Download 8.1 Nutrients - R.F. Staples School

Unit D – Human systems
Chapter 8 – Nutrients, Enzymes and
the Digestive System
Text pages 240 - 279
Essential Nutrients
• Chemicals of life:
– Proteins (PRO)
• Structural components of the cells
•
– Carbohydrates (CHO)
• Main source of _______ for cells
• Structural material of plant cell walls
– Fats/lipids (FAT)
• Energy storage compound
• Structural component of cell membrane
Essential nutrients
– Vitamins and minerals
• Help in chemical reactions (ex. Coenzymes)
• Often found in complex chemicals
– Nucleic acids
• Genetic material that directs cell activity
• Made up of
Essential Nutrients
•
Food can be classified into three major
groups of nutrients:
1.
(CHO)
2.
(PRO)
3. Fats or lipids
8.1 - Essential Nutrients - Carbs
Carbohydrates:
• Primary fuel source for cells
• Carbohydrates contain C, H and O
• (C:H:O is a
ratio)
• ‘ose’ suffix.
• The human body is not able to make Carbs so
you rely on gaining carbs from your diet
• Classified by # of sugar units they have
– 3 types of sugar:
1. Monosaccharides –
1 sugar unit
2. Disaccharides –
2 sugar units
3. Polysaccharides –
many sugar units
8.1 - Essential Nutrients - Carbs
1. Monosaccharides (simple sugars)
• Examples:
• isomers... same molecular formula, different structural
arrangements.
a.
– energy source for cellular respiration,
soluble and easy to transport.
b.
– very sweet tasting, used to build more
complex molecules.
c. Galactose – not found ‘free’ in nature – always
bonded to another monosaccharide.
(Ex. lactose is glucose + galactose)
8.1 - Essential Nutrients - Carbs
2. Disaccharides:
• (double sugars)
• formed
by
dehydration
synthesis.
8.1 - Essential Nutrients
• Three disaccharides are:
1. Sucrose (sugar cane)
–
– (glucose + fructose)
2. Maltose (malt sugar)
– found in germinating barley
– (glucose +
)
3. Lactose (milk sugar)
– (glucose +
)
8.1 - Essential Nutrients
3.
•
•
•
•
•
Polysaccharides
Largest sugars
Also formed by dehydration synthesis.
These sugars are broken down by our digestive
system by hydrolysis into simple sugars and
then absorbed into the body.
Poly  di  mono (then absorbed)
8.1 - Essential Nutrients - Carbs
Polysaccharides: 3 types:
A. Starch:
– produced by plants
– Examples:
B. Cellulose: supplies ‘roughage’ because not
easily digested
– Examples:
C. Glycogen: extra glucose is converted into
glycogen for storage
8.1 - Essential Nutrients - Carbs
• Carbohydrates
• digested to simple
sugars
– absorbed in the
8.1 - Essential Nutrients - Lipids
• Lipids are made up of the same elements as
carbohydrates, but cannot be broken down into
H2O.
• Since fats are non-soluble in water, they cannot
be dissolved in the blood.
• What does bile do?
• Functions:
Lipids
– Storage of energy for when glycogen stores are
used up
– Components in cell membranes
–
–
– Raw materials for the synthesis of hormones
and other important chemicals
Lipids
1. Triglycerides – glycerol and 3 fatty acids
– If solid at room temp =
– Saturated fatty acids = only single bonds exist
between carbon atoms
– If liquid at room temp =
– Polyunsaturated = double bonds between
some of the carbon atoms in a fatty acid
– Which fats are easier to break down?
8.1 - Essential Nutrients -lipids
• Saturated fats:
– animal origin, solid at room temp.
– Examples:
• Unsaturated fats:
– plant origin, liquid at room temp.
– Examples:
• _____________: is hardening of the arteries
due to a build up of fat.
Lipids
2. Phospholipids – phosphate group bonded to
the glycerol backbone
–
3. Waxes – long-chain fatty acids joined to
long-chain alcohols or carbon rings
–
Phospholipids
Liposome
Proteins
• Used to form the structural parts of a cell
• Composed of building blocks called amino
acids
– Amino group (NH2)
– Carboxyl group (COOH)
– Different amino acids (AA) – the “R” group
– 20 AA to build from
Proteins
• Proteins are found as:
– Cytoplasmic organelles (mitochondria, ribosomes)
– Muscles
– Nerves
– Skin
– Hair
– Antibodies
– Enzymes
8.1 - Essential Nutrients - Proteins
Functions of Proteins:
a)
b) proteins are necessary for a healthy immune
system (enzymes, hormones)
c) regulate acid/base as protein acts as a buffer for
H+ concentrate.
Proteins
• The sequence of AA is determined by the
genes located on your chromosomes
• Joining AA involves removal of water and
formation of a peptide bond
• Chains of AA are called polypeptides
Protein Dehydration Synthesis
Source: http://img.sparknotes.com/content/testprep/bookimgs/sat2/biology/0003/peptide.gif
Proteins
• The body is able to synthesize many of the AA
if they are not found in the diet
• BUT, there are 8 AA, called essential amino
acids, that you can only get from food
• Structure:
Proteins
– The polypeptide chain(s) are folded into 3-D
shapes
–
– Four levels of protein structure:
•
•
•
•
Primary
Secondary
Tertiary
Quaternary
Proteins
Structure:
• Primary structure – the sequence of AA in the chain
• ____________– folds and coils that occur due to
hydrogen bonding (into helical coils or pleated
sheets)
• Tertiary structure –
• Quaternary structure – two or more polypeptides
joined together (ex. Hemoglobin is made up of 4
polypeptides)
Protein
Structure
Source: http://upload.wikimedia.org/wikipedia/en/thumb/a/a6/Protein-structure.png/300px-Protein-structure.png
Proteins
• Denaturation and Coagulation:
– Exposing a PRO to excess ______, ________ or a
change in pH will alter its ______
– Denaturation – the process that occurs when the
bonds of a protein molecule are disrupted causing
a TEMPORARY change in shape
• Alters their biological activity
– _________– the process that occurs when the
bonds of a protein molecule are disrupted causing
a PERMANENTchange in shape