, 10.1 - The Function of Digestion
The Digestive System: The system that breaks down intaken food in order absorb its nutrients
and egest the remainders
Fluid Compartments in the Human Body
- Composed mainly of water with different molecules and ions
- Water makes up 60%+ of our bodies
3 Main Fluid Compartments:
1. Cytoplasm: intercellular fluid
2. Fluid between cells: interstitial fluid
3. Fluid in the blood: plasma
An average adult has about 55L-63L of fluid in their body.
Functions of Water:
- Aids in diffusion (osmosis) to transport nutrients in and out of cells, lubrication
in joints, forms essential body fluids, thermoregulation, elimination of toxins and
waste
Inorganic vs. Organic Molecules
Inorganic molecules: Molecules and ions that may contain only C or H or neither atoms
(but C and H are never bonded together)
Organic molecules: Molecules containing multiple C, H, O, S or N atoms bonded
together
Macromolecules
- Many smaller organic molecules linked to form a larger complex molecule
- Provide energy, regulate cellular activities and build/repair tissues
- 4 Categories known as essential nutrients
- Essential Nutrient: A nutrient that cannot be made by the body and must
therefore be obtained from food
- When macromolecules are broken down, they release energy and supply raw
materials for cellular activities to maintain the body’s metabolism
- Metabolism: The sum total of all of the chemical reactions that occur in
an organism
4 Essential Nutrients (Macromolecules):
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic Acid
,Carbohydrates
Composition:
- Molecules that contain C, H, and O, in the proportion CnH2nOn
Function:
- Primarily used to provide short-term energy or long-term energy storage
Foods with carbohydrates:
- Bread, pasta, rice, cereal, fruits and vegetables
2 Main Types of Carbohydrates:
1. Simple Sugars
a. Monosaccharides
b. Disaccharides
2. Polysaccharides
Simple Sugars
- Simplest carbohydrates
- Soluble in water
1. Monosaccharides:
- Have 3-7 carbon atoms with corresponding numbers of hydroxyl (OH)
- Common monosaccharides: glucose, fructose, galactose
2. Disaccharides:
- [monosaccharide] + [monosaccharide] = [disaccharide]
- Common disaccharides:
- glucose + fructose = sucrose (table sugar)
- glucose + glucose = maltose (sugar in germinating grain)
- galactose + glucose = lactose (sugar in dairy products)
Polysaccharides
- A larger molecule made up of many linked monosaccharide molecules
- Insoluble in water
- Plants:
- Store starch for energy
- Also contain cellulose in cell walls
- Indigestible in humans, therefore prevents constipation
- !!! High in fiber = High in cellulose !!!
- Animals:
- Store glycogen for energy
- Glycogen: A polysaccharide made up of glucose units
- Some animals have a modified form of cellulose (chitin)
- Chitin is found as the hard exterior skeletons of insects,
crustaceans, fungi
- Used to make contact lenses and dissolvable stitches
Terms to describe polysaccharide structures:
, Lipids
Identification:
- Molecules that contain C, H, O; with higher proportion of H
Function:
- Used by animals as a major energy storage
- Stores 2.25 times more energy per gram than other macromolecules
Foods with carbohydrates:
- Oils, fats, waxes, phospholipids, steroids
Other:
- Insoluble in water but soluble in oils and other non-polar solvents
Starches
Composition:
- Steroids always have a 4 ring structure (ABCD)
Oils and Fats
- Composed of lipid molecules called triglycerides (TGs)
Composition:
Each triglyceride contains 4 subunits:
- 1 Glycerol (3 carbons each with a hydroxyl group)
- 3 Fatty acids (Long chains with a carboxyl group at one end)
The Digestive System: The system that breaks down intaken food in order absorb its nutrients
and egest the remainders
Fluid Compartments in the Human Body
- Composed mainly of water with different molecules and ions
- Water makes up 60%+ of our bodies
3 Main Fluid Compartments:
1. Cytoplasm: intercellular fluid
2. Fluid between cells: interstitial fluid
3. Fluid in the blood: plasma
An average adult has about 55L-63L of fluid in their body.
Functions of Water:
- Aids in diffusion (osmosis) to transport nutrients in and out of cells, lubrication
in joints, forms essential body fluids, thermoregulation, elimination of toxins and
waste
Inorganic vs. Organic Molecules
Inorganic molecules: Molecules and ions that may contain only C or H or neither atoms
(but C and H are never bonded together)
Organic molecules: Molecules containing multiple C, H, O, S or N atoms bonded
together
Macromolecules
- Many smaller organic molecules linked to form a larger complex molecule
- Provide energy, regulate cellular activities and build/repair tissues
- 4 Categories known as essential nutrients
- Essential Nutrient: A nutrient that cannot be made by the body and must
therefore be obtained from food
- When macromolecules are broken down, they release energy and supply raw
materials for cellular activities to maintain the body’s metabolism
- Metabolism: The sum total of all of the chemical reactions that occur in
an organism
4 Essential Nutrients (Macromolecules):
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic Acid
,Carbohydrates
Composition:
- Molecules that contain C, H, and O, in the proportion CnH2nOn
Function:
- Primarily used to provide short-term energy or long-term energy storage
Foods with carbohydrates:
- Bread, pasta, rice, cereal, fruits and vegetables
2 Main Types of Carbohydrates:
1. Simple Sugars
a. Monosaccharides
b. Disaccharides
2. Polysaccharides
Simple Sugars
- Simplest carbohydrates
- Soluble in water
1. Monosaccharides:
- Have 3-7 carbon atoms with corresponding numbers of hydroxyl (OH)
- Common monosaccharides: glucose, fructose, galactose
2. Disaccharides:
- [monosaccharide] + [monosaccharide] = [disaccharide]
- Common disaccharides:
- glucose + fructose = sucrose (table sugar)
- glucose + glucose = maltose (sugar in germinating grain)
- galactose + glucose = lactose (sugar in dairy products)
Polysaccharides
- A larger molecule made up of many linked monosaccharide molecules
- Insoluble in water
- Plants:
- Store starch for energy
- Also contain cellulose in cell walls
- Indigestible in humans, therefore prevents constipation
- !!! High in fiber = High in cellulose !!!
- Animals:
- Store glycogen for energy
- Glycogen: A polysaccharide made up of glucose units
- Some animals have a modified form of cellulose (chitin)
- Chitin is found as the hard exterior skeletons of insects,
crustaceans, fungi
- Used to make contact lenses and dissolvable stitches
Terms to describe polysaccharide structures:
, Lipids
Identification:
- Molecules that contain C, H, O; with higher proportion of H
Function:
- Used by animals as a major energy storage
- Stores 2.25 times more energy per gram than other macromolecules
Foods with carbohydrates:
- Oils, fats, waxes, phospholipids, steroids
Other:
- Insoluble in water but soluble in oils and other non-polar solvents
Starches
Composition:
- Steroids always have a 4 ring structure (ABCD)
Oils and Fats
- Composed of lipid molecules called triglycerides (TGs)
Composition:
Each triglyceride contains 4 subunits:
- 1 Glycerol (3 carbons each with a hydroxyl group)
- 3 Fatty acids (Long chains with a carboxyl group at one end)
