151 terms

Chapter 5-Proteins

Proteins are also called
nitro-containing macronutrients made from amino acids and joined together by peptide bonds
Peptide bond
a chemical bond that joins amino acids
protein size is
protein size depends on the
number of amino aicds
Most proteins have how many amino acids
250 to 300
dipeptides have
two amino acids
tripeptides have
three amino acids
2-12 amino acids are called
12 amino acids
Parts to a protein
central carbon atom bonded to a hydrogen atom, amino group, carboxlyic group, and R-group
amino group
-NH2. Central carbon boned to an amino group, carboxylic acid group, and R-group
carboxlyic acid goup
R group
part of amino acid strucutre that distinguishes it from other amino acids
What causes protein to bend and take on unique and complex shapes
the three charged components-amino group carboxylic acid group, and the R group
Body needs how many amino acids to make all the protein it requires?
types of amino acids
essential, nonessential, and conditionally essential
essential amino acids
consume through diet because the body can't make them
α-keto acid
compound that accepts an amino group from an amino acid in the process of transamination
process where an amino group is formed via the transfer of an amino group from one amino acid to α-keto acid
body canot convert phenylaline into tyrosine. Cause nonessential amino acids to become conditionally essential
Foods with the same amount of protein may differ in
combination of amino acids
Food proteins can be categorized based on the balance of
amino acids they have
complete protein sources
those that contain adequate amounts of essential amino acids
Incomplete protein source
a food that lacks or contains very low amounts of one or more essential amino acids
limiting amino acid
the essential amino acid in the lowest concentration in an incomplete protein source
Protein complementation
combining incomplete protein sources to provide all of the essential amino acids in relatively adequate amounts
High-quality protein
a complete protein source with high amino acid bioavailability
low-quality protein
a food that is either an incomplete protein source or one that has low amino acid bioavailability
organism made by genetic engineering
Steps in protein synthesis
cell signaling, transcription and translation
Cell signaling
cell receives a signal to produce a protein.
Turning on of protein synthesis by cell signaling is called
turn of of protein synthesis by cell signaling is called
increased expression of a gene
decreased expression of a gene
up and down regulation regulate
the body's ability to produce only the proteins it needs and to stop when needed
Transcription definition
mRNA is made using DNA as a template
a strand of DNA and associated proteins in a cell's nucleus
Each chromosome is subdivided into thousands of units called
portion of chromosome that codes for the primary structure of protein and has instructions to make peptides
a form of RNA involved in gene transcription
Translation definition
process whereby amino acids are linked together via peptide bonds on ribosomes using mRNA and tRNA
Translation process
mRNA leaves the nucles and binds to ribosomes in the cytoplasm. tRNA translates the info carried by the mRNA by delivering amino acids in the correct sequence to the ribosome, resulting in the production of a polypeptide strand.
organelle that is associated with the endoplasmic reticulum in the cytoplasm, involved in gene translation
a form of RNA in the cytoplasm involved in gene translation
Proteins get their shape by
folding and combing with other peptide chains or substances
Primary structure
single peptide chain that is determined by DNA code
The primary structure and it s effect on the protein
determines protein's basic chemical and physical characteristics. It's the basic identity
Sickle cell anemia
a disease in which a small change in he amino acid sequence of hemoglobin causes red blood cells to become misshapen and decreases the ability of the blood to carry oxygen and carbon dioxide
folding of a protein because of weak bonds that from between elements of the amino acid backbone
spiral stair case (2ndary)
β-folded sheet
2ndary-folded paper fan
Tertiary structure
folding of a polypeptide chain because of interactions among the r-groups of the amino acids (3d structure)
Quaternary structure
combining of peptide chains with other peptides chains in a protein t
to function properly, some proteins have precisely positioned nonprotein components called
prosthetic groups
prosthetic groups
nonprotein component of a protein that is part of the quaternary structure
what determines protein shape?
primary, secondary, tertiary, and quaternary structure
shape determines
alteration of a protein's three dimensional structure by heat, acid, chemicals, enzymes or agitation
Denaturation occurs when
a protein unfolds
what is affected by denaturation
secondary, tertiary, quaternary
Denaturing agents
compounds and conditions that cause denaturation
examples of denaturation
physical movement, heat, detergents, acids, bases, salts, alcohol, and heavy metals (lead and mercury)
Genetic makeup
particular DNA contained in a person's cells
the alteration of a gene
Some mutations are
good and bad
an mutation in a gene that is present in at least 15 of the population
Mutation-how does it affect health?
Impacts it
alterations in gene expression that don't involve changes in the DNA sequence
Epigenetic modifications are responsible for
diverse gene expressions
epignetic influence on chronic ****
developing chronic diseases
Human Genome Project-aim of study
study of nutrigenomics
Nutrigenomic perspective-what is their goal in terms of nutrition?
Developing a precise dietary plan specific to someone's DNA and genetic make up
science of how genetics and nutrition together influence health
Protein digestion begins
when it enters the stomach
Step 1 of protein digestion
gastric cells release gastrin which enters the blood causing the release of gastric juices
hormone secreted by endocrine cells in the stomach, which stimulates the release of gastric juices
Step 3 of protein digestion
partially digested proteins enter the small intestine and cause the release of hormones secretin and CCK
Step 2 of protein digestion
hydrochloric acid in gastric justice denatures proteins and converts pepsinogen to pepsin, which begins to digestion proteins by hydrolyzing peptide bonds
the inactive form of pepsin, produced in the stomach
Step 4 of protein digestion
secretin stimules the pancreases to release bicarbonate into the intestine. Bicarbonate neutralizes chyme. CCK stimulates the pancreas to release proenzymes into the small intestine
inactive precursor of any enzyme
enzyme needed for protein digestion
enzyme that cleaves peptide bonds
step 5 protein digestion
pancreatic enzymes are converted to active enzymes in the small intestine. These enzymes digest polypeptides into tripeptides, dipeptides, and free amino acids
step 6 protein digestion
intestinal enzymes in the lumen of the small intestine and within the mucosal cells complete protein digestion
trypsinogen, chymotrypsinogen, proelastase, poricarbixtoeotidase
inactive proenzymes produced in the pancreas and released into the small intestine in response to CCK
trypsinogen, chymotrypsinogen, proelastase, poricarbixtoeotidase converted to what in the small intestine
trypsin, chymotrypsin, elastase, carboxypeptidase
trypsin, chymotrypsin, elastase, carboxypeptidase
active enzymes involve din protein digestion in the small intestine
food allergy
a condition in which the body's imune system reacts against a protein in food
Food intolerance
a condition in which the body reacts negatively toa food or food component but doesn't mount an immune response
a severe and potentially life threatening allergic reaction
effects of anaphylaxis
imune response-drop in blood pressure, rapid pulse, dizziness, narrowing airways
Protein and its involvement in structure
cell membranes, organelles, muscles, skin, bones, hair and fingernails
an enzyme is a
increase rate of reaction without being consumed
protein fascinates movement
Proteins major involvement with the body
structure, catalyzing,movement, transportation, fluid balance, pH balance, energy source(glucose and energy), communication devices
protein transportation
transport proteins which escort substances into and around the body and the cell membrane
examples of transport proteins
hemoglobin-transports gases like o2 and CO2 and binding proteins that carry hromones and fat-soluble vitamins in the blood
protein in communication
proteins and hormones make up the body's communication network
protein in protecting the body
skin protecting the inner parts, blood clots from proteins closing off wounds, antibodies fight of disease
protein produced by the immune system that helps fight infection
Fluid balance-protein
how fluids are distributed in the body and balances between intracellular space and extracellular space and between intravascular fluid and intestinal space
protein in blood that regulates fluid between intravascular and intestinal spaces
buildup of fluid in the interstitial space-swelling in the body
Protein regulate PH
regulate base and acid
Protein for energy
use amino acids for glucose synthesis(maintain glucose levels), store excess energy when protein intake is more than adequate, and ATP production
When does the body look for protein as an alternate source of glucose
when ATP and glycogen are low
To convert amino acids to glucose
muscle tissue is broken down and th eliver takes up the amino acids
Gluconeogensis the
process whereby glucose-yielding amino acids called glucogenic amino acids are converted to glucose
Glucogenic amino acids
amino acid that ca be converted to glucose via gluconeogensis
synthesis of glucose from nocarbonhydrate sources
removal of an amino group from an amino acid
Gluconeogensis-the process needs what before amino acids can be converted glucose or used as a source of energy
eating extra protein during times of glucose and energy sufficiency
fat storage
Protein turnover
the cycle of protein synthesis and protein degradation in the body, which is regulated by hormones
proteins-do they get used up again?
Labile amino acid pool
Amino acids that are immediately available to cells for protein synthesis and other purposes
what contributes to the amino acid pool
amino acids from protein degradation (proteolysis) and dietary amino acids
New proteins are produced from
recycled and newly obtained amino acids
Deanimation produced what
ammonia NH3-toxic to cells
in response to ammonia production, the liver
converts ammonia to urea-less toxic substance
nontoxic nitrogen containing compound that is produced from ammonia
Nitrogen balance
protein intake is equal to protein loss by the body
Negative nitrogen balance
protein intake is less than protein intake loss by the body
positive nitrogen balance
protein intake is greater than protein loss by the body
nitrogen balance-why does it matter
helps clinicians diagnose and treat certain diseases and physiological conditions
why eat protein
amino acids and additional nitrogen to make nonessential amino acids and other nonprotein, nitrogen-containing compounds such as DNA
When should we eat lots of protein
prego, recovering from trauma like burns or illness
UL for protein
NO UL because people who are healthy and eat lots of protein show little harmful effects
debate-some says they need more some say they don't
AMDR protein
10 to 35%
those who don't consume any or selected foods and beverages made from animal products (no dairy and no meat)
lacto-ovo vegetarian
type of vegetarian who consumes diary products and eggs
vegetarian that consumes dairy products but no eggs
avoid all animal diets
vegans deficient in
calcium, zinc, iron, vitamin b12
vegetarians deficient in
protein, iron, calcium, zinc, and vitamin b12
vegetarians and diary products
watch saturated fat and cholesterol
protein energy malnutrition
protein deficiency accompanied by inadequate intake of protein and often of other essential nutrients as well
Protein deficiency in places where
amount and variety of food is scarse. Children mostly affected because they need high protein amounts
PEM form characterized by extreme wasting of muscle and adipose tissue
PEM form characterized by edema in the hands and feet
abnormal accumulation of fluid in the abdominal activity
children with kwashiorkor
cracked, peeling skin, enlarged fatty livers, and unnaturally blond or red hair
Adults and PEM
most have Marasmus-low muslce, fatty liver, edma
high protein consumption
don't have bad health outcomes if lean meats are considered (watch high satured fat and cholesterol)
high amounts of red meat and processed meats
associated with risk of colorectal cancer
red meat-how much should we wat
18 oz a week-it is healthy in moderation