Transcript Fatty Acids

BIOL 2401-094
• Fundamentals of Anatomy and Physiology
• Chapter 2
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• (210) 643-8968
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2-9 Carbohydrates
Organic Molecules
• Contain H, C, and usually O
• Are covalently bonded
• Contain functional groups that determine chemistry
• Carbohydrates
Lipids
Proteins (or amino acids)
Nucleic acids
Grouping of atoms occurring repeatedly that influence the properties of any molecule they are in.
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2-9 Carbohydrates
• Carbohydrates
Contain carbon, hydrogen, and oxygen in a 1:2:1 ratio
• Monosaccharide — simple sugar
• Disaccharide — two sugars
• Polysaccharide — many sugars
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2-9 Carbohydrates
• Monosaccharides
• Simple sugars with 3 to 7 carbon atoms
• Glucose, fructose, galactose
• Disaccharides
• Two simple sugars condensed by dehydration
synthesis
• Sucrose, maltose
• Polysaccharides
• Many monosaccharides condensed by dehydration
synthesis
• Glycogen, starch, cellulose
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Carbohydrates
Isomers are molecules with the same types of and numbers of atoms—but different structure.
How many hydroxyl groups does a molecule of glucose have? How many carbon
atoms are part of glucose’s carbon skeleton?
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Figure 2-12a The Formation and Breakdown of Complex Sugars
Two monosaccharides joined together form a disaccharide. Add additional monosaccharides or
dissacharides, and you get polysaccharides.
They are formed in a process called dehydration synthesis (condensation). Water is released.
DEHYDRATION
SYNTHESIS
Glucose
Fructose
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Sucrose
Figure 2-12b The Formation and Breakdown of Complex Sugars
Hydrolysis reverses the steps of dehydration synthesis. A complex molecule is
broken down by the addition of water.
HYDROLYSIS
Sucrose
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Glucose
Fructose
Figure 2-13 The Structure of the Polysaccharide Glycogen (animal starch)
Glucose
molecules
Which body cells store glycogen?
Muscle Cells
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Table 2-4 Carbohydrates in the Body
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2-10 Lipids
• Lipids
• Mainly hydrophobic molecules such as fats, oils, and
waxes
• Made mostly of carbon and hydrogen atoms
• Include:
• Fatty acids
• Eicosanoids
• Glycerides
• Steroids
• Phospholipids and glycolipids
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2-10 Lipids
• Fatty Acids
• Long chains of carbon and hydrogen with a carboxyl
group (COOH) at one end
• Are relatively nonpolar, except the carboxyl group
• Fatty acids may be:
• Saturated with hydrogen (no covalent bonds)
• Unsaturated (one or more double bonds)
• Monounsaturated = one double bond
• Polyunsaturated = two or more double bonds
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Figure 2-14a Fatty Acids
Lauric acid (C12H24O2)
Lauric acid demonstrates two structural
characteristics common to all fatty acids: a
long chain of carbon atoms and a carboxyl
group (—COOH) at one end.
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Figure 2-14b Fatty Acids
Saturated
Unsaturated
Double Bond
A fatty acid is either saturated (has single
covalent bonds only) or unsaturated (has
one or more double covalent bonds). The
presence of a double bond causes a
sharp bend in the molecule.
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BIOL 2401
Something to Consider:
A diet containing large amounts of saturated fatty
acids has been shown to increase the risk of heart
disease and other cardiovascular problems.
The healthiest choices of unsaturated oils to use are
canola oils and olive oil.
Be careful of trans fatty acids (compounds from
polyunsaturated oils such are margarine) seem to
increase the risk of heart disease.
Foods high in omega-3 fatty acids (fish flesh and fish
oils) seem to reduce the risk of heart disease and
other inflammatory diseases. (rheumatoid arthritis).
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2-10 Lipids
•
Eicosanoids (Derived from the fatty acid called arachidonic acid)
• Leukotrienes –Active in the immune system
• Prostaglandins –Local hormones, short-chain fatty acids that produce
sensation of pain and in the uterus, help trigger labor contractions.
• Prostaglandins are called local hormones
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2-10 Lipids
•
Glycerides are fatty acids attached to a glycerol molecule
•
Monoglyceride (glycerol + one fatty acid)
•
Diglyceride (glycerol + two fatty acids)
•
Triglycerides are the three fatty-acid tails
•
Also called triacylglycerols or neutral fats
•
Have three important functions
1. Energy source
2. Insulation
3. Protection
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Figure 2-16 Triglyceride Formation
Glycerol
Fatty acids
Fatty Acid 1
Saturated
Fatty Acid 2
Saturated
Fatty Acid 3
Unsaturated
DEHYDRATION
SYNTHESIS
HYDROLYSIS
Breakdown
Formation
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Triglyceride
2-10 Lipids
• Steroids (large lipid molecules with a distinctive carbon framework)
• Four rings of carbon and hydrogen with an assortment of
functional groups
• Types of steroids:
• Cholesterol
• Component of plasma (cell) membranes
• Estrogens and testosterone
• Sex hormones
• Corticosteroids and calcitriol
• Metabolic regulation
• Bile salts
• Derived from steroids
What is the danger of a diet high in cholesterol?
The development of heart disease is the danger of high cholesterol
blood levels.
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Figure 2-17 Steroids
Cholesterol
Estrogen (females)
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Testosterone (males)
2-10 Lipids
• Phospholipids and Glycolipids
• Diglycerides attached to either a phosphate group
(phospholipid) or a sugar (glycolipid)
• Generally, both have hydrophilic heads and
hydrophobic tails and are structural lipids,
components of plasma (cell) membranes
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Which portion of a phospholipid is hydrophilic, and which portion is hydrophobic?
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Table 2-5 Representative Lipids and Their Functions in the Body
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2-11 Proteins
• Proteins
• Are the most abundant and important organic
molecules
• Contain basic elements
• Carbon (C), hydrogen (H), oxygen (O), and
nitrogen (N)
• Basic building blocks
• 20 amino acids
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2-11 Proteins
• Seven Major Protein Functions
1. Support
•
Structural proteins
2. Movement
•
Contractile proteins
3. Transport
•
Transport (carrier)
proteins
4. Buffering
•
Regulation of pH
5. Metabolic Regulation
•
Enzymes
6. Coordination and
Control
•
Hormones
7. Defense
•
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Antibodies
2-11 Proteins
•
Protein Structure
•
Long chains of amino acids
•
Five components of amino acid structure
1.
Central carbon atom
2.
Hydrogen atom
3.
Amino group (—NH2)
4.
Carboxyl group (—COOH)
5.
Variable side chain or R group
Hydrogen atom
Amino Acid
Central Carbon
Carboxyl Group
R group(variable side chain)
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2-11 Proteins
Hooking Amino Acids Together
• Requires a dehydration synthesis between:
• The amino group of one amino acid and the carboxyl group of
another amino acid
• Forms a peptide bond resulting in a peptide
Two amino acids – dipeptide
Three amino acids – tripeptide
Chain of amino acids - polypeptide
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Figure 2-20 The Fomation of Peptide Bonds
Peptide Bond Formation
Glycine (gly)
DEHYDRATION
SYNTHESIS
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Alanine (ala)
HYDROLYSIS
Peptide bond
BIOL 2401
Essential Amino Acids: Arginine Isoleucine
Histidine Leucine Methionine Lysine
Phenylalanine Tryptophan Threonine Valine
These cannot be made by the body and must be
obtained in the foods we eat.
Non-Essential Amino Acids: Alanine
Asparagine Aspartic Acid Cysteine Glutamic Acid
Cysteine Glutamine Glycine
These are made by the body.
Differentiate between essential amino acids and non-essential amino acids.
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2-11 Proteins
• Protein Shape
• Primary structure
• The sequence of amino acids along a polypeptide
• Secondary structure
• Hydrogen bonds form spirals or pleats
• Tertiary structure
• Secondary structure folds into a unique shape
• Quaternary structure
• Final protein shape — several tertiary structures together
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Figure 2-21 Protein Structure
A1
A3
A2
A5
A4
A7
A6
A8
A9
Primary
A2
A3
Linear chain of amino acids
A1
Hydrogen bond
Hydrogen
bond
A6
A2
A1
A3
A5
A4
A5
A9
A8
A7
A6
A11
A12
A13
A14
A10
A7
A9
Alpha-helix
OR
Secondary
Pleated sheet
OR
Heme units
Tertiary
Hemoglobin
(globular protein)
Keratin or collagen
(fibrous protein)
Do all proteins have a quaternary structure?
Quaternary
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2-11 Proteins
Classes of proteins are based on overall shape and properties.
•
Fibrous Proteins
• Structural sheets or strands
•
Globular Proteins
• Soluble spheres with active functions
• Protein function is based on shape
•
Shape is based on sequence of amino acids
•
20 amino acids can be linked in many combinations creating many
proteins of varied shape and function.
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2-11 Proteins
• Enzyme Function
• Enzymes are catalysts
• Proteins that lower the activation energy of a chemical
reaction
• Are not changed or used up in the reaction
• Enzymes also exhibit:
1. Specificity — will only work on limited types of
substrates
2. Saturation Limits — by their concentration
3. Regulation — by other cellular chemicals
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Figure 2-22 A Simplified View of Enzyme Structure and Function
Cofactors and Enzyme Function
Cofactor
An ion or molecule that binds to an enzyme before substrates can
bind -- Ca2+ Mg2+
Coenzyme
Non-protein organic cofactors (vitamins)
Isozymes
Two enzymes that can catalyze the same reaction
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2-11 Proteins
• Effects of Temperature and pH on Enzyme Function
• Denaturation
• Loss of shape (tertiary or quaternary) and function
(becomes non-functional)
• Due to heat (temperatures above 1100
pH (acidic or basic depending on enzyme)
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2-11 Proteins
• Glycoproteins and Proteoglycans
• Glycoproteins
• Large protein + small carbohydrate
• Includes enzymes, antibodies, hormones, and mucus
production
• Proteoglycans
• Large polysaccharides + polypeptides
• Promote viscosity
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2-12 Nucleic Acids
• Nucleic Acids
• Are large organic molecules, found in the nucleus, which store and
process information at the molecular level
• Deoxyribonucleic acid (DNA)
• Determines inherited characteristics
• Directs protein synthesis
• Controls enzyme production
• Controls metabolism
• Ribonucleic acid (RNA)
• Controls intermediate steps in protein synthesis
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2-12 Nucleic Acids
Structure of Nucleic Acids
DNA and RNA are strings of nucleotides
Nucleotides are the building blocks of DNA and RNA
Have three molecular parts
1.
A pentose sugar (deoxyribose or ribose)
2.
Phosphate group
3.
Nitrogenous base (A, G, T, C, or U)
Sugar
Phosphate Group
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Nitrogenous Base
Purines
Adenine
Guanine
Pyrimidines
Cytosine
Thymine
DNA only
Uracil
RNA only
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2-12 Nucleic Acids
• DNA and RNA
• DNA is double stranded, and the bases form hydrogen bonds to hold
the DNA together
• Sometimes RNA can bind to itself but is usually a single strand
• DNA forms a twisting double helix
• Complementary base pairs
• Purines pair with pyrimidines
• DNA
• Adenine (A) and thymine (T)
• Cytosine (C) and guanine (G)
• RNA
• Uracil (U) replaces thymine (T)
• Types of RNA
Messenger RNA (mRNA) Transfer RNA (tRNA) Ribosomal RNA (rRNA)
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Figure 2-24 The Structure of Nucleic Acids
Phosphate
group
Deoxyribose
Adenine
Thymine
Hydrogen bond
DNA strand 1
DNA strand 2
RNA molecule.
Which bases always pair with
each other?
A to T and G to C
Cytosine
DNA molecule.
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Guanine
Table 2-6 Comparison of RNA with DNA
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2-13 High-Energy Compounds
• Nucleotides Can Be Used to Store Energy
• Adenosine diphosphate (ADP)
• Two phosphate groups; di- = 2
• Adenosine triphosphate (ATP)
• Three phosphate groups; tri- = 3
• Phosphorylation
• Adding a phosphate group to ADP with a high-energy
bond to form the high-energy compound ATP
• Adenosine triphosphatase (ATPase)
• The enzyme that catalyzes the conversion of ATP to
ADP
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Figure 2-25 The Structure of ATP
Adenine
Ribose
Phosphate
Phosphate
Phosphate
High-energy bonds
Adenosine
Adenosine monophosphate (AMP)
Adenosine diphosphate (ADP)
Adenosine triphosphate (ATP)
Adenine
Phosphate groups
Ribose
Adenosine
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2-14 Chemicals and Cells
•
Chemicals and Cells
•
Biochemical building blocks form functional units called cells
•
Metabolic turnover lets your body grow, change, and adapt to new conditions
and activities
•
Your body recycles and renews all of its chemical components at intervals
ranging from minutes to years
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Table 2-7 Classes of Inorganic and Organic Compounds
Critical Thinking Question: During chemistry lab, Maria places sucrose (table sugar) in a glass
beaker, adds water and stirs. As the table sugar disappears, she loudly proclaims that she has
chemically broken down the sucrose into fructose and glucose. Is Maria’s chemical analysis
correct?
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