Unit 15 Flashcards
Protein and Amino Acids
Can the body produce enough essential amino acids?
No
What happens if a cell is building protein and cannot find a needed aa?
aa - amino acid
synthesis stops
T/F: we cannot produce non-essential aa?
false
How many total amino acids are there?
20
How many NEAA are there?
11
How many EAA are there?
9
Do all proteins have a quarternary structure?
No, only some (hemoglobin, DNA polymerase, ion channels)
What can cause proteins to denature?
- heat
- acids
- basses
- alcohol
- heavy metals
Why is it good that protein can denature?
allows stomach acid to open protein structure for digestion
T/F: cooking things like egg whites, denatures the protein
true
T/F: fevers cannot denature body proteins
false, they can
How are the toxic effects of heavy metals, such as mercury, produced?
protein precipitation, enzyme inhibition and generalized corrosive action - all toxic effects
What do HCI and pepsin do to protein in the stomach?
HCI - denatures proteins and converts pesinogen to pepsin
Pepsin - cleaves large polypeptides into smaller polypeptides
How are proteins further digested in the SI?
- pancreatic protease breaks polypeptides into di- and tripeptides and some amino acids
- intestinal di- and tri-peptidases complete the break down of peptides into amino acids
- once in enterocyte, di-/tri-peptides are broken down into free amino acids which are absorbed into the blood stream
What are the 3 main functions of proteins in our body?
- building materials - muscle, fetus, scar tissue, RBC, intestinal cells
- maintenance of osmotic pressure
- synthesis of substances - hemoglobin, antibodies, enzymes, hormones, plasma, proteins, coagulation factors
Can protein provide energy?
Yes!
How many calories come from protein?
4 kcal/gram
How does protein differ from carbohydrate and fat?
contains nitrogen that can be used for protein formation or is excreted as urea by kidney if extra
T/F: protein can be stored like glucose is stored as glycogen
false, protein cannot be stored
Can amino acids be converted into glucose?
Yes, certain ones
When blood glucose levels are low and no other available glucose or glycogen, body will break down protein stores (like muscle) to replensih blood glucose
Called gluconeogenic amino acids
What is the most digestible dietary protein? The least?
Animal protein >90%
legume protein - 80%
grains and other plants - 60-90%
What determines protein quality?
EAA limit protein sythesis, if missing some EAA’s not as good of a protein
What is a complete protein?
contains all essential amino acids in amounts to sustain protein formation in body
What is incomplete protein?
lacks 1 or more of the essential amino acids
List some complete proteins.
Animal derived proteins (majority)
- meat
- fish
- poultry
- cheese
- eggs
- milk
- many soybean products
quinoa falls very close but falls short of lysine requirements
List some incomplete proteins.
Most plants
- cereals
- beans
- nuts
- seeds
Why do incomplete proteins have lower nutritional quality?
Due to low levels of select EAA’s and presence of antinutritional factors such as protease inhibiotrs that decrease protein digestibility
What a.a do grains not contain enough of?
lysine
What a.a do legumes not contain enough of?
methionine
What are complementary proteins?
Grains and legumes together
All essential a.a’s are present making in a complete protein
How much protein does a sedentary person need?
measured in g/kg BW
0.8
Who needs 2.2 g/kg of protein?
Infants up to 6 months
Who needs 1.2-1.4 g/kg of protein?
Strength-trained people who are maintaining
How much protein does a strength-trained and gaining individual need?
measured in g/kg BW
1.6-1.8
How much protein does a endurance trainined individual need?
measured in g/kg BW
1.2-1.4
How much protein does a infant need?
measured in g/kg BW
1.2
Who needs a positive nitrogen balance (retaining more than excreting)?
- growing child
- pregnant women
- person building muscle
Is a normal individual in a + nitrogen balance, - nitrogen balance or a nitrogen equilibrium?
Equilibrium
Are trauma patients and astronauts in a + or - nitrogen balance (lose more than we take in)?
negative
Rank the following most to least protein.
- greek yogurt
- milk
- egg
- lentils
- Peanut butter
- chicken
- chicken
- milk
- greek yogurt
- egg
- lentils
- peanut butter
Are individual a.a found naturally in foods?
No, we eat proetin which gets broken down into individual a.a
What are some negative effects of individual a.a supplements?
- contamination
- interfere with absoprtion of other EAA (all a.a use same transporter)
- excess consumption of methionine has many negative effects
What are some negetive effects of excess intake of methionine?
- worsens symptoms of schizophrenia
- promotes hardening of arteries
- impairs fetal and infant development
- leads to nausea, vomiting, bad breath and constipation
How can individual a.a supplements be used in sports?
glutamine and branched chain amino acids may have some performance benefits
What is milk protein made up of?
20% whey + 80% casein
What are some benefits of whey protein?
- immune enhancing properties
- low in fat and nutrient dense
- can improve body composition (accelerates recover, decreases muscle soreness, increases muscle strength and size)
Can eating protein alone increase muscle size?
No, extra strength training is what leads to muscle growth however sufficient protein is needed
What is kwashiorkor disease?
severe form of protein deficiency seen in children
What are the signs and symptoms of kwashiorkor?
- swealling in arms, legs and stomach
- moon face (edema)
- patchy dermatitis (from zinc deficiency)
What is marasmus disease?
Protein and calorie deficiency
maramus = more (protein + calories)
What are the issues with consuming too much protein?
- protein rich foods are often high fat foods (saturated)
excessive red meat linked to colon cancer - Calcium : protein ratio
20 :1 is good, but majority if 9:1 (high protein intake increases Ca loss in the urine - dehydration
burdens the kidney to excrete excess nitrogen (kidneys usally adapt if kidneys are healthy)
What is the ideal calcium:protein ratio? What is it actually?
Good - 20 : 1
Actual - 9 : 1
