Lesson 6 Flashcards
what are carbs mostly composed of
monosaccharides
what are fats mostly composed of
fatty acids
what are the three parts of the amino acid
the amino group (NH2), the acid group (COOH) are the backbone and the unique side group
what are the two acidic (negatively charged) polar amino acids ?
aspartic acid and glutamic acid
what are the three basic (positively charged) polar amino acids ?
histidine, lysine, arginine
what are the 5 uncharged polar amino acids ?
serine threonine tyrosine asparagine glutamine
how many aa
20
how many essential aa
9
how many non essential aa
11
what are the two ways of sorting aa
polarity and side chain
what makes aa non polar
absence of oxygen in side group (no hydrogen bonds)
what are the two types of polar aa? what do they have in common
uncharged and charged
can both make hydrogen bonds
what is a protein?
completed polypeptide
what is the structure of hemoglobin ?
4 polypeptides formed together
if you took aa and linked them together and placed in water
polar and charged aa would be drawn to each other w hydrogen bonds
non polar would cluster, avoiding h bonds
what is protein shape determined by
the sequence of aa in the chain
what will cause the protein to unfold
broken h bonds denature protein
what will cause a protein to denature ?
change in temperature or pH
in food, a denatured protein changes___
texture and consistency
in body, a denatured protein ___
is no longer functional
how does slow cooking affect protein structure ?
muscle bundles held together by collagen (a protein). collagen denatured, reducing toughness of meat
if a meat is unpleasant to chew and is tough, what is this usually due to?
not enough denatured collagen
what does collagen look like ?
woven rope
the older the animal, what changes w quantity of collagen?
more collagen which is why veal is more tender
what does collagen become when slow cooked ?
gelatin
which macro is a jack of all trades
protein
what protein is at the foundation of bone ?
collagen fibres
what are two key structural proteins
collagen and keratin
what is the most common substance in the body next to water
protein
is insulin a protein
yes
why does it need to be injected ?
bc it is a protein, so if taken orally it is denatured in the stomach acid and separated into amino acids and would need to be built from scratch, but in type I diabetes you can’t
what do plasma proteins do ?
remain in blood vessels intravascularly, work to bring back fluid from interstitial space into capillaries to prevent swelling
h-bond prevents water from leaking back out
what happens to plasma proteins if protein levels drop
plasma proteins h-bond in interstitial fluid
edema
what is the tell tale sign of malnutrition
edema
what is the ideal pH in blood and tissue
7.35-7.45
why is it important for blood and tissues to keep a certain pH
if it changes, hemoglobin denatures and can’t transport oxygen
how do proteins maintain pH
act as buffers, picking up or dropping H+ in solution
how do proteins aid in transport ?
pumps across lipid bilayer
how do protein help against disease ?
as antibodies
what percentage of our genes code for protein
90%
in each nucleus, there is the same DNA, but do they have the same genes turned on ?
no
what is the machine that builds the protein ?
ribosome
what is mRNA?
copies instructions for making some protein the cell needs. leaves DNA in nucleus and attaches itself to ribosome. assembles polypeptide
what happens in protein synthesis if missing an essential aa ?
production of protein stops, and the partially made polypeptide is dismantled and aa returned to pool
what is the main point of protein digestion
disassemble protein into aa that you then reassemble in a more fitting way
in the stomach how is protein digested
by HCl and HCl-activated pepsin
how does the pancreas help in protein digestion
secretion of enzymes
how does the small intestine digest protein
by pancreatic enzymes
where do aa go to when absorbed
to hepatic portal vein to liver and then the rest of body
very little protein escapes digestion: true or false ?
true
liver keeps some aa for its function: true or false ?
true
what is protein turnover ?
the recycling of protein which makes us need less protein in our food
what is the protein found in RBC
hemoglobin
how many hemoglobin molecules per RBC
280 million
what % nitrogen is protein
16%
what is nitrogen crucial for ?
synthesis of hormones, etc
protein turnover is important for the synthesis of two things
protein and nitrogen containing compounds
what is the nitrogen equilibrium ?
intake (diet) + retention (protein turnover) = losses (in urine, feces, sweat)
a normal body will have what nitrogen balance ?
equilibrium
when will you find positive nitrogen balance ? (5)
pregnancy, lactation, resistance exercise, recovery from illness, growing children (building muscle tissue)
when will you find negative nitrogen balance ? (2)
starvation, emotional trauma
astronauts will have what kind of nitrogen balance ?
negative
through what process does the body use proteins for energy ?
deamination (using carbon skeleton of deaminated aa)
if you eat too much protein what happens ?
deamination and storage as fat
what are allergies and celiac disease responding to ?
proteins as pathogens
most children outgrow food allergies by what age
5
what is the pathology of celiac disease
damage to villi due to immune response to gluten.. villi atrophy leads to malabsorption of nutrients
what is non celiac gluten sensitivity?
develop symptoms when they consume gluten containing foods and feel better on gluten free diet but don’t have celiac
what is the EAR for protein ? what is the RDA ?
EAR 0.66 protein/kg BW
RDA 0.8 protein/kg BW
what is the goal of estimating the RDA of essential aa ?
positive nitrogen balance in kids, balance maintenance in adults
what is protein quality influenced by (2)
aa composition and protein digestibility
what is an incomplete protein
lacks 1+ essential aa and is poorly absorbed
how many essential aa do animal protein have
9
how many essential aa do legumes lack
at least 2
what is protein complementations
mixing incomplete plant based protein
grains are low in which 2 aa? high in which 2?
low in isoleucine and lysine
high in methionine and tryptophan
legumes low in which 2 aa? high in which 2?
high in isoleucine and lysine
low in methionine and tryptophan
why arent protein bars good ?
high in sugar
how is protein listed in nutrition facts ?
as amount in grams
how can you judge protein quality
by looking at ingredient list, for eggs and milk
