Chapter 2&24: Lipids & Proteins
The All-orNone Rule
All amino acids must be present in sufficient amounts. If one is missing, the proteins cannot be synthesized.
Non-essential
amino acids that can be within the body
Essential amino acids
amino acids that cannot be made in the body and must be obtained through diet (8 essential a.a's)
Tertiary Proteins
globular proteins (functional proteins - have an active site) - A more complex structure, resulting from protein folding upon itself to form a ball-like structure. - Used for controlling the physiology/function examples: enzymes, antibodies.
Derived
used in regulation of bodily functions. - Steroids: cholesterol & sex steroids (testosterone & progesterone). - Prostaglandins - Body produces some on own Sources of lipid: primarily from meats, eggs, milk lard plant oils.
Triglycerides
Number of carbon atoms in tails is dependent on the type of fatty acid. Saturated: single bonds between carbon atoms. Sources: animal products, shellfish. Unsaturated: double bonds between carbon atoms. Sources: plant sources.
Proteins
Percent of body weight 17% Major Atoms: Carbon, Hydrogen, Oxygen and nitrogen. Atoms. Atoms make amino acids. Polymers of amino acids - joined by peptide bonds.
Lipids
Percent of body weight: 15-25% Average male: 15% Average female: 25%
Phospholipids have been used for cell membrane construction by all members of the cellular world. What special properties do these molecules have to explain this phenomenon?
Phospholipids have both polar and non polar ends. The polar ends interacts with water.
Properties of Water
Polar solvent properties dissolves and dissociates ionic substances body's major transport medium (polar means that there is a positive and negative charge)
A 64 year old man is admitted to the hospital for non-healing pressure ulcers to his heels. He has been bedridden for 10 years because of a degenerative muscle disease. Explain why protein would be important part of his diet to promote wound healing.
Protein is the basic scturaul material of the body. Protein regulates body processes. Skin, hair and eyes re made of protein, as are the enzymes needed for disgestion and absroption. Protein is essential for growht, maintence, and repair of tissue.
Amino Acids
Proteins are long chains of subunits (monomers) called amino acids. 20 different amino acids used to make proteins; however, about 300 different types
Protein Denaturation
Shape change and disruption of active sites due to environmental changes (decreased pH or increased temperature). Reversible in most cases, if normal conditions are restored. Irreversible if extreme changes damage the structure beyond repair.
Are saturated fats liquid at room temperature or solid?
Solid because of the single bonding, saturated fat can be straight and compact with one another.
Complete Protein
a protein source that contains all essential amino acids; meeting the bodies needs for all amino acids. -soy, kenoa
Incomplete Protein
a protein source that does not contain a high quantity of essential amino acids they are low in one or more of the essential amino acids.
Simple Lipid
Triglycerides: composed of three fatty acids bonded to glycerol molecule. Non-polar. Length of fatty acid chains and degree of saturation.
Primary Structure Protein
Unique amino acid and sequence The linear sequence of amino acids is the primary structure Backbone of the protein molecule
Compound
Used for making anatomical structures - Phospholipids and Lipoproteins.
Energy source/Reserve
-Energy Source/Reserve: fat is the ideal energy source because each molecule carries large quantities of energy per unit weight and is easily converted to energy.
Role of Lipid in the Body
-Like carbohydrates, lipids help spare protein. -Protection. -Insulation for the body/organs. -Vitamin Carriers - dietary fat serves as a carrier for 4 fat soluble vitamins: A, D, E, K. - Hunger Depressant - Major roles in cell structures (membranes/organelles)
Cell structure & function of protein
1) provide cell framework. a) structural proteins - secondary structure (fibrous proteins) b) functional proteins - tertiary structure (globular proteins) 2.) Regulate body functions a) acid-base balance b) muscular contraction c) protection 3.) Energy Source 4.) Catalyst for chemical reactions a) Enzymes- biological catalysts b) Not all proteins are enzymes but all enzymes are proteins (globular proteins)
Nucleic Acids
2% body weight. Major atoms: carbon, hydrogen, oxygen, nitrogen, and phosphorus. - Atoms makeup nucleotides - Nucleotides are the basic building blocks for making nucleic acids.
Recommended amount of lipid
80-100 grams 30% or less of total caloric intake
Triglycerides: trans fatty acid
A type of unsaturated fat. Most trans fat are industrially created. Unlike other fats, trans fats are neither required or beneficial for health. Eating trans fat increases the risk of coronary heart disease. - if 0.5 grams, they're allowed to say its trans-free.
Quaternary
Bonding between globular or fibrous proteins. - Results from 2 or more polypeptide chains grouped together to form a complex protein example: hemoglobin, 4 amino acid chains
Conditions associated with Proteins
Excesses - obesity Deficiencies - extreme weight loss, wasting, anemia, growth defects.
Conditions associated with lipids
Excesses: obesity, increased serum cholesterol & heart disease risk. Deficiencies: weight loss, poor growth, skin lesions, changes in menstruation.
Triglycerides: Omega-3 fatty acids
Family of polyunsaturated fatty acids which have in common a C=C double bond in the w-3 position. Omega-3 fatty acids, found naturally in cold water fish - appear to decrease the risk of heart disease and some inflammatory disease.
Secondary Protein
Fibrous proteins (usually) - Proteins twist and turn themselves to form a more complex structure. - used for building anatomical/structural components examples: collagen, keratin, elastin, actin, myosin.
Major atoms of lipids
carbon, hydrogen, and oxygen (proportion of oxygen is less than that found in CHO). - some contain phosphorus. - insoluble in water because they're non polar.
