nfs 3115 exam 1
Terms in this set (223)
AMDR for protein
AMDR for fat
AMDR for carb
high fructose corn syrup are made of what two monosaccharides
glucose and fructose
Glucose, fructose, and galactose
maltose, lactose, and sucrose
-maltose=glucose + glucose
-lactose=galactose + glucose
-sucrose=glucose + fructose
3-10 sugar units
raffinose, stachyose, verbacose
-verbacose=glucose + galactose + fructose
>10 sugar units
starch, glycogen, dietary fiber
glucose and galactose are __________ and fructose is a _______
Structures that have 2 or more chiral carbons with the same 4 groups attached but are not mirror images of each other
what determines D or L configuration of a carb?
highest numbered chiral carbon. If the OH group is on the right, then it is D configuration. If it is on the left, then it is L configuration
a molecule with n chiral carbons can have _____ stereoisomers
the conversion between alpha and beta configuration
how to distinguish between alpha and beta configuration
Alpha: the OH group on the C1 carbon is on the opposite side of the CH2OH group on the C6
Beta: the OH group on the C1 carbon is on the same side of the CH2OH group on the C6
What properties does a reducing sugar must exhibit?
Must have an anomeric carbon and exhibit mutarotation
Amylase is (branched or linear) molecule of glucose units bonded together by ____________ glycosidic bonds
linear; alpha-1,4 glycosidic bonds
What kind of bonds does amylopectin have and where do they occur? WHat kind of arrangement does an amylopectin molecule have?
Has both alpha-1,4 and alpha-1,6 glycosidic bonds. The alpha-1,6 bonds occur at branch points.
Highly branched arrangement
what enzyme is responsible for digestion of disaccharides and where is it active?
disaccharidases; active in microvilli of enterocytes
The salivary glands release ________ to hydrolyze alpha-1,4 glycosidic bonds in ___________ and ___________-
alpha-amylase; amylose and amylopectin
Most starches are ~80% __________
Which is easier to digest, amylopectin or amylose? why?
amylopectin because of all the branching except for 2 end sites because of folding
absorptive capacity of glucose
absorptive capacity of fructose
Which one is harder to digest, glucose or fructose?
Describe active transport of glucose/galactose into the enterocyte
Occurs by active transport. Na+ ATPase powered symport pumps both glucose and sodium into the cell through the cell membrane. Glucose gets transported into the bloodstream by GLUT2 and sodium gets into the bloodstream by Na/K ATPase and K is moved back into the cell from the blood
Describe factilitated transport of glucose/galactose into the enterocyte
Carried into the cell by GLUT2 when the intestinal lumen glucose levels are high. they also exit the cell by GLUT2
Describe transport of fructose
Factilitated transport by GLUT5 into the cell. It exits the cell by GLUT2
Conversion of galactose to glucose 1-phosphate proceeds through what sugar derivative?
how is UDP galactose formed?
when galactose 1-phosphate displace glucose 1-phosphate from UDP-glucose
what converts UDP galactose to UDP glucose?
how does UDP-glucose 4-epimerase convert UDP galactose to UDP glucose?
Oxidation of C-4 by NAD+ then reduction of C-4 by NADH which results in inversion of configuration at C-4
This enzyme catalyzes the phosphorylation of fructose to fructose 1-phosphate
fructokinase in liver (and kidney and intestine)
which enzyme is affected by fasting and insulin? and which is not? (fructokinase and glucokinase)
glucokinase is affected by fasting and insuline while fructokinase is not
why is fructose considered an 'instant triose'?
because it undergoes more rapid glycolysis in the liver than glucose because it bypasses the regulatory steps. This enhances fatty acid synthesis from the conversion of pyruvate to acetyl-CoA and glycerol from trioses
trioses of glycolysis
glycerol 3-phosphate, dihyroxyacetone phosphate, glyceraldehyde 3-phosphate
Describe the structure of the glucose transporter in the erythrocyte membrane
The transmembrane segments consist of mainly of hydrophobic amino acids. The loops on the extracellular and cytoplasmic sides are primarily hydrophilic
Major sites of expression for GLUT1
erythrocytes, central nervous system, blood brain barrier, placenta, fetal tissues
Major sites of expression for GLUT2
Liver, beta cells of pancreas, kidney, small intestine
Major sites of expression of GLUT3
brain, spermatozoa, placenta, preimplantation embryos
Major sites of expression of GLUT4
muscle, heart, brown and white adipocytes
Major sites of expression of GLUT5
intestine, kidney, brain, skeletal muscle, adipose tissue
which glucose transporter transports fructose, not glucose?
which glucose transporter is insulin dependent?
which GLUT is a high affinity transporter?
which GLUT is a low affinity transporter?
Static model of GLUT4
GLUT4 gets synthesized in the trans-Golgi network and remains in there in the absence of insulin. When there's insulin, GLUT4 gets moved to the plasma membrane
Dynamic model of GLUT4
There is constant movement of GLUT4 from the GSVs to the plasma membrane and back again. When there is insulin, more of the GLUT4 remains the membrane
Anabolic hormone that promotes storage of carbohydrates, lipids, and protein by increasing expression of enzymes that catalyze the synthesis of glycogen, lipids, and protein
Insulin receptors stimulate _________ pathway that phosphorylates _______ group of ________
tyrosine kinase; hydroxyl; tyrosine
Activated kinases in insulin pathway phosphorylates _______ and ________ to produce insulin receptor substrates
serine and threonine
Rate at which glucose is absorbed
Considers the actual amount of CHO in the food
Making of glycogen
breakdown of glycogen
oxidation of glucose
production of glucose from noncarbohydrate intermediates
production of 5-carbon monosaccharides and NADPH
hexose monophosphate shunt
oxidation of pyruvate and acetyl CoA
tricarboxylic acid cycle (TCA)
2 carbon rule
long chain fatty acids and ketogenic amino acids canot provide net carbons for glucose synthesis because they are broken down into 2 carbon units (acetyl CoA) and acetyl CoA does not get converted to pyruvate
3 carbon rule
glucogenic amino acids can contribute to net carbons for glucose synthesis because they break down to 3 (pyruvate, 4, 5, or 6 carbons (which are all part of the CAC intermediates)
Oxaloacetate can be converted to _________
propionyl-CoA can be converted to ___________ which can then be converted to _____________
How does D-methylmalonyl-CoA get converted to succinyl-CoA?
Undergoes epimerization of D to L-methylmalonyl-CoA followed by a switch of substituents on adjacent carbon atoms
Where is the origin of blood glucose in Phase I of glucose homeostasis?
when does the brain start adapting to using ketone bodies in glucose homeostasis?
Where is the origin of blood glucose in Phase II of glucose homeostasis?
mostly glycogen and some hepatic gluconeogenesis
where is the origin of blood glucose in phase III of glucose homeostasis?
mostly hepatic gluconeogenesis and some glycogen
Nondigestible CHO and lignin that are intact and intrinsic in plants
nondigestible CHO that are isolated, extracted, or manufactured and known to have physiological benefits in humans
Fiber that has beta 1-4 linked glucose units. Main component of plant cell walls. Common in food additives. Insoluble in water
This fiber is a heterogenous group of polysaccharide substances with sugars in the backbone and side chains. They have acids in the side chain to make it water soluble.
This fiber is found in the cell wall and middle lamella in plants. They are water soluble, gel forming, have a high ion binding potential, and are almost completely fermented by bacteria in large intestine. stable at low pH
food sources of pectins
citrus fruits, strawberries, apples, raspberries, legumes, nuts, some vegetables, and oat products
This fiber is an integral part of secondary cell walls of plants and algae. One of the most abundant organic polymers on earth. not considered a carbohydrate. Plays a crucial part in conducting water in plant stems
Highly fermentable fiber that gets secreted at site of plant injury by specialized secretory cells. Composed of a variety of sugars and derivatives
A commonly used functional fiber because of its effectiveness in serum cholesterol lowering and reduction in postprandial blood glucose. Water-soluble, highly fermentable and found in high amounts in cereal brans like oats and barley
sources of fructans
chicory, asparagus, onions, garlic, artichokes, tomates, bananas, wheat, barley, and rye
promote the growth and/or activity of beneficial bacteria by feeding them
starch that is not easy enzymatically digested and reaches the large intestine
which RS are dietary fibers?
RS1 and RS2
Which RS are functional fibers?
RS3 and RS4
Which RS is found in plant cell walls (whole grains)?
Which RS is found in ungelatinized starch granules ?
Which RS is retrograde starch from cooking then cooling or extruding foods?
Which RS is a chemically modified starch?
Type of fiber that is a modified polysaccharide that contains nitrogen. found in the exoskeleton of arthropods.
Chitosan is the __________ form of chitin
An alcohol containing multiple hydroxyl groups
polysaccharide of glucose and sorbitol units that have been polymerized at high temperatures. this is added to foods as a bulking agent or sugar substitute
Glucose polymers containing a 1-4 and a 1-6 glucosidic bonds and a 1-2 and a 1-3 bonds. Generated by treating cornstarch with heat and acid and then with amylase
Food sources of cellulose
all plant foods especially wheat bran, legumes, nuts, peas, root vegetables, vegetables of cabbage family, celery, broccoli, coverings of seeds, and apples
Food sources of hemicellulose
whole grains, especially bran, nuts, and legumes
food sources of lignin
whole grains, especially wheat bran, mature root vegetables, fruits with edible seeds, and broccoli (esp the stalk)
food sources of gums
oatmeal, barley, and legumes
food sources of beta glucans
oat products, barley, and some mushrooms
food sources of RS1
whole grains, partially milled grains and seeds
food sources of RS2
unripe bananas, legumes, raw potato, and high amylose cornstarch
food sources of RS3
rice, pasta, cold cooked potatoes, and high-amylose corn
Soluble fibers. Which are viscous?
Fructans, psyllium (v), beta glucans (v), pectins (v), gums (v), some hemicelluloses
Insoluble, non-viscous fibers
lignin, cellulose, and some hemicelluloses
Insoluble fibers can bind to water which causes......
increased fecal volume and decreased transit time which leads to an increased frequency of defecation
Insoluble fibers can be degraded/fermented to....
generate lactate and short chain fatty acids and to promote growth of good bacteria in the colon
Soluble fibers (increase/decrease) transit time and (increase/decrease) nutrient absorption
increase transit time (delays gastric emptying); decrease nutrient absorption
(fermentable/nonfermentable) fibers are prebiotics
recommended fiber intake for men age 19 to 50; >51 years?
38 g/day; 31 g/day
recommended fiber intake for women age 19 to 50; >51 years?
25 g/day; 21 g/day
recommended fiber intake for children age 1 to 3; 4 to 8?
recommended fiber intake for girls age 9 to 18
recommended fiber intake for boys age 9 to 13; 14 to 18?
enzyme that cleaves compounds
enzyme that transfers atoms in a molecule
enzyme that joins compounds
enzyme that transfers electrons
enzyme that moves functional groups
Structure of immunoglobulins
Y shaped with four polypeptide chains. Two chains are small and called light chains (L) and two are large and called heavy chains (H)
iron transport protein
a copper transport protein
protein that transport lipids
protein that transport oxygen and carbon dioxide
protein that complexes with retinol binding protein to transport retinol (vitamin A)
Proteins that contain oligosaccharide chains covalently attached to polypeptide side chains
List the functions of proteins
catalysts (enzymes), messengers, structural elements, immunoprotectors, transporters, buffers, fluid balancers, other roles (adhesion, signaling, receptors, storage)
proteins that are heavily glycosylated. Consists of a 'core protein' with one or more covalently attached glycosaminoglycan chain(s).
long unbranched polysaccharides consisting of a repeating disaccharide unit which consists of a hexose or hexuronic acid linked to a hexosamine
glycosaminoglycans or mucopolysaccharides
where can proteoglycans be found?
skin, bone, and cartilage
Disulfide bridges are formed when there is strong covalent bonding between ________ residues in _________ structure
General structure of an amino acid
Central C, a hydrogen, an amino group, a carboxy acid group, and a side chain
where is the alpha carbon in an amino acid
the central carbon
amino acids (accept/donate) hydrogens when the pH is too low
amino acids (accept/donate) hydrogens when the pH is too high
Amino acids with aliphatic side chains
glycine, alanine, valine, leucine, isoleucine
Amino acids with hydroxyl groups in their side chains
serine and threonine
Amino acids with side chains containing sulfur atoms
cysteine and methionine
Amino acids with side chains containing acidic groups or their amides
aspartic acid, glutamic acid, asparagine, glutamine
Amino acids with side chains containing basic groups
arginine, lysine, and histidine
amino acids with side chains containing aromatic ring
phenylalanine, tyrosine, tryptophan
Which amino acid is also known as an imino acid?
Negatively charged amino acids
aspartic acid, glutamic acid
Positively charged amino acids
arginine, histidine, and lysine
Polar amino acids
asparagine, cysteine, glutamine, serine, threonine, arginine, lysine, histidine, glutamate, aspartate
nonpolar amino acids
alanine, glycine, isoleucine, methionine, proline, valine, phneylalanine, tryptophan, tyrosine
Essential/indispensable amino acids
phenylalanine, valine, threonine, methionine, tryptophan, histidine, isoleucine, leucine, lysine
Conditionally indispensable amino acids
tyrosine, cysteine, proline, arginine, glutamine
what's the precursor for tyrosine?
what's the precursor for cysteine?
methionine and serine
what's the precursor for proline?
what's the precursor for arginine?
glutamine or glutamate, aspartate
what's the precursor for glutamine?
an amino acid that cannot be synthesized in the body and must be supplied in the diet
essential/indispensable amino acid
Synthesis of amino acids focuses on ___________ amino acids
glutamate is produced from ___________ and ____________ via _______________
alpha ketoglutarate and an alpha amino acid via transamination
branched chain amino acids
valine, leucine, isoleucine
what makes essential amino acids essential?
the carbon skeleton
alanine amino transferase catalyzes what reaction?
Alanine + alpha ketoglutarate --> pyruvate + glutamate
aspartate amino transferase catalyzes what reaction?
aspartate + alpha ketoglutarate --> oxaloacetate + glutamate
transfer of amino group from one amino acid to an amino acid carbon skeleton or alpha keto acid
All amino acids except..... can be synthesized from precursor carbon skeletons, making them truly essential amino acids because they do not participate in transamination
lysine, threonine, histidine, and tryptophan
Endogenous proteins come from where?
Desquamated mucosal cells
Digestive enzymes and glycoproteins
what digestive enzymes hydrolyzes peptide bonds of proteins in the stomach?
Trypsin, chymotrypsin, carboxypeptidases, proelastase, collagenase
Tripeptides are hydrolyzed or absorbed at ________
the brush border
Overview of protein digestion
1) Gastric cells release the hormone _________ to cause release of gastric juices
2) HCl in gastric juices denatures proteins and converts ______________ to ___________, which begins to digest proteins by hydrolyzing peptide bonds
3) Partially digested proteins enter SI and cause release of the hormones ___________ and __________
4) These hormones stimulate the pancreas to release pro-enzymes and __________ which neutralizes chyme
5) Pancreatic proenzymes are converted to ______________, which digest polypeptides into __________, _________, and free amino acids
6) Intestinal enzymes in the ___________ of the SI and within mucosal cells complete protein digestion
2) pepsinogen; pepsin
3) secretin and CCK
5) active enzymes; tripeptides; dipeptides
what transports di- and tripeptides across brush border membrane?
Explain sodium dependent transport of an amino acid into a cell
An extracellular sodium ion binds to the amino acid transporter which increases the carrier's affinity for the amino acid which then binds to the carrrier. A conformation change in the complex occurs and results in the delivery of the sodium and amino acid into the cytosol of the cell. Sodium gets pumped out of the cell and potassium into the cell by Na-K ATPase
Explain peptide transport by PEPT1
Peptides are transported into the intestinal cell along with H+. H+ is pumped back into the intestinal lumen in exchange for Na+. Na+ gets pumped back out in exchange for K+ by Na-K ATPase
All water soluble substances are transported into the ___________ and go to the _____________
portal blood; liver
6 membered rings with N in positions 1 and 3.
Uracil, cytosine, and thymine
2 fused rings with N in positions 1, 3, 7, 9
Adenine and guanine
Nitrogen containing nonprotein compounds
glutathione, carnitine, creatine, carnosine, choline
Where do the carbon and nitrogens come from in pyrimidines?
Carbons: from aspartate and carbon dioxide
Nitrogens: from aspartate and glutamine
Where do the carbons and nitrogens come from in purines?
Carbons: carbon dioxide, glycine, 10-formyl THF
Nitrogens: aspartate, glycine, glutamine
________ (fed state) and growth hormones promotes protein synthesis
_________ (fasting state) and stress hormones promote protein degradation
1) NH3 combines with CO2 or HCO3 to form (a)
2) (a) reacts with ornithine to form (b)
3) Aspartate reacts with (b) to form (c)
4) (c) is cleaved to form (d) and (e)
5) (f) is formed and ornithine is re-formed from cleavage of (d)
a) carbamoyl phosphate
what is the source of nitrogens in urea?
where does the urea cycle occur?
An increase in circulating ammonia to about 400 micrometers causes _________ and ___________. Normal ammonia concentration would be between ____ and ____ micrometers
alkalosis and neurotoxicity; 20-40
Urea and glutamine get rid of excess ________. E.g. bringing them to the kidney for excretion as ______ or ______
excess amino groups; urea or ammonia
Glutamine synthetase catalyzes what reaction?
glutamate --> glutamine
glutaminase catalyzes what reaction?
glutamine --> glutamate
What happens to threonine, lsine, tryptophan, and histidine if they do not get transaminated?
They can get converted by other methods to other amino acids that do get transaminated
-Threonine --> glycine
-Lysine --> glutamate
-Tryptophan --> alanine
-Histidine --> glutamate
Branched chain amino acids are oxidized as fuels primarily in the muscle, adipose, kidney, and brain tissue. Why?
These extrahepatic tissues contain an aminotransferase that's absent in the liver that acts on the BCAAs to produce the corresponding alpha keto acids which can go on and form acyl-CoA derivatives (acetoacetyl-CoA, acetyl-CoA, succinyl-CoA)
Describe glucose-alanine cycle in muscle and liver
Alanine serves as a carrier for ammonia and of the carbon skeleton of pyruvate from the skeletal muscle to the liver. The ammonia gets excreted and the pyruvate is used to make glucose by gluconeogenesis which gets returned to the muscle
Limiting amino acid of legumes
limiting amino acids of rice, corn, or other grain products
lysine, sometimes threonine and tryptophan
Protein RDA for adults
RDA for protein is based on
indispensable amino acids
Why is the RDA for athletes the same for non-athletes?
Individuals who were in nitrogen balance in their daily life went into negative nitrogen balance for almost 2 weeks after starting exercise, but after the initial 2 weeks, they could maintain nitrogen balance during training without increasing nitrogen intake
RDA is highest for which amino acid? lowest?
Which protein deficiency is characterized by having adequate energy with insufficient protein resulting in edema?
Which protein deficiency is characterized by wasting and emaciation due to chronic insufficiency of energy and protein?
concerned with the effects of gene variations on the organism's functional ability, specifically its ability to digest, absorb, and use food to sustain life
concerned with how bioactive components within food affect gene expression and function
Key enzyme in recycling reduced vitamin K and is important in gamme carboxlyation of vitamin K dependent coagulation factors, promoting blood clotting
Vitamin K epoxide reductase complex subunit 1 (VKORC1)
Disadvantage of nutrigenomics?
Food contains many compounds in highly varying amounts
Advantage of pharmacogenomics?
There's decades of research into drug doses and metabolism. Usually involves a single, highly purified compound in a defined chemical form and known amount
Nutrition and lifestyle changes usually may not affect highly penetrant single gene disorders, especially those _______________ for the allele. ___________ usually would be more responsive to diet and lifestyle changes
People with the SNP MTHFR have problems when the consume less than adequate ___________
What does A2756G (D919G) mean?
A to G transition at the base pair 2756 in the gene. D to G transition at the codon 919 in the protein
The variants E2, E3, and E4 are for what gene?
APOE (apoprotein E)
APOE is important for _______________ and its receptor
IDL (intermediate density lipoprotein)
People with at least one ______ allele have highest basal levels of lipids and respond best to a low fat diet to lower lipid levels; they do not respond to soluble fiber to lower serum lipids and do not respond to exercise to raise HDL
Those with one or more ____ allele have low LDL cholesterol, but high triglycerides and do not respond to a low fat diet. They respond to oat bran and other soluble fibers and fish oil and exercise to increase HDL
This is the primary protein in HDL
APOA1 (apoprotein A1)
Women with the ____ allele in APOA1 have their HDL drop if they increase polyunsaturated fat in the diet; they benefit from an increase in monounsaturated fat
Women with the ___ allele in APOA1 increase HDL with increases in dietary polyunsaturated fat
What is known as the "lipid transfer protein" as it transfers cholesterol ester from HDL to other lipoproteins
CETP (cholesterol ester transport protein)
People with 2 copies of the G allele in CETP tend to have low _____ and high elevated levels of _____ and ______
HDL; LDL and VLDL
With a variation (279G>A) in CETP gene, there tends to be increased _____ and lowered _____ and _____; these people respond to moderate alcohol consumption to increase HDL
HDL; LDL and VLDL
Two transcription factors that form a heterodimer
Retinoic acid receptor (RXR) and peroxisome proliferator activator receptor gamme (PPARgamma)
RXR binds a derivative of __________ and PPARgamma has dietary _________________ as a ligand
vitamin A; polyunsatruated fats
Enduring changes in gene expression that do not involve any change in DNA sequence. They may endure for varying times within a long lived cell, from cell to daughter cell during development, or sometimes from parent to offspring
a structural domain common to all core histones
HFD (histone fold domain)
____________ of H3 and H4 is associated with active chromatin, whereas _____________ is associated with inactive chromatin
what does H4K12ac mean?
Acetylation of lysine-12 of histone H4
In _____________, the nucleosomes are loosly packed with nucleosome-free regions that can bind regulatory proteins.
In ______________, the nucleosomes are densely packed and associated with heterochromatin protein 1 (HP1). Gene-poor, contains much reptitious DNA sequences, replicates late during S phase of cell cycle
________ and _________ needed for methyl group transfers
folate and choline
Resistant starch produces ___________
miRNAs and siRNAs
miRNA can be generated from _____________ or _____________
from its own gene or an intron from another gene
miRNA can prevent translation of a protein 'directly' by _______________
hybridizing to its mRNA
miRNA can prevent translation of a protein 'indirectly' by _____________________
hybridizing to mRNA for transcription factors for one or more protein steps preceding transcription of the final protein
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