Values or Beliefs
Weight
Nutritional Value
What are some common side effects of people who eat planned vegetarian diets in affluent countries? x5
-Decreased Obesity Rates
-Decreased Heart Disease Rates
-Decreased high blood pressure rates
-Decreased Cancer Rates
-Increased life span
Why may veggie diets help weight loss?
Increased Fibre
Low Fat
Veggie diets generally contain more of these things x3
Fibre
Potassium
Vitamins associated with reduced disease risk
The healthiest meat eaters base their diets on x2
Abundant veggies, fruit, whole grains and milk
Small Servings of fish poultry and meat
What are the 2 reasons meat lovers and misguided weight loss dieters are at more risk?
-Eliminate many fruits, veggies and grains
-Risk of nutrient deficient and increased chronic disease
Poorly planned veggie diets can result in lack of x7?
1)Protein
2)Iron
3)Zinc
4)Calcium
5)Vit B12
6)Vit D
7)Omega-3
Poorly planned omnivore diets can result in lack of x4?
1)Vit A
2)Vit C
3)Folate
4)Fibre
What should the dietary intake of iron for vegetarians be increased by?
1.8x cuz iron in plants is poorly absorbed
What deficiency does vit B12 result from?
Rickets
What are 6 guidelines to follow when choosing a veggie diet?
1)Choose fresh, whole foods
2)Avoid reliance of heavily processed convenience foods that contain added sugars, salt, sat fats, and trans fat
3)Soy beverages and tofu fortified with calcium, vit D and b12 can substitute for cow’s milk
4)Dark green veggies and legumes help meet iron and zinc needs
5)To ensure adequate intakes of vit B12, Vit D and Calcium selected fortified foods or use supplements
