Chapter 39 – Nutrition, Digestion, and Absorption
Nutrition – process of consuming and using food and nutrients
Nutrient – any substance consumed by an animal that is needed for survival, growth,
development, tissue repair, or reproduction
All organisms require nutrients to survive
Animals Require Nutrients
Organic nutrients required
o Carbohydrates
o Proteins
o Lipids
o Nucleic acids
o Vitamins
Inorganic nutrients
o Water and minerals
Basic similarities in animal cells lead to basic similarities in nutrition
However, different animal physiologies can have different nutritional demands
o Herbivores – eat only plants
o Carnivores – consume animal flesh or fluids
o Omnivores – eat both plant and animal material
Ingested organic macromolecules are used for two general purposes
o To provide energy (used in synthesis of ATP)
o To make new molecules
All animals require the same fundamental organic macromolecules
Essential Nutrients
Certain compounds cannot be synthesized from any ingested or stored precursor
molecule – must be obtained in diet
Four groups
o Essential amino acids
8 required by many animals
isoleucine, leucine, lysine, methionine, phenylalanine, threonine,
tryptophan, and valine
cannot be synthesized by animal’s cells
are not stored
Carnivores and omnivores readily obtain all 8 in meat
Most plants do not contain every essential amino acid in sufficient
quantity
Most plant proteins are incomplete in amino acid makeup
So individuals who must eat only plant proteins need to eat a
variety to ensure that they get all the essential amino acids
o Essential fatty acids
Certain polyunsaturated fatty acids that cannot be synthesized by animal
cells
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, Linoleic acid is a vital precursor to arachidonic acid (prostaglandin)
Unsaturated fatty acids found primarily in plants
Strict carnivores obtain them from fish or adipose tissue of birds and
mammals
Important in oxygen transfer, hemoglobin production, and control of
nutrient transfer across cell membranes
Deficiency symptoms: stunted growth, hair loss, slow-to-heal wounds,
eczema-like skin eruptions
o Vitamins
Important organic nutrients that serve as coenzymes
Water-soluble vitamins – vitamin C – not stored
Fat-soluble vitamins – vitamin A – stored in adipose tissue
Not all animals require the same vitamins
Only primates and guinea pigs can’t synthesize vitamin C
Water Soluble Vitamins
Not stored in the body, must be replaced frequently
If in excess, excreted from body
Several are synthesized in the gut by intestinal flora but the
remaining ones must be obtained from diet
o E.g., vitamin C required for synthesis of collagen (fibrous
protein, integral component of connective tissue)
o Sources: citrus fruits, vegetables (broccoli, cabbage,
tomatoes, peppers)
Fat Soluble Vitamins
Vitamin A, E, K, D
The fat soluble vitamins are required by most vertebrate organisms
Invertebrates generally retain the ability to synthesize the
compounds although some invertebrates have dietary requirements
for A & E
Dietary fat is required for the absorption of fat soluble vitamins
The fat soluble vitamins can be stored in cells
The principle storage site for these vitamins is the liver
Vitamin A is a Carotene Derivative
Required for the formation of the light sensitive pigment,
rhodopsin
General health of epithelial cells
Growth of bones and teeth
Vitamin A deficiency results in:
o Night blindness (affects pigment in retina)
o Rough, dry skin
Vitamin D, a cholesterol derivative, activated in the presence of sunlight
Essential for the absorption and utilization of calcium and
phosphorus from the gut
This study source was downloaded by 100000837653068 from CourseHero.com on 01-21-2022 02:28:27 GMT -06:00
https://www.coursehero.com/file/21755184/Chapter-39-Nutrition/
Nutrition – process of consuming and using food and nutrients
Nutrient – any substance consumed by an animal that is needed for survival, growth,
development, tissue repair, or reproduction
All organisms require nutrients to survive
Animals Require Nutrients
Organic nutrients required
o Carbohydrates
o Proteins
o Lipids
o Nucleic acids
o Vitamins
Inorganic nutrients
o Water and minerals
Basic similarities in animal cells lead to basic similarities in nutrition
However, different animal physiologies can have different nutritional demands
o Herbivores – eat only plants
o Carnivores – consume animal flesh or fluids
o Omnivores – eat both plant and animal material
Ingested organic macromolecules are used for two general purposes
o To provide energy (used in synthesis of ATP)
o To make new molecules
All animals require the same fundamental organic macromolecules
Essential Nutrients
Certain compounds cannot be synthesized from any ingested or stored precursor
molecule – must be obtained in diet
Four groups
o Essential amino acids
8 required by many animals
isoleucine, leucine, lysine, methionine, phenylalanine, threonine,
tryptophan, and valine
cannot be synthesized by animal’s cells
are not stored
Carnivores and omnivores readily obtain all 8 in meat
Most plants do not contain every essential amino acid in sufficient
quantity
Most plant proteins are incomplete in amino acid makeup
So individuals who must eat only plant proteins need to eat a
variety to ensure that they get all the essential amino acids
o Essential fatty acids
Certain polyunsaturated fatty acids that cannot be synthesized by animal
cells
This study source was downloaded by 100000837653068 from CourseHero.com on 01-21-2022 02:28:27 GMT -06:00
https://www.coursehero.com/file/21755184/Chapter-39-Nutrition/
, Linoleic acid is a vital precursor to arachidonic acid (prostaglandin)
Unsaturated fatty acids found primarily in plants
Strict carnivores obtain them from fish or adipose tissue of birds and
mammals
Important in oxygen transfer, hemoglobin production, and control of
nutrient transfer across cell membranes
Deficiency symptoms: stunted growth, hair loss, slow-to-heal wounds,
eczema-like skin eruptions
o Vitamins
Important organic nutrients that serve as coenzymes
Water-soluble vitamins – vitamin C – not stored
Fat-soluble vitamins – vitamin A – stored in adipose tissue
Not all animals require the same vitamins
Only primates and guinea pigs can’t synthesize vitamin C
Water Soluble Vitamins
Not stored in the body, must be replaced frequently
If in excess, excreted from body
Several are synthesized in the gut by intestinal flora but the
remaining ones must be obtained from diet
o E.g., vitamin C required for synthesis of collagen (fibrous
protein, integral component of connective tissue)
o Sources: citrus fruits, vegetables (broccoli, cabbage,
tomatoes, peppers)
Fat Soluble Vitamins
Vitamin A, E, K, D
The fat soluble vitamins are required by most vertebrate organisms
Invertebrates generally retain the ability to synthesize the
compounds although some invertebrates have dietary requirements
for A & E
Dietary fat is required for the absorption of fat soluble vitamins
The fat soluble vitamins can be stored in cells
The principle storage site for these vitamins is the liver
Vitamin A is a Carotene Derivative
Required for the formation of the light sensitive pigment,
rhodopsin
General health of epithelial cells
Growth of bones and teeth
Vitamin A deficiency results in:
o Night blindness (affects pigment in retina)
o Rough, dry skin
Vitamin D, a cholesterol derivative, activated in the presence of sunlight
Essential for the absorption and utilization of calcium and
phosphorus from the gut
This study source was downloaded by 100000837653068 from CourseHero.com on 01-21-2022 02:28:27 GMT -06:00
https://www.coursehero.com/file/21755184/Chapter-39-Nutrition/
