ASC 389- Quiz 1

do all tissues require insulin for the uptake of glucose?

NO!! i.e. the brain and liver --> have another transporter than isn't insulin-dependent

what is Fructan?

a storage carbohydrate found in some plants, it is comprised mainly of fructose. -can vary in chain length, so may be found as an oligosaccharide or as a polysaccharide.

define carbohydrates

compounds consisting of carbon, hydrogen and oxygen; usually in a ratio of 1 carbon, 2 hydrogens, and 1 oxygen

what happens when insulin levels drop in the blood?

glycogen synthesis in the liver diminishes and enzymes responsible for breakdown of glycogen become active

What is a limiting amino acid & an example in some diets?

An amino acid found in the shortest supply relative to the amount needed for protein synthesis -Ex: lysine

Biotin: technical name/abbreviation, functions, and units of measure for requirements

(no other name or abbreviation) - Functions in carbohydrate, protein and fat metabolism, including skin and hooves. - Milligrams per day (but minimum requirement has not been established for horses)

why are fatty acids made? & where are fatty acids made & secreted?

-When the liver is saturated with glycogen, any additional glucose taken up by hepatocytes is shunted into pathways leading to synthesis of fatty acids -in liver & exported from the liver as lipoproteins.

other effects of insulin

-stimulates the uptake of amino acids, again contributing to its overall anabolic effect. -increases the permiability of many cells to potassium, magnesium and phosphate ions through the NA/K ATPases

Chloride: technical name/abbreviation, functions, and unit of measure for requirement

= Cl - Component of gastric acid as HCl. Plays a role in acid base and fluid balance, helping regulate blood pressure, sweating, muscle contraction, nerve impulse transmission etc. - Grams per day

forms of carbohydrates & examples

1) monosaccharides- i.e. glucose, fructose, galactose (all hexoses) & ribose (pentose; part of RNA) 2) disaccharides (2 carbs)- i.e. lactose (glu & gal), sucrose (glu & fru) 3) trisaccharide 4) oligosaccharides= 4-10 monosacccharides; i.e. fructan, which can also be poly- 5) polysaccharides= long chains of mono-; i.e. starch, cellulose, & glycogen 6) mixed carbs- i.e. hemicellulose

two types of fatty acids

1) short chain (2-4 Cs)= VFAs 2) long chain (<20 Cs) a. triglycerides b. PUFA (polyunsaturated fatty acids)= fatty acids with multiple double bonds; i.e. n-3 (omega-3) or n-6 fatty acids

insulin effects on glucose metabolism

1. Insulin facilitates entry of glucose into muscle, adipose and several other tissues. 2. Insulin stimulates the liver to store glucose in the form of glycogen 3. Insulin decreases the concentration of glucose in blood

Cobalt: technical name/abbreviation, functions, and unit of measure for requirement

= Co - Used by gastrointestinal microflora to synthesize vitamin B12. B12 has roles in energy and red blood cell metabolism. - Milligrams per day

Chromium: technical name/abbreviation, functions, and unit of measure for requirement

= Cr - Plays a role in carbohydrate metabolism - measurement unsure

effects of insulin on fat/lipid metabolism

1. Insulin promotes synthesis of fatty acids in the liver. 2. Insulin inhibits breakdown of fat in adipose tissue by inhibiting the intracellular lipase that hydrolyzes triglycerides to release fatty acids. (glycerol synthesized from glucose + fatty acids = triglycerides)

Vitamin C: technical name/abbreviation, functions, and units of measure for requirements

= Ascorbic acid -Plays a role in antioxidant reactions and synthesis of several important compounds including collagen. - Grams per day (but minimum requirement has not been established for horses)

Calcium: technical name/abbreviation, functions, and unit of measure for requirement

= Ca - Formation of bones and teeth. Involved in many aspects of physiology (muscle contraction, enzyme activation, blood clotting, nerve impulse transmission, acid base balance, etc.) - grams per day

Copper: technical name/abbreviation, functions, and unit of measure for requirement

= Cu (for Cupric) - Important in enzymes related to connective tissue synthesis and maintenance and plays a role in iron metabolism and other metabolic reactions - Milligrams per day

Vitamin D: technical name/abbreviation, functions, and units of measure for requirements

= Ergocalciferol (D2) or cholecalciferol (D3) - Once converted to its active form it plays a role in calcium metabolism and also has a role in cellular development. - IU per day (but horses may synthesize adequate amounts under many conditions)

Iron: technical name/abbreviation, functions, and unit of measure for requirement

= Fe (for Ferrous or Ferric) - Important in oxygen metabolism because of its role in hemoglobin in red blood cells and myoglobin in muscle cells. Also plays a role in numerous chemical reactions in the body - Milligrams per day

Flourine: technical name/abbreviation, functions, and unit of measure for requirement

= Fl - Plays a role in bone and teeth development - measurement unsure

Folate: technical name/abbreviation, functions, and units of measure for requirements

= Folic acid - Necessary for DNA synthesis and methionine synthesis - Milligrams per day (but minimum requirement has not been established for horses)

Iodine: technical name/abbreviation, functions, and unit of measure for requirement

= I - An important component of thyroid hormone which has many metabolic effects - Milligrams per day

Potassium: technical name/abbreviation, functions, and unit of measure for requirement

= K (for "kalium") - Plays a role in acid base and fluid balance, helping regulate blood pressure, sweating, muscle contraction, nerve impulse transmission, transport across membrane, etc. - Grams per day

Magnesium: technical name/abbreviation, functions, and unit of measure for requirement

= Mg - Plays a role in regulating energy metabolism, muscle contraction, protein synthesis, glucose metabolism, bone metabolism - Grams per day

Manganese: technical name/abbreviation, functions, and unit of measure for requirement

= Mn - Plays a role in metabolic reactions and maintenance of connective tissues. -Milligrams per day

Molybdenum: technical name/abbreviation, functions, and unit of measure for requirement

= Mo - Involved in some metabolic reactions - measurement unsure

Sodium: technical name/abbreviation, functions, and unit of measure for requirement

= Na (for natrium) - Plays a role in acid base and fluid balance, helping regulate blood pressure, sweating, muscle contraction, nerve impulse transmission , transport across membranes etc. - Grams per day

Niacin: technical name/abbreviation, functions, and units of measure for requirements

= Nicotinamide, nicotinic acid - Part of NAD and NADH which are essential to energy production and other essential cellular reactions. - Milligrams per day (but minimum requirement has not been established for horses)

Phosphorus: technical name/abbreviation, functions, and unit of measure for requirement

= P - Formation of bones and teeth. Important in cell membranes, DNA and high energy compounds used in metabolism (ATP, ADP etc) - Grams per day

Pantothenic acid: technical name/abbreviation, functions, and units of measure for requirements

= Pantothenate - Functions in energy metabolism - Milligrams per day (but minimum requirement has not been established)

Vitamin K: technical name/abbreviation, functions, and units of measure for requirements

= Phylloquinone (K1) or menaquinone (K2) - A cofactor in synthesis of proteins important for blood clotting, bone metabolism etc. - K1 occurs in plants, K2 is produced by gastrointestinal microbes. These sources are considered sufficient for most horses and additional vitamin K is not usually added to diets. **In horses fed normal diets, no vitamin K deficiency signs have ever been reported.

Vitamin A: technical name/abbreviation, functions, and units of measure for requirements

= Retinol - Important for skin integrity/maintenance, mucous membranes and night vision. Also plays a role in bone development and reproduction. - International units of activity per day. Horses can produce vitamin A from beta-carotene in feeds or vitamin A can be added to the diet

Sulfur: technical name/abbreviation, functions, and unit of measure for requirement

= S - Part of important amino acids, methionine and cysteine. Ivolved in many body tissues and structures including hoof, hair, cartilage. Also important for many enzymes important in normal physiology - Grams per day

Selenium: technical name/abbreviation, functions, and unit of measure for requirement

= Se - Plays a role in protecting cells from oxidative damage and is involved in thyroid hormone metabolism. **antioxidant** - Milligrams per day

Silicon: technical name/abbreviation, functions, and unit of measure for requirement

= Si - A component of bone and connective tissue - measurement unsure

Vitamin E: technical name/abbreviation, functions, and units of measure for requirements

= Tocopherol - Protects cells and cell membranes from oxidative damage and thus plays a role in many processes including immune function, muscle function etc. **antioxidant** - International units of activity or milligrams per day

Thiamin: technical name/abbreviation, functions, and units of measure for requirements

= Vitamin B-1 - A component of an important enzyme involved the conversion of carbohydrates to energy in cells. Important for all tissues including the central nervous system - Milligrams per day

Cyanocobalamin: technical name/abbreviation, functions, and units of measure for requirements

= Vitamin B-12 - Involved in numerous essential reactions in body including red blood cell metabolism , DNA and neural tissue maintenance - Micrograms per day but minimum requirement has not been established for horses)

Riboflavin: technical name/abbreviation, functions, and units of measure for requirements

= Vitamin B-2 - A precursor to co-enzymes important to energy metabolism, helps support antioxidant mechanisms . - Milligrams per day

Pyridoxine: technical name/abbreviation, functions, and units of measure for requirements

= Vitamin B-6 - Involved in many cell processes including energy and protein metabolism - Milligrams per day (but minimum requirement has not been established for horses)

Zinc: technical name/abbreviation, functions, and unit of measure for requirement

= Zn - Present in many enzymes involved in normal physiology including energy production, protein synthesis and immune function. - Milligrams per day

what are volatile fatty acids? & most common ones?

= short chain fatty acids contain 2 to 4 carbons - produced primarily from carbohydrates during microbial fermentation in the large intestine - most common: acetate (2 Cs), propionate (3 Cs) & butyrate (4 Cs)

How does the body store glucose?

A large fraction of glucose absorbed from the small intestine is immediately taken up by hepatocytes, which convert it into the storage polymer glycogen in the LIVER.

define amino acids

Amino acids consist of carbon, hydrogen, oxygen and an amino group (which contains nitrogen and hydrogen). - Some amino acids contain multiple amino groups && may contain some minerals as well. - Methionine contains sulfur. *essential (dispensable) or non-essential

Major/macro minerals & their unit of measure for requirement?

Ca, P, Na, K, Mg, S, Cl --> ALL in grams per day

insulin deficiency disease

Diabetes mellitus a. Type 1 or insulin-dependent diabetes (childhood; due to destruction pancreatic beta cells, most likely the result of autoimmunity to those cells) b. Type 2 or non-insulin-dependent diabetes (adulthood; insulin-resistance; controlled through dietary therapy and hypoglycemic agents but may later require insulin)

what is most important component in a horse's diet?

Carbohydrates- responsible for providing most of the dietary calories.

Trace or micro minerals, & are they essential nutrients that must be supplied in a horse's diet? Also what is their unit of measure for requirement?

Co, Cu, I, Fe, Mn, Se, Zn, & others (Cr, Fl, Si, Mo)--> ALL in "mg per day" but "others" which don't have a requirement (see below) **Others--> Although these minerals are found in the body, they may or may not be considered essential nutrients that must be supplied in the diet. Dietary requirements for horses have not been determined.

contents of lipids & how characterized

Fats also contain carbon, hydrogen and oxygen, but in different proportions than carbohydrates. Fatty acids are often characterized by the number of carbons, and the number and location of double bonds occurring between adjacent carbons.

What kind of effect does insulin have on the whole body?

From a whole body perspective, insulin has a fat-sparing effect. Not only does it drive most cells to preferentially oxidize carbohydrates instead of fatty acids for energy, insulin indirectly stimulates accumulation of fat in adipose tissue.

insulin excessive disease & why is it so dangerous?

Hyperinsulinemia= excessive insulin secretion -results from an insulin-secreting tumor (insulinoma) in the pancreas -due to accidental or deliberate injection of excessive insulin **bad b/c blood levels of glucose drop rapidly and the brain becomes starved for energy (insulin shock)

Fat soluble vitamins

Vitamins A, D, E, K

Phosphorylation substrate for insulin receptor & purpose

insulin receptor substrate 1 or IRS-1 --> serves as a type of docking center for recruitment and activation of other enzymes that ultimately mediate insulin's effects

what happens to insulin when blood glucose levels drop (2)? & what's the exception??

insulin secretion ceases. In the absense of insulin, a bulk of the cells in the body become unable to take up glucose, and begin a switch to using alternative fuels like fatty acids for energy. **exception: Neurons, require a constant supply of glucose, which in the short term, is provided from glycogen reserves. 2) glucagon is secreted

how does insulin stimulate glycogen synthesis, & how it decreases the blood concentration of glucose?

it activates the enzyme hexokinase, which phosphorylates glucose, trapping it within the cell. Coincidently, insulin acts to inhibit the activity of glucose-6-phosphatase. Insulin also activates several of the enzymes that are directly involved in glycogen synthesis, including phosphofructokinase and glycogen synthase.

where & what is glucose derived from?

liberated from dietary carbohydrate such as starch or sucrose by hydrolysis within the small intestine, and is then absorbed into the blood

can cellulose be digested by animals?

no, but some microbes can--> have enzyme cellulase

define "protein quality"

often used to describe the amount and balance of essential amino acids in the protein of a feedstuff. It may also include an assessment of the digestibility of the protein.

water soluble vitamins

thiamin, riboflavin, niacin, pyridoxine, pantheothenic acid, biotin, cyanocobalamin, folate, vitamin C

how does insulin facilitate entry of glucose into muscle, adipose, & other tissues?

through a family of hexose transporters like GLUT4 (for muscle) --> held in vesicles until needed & then recycled **the ONLY mechanism by which cells can take up glucose is by facilitated diffusion

composition of insulin receptor

two alpha subunits (extracellular) and two beta subunits (in mem. & intra-) linked by disulfide bonds

type of receptor & function: insulin

tyrosine kinase --> functions as an enzyme that transfers phosphate groups from ATP to tyrosine residues on intracellular target proteins