Module 6: Proteins Flashcards
what elements are proteins made of
- carbon
- hydrogen
- oxygen
- nitrogen
how much energy per gram does protein provide
4 kcal/g
is supplying energy proteins primary function
no
is there a storage form of protein
no
what are proteins composed of
amino acids
what are the components of an amino acid
- central carbon (C)
- amino group (NH3)
- carboxyl group (COOH)
- hydrogen group (H)
- r group (unique to each amino acid)
how many amino acids are coded in the genome
20
what is the most simple amino acid and describe its composition
- glycine
- r group is just an H
define essential amino acids
must be acquired form our diet
define nonessential amino acids
normally made by the body in adequate amounts
define transamination
- transfer of amino group from one molecule to another to create an amino acid
- how nonessential amino acids are made
give an example of transamination
pyruvate + glutamate = alphaketoglutinate + alanine
what is the general equation for transamination
alpha keto acid (AKA) + amino acid (AA) = AKA + AA
define conditionally essential amino acids
- must acquire from diet under certain conditions
- car accident, burns, etc.
what type of bonds link amino acids
peptide bonds
what is the first amino group in a protein structure known as
N terminus
what is the last carboxyl group in a protein structure known as
C terminus
describe how amino acids are attached
- OH of carboxyl group connects with H of amino group
- the OH and H become H2O and are given off when amino acids are linked
- C-OH + H-N = C-N + H2O
define dehydration synthesis/condensation reaction
- two things combining and water being released
- occurs when combining amino acids
what dictates protein function
shape
describe the outcome of a correct amino acid sequence
predictable structure and function
describe the outcome of an incorrect amino acid sequence
- structure changes
- error in function
- ex: sickle cell anemia
why are protein structures curled
interactions between r groups of amino acids
how can protein structure be changed
- heat
- acid
- enzymes
- agitation
- alcohol
- electrolysis
- salting
can denaturation be undone
no
does cold alter protein structure
- no
- preserves proteins
does denaturation change nutritional value
no
what are the functions of protein in the body
- hormones (insulin)
- growth/maintenance/repair
- body structure and blood
- fluid balance
- transport
- enzymes
- immune function (antibodies)
- acid base balance
where does water enter and exit from capillaries
between endothelial cells
how many red blood cells can fit through a capillary at once
1
what provides the pressure that moves blood through the body
heart
define hydrostatic pressure
- pressure against walls of vessels
- pushes water out of vessels and into tissues and lacteals
does your lymphatic system have a pump
no
define osmotic pressure
- pushes water into vessels
- due to concentration of proteins and electrolytes (sodium) in blood
what is the relationship between hydrostatic and osmotic pressure
opposing forces
does osmotic pressure or hydrostatic pressure win
- hydrostatic
- pushes more water out of cell than is pulled in
defien albumin
- protein solute in blood
- helps maintain fluid balance
define edema
- swelling
- water in tissues
- due to low blood albumin
why does low blood albumin cause edema
- low proteins in blood creates low osmotic pressure
- water isn’t being brough back into blood vessels
- water stays in tissues causing swelling
what is the pH range of the body
7.35-7.45
how do proteins maintain acid base balance
- act as buffers
- neutralization of acidic and basic conditions
is the body more acidic or more basic
more basic
define antigen
- foreign substance that enters the body and triggers an immune response
- virus, bacteria, splinter, etc.
what is the body’s first barriers against immune invaders
- skin
- mucus
define antibodies
- proteins produced by immune system in response to antigen
- y-shaped
- attach to antigen and mark for elimination
describe how your immune cells protect against antigens
- immune cells (like macrophages) engulf an antigen and take part of it to B cells
- the B cells then make antibodies from the antigen
describe enzymes
- protein scissors
- speed up chemical reactions
- strings of 100 to 1000 amino acids
what are some causes of deficiencies in enzymes
- genetic: error in metabolism
- non genetic: illness, inadequate nutrition, medications
define hormones
messengers that help regulate the various systems and functions of the body
what are hormones made out of
- lipids
- proteins
what is an example of proteins transporting substances across cell walls/membranes
sodium potassium pump
what is the purpose of the sodium potassium pump
maintain electrical potential around the cell membrane
what is an example of proteins transporting nutrients through the bloodstream
retinol binding proteins
what is retinol
vitamin A
what are two ways that proteins can be used for transport
- across cell walls/membranes
- through bloodstream
does albumin contribute to hydrostatic or osmotic pressure
osmostic
what is the purpose of proteins on the outside of lipoproteins
communication between lipoproteins and other body tissues
what is the least efficient function of proteins
energy production
is there a storage form of protein
no
does 100 cal of protein = 100 cal of carbs
no
when and how does the body use protein for energy
- when: carb and fat intake is low
- how: breaks down muscle and uses amino acids for energy
what is included in protein turnover
- protein synthesis
- protein breakdown
what protein has the highest turnover rate
collagen
what does protein synthesis require
presence of essential amino acids in adequate amounts
define limiting amino acids
present in low amounts relative to the body’s needs
what happens during protein breakdown
free amino acids become part of the amino acid pool
is your amino acid pool usually low or high
usually very low
define deamination
- removal of an amino group
- removal of nitrogen
why is deamination essential
required for elimination of excess amino acids
where does deamination primarily occur
liver
what happens during deamination
the amino group (NH3) is converted to urea which then gets excreted in urine
define nitrogen balance
- nitrogen consumed vs. nitrogen excreted
- basis of many nutrition recommendations
when would you have a positive nitrogen balance
eating enough or excess protein
when would you have a negative nitrogen balance
eating not enough protein
how many times must deamination be done to make one urea
twice
what is the general equation for deamination
NH3 + CO2 = urea + water
when does a positive nitrogen balance occur
- growth
- recovery from illness
- pregnancy
when does a negative nitrogen balance occur
- AIDS
- cancer
- starvation
- low calorie diets
define complete/high quality proteins
- provides all essential amino acids
- easily digested and absorbed
what are sources of complete/high quality proteins
- animal products (meat, dairy)
- soy
- quinoa
what are the 2 plant based complete proteins
- soy
- quinoa
define protein digestibility-corrected amino acid score (PDCAAS)
- value assigned to proteins that accounts for protein quality and digestibility
- based on scale of 0-100
define incomplete proteins
do not contain all essential amino acids
examples of incomplete proteins
- legumes
- grains
- vegetables
define complementary proteins
foods that contain all essential amino acids when combined
what is a common example of complementary proteins
rice and beans
define supplemental proteins
- additional source of protein for specific populations
- vegetarians, highly active people, underweight people
does soy contain cholesterol
no, it is plant-based
what are health benefits associated with soy consumption
- protection against certain cancers and CVD disease
- prevention of bone loss
what is the nutritional composition of soy
- complete protein
- low in saturated fat and cholesterol
- B vitamins, calcium, potassium, vitamin A, iron
what is another bioactive compound found in soy
- isoflavones (a phytochemical)
- act as phytoestrogens
what is the RDA for protein
0.8g per kg of body weight
what is the AMDR for protein
10-35%
why might protein needs increase
- injury
- illness
- pregnancy
- competitive athletes
define vegan
omit all animal products
define lacto-vegetarians
include dairy
define lacto-ovo-vegetarians
include dairy and eggs
define pescatarians
include seafood
why do people choose to be vegetarians
- treatment of animals
- hormones and antibiotics
- environmental impact
- health
- religion
what are potential health benefits of vegetarianism
- low risk of heart disease
- low rates of obesity
what vitamin do we get mostly from animal products
vitamin B12
what are nutrients of concern for vegetarians
- vitamin B12
- zinc
- iron
- calcium
- vitamin D
- protein
define protein energy malnutrition (PEM)
disorder that occurs with inadequate protein and/or energy consumption
what would your nitrogen balance be if you had protein energy malnutrition (PEM)
negative nitrogen balance
what is the most common nutrient deficiency in hospitals and nursing homes in the US
protein energy malnutrition (PEM)
who is most at risk for protein energy malnutrition (PEM) internationally
infants and young children
what is the most lethal form of malnutrition
protein energy malnutrition (PEM)
what are the two types of protein energy malnutrition (PEM)
- marasmus
- kwashiokor
define marasmus and its causes
-condition of starvation characterized by emaciation, or skeletal appearance
- causes: inadequate protein and calorie intake
define kwashiokor and its causes
- characterized by swollen appearance, especially in the abdomen from fluid in tissue caused by decreased osmotic pressure
- causes: low protein intake, altered hut bacterial populations
who is often seen having kwashiokor
children being weened from breast milk
are high protein diets associated with longevity
- no
- survival and reproduction
what are the health benefits of excess protein
weight loss/fat loss
what are the health risks of excess protein
- increased risk of certain types of cancer
- kidney disease and kidney stones
- increased risk of heart disease (if diet is high in saturated fats)