Term
| What form of cysteine would you administer to someone with liver failure to help them increase glutathione levels? |
|
Definition
|
|
Term
| Which glucose transporter is sensitive to insulin? |
|
Definition
|
|
Term
| What is the equation for Glycemic Load? |
|
Definition
|
|
Term
| 5. Why is the effect of consuming 50g of carbohydrate as starch (white bread) or glucose on blood glucose concentrations basically the same? |
|
Definition
| White bread has no fiber and nothing to slow gastric emptying, so it gets absorbed just as fast as glucose does. |
|
|
Term
| Protein digestion begins in the stomach as a result of the secretion of two molecules; what are they, what cells secrete them, and how do they participate in protein digestion? |
|
Definition
Parietal cells secrete HCL - denatures proteins
Chief cells secrete Pepsinogen - endopeptidase cleaves proteins |
|
|
Term
| If one wanted to increase circulating SAM levels, what should they supplement with – methionine or SAM – and why? |
|
Definition
| SAM - because Methionine is used for repairing proteins within cells and is in high demand by other cells. It would be used before it could turn into SAM. |
|
|
Term
| Describe the digestion and absorption of dietary carbohydrates. |
|
Definition
| Salivary Amylase (breaks small amount of alpha-1-4 linkages). Pancreatic Amylase then further breaks them down. Brush boarder enzymes maltase, sucrase and latase break down disaccharides into monosaccharides. Glucose and Galactose get absorbed by the enterocytes via NA dependent active transport. Fructose goes through GLUT5. |
|
|
Term
| Name two molecules for which cholesterol is a precursor. |
|
Definition
| Vitamin D and Bile Salts. |
|
|
Term
|
Definition
| A disaccharide of 1-1 glucose linkage |
|
|
Term
| What do non-digestible oligosaccharides look like? |
|
Definition
| Sucrose + x (fructose, galactose, etc.) |
|
|
Term
| Differentiate between starch (amylose & amylopectin) and glycogen in terms of structure. |
|
Definition
Amylose is simple 1-4 a linkage w/ no branching
Amylopectin involves branches every 25-30 glucose molecules
Glycogen involves branches roughly every 10 glucose molecules |
|
|
Term
| What differentiates cellulose from hemicellulose? |
|
Definition
The average length of the molecule
Cellulose ~ 1000 units, is insoluble
Hemicellulose ~ 150 - 200 units, can be soluble or insoluble depending on the molecule |
|
|
Term
|
Definition
| A polysaccharide with phenol subunits |
|
|
Term
| True or false, gums are soluble and fermentable? |
|
Definition
|
|
Term
| What are the functions of the GI tract? (6) |
|
Definition
| Motility, Secretion, Digestion, Absorption, Elimination, Nutrient Absorption |
|
|
Term
| What transporter is used for both glucose and galactose in enterocytes? |
|
Definition
|
|
Term
| Where are glut2 transporters found and what specific function do they have? |
|
Definition
| They transfer glucose from enterocytes into the blood |
|
|
Term
| Where are glut5 transporters found and what are they responsible for? |
|
Definition
| In the intestines; fructose absorption |
|
|
Term
| What are the approximate lengths of the portions of the small intestine? |
|
Definition
| Duodenum ~10” to Jejunum 4-8’ to Ileum 5-10’ |
|
|
Term
| Roles of the large intestine (5) |
|
Definition
| Capacity to absorb water, sodium, potassium, short-chain fatty acids, vitamin K production |
|
|
Term
| Health benefits of non-starch polysaccharides (6) |
|
Definition
•Delayed gastric emptying of foods from stomach
•Decreased nutrient diffusion rate
•Increased fecal bulk (workout for intestines—helps to prevent diverticulosis)
•Increased substrate for gut bacteria
•Increased fecal bile acid excretion
•Decreased absorption of lipids |
|
|
Term
| What glycolysis step does excess fructose bypass when in abundance/excess? |
|
Definition
| Fructose bypasses PFK step |
|
|
Term
| Why are blood levels of galactose and fructose independent of absorption? |
|
Definition
| The liver removes galactose and fructose to keep them from going into circulation, and converts them into glucose byproducts that can be used by the liver |
|
|
Term
| Where are glut 2, 4, and 5 located? |
|
Definition
GLUT2: Kidney, Pancreatic B-cell, serosal surface of intestinal mucosa cells, liver
GLUT4: Brown & White Adipose Tissue, Skeletal Muscle, Heart Muscle (muscle & fat)
GLUT5: Intestinal epithelium, spermatozoa, kidney |
|
|
Term
| Why are protease enzymes secreted as zymogens that need to be cleaved in order to become active? |
|
Definition
| So they don't degrade the proteins found in our bodies, on our cells. |
|
|
Term
|
Definition
| = indispensable amino acid content in test food (mg/g protein) / content of same amino acid in reference protein (mg/g) |
|
|
Term
|
Definition
| A classification system that quantifies the impact of a dietary carbohydrate on the elevation of blood glucose levels relative to a reference food. Reflects ease of absorption. |
|
|
Term
| Carbohydrate and Fiber Recommended Intake Levels of Adults |
|
Definition
o 130 g/d for adults
Fiber:
o 25 g/d for women
o 38 g/d for men |
|
|
Term
| What are five consequences of a low-carb diet? |
|
Definition
Potential nutritional deficiencies
Bone mineral loss
Hypercholestemia
Low glycogen stores
ketosis |
|
|
Term
| What is the minimum Carbohydrate g/day recommendation based on? |
|
Definition
| 130 g/day is the average minimum to avoid ketosis |
|
|
Term
| What are the 5 protein classifications? |
|
Definition
• Enzymes
• Hormones
• Structural proteins
• Immunoproteins
• Transport |
|
|
Term
| What occurs in the stomach regarding protein digestion (3)? |
|
Definition
HCl - parietal cells, denatures proteins
Pepsinogen - chief cells, cleavage to form pepsin activated by HCl
Pepsin- endopeptidase, non-specific, pH<3.5 (cleaves NOT at the ends) results in AA's |
|
|
Term
| What cofactor do carboxypeptidases require, and where do they cleave? |
|
Definition
Require Zn
Are exopeptidases |
|
|
Term
| What protease enzymes do we need to know, and their sites of activity (6) |
|
Definition
Pepsin stomach
Trypsin intestine
Chymotrypsin intestine
carboxypeptidase intestine
Elastase intestine
Collagenase |
|
|
Term
| 3 general rules regarding AA rate of absorption |
|
Definition
BCAA > smaller AA
Neutral AA > basic or acidic AA
EAAs > dispensible AAs |
|
|
Term
| What four AA's are used by enterocytes for a variety of processes (4) and what are those processes? |
|
Definition
Glutamine, arginine, glutamate, and aspartate
used by enterocytes for energy, protein synthesis, glutathione synthesis, amino acid synthesis |
|
|
Term
| Define Essential Nutrient |
|
Definition
| A nutrient that the body cannot create and needs to consume |
|
|
Term
| What is the RDA for protein? What is the EAR for protein? |
|
Definition
EAR = 0.66g protein/kg/d
RDA = 0.8 g/kg/d |
|
|
Term
|
Definition
| The ability of a given amount of a particular protein to meet the body’s amino acid requirements |
|
|
Term
| What is complementarity or mutual supplementation for protein? |
|
Definition
| – Consuming certain protein containing foods together so that their separate amino acid limitations are eliminated |
|
|
Term
| What are the four sulfur containing -thiols? |
|
Definition
• Methionine
o Essential amino acid as sulfide (-S-CH3)
• S-adenosylmethionine
o Methyl group donor
• Cysteine
o Carbon skeleton from methionine
o Considered conditionally essential
• Glutathione
o Tripeptide antioxidant |
|
|
Term
| Practice Drawing Methylation Diagram from p. 3 on outline 4 |
|
Definition
-
SAM is a methyl donor, needed for synthesis of many molecules/compounds including creatine, epinephrine, carnitine, phospholipids, choline, DNA, and RNA
After methylation reactions are complete, product is S-adenosyl homocysteine which is hydrolyzed to homocysteine
Remethylation – homocysteine to methionine (methionine synthase or betaine Hcy-methyltransferase)
Transsulfuration – homocysteine to cysteine |
|
|
Term
| Name some of the things SAM is required for (6) |
|
Definition
| creatine, epinephrine, carnitine, phospholipids, choline, DNA & RNA |
|
|
Term
| What three ways/locations can transulfuration occur? |
|
Definition
Enterocytes and pancreatic cells can transulfurate
Alternate route using Betaine occurs in Liver |
|
|
Term
| What four functions does glutathione have? |
|
Definition
Antioxidant – independent antioxidant effects; serves as a substrate for an antioxidant enzyme; and can regenerate other antioxidants (vit c)
Detoxification – GSH is a substrate for glutathione-S-transferases. These enzymes form GSH conjugates to detoxify and increase the solubility of many endogenous and xenobiotic compounds including estrogen, prostaglandins, heavy metals, some drugs and pesticides.
Other function – transport of amino acids via the γ-glutamyl transpeptidases, and is involved in leukotriene and melanin synthesis.
Sulfur storage. |
|
|
Term
| Three conditions where glutathione becomes conditionally essential |
|
Definition
Requirement increases under conditions of oxidative stress
Synthesis increased with inflammation, ionizing radiation, heavy metals
Synthesis decreased with low protein diets |
|
|
Term
| Why would you not want to supplement in cysteine? |
|
Definition
| Cysteine is oxidized to insoluble disulfide form in stomach |
|
|
Term
| Name 4 uses for N-acetyl cysteine |
|
Definition
Used to treat acetaminophen toxicity
Other uses – bronchitis, heart disease, heavy metal poisoning |
|
|
Term
| Why is cysteine considered conditionally essential? When (life stage) might it be conditionally essential? |
|
Definition
Hepatic dysfunction or cirrhosis
Total parenteral nutrition
Premature infants
Growth Spurts? |
|
|
Term
| If you consumed a diet low in methionine but high in cysteine, what would happen? |
|
Definition
| less transsulfuration to cysteine |
|
|
Term
| What does Cystathionine B-synthase do? |
|
Definition
| Homocysteine --B6--> Cystathionine |
|
|
Term
| What are the fat digesting enzymes secreted by the mouth? What enzymes are secreted by the stomach? |
|
Definition
Lingual lipase - secreted in mouth activated in low pH of the stomach
Gastric lipase - secreted by the chief cells of the stomach and active in low pH of stomach |
|
|
Term
| Recreate Lipoprotein Picture from outline 5 page 4 |
|
Definition
|
|
Term
| What fat enzymes are secreted by the pancreas (2) and what are their functions? |
|
Definition
Lipase- forms monoglycerides and fatty acids and co-lipase
Colipase enables lipase to attach to lipid
Lipase hydrolyzes fatty acids in positions 1 and 3 |
|
|
Term
| What two roles does CCK have? |
|
Definition
Stimulates pancreas to release pancreatic lipase and colipase, phospholipases and cholesterol esterase
Stimulates the release of bile to help emulsify fat |
|
|
Term
| What do phospholipases do? |
|
Definition
| Hydrolyzes position 2 fatty acid |
|
|
Term
| What does Cholesterol esterase do? |
|
Definition
| Cleaves a fatty acid and cholesterol from a cholesterol ester |
|
|
Term
| Name the Lipoprotein Association and Function of Apo: A1, B48, B100, C1, C2, E |
|
Definition
-apo-A-I
Chylomicrons, HDL
major protein of HDL, activates LCAT
-apo-B-48
Chylomicrons
exclusively found in chylomicrons, derived from apo-B-100 gene by RNA editing in intestinal epithelium; lacks the LDL receptor-binding domain of apo-B-100
-apo-B-100
VLDL, IDL and LDL
major protein of LDL, binds to LDL receptor; one of the longest known proteins in humans
-apo-C-I
Chylomicrons, VLDL, IDL and HDL
may also activate LCAT
-apo-C-II
Chylomicrons, VLDL, IDL and HDL
activates lipoprotein lipase
-Apo-E
(at least 3 alleles [E2, E3, E4] each of which have multiple isoforms)
Chylomicron remnants, VLDL, IDL and HDL
binds to LDL receptor, apo-Ee-4 allele amplification associated with late-onset Alzheimer's disease |
|
|
Term
| Describe exogenous lipid transport/chylomicrons and their fate (7) |
|
Definition
Nascent chylomicron contains b-48 and A apolipoproteins
Apolipoproteins E and C are transferred to the chylomicron from HDL
Chylomicrons deliver the TAGs to other tissues other than the liver, particularly adipose and muscle
Adipose tissue and muscle cannot phosphorylate glycerol so transfers to the serum to be picked up by the liver or kidney
When much of the TAGs are transferred from the chylomicrons they become chylomicron remnants
The chylomicron remant transfers the apolipoproteins C back to HDL
The chylomicron remnant attaches to a liver binding site containing hepatic lipase, and the fatty acids, cholesterol, and cholesteryl esters are transferred to the liver |
|
|
Term
| Endogenous lipid transport/VLDL and their fate (6) |
|
Definition
Nascent VLDL are made in the Golgi
apparatus of the liver.
Additional apolipoproteins C and E are
transferred from HDL.
The fatty acids from triacylglycerols
(TAG) are hydrolyzed by lipoprotein
lipase found in adipose, aorta, heart,
spleen, etc. (non-hepatic tissue).
As the TAG is removed from the VLDL
the particle becomes smaller and
becomes an IDL.
Further loss of TAG and it becomes a LDL.
LDL are taken up by B-100 receptors
found in the liver and non-hepatic tissue. |
|
|
Term
| Reverse cholesterol transport (7) |
|
Definition
HDL is synthesized primarily in the liver with a lesser amount from the intestine. APO-E and APO-C are synthesized in the liver and added to HDL.
The nascent or discoidal HDL contains phospholipids (PL), cholesterol (C) and lecithin: cholesterol acyl transferase (LCAT).
Receptors of the adenosine triphosphate
(ATP)-binding cassette transporter family (ABCA1) transport cholesterol and PL to HDL unidirectionally.
Receptors of the scavenger receptor family (SR-B1) transfer the lipids bidirectionally.
As the HDL particle picks up PL and CE a
polar bilayer of PL is formed with a
non-polar core of C and CE.
The HDL spherical particle cycle in size and lipid content by transferring CE to the liver via SRB-1 site. PL is transferred to the liver and lysolecithin is transferred to albumin.
The life span of HDL is about 2 days and
during this time it actively works at the reverse transport of cholesterol to the liver for excretion via bile. |
|
|
Term
| What are the two essential fatty acid family starting points? |
|
Definition
linoleic acid 18:2n6
a-linolenic acid 18:3n3 |
|
|
Term
| What is the notation for arachidonic acid? y-linoleic acid? |
|
Definition
Arachidonic 20:4n6
y-linoleic 18:3n6 |
|
|
Term
| What is the only natural trans fatty acid? |
|
Definition
|
|
Term
| Which FA desaturases do mammals have and lack? |
|
Definition
have: Delta-9, delta-5 and delta-6
lack: delta-12 and delta-15 |
|
|
Term
| What do COX (2) enzymes yield? LOX enzymes? |
|
Definition
COX: prostaglandins (PG) and thromboxanes (TX)
LOX: leukotrienes (LT) |
|
|
Term
| Essential fatty acid precursors of eicosanoids (subtraction rule of eicosanoids) |
|
Definition
Dihomo-γ-linolenic acid (DHGLA, C20:3, n-6) is the precursor or the 1-series of PGs and 3-series of LTs
Arachadonic acid (C20:4, n-6) yields the 2-series of PGs and 4-series of LTs
EPA (C20:5, n-3) yields the 3-series of PGs and 5-series of LTs |
|
|
Term
|
Definition
| structure (cell membranes), precursor for eicosanoids (locally active hormones), emulsifiers, energy |
|
|
Term
|
Definition
| energy storage, insulation, protective cushion |
|
|
Term
|
Definition
Colipase enables lipase to attach to lipid
Lipase hydrolyzes fatty acids in positions 1 and 3 |
|
|
Term
| Risk factors for heart disease (the specific ones she gave us) |
|
Definition
High LDL cholesterol
Low HDL cholesterol
Hypertension
Family history
Obesity
Diabetes
Gender
Systemic inflammation
High fat diet
Smoking
Infectious agents
Inactivity / Sedentary lifestyle |
|
|
Term
| Name the four functions of PGs listed |
|
Definition
Smooth muscle cell contraction
Blood pressure regulation
Vasodilation
Platelet aggregation (some PGs reduce, some TXs increase) |
|
|
Term
|
Definition
Platelet aggregation (some PGs reduce, some TXs increase)
Vasoconstriction (TXs) |
|
|
Term
| What fat enzymes are inactive in premature infants? What does this result in? |
|
Definition
| Desaturases; results in an importance in the supplementation of EPA and DHA for optimum vision and learning |
|
|
Term
| Why would pancreatic lipase inhibition lead to weight loss? |
|
Definition
| People's ability to digest fats would go down, thus their calories would go down. |
|
|
Term
| Describe the process of atherosclerosis |
|
Definition
| LDLs that enter the tunica intima become oxidized, but oxLDL is cytotoxin, which activates endothelial cell immune response, which then causes monoctyes to enter tunica intima, differentiate to macrophages, and then look for the source of the problem, consume oxLDL but sometimes become overwhelmed and turn into foam cells. New/Additional Medial layer formed by an increase in and migration of smooth muscle cells to the intima (which are signaled to do so by cytokines), new layer then forms a fibrous cap of elastin, then the foam cells explodes and creates a necrotic core gruel (cereal), new foam cells being made degrade/eat the new elastin layer, then the endothelial tissue gets damaged and then platelet aggregation occurs because after the foam cells explode they become more active. |
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