chapter 7 proteins Flashcards
proteins are complex organic molecules made up of
amino acid
protein composed of which elements
carbon, hydrogen, oxygen
only macronutrient that contains nitrogen
protein
the body uses proteins to make or function as
new cells, components of cells
hair, nails
enzymes
lubricants
clotting compounds
antibodies
compounds that maintain fluid and pH balance
certain hormones and neurotransmitters
energy source
edema
swollen tissue
edema arterial end
fluid forced into tissue spaces by blood pressure generated by pumping action of the heart
edema venous end
fluid drawn into bloodstream by the proteins as blood pressure declines in the capillaries
human proteins have ___ amino acids
20
each amino acid is composed of
1. ____ group
2. ____ group
3. ____ group
amino or nitrogen containing group
R group
acid group
R group
varies, used to identify molecule
essential amino acids
cannot be made by the body or in amounts great enough to meet needs, must be supplied by the diet
how many amino acids are essential
9
nonessential amino acids
can be made by the body
how many amino acids are nonessential
11
some of the nonessential amino acids are “conditionally essential” which means they
become essential in certain situations
9 essential amino acid names
histidine
isoleucine
leucine
lysine
methionine
phenylalanine
threonine
tryptophan
valine
11 nonessential amino acid names
alanine
aspartic acid
asparagine
glutamic acid
serine
agrinine
cysteine
glutamine
glycine
proline
tyrosine
conditionally essential amino acid names
arginine
cysteine
glutamine
glycine
proline
tyrosine
food from ____ sources typically have more protein per serving than similar quantities of foods from ___
animal
plants
___, ____ and ____ supply more protein per serving than fruit or edible leaves, roots, flowers, and stems of vegetables
seeds
tree nuts
legumes
legumes
plants that produce pods with a single row of seeds, such as soybeans, peas, peanuts, lentils, beans
which food has the most amount of protein per serving
chicken breast
high quality protein
contains all 9 essential amino acids in amounts that support protein deposition in tissue and a Childs growth
high quality protein is most ___ products
animal
plant sources that are high quality protein
soy, qunioa
low quality protein
lacks or has inadequate amounts of one or more essential amino acid
limiting amino acids
essential amino acids in lowest amounts in a food
most ___ sources are low quality protein
plant
cells assemble the 20 amino acids in specific sequences and lengths according to
information provided in DNA
amino acids are connected by
peptide bonds
polypeptide forms when
two or more amino acids form a chain
peptides
small chains of amino acids
protein synthesis begins with
DNA in the cells nucleus
gene
portion of DNA that contains information about the order of amino acids in a specific protein
___ and ___ help to form the protein
mRNA, tRNA
mRNA is formed by
transcription and “read” by ribosomes during translation
tRNA brings
amino acids to the ribosomes during translation
when translation is complete, the polypeptide
chain coils and folds into a 3D shape for that specific protein
basic steps of protein synthesis:
1. in the cell nucleus, protein synthesis begins when
a section of DNA unwinds, exposing a single portion
basic steps of protein synthesis:
2. the gene undergoes _____, forming ___
transcription
mRNA
basic steps of protein synthesis:
3. mRNA transfers information concerning the amino acid sequence from the ____ to ____
nucleus to ribosome protein manufacturing sites in the cytoplasm
basic steps of protein synthesis:
4. during the translation process, ____ read mRNA. the coded instructions indicate
ribosomes
which amino acid to add to the polypeptide chain and its sequence
basic steps of protein synthesis:
5. each specific tRNA molecule conveys
a particular amino acid to the ribosome
basic steps of protein synthesis:
6. at the ribosome, the amino acid that has been delivered
attaches to the peptide chain
basic steps of protein synthesis:
7. when the translation process is complete, the ribosome _______ and the new protein undergoes ______
releases the polypeptide
further processing
the shape of a protein is important because it
determines the activity of the protein
if the wrong amino acid is inserted in the chain
a genetic defect can occur
sickle cell anemia
defective hemoglobin cannot transport oxygen efficiently
denaturation
altering a proteins natural shape and function by exposing it to various conditions
denaturaition can can be caused by
heat, acid, physical agitation
chemical digestion of protein begins in the
stomach
_______ denatures protein
hydrochloric acid
the enzyme ____ digests proteins into smaller polypeptides
pepsin
polypeptides are broken down further in the
small intestine
the enzymes ___ and ____ break down polypeptides into shorter peptides and amino acids
trypsin
chymotrypsin
enzymes from absorptive cells of the small intestine break down shortened peptides into
dipeptides, tripetides, amino acids
protein absorption occurs in the
small intestine
amino acids travel to the ___ via the___
liver
hepatic portal vein
protein digestion:
stomach
proteins undergo denaturation by stomach acid, and partial digestion by pepsin
protein digestion: small intestine
further digestion occurs as the pancreas secretes protein-splitting enzymes, including trypsin and chymotrypsin
protein digestion:
small intestine cells
final digestion occurs within absorptive cells
protein digestion:
liver
after being absorbed, amino acids enter the hepatic portal vein travel to the liver
protein digestion:
rectum
very little dietary protein is excreted in feces
protein turnover
process of breaking down old or unneeded proteins into their component amino acids and recycling them to make new proteins
amino acid pool
amino acids that have not been incorporated into proteins and can be used for future protein synthesis
endogenous amino acids
those available from the bodys amino acid pool
exogenous amino acids
those from dietary sources
deamination
removal of the nitrogen-containing group from an unseeded amino acid, forms a carbon skeleton
transamination
transfer of the nitrogen-containing group from an unneeded amino acid to a carbon skeleton, forming an amino acid
the liver removes excess amino groups (NH2) from the bloodstream, forming
ammonia (NH3), a highly poisonous product
the liver converts ammonia to
urea
the ___ excrete urea
kidneys
nitrogen balance
balancing nitrogen intake and protein turnover with nitrogen losses
positive nitrogen balance
body retains more nitrogen than it loses
negative nitrogen balance
body loses more nitrogen than it retains
positive nitrogen balance occurs in
growth
pregnancy
recovery from illness/injury
increased levels of insulin, testosterone, growth hormone
resistance exercise
nitrogen equilibrium occurs in
healthy adult meets protein and energy needs
negative nitrogen balance occurs in
inadequate protein intake or digestive tract diseases that interfere with protein absorption
increased protein losses resulting from certain kidney diseases or blood loss
bed rest, fever, injuries, burns
increased secretion of thyroid hormone or cortisol
protein RDA
.8g/kg body weight
protein needs increase during periods of
growth, pregnancy, lactation, recovery from serious illness or injury
using the RDA formula of .8 G protein/kg body weight, what is the RDA for protein for a healthy adult weighing 165lb
165/2.2=75kg
75x.8= 60g protein
AMDR for protein
10-35%
protein provides about ___% of average Americans daily energy intake
16
_______ provide most of the protein
meat, fish, poultry, dairy, eggs
meat, fish, poultry, dairy and eggs provide ____% of protein
70-85
plant food sources supply ___% of the protein
20-30
high amounts of red or processed meat is associated with
increased risk for CVD and some forms of cancer
processed meat contains a lot of
saturated fat, sodium
scientific evidence links red meat and processed meat intake with
colorectal, pancreatic, and stomach cancer
in 2015-2016, ___% of meat consumed by Americans was processed
25
MyPlate recommendation for protein intake:
choose ______ foods
lean, low-fat protein foods
lean cuts of beef
extra lean ground beef
lean cuts of pork
MyPlate recommendation for protein intake:
trim _____
limit _____
visible fat from meat
intake of processed meat products for sandwiches
substitute eggs, milk, cheese and yogurt for
meat, fish, poultry
my mixing plant and animal sources of protein you
extend the quality of protein in the meal
complementary combinations
mixing certain plant foods to provide all essential amino acids without adding animal protein
amino acids often low or limiting in plant proteins:
legumes
seeds
grains
low in methionine or cysteine
low in lysine
low in lysine ,sometimes tryptophan or threonine
semivegetarian
occasionally includes various types of animal flesh
lactovegetarian
includes milk and milk products
ovovegetarian
includes eggs
lacto-ovo-vegetarian
includes milk products and eggs
pescatarian
includes fish and shellfish
vegan
no animal products
vegetarian diet advantages
high in vit c, e, folate, beta-carotene, fiber, magnesium, potassium
low in saturated fat, cholesterol
vegetarian possible disadvantages
low in B-12, d, iron, zinc, calcium, omega 3 fatty acid, certain essential amino acids, energy
vegetarian special consideration for children
may be difficult to consume adequate protein and energy because plant foods add bulk to the diet, important to monitor growth rates
vegetarian special consideration for teens
may be lacking key nutrients for proper development
vegetarian special consideration for females who are pregnant or breastfeeding
need to ensure adequate nutrients available for infants (e.g. b-12)
excess protein intake may lead to
higher than normal urinary losses of calcium and dehydration
protein rich foods are high in
purines
purines
nitrogen-containing chemicals that are broken down by the liver to form uric acid
high blood uric acid level can lead to
gout
high uric acid in urine may contribute to
kidney stones
diets such as ___, ____ and ___ promote high intakes of protein
Atkins, protein power, paleo
high intakes of protien may reduce feelings of ____ and increase sense of _____
hunger, fullness
high intakes of protein may promote the loss of
excess body fat if combined with a reduction in total calorie intake
protein deficiency may occur in
older adults or low income
people with chronic diseases
protein-energy malnutrition results when
the diet lacks sufficient energy and high-quality protein
kwashiorkor
form of undernutrition that results from consuming adequate energy but insufficient high-quality protein
kwashiorkor primary occurs when
an infant is abruptly weaned from breast milk and given a low quality protein diet
kwashiorkor leads to
edema, stunted growth
marasmus
sever form of PEM
starvation, wasting occurs
marasmic kwashiorkor
inadequate energy and protein intake
allergy
inflammatory response that results when the body immune system reacts inappropriately to a substance that is typically harmless
allergen
the offending substance
most food allergies are proteins that
escape digestion and are absorbed as whole proteins
common signs and symptoms of food allergy
hives
swollen, itchy lips
skin flushing
scaly skin rash
difficulty swallowing
wheezing and difficulty breathing
abdominal pain, vomiting, diarrhea
anaphylaxis
serious, life threatening allergic response
common food allergens
cows milk
eggs
peanuts
tree nuts
wheat
fish
shellfish
soybeans
sesame
treatment of food allergies
avoid offending foods
read foods labels to carefully check for allergens
educate
celiac disease
inherited condition that results in malabsorption of nutrients from the small intestine
after a person with celiac disease eats gluten
a component of the protein stimulates the body to mount an immune response in the small intestine that inflames or destroys villi
celiac disease diagnosis usually involves
intestinal biopsies
celiac disease signs and symptoms
abdominal bloating, chronic diarrhea, weight loss, poor growth
PKU
rare genetic metabolic disorder caused by lack of enzyme that converts the essential amino acid phenylalanine to another compound
if PKU is undiagnosed
infant will develop intellectual disability by its first birthday
diet for PKU:
infancy allowed
phenylalanine-free formula
diet for PKU:
childhood and adult years: allowed
fruit, vegetables, special low-phenyalanine foods
diet for PKU:
childhood and adult years: avoided
nuts, milk, milk products, eggs, meats, other animal foods, aspartame
nutritional genomics investigates
complex interactions among gene functioning, dietary choices, environment
nutrigenetics
study of how a person’s genetic makeup affects the way their body responds to food
nutrigenomics
study of how nutrients and other food components can affect a persons genetic expression
animal products such as meet and eggs are almost 100% protein. true or false?
false
foods made from soybeans can be sources of high quality protein. true or false
true
Americans typically consume more protein from animal sources than from plant foods. true or false
true
registered dietitian nutritionists generally recommend that people with liver or kidney disease take amino acid supplements to increase their protein intake. true or false
false
people can nourish their hair by using shampoo that contains protein. true or false
false
