Vitamins Flashcards
are a group of chemically unrelated organic molecules that are needed in minute amounts for different physiological functions.
Vitamins
although organic compounds, do not provide energy like other macronutrients and are not used for the synthesis of structural compounds.
Vitamins
This vitamin was discovered by M. Mori in 1922 as a “fat-soluble factor” present in butter and fish oil, and he named it.
Vitamin A
The general term vitamin A includes several related compounds called?
retinol (alcohol), retinal (aldehyde), and retinoic
acid
is required in the diet of all animals.
Vitamin A
Vitamin A in the diet can be provided as a vitamin or through its precursor ? present in plants.
carotenoids
are the plant form of or the precursor of vitamin A
Carotenoids
There are two forms of carotenoids:
carotenes and xanthophylls.
have vitamin A activity.
carotenes (especially β-carotenes)
In the rods of the retina, retinal combines with a protein called
opsin to form?
rhodopsin
rhodopsin also called
visual purple
is light sensitive and enables the eye to adapt to changes in light intensity.
Rhodopsin
is a condition in humans and animals that is caused by vitamin A deficiency; it leads to dryness and irritation of the cornea and conjunctiva of the eye and results in cloudiness and infection.
Xerophthalmia
is also needed for normal skeletal and tooth development and reproductive processes.
Vitamin A
can function as antioxidants thereby protecting cells from oxidative stress and are also involved in modulating cell-mediated and humoral immune responses in animals.
Vitamin A and carotenoids
Upon reaching the microvilli, they are transferred to mucosal
cells, where they are reesterified and are incorporated into the chylomicrons and transported to the lymph for storage
in the liver as
retinyl esters
are split into two within the intestinal mucosal cells to form retinal and are reduced to form retinol.
Carotenoids
As a fat-soluble vitamin, long-term consumption of ? may lead to toxic symptoms
vitamin A
Skeletal abnormalities and thickening of the skin are reported with
hypervitaminosis
includes a group sterol compound that regulates calcium and phosphorus metabolism in the body.
Vitamin D
(vitamin D2, activated plant form)
ergocalciferol
(D3, activated animal form)
cholecalciferol
In the body, vitamin D3 is synthesized from cholesterol when it is converted to ? in the skin upon exposure to ultraviolet irradiation
7-dehydrocholesterol
To become active, it is transported from the skin to the liver, where it is hydroxylated to form?
25-hydroxycholecalciferol
This compound is transported through the blood to the kidneys, where it is further hydroxylated to form?
1,25hydroxycholecalciferol
work in conjunction with vitamin D in blood calcium homeostasis and bone calcification.
parathyroid hormones
are needed for proper absorption of calcium and phosphorus from the gut.
Calcium-binding proteins
A deficiency of vitamin D leads to impaired bone mineralization and abnormal skeletal development and results in a condition called ? in young animals
rickets
A deficiency of vitamin D leads to impaired bone mineralization and abnormal skeletal development and results in a condition called rickets in young animals and ? in growing animals.
osteomalacia
is a term that is used to describe a group of chemically related compounds called tocopherols and tocotrienols
Vitamin E
is the most active biological form of vitamin E and is the one that is added to animal diets
α-tocopherol
The function of ? in the body is to serve as a biological chain-breaking antioxidant and to protect cells and tissues from oxidative damage induced by free radicals and other lipid oxidation products.
vitamin E
prevents the oxidation of lipids by serving as a free radical scavenger and donates electrons from the hydroxyl group of the molecule
Vitamin E
causes damage to unsaturated lipids in cell membranes resulting in the disruption of the structural membrane and cell integrity.
Lipid peroxidation
Vitamin E also has a sparing action on the mineral ?, which is a cofactor for the enzyme glutathione peroxidase, which functions to reduce lipid peroxides.
selenium
Vitamin E deficiency can produce?
white muscle disease, exudative diathesis, and encephalomalacia.
is caused by the degeneration of skeletal and heart muscle fiber, which leads to rapid death due to heart failure.
White muscle disease
in chickens is caused by leaky capillaries in the breast muscle
Exudative diathesis
can only respond to vitamin E treatment.
encephalomalacia (crazy chick disease)
includes a group of compounds called the quinones.
Vitamin K
Vitamin K includes a group of compounds called the
quinones
Vitamin K1 is found in green plants
phylloquinones
Vitamin K1 is found in green plants (phylloquinones)
and vitamin K2 ? is synthesized by hindgut bacteria.
vitamin K2 (menaquinones)
converts vitamin K1 and K3 to K2 before it is used.
liver
The metabolically active form of vitamin K is?
menaquinones
is the most common version of vitamin K that is included in animal diets.
Menadione (vitamin K3, synthetic form)
Vitamin K is needed for the synthesis of ?, a blood-clotting protein.
prothrombin
Gastrointestinal bacterial can provide the needed vitamin K to most animals either through absorption from the hindgut
or through?
coprophagy
Certain coccidiostats containing ? can cause vitamin K deficiency as sulfa drugs are an antagonist of vitamin K.
sulfa drugs
Mold growing on weather-damaged sweet clover hay or silage contains ?, which is very similar to vitamin K in structure.
dicoumarol
is a competitive inhibitor of vitamin K.
Dicoumarol
Another antagonist of vitamin K is ?, a rat poison causing anticoagulation.
Warfarin
given in prolonged high doses produces anemia and other abnormalities in animals.
menadione
originally grouped together because of their similar metabolic functions.
B vitamins (also called B complex vitamins) are
consists of one molecule of pyrimidine joined with one of thiazole.
Thiamine
Thiamine is a component of the enzyme ?, which is involved in several key reactions in energy-producing pathways.
thiamin pyrophosphate (TPP)
is converted into TPP inside cells to participate in the energy-producing pathway.
Dietary thiamine
Due to its role in carbohydrate metabolism, an animals’ thiamine requirement is influenced by the level of ? in their diet.
carbohydrates
Thiamin also plays a specific role in neurophysiology because a typical thiamin deficiency is ?, a dysfunction in the nervous system.
beriberi
is another typical symptom of thiamin deficiency in chicks.
Polyneuritis
Raw fish and bracken ferns (a perennial) contain an enzyme ?, which destroys thiamin, causing a deficiency that causes a neurological disorder called Chastek paralysis, named after a farmer who observed similar condition in silver foxes.
thiaminase
Raw fish and bracken ferns (a perennial) contain an enzyme, thiaminase, which destroys thiamin, causing a deficiency
that causes a neurological disorder called ?, named after a farmer who observed similar condition in silver foxes.
Chastek paralysis
denatures thiaminase and prevents the problem.
Heat treatment
blocks activation of TPP and can cause a thiamine deficiency
Amprolium (coccidiostat)
is named for its yellow color (flavin) and sugar (ribose).
Riboflavin
functions in the body as a component of two different coenzymes: flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD).
Riboflavin
can cause lesions in the corners of the mouth and anorexia and can cause loss of hair and diarrhea in young animals.
Diets low in riboflavin
Niacin is the accepted generic description for
pyridine 3 carboxylic acid
is the accepted generic description for pyridine 3-carboxylic acid and its derivatives showing the nutritional activity of nicotinic acid.
Niacin
These coenzymes ( nicotinamide adenine dinucleotide (NAD) and NADPH ) serve as ? in several important metabolic processes involving carbohydrate metabolism (glycolysis) and other energy deriving pathways involving carbohydrates, fats, and proteins, such as the TCA cycle and oxidative phosphorylation.
hydrogen carriers
one of the bound forms of niacin in wheat is called ? and is not biologically available.
niacytin
Corn contains ?, which binds niacin tightly and makes it unavailable for absorption. Niacin from animal sources is highly available.
niacinogen
In addition to dietary sources, most animals (except cats) are capable of synthesizing niacin from the essential amino acid?
tryptophan
Niacin deficiency causes a condition called ? in dogs,
black tongue disease
Niacin deficiency in chickens, it causes poor feathering
around the eyes, also called?
spectacled eyes
comprises three different forms: pyridoxine (plant), pyridoxal (animal), and pyridoxamine (animal)
Pyridoxine
is also required for the synthesis of hemoglobin and the conversion of tryptophan to niacin.
Pyridoxal phosphate
occurs in all tissues of the body.
Pantothenic acid
was identified as a constituent of coenzyme A
Pantothenic acid
is required in the formation of two-C fragments from fats, amino acids, and carbohydrates for entry into the citric acid cycle and for the synthesis of steroids.
CoA
an abnormal gait, due to nerve degeneration.
goose-stepping
Feeding raw egg whites to rats causes skin lesions and loss of hair and were cured by a protective factor found in the
liver.
Biotin
was isolated from egg yolk in 1936, a growth factor for yeast.
Biotin
Biotin is a prosthetic group that binds to the lysine of the enzyme via a peptide bond to form biocytin, which serves as a cofactor in carboxylase reactions such as
acetyl CoA carboxylase carboxylase (the first step in lipogenesis) and pyruvate carboxylase (the first step in gluconeogenesis)
the antivitamin ? binds biotin and makes it unavailable for digestion and absorption
avidin
egg whites contain?
avidin
Lack of biotin has been shown to cause a condition called ? in chickens fed wheat-based diets.
footpad dermatitis
is a generic term used to describe folic acid and related compounds
Folacin
The active form of folacin in the body is called
tetrahydrofolic acid
Dietary sources of folacin are converted mainly in the liver to
tetrahydrofolic acid
enhances the conversion of folacin to tetrahydrofolic acid.
Vitamin B12
is required for purine, pyrimidine, glycine, serine, and creatine
synthesis.
Tetrahydrofolic acid
the last B vitamin, was discovered in 1948.
Cobalamin (Vitamin B12)
Vitamin B12 is unique in that it has a ? as its active site.
trace element mineral (cobalt)
provides the acidity and pepsin to release the tightly bound vitamin B12 from the dietary source.
stomach
also secretes an intrinsic factor, a specific binding glycoprotein.
stomach
is required for B12 absorption in the ileum
Calcium
is required only for ruminants; the rumen microbes will synthesize cobalamin.
Cobalt
It was discovered in 1747 that scurvy can be prevented by the ingestion of lemon juice.
Vitamin C
can be prevented by the ingestion of lemon juice.
scurvy
was recognized as a vitamin in 1933. Ascorbic acid has a structure closely related to monosaccharide sugars.
Ascorbic acid (Vitamin C)
is important for normal bone formation. It also functions as an antioxidant, reducing oxidative stress.
Collagen
a disease affecting humans with impaired wound healing, capillary bleeding, faulty bone formation, and anemia; it was first reported in sailors at sea.
scurvy
Normally, no Vitamin C deficiency symptom can be detected in
all mammals except
primates and guinea pigs
