Chapter 7 Flashcards
What are some examples of protein foods?
tuna, broiled chicken, beef chuck roast, yogurt, kidney beans
What elements are found in protein?
nitrogen, carbon, hydrogen, oxygen
Carbs and lipids don’t contain which element?
doesn’t contain nitrogen
Amino acids
-central carbon
-nitrogen group
-acid group
-hydrogen
-side chain (R-portion)
How many essential amino acids?
9
How many non-essential amino acids?
11
What does it mean for an amino acid to be conditionally essential?
essential during infancy, during certain disease states, or following trauma
What are some examples of conditionally essential amino acids?
glutamine (experienced trauma) and arginine (trauma) tyrosine (infancy)
PKU
prevents phenylaniline-> tyrosine
phenylaniline-> high amounts can be toxic to the brain
Essential Amino Acids
Phenylalanine
Valine
Tryptophan
Threonine
Isoleucine
Methionine
Histidine
Leucine
Lysine
What are the 3 Branched Chain Amino Acids?
-isoleucine
-valine
-leucine (triggers muscle-protein synthesis)
What is transamination?
transferring an amino group from one amino acid to a carbon skeleton to form a new amino acid
What is deamination?
Amino group is lost from an amino acid and not transferred to another carbon skeleton
Amino acid catabolism (breakdown) generates ___, which is converted to urea by the ___.
ammonia, liver
What can happen if the liver is diseased, and ammonia builds up in the blood? Which organ is particularly sensitive to ammonia?
brain becomes confused, disorientated, and a coma can result
What are complete proteins?
adequate amount of all the essential amino acids
EX: most animal proteins (except gelatin)
What are incomplete proteins?
inadequate amount of the essential amino acids
EX: most plant proteins (except soy & quinoa)
What are complementary proteins?
combining 2 or more plant proteins to compensate for limiting amino acids
EX: rice & beans, bread & peanut butter
Soy and quinoa are complete or incomplete proteins?
complete
Gelatin is complete or incomplete protein?
incomplete
What is a limiting amino acid?
not present in food in sufficient quantities
What are the bonds linking amino acids called?
peptide bonds
What is a dipeptide?
2 amino acids
What is tripeptide?
3 amino acids
What is oligopeptide?
4-9 amino acids
What is polypeptide?
10 or more amino acids
What is a codon?
specific sequence of 3 nucleotide units found within DNA that code for an amino acid needed in protein synthesis
Where does transcription take place?
nucleus
Where does translation take place?
cytosol
requires ATP
What is mRNA?
code
What is tRNA?
complementary to mRNA
Protein Synthesis
- gene transcribed to mRNA in nucleus
- mRNA travels to cytosol
- Ribosomes translate to polypeptide chain
- released from ribosome and fold into active 3D form
If a scientist was discussing the primary structure of a protein, they would be talking about?
order/sequence of amino acids
Secondary structure of protein includes
-alpha helixes
-beta pleated sheets
Tertiary structure represents
active, folded protein
What is an example of a quaternary protein structure?
hemoglobin
What causes sickle cell anemia?
valine replaces glutamic acid
difference in primary structure
When is denaturation good?
cooking
When is denaturation bad?
in body when lose their function
What is protein turnover?
body proteins are in a constant state of breakdown, rebuilding, repair
In the standard American diet, does most of our protein come from animal or plant-based protein sources?
animal sources
Why should Americans incorporate more plant foods into their diet?
plant foods contain more fiber, vitamins and minerals, and phytochemicals
contain no saturated fat or cholesterol
Plant-based diet?
most consumption is of plant foods
What are the 8 common food allergens?
peanut/tree nuts, milk products, soy, wheat, eggs, fish/shellfish
Which macronutrient within the food triggers the allergy?
protein
What is BV?
biological value: measure of how efficiently the absorbed food protein is converted into body tissue protein
Which food has a BV of 100?
egg white protein
What is PER?
Protein Efficiency Ratio: compares the amount of weight gain of a lab animal consuming protein being studied against the weight gain of lab animal consuming reference protein
What is PDCAAS?
Protein Digestibility Corrected Amino Acid Score: calculated by multiplying a food’s chemical score by its digestibility (%DV for protein) (highest score= 1)
There are several different ways to asses and evaluate protein quality; which of these ways is the most widely used?
PDCAAS
When would someone be in positive nitrogen balance?
protein intake exceeds protein losses
When might someone be in negative nitrogen balance?
protein losses exceed protein intake
What groups of people should be in positive nitrogen balance?
children, elderly, pregnancy, athletes
Nitrogen intake?
Protein (g)/ 6.25
How does cortisol impact protein turnover?
increases
What is AMDR for protein?
10-35%
How many pounds are in a kg?
2.2lbs
What is the RDA for protein for healthy adults?
0.8g per kg
How does recovery impact protein needs?
patients with burns, cancer, and trauma always need more protein
How does illness and activity impact protein needs?
increases
Protein Digestion and Absorption in stomach
hydrochloric acid
pepsin
gastrin
Protein Digestion and Absorption in small intestine
secretin
CCK
proteases
Hydrochloric Acid
denatures protein & activates pepsin
Pepsin
breaks long polypeptide chains into shorter chains of AAs
Gastrin
controls the release of pepsin & HCL
CCK
stimulates pancreas to release proteases
proteases
trypsin, chymotrypsin, carboxypeptidase
secretin
stimulates pancreas to release proteases
In the body, where does enzymatic protein digestion begin?
stomach
In what form are proteins absorbed in the body?
amino acids
How long should infants be breastfed?
first 6 months of life
Breastfeeding should continue through at least the ___ year of life while complementary foods are introduced
first
Why shouldn’t infants be given cow’s milk?
gastrointestinal bleeding and damage immature kidneys
What is albumin?
blood proteins that have an impact on fluid balance
(water-magnets)
What is the most abundant protein in the body?
collagen
What is edema?
side effect of low albumin levels
fluid remains in tissue and swells
How does protein impact immune function?
antibodies (immunoglobulins)
Explain how a poor protein intake can have a negative impact on immunity and increase an individual’s likelihood of getting sick
without sufficient dietary protein, antibodies cannot be formed and the body’s ability to fight infection is reduced
What are some hormones and enzymes made from protein?
insulin, thyroid hormones
What does hemoglobin do?
carries oxygen
What is Retinol-Binding Protein?
carries vitamin A
What is transferrin and ferritin?
carry and store iron
What is gluconeogenesis?
forms glucose
What contributes to your body’s amino acid pool?
amino acids from diet and cell breakdown
How are amino acids used?
synthesis, energy production, and glucose production
How many kcal/g do amino acids provide?
4kcal/g
What happens to the ammonia that is formed from protein metabolism?
helps urea synthesis in liver
How could liver disease impact this process?
no synthesis
How might kidney disease impact the excretion of urea from the body?
less excretion
What are some of the negative impacts of protein deficiency?
-fail to grow and develop normally
-experience diarrhea, infections, and diseases at higher rates
-more likely to die early in life
Marasmus
Cause: not enough kcal or protein
Looks: skin and bone
Kwashiorkor
Cause: moderate kcal and no protein
Looks: swollen belly (ascites)
Do we produce enough food to feed the world? If so, why are people hungry?
conflict, distribution problems, waste
What are some potential issues with over-consuming protein?
dehydration and toxicity
What are some nutrients of concern in a poorly planned vegan or vegetarian diet?
Iron, vitamin B12, vitamin D, zinc, calcium
Why do parents need to be careful with bulky, high fiber, low kcal foods when feeding their children?
can cause early fullness and prevent children from consuming enough kcal and nutrients
DNA bases
A-T
C-G
Ig G food tests
only tells recent exposure to food. It doesn’t tell you sensitivity to food
