Chemical Basis of Life Notes (1) PDF

Session Two - The Chemical Basis of Life IDENTIFY THE PRIMARY ELEMENTS COMPOSING THE HUMAN BODY. The primary elements include: OXYGEN / CARBON / HYDROGEN / NITROGEN CHON DISCUSS THE TERM TRACE ELEMENT. Definition = an element essential to nutrition or physiological processes / fo...

Session Two - The Chemical Basis of Life IDENTIFY THE PRIMARY ELEMENTS COMPOSING THE HUMAN BODY. The primary elements include: OXYGEN / CARBON / HYDROGEN / NITROGEN CHON DISCUSS THE TERM TRACE ELEMENT. Definition = an element essential to nutrition or physiological processes / found in such minute quantities that analysis would yield a presence of virtually nil amounts Many trace elements are part of enzymes or are essential for enzyme activation FLUORINE – a component of the fluoride component / often put in municipal water supply as a prevention to tooth decay / also part of some insecticides / strengthens bones and teeth IODINE – an essential micronutirent / 80% of the body’s iodine is found in the form of thyroglobulin / necessary to synthesize our thyroid hormones IRON – a metallic element essential for the synthesis of hemoglobin / the “heme” portion / also catalyzes the formation of Vitamin A / found primarily in the blood / also stored in liver / spleen / bone marrow Other examples of trace elements include; COBALT / TIN / ZINC EXPLAIN THE SIGNIFICANCE OF WATER IN THE HUMAN BODY. Water is the most abundant compound in the body 2/3 of our body weight 40 liters the major ingredient of our blood and body fluids survival depends of water / too much / too little upset homeostasis water needs to be available within the homeostatic range to maintain homeostasis IDENTIFY THE HOMEOSTATIC AMOUNT OF BODY WATER AND ITS DISTRIBUTION. Recall 2/3 and 40 liters Body fluids are distributed in compartments Within these compartments are varying degrees of “ingredients” Movement of water / electrolytes are regulated within these compartments so their distribution remains stable Two main compartments: INTRACELLULAR – all water / electrolytes enclosed by the cell membrane / 63% of all total body water Session Two - The Chemical Basis of Life EXTRACELLULAR – all fluid outside of the cell membrane / within the tissue spaces (interstitial fluid) / all fluid within the blood vessels (intravascular – plasma) / fluid within the lymphatic vessels ( lymph fluid) Another portion of extracellular fluid includes the small amounts of circulating fluids (CSF / aqueous humor / vitreous humor / synovial fluids / glandular secretions) Collectively ECF = 37% of all body fluids DISCUSS THE FUNCTIONS OF WATER. SOLVENT – median for chemical reactions REACTANT – an active participant in chemical reactions / hydrolysis TEMPERATURE CONTROL – absorbs heat which increases its temperature rapidly / transports heat to superficial blood vessels where heat is then lost via radiation TRANSPORT – major transport mechanism is blood which is 91% water / blood is responsible for transporting nutrients, gases, hormones, wastes, regulatory substances LUBRICANT – saliva helps us break down food in the mouth / organs are surrounded by a membrane that prevent them from “sticking to one another / all “tissue” cells are bathed in water (interstitial fluid) IDENTIFY THE PRIMARY SOURCE OF WATER INTAKE AND WATER LOSS. In order to have water balance what goes in must come out Intake = most water taken into the body is the result of taking in fluids by mouth or p.o. / 60% of all water intake The remainder comes from moist foods and the end product of metabolism Output = the largest source of water loss is through the kidneys Other sources include perspiration / stool Less obvious loss of water includes: diffusion / evaporation from the lungs during breathing Intake primarily is through beverages / 60% / usually about 1500 ml daily Secondary sources include metabolism and water from moist foods Output primarily is urine from the kidneys / 60% / usually about 1500 ml daily Other losses (sensible) include stool / perspiration DEFINE THE TERM INSENSIBLE WATER LOSS. Insensible refers to less obvious water loss that the body sustains Examples include evaporation from the skin and lungs Session Two - The Chemical Basis of Life EXPLAIN THE RELATIONSHIP BETWEEN WATER INTAKE AND WATER OUTPUT IN THE BODY. Intake must equal output DEFINE THE TERM ELECTROLYTE AND GIVE EXAMPLES. Water is seldom seen as a pure state Body water also has many substances in it Some substances “dissolve / dissociate” in water and produce ELECTROLYTES Examples include NaCl / salt and Na HCO3 / sodium bicarbonate or baking soda DEFINITION : a substance that ionizes in water / capable of conducting an electrical current Substances that do not dissociate readily (sugars / lipids) are called NON ELECTROLYTES DEFINE THE TERM ION AND DIFFERENTIATE BETWEEN ANIONS AND CATIONS. When electrolytes dissociate in water they form electrically charged particles or IONS Definition: an atom or a group of atoms with an electrical charge / either positive or negative Example: Na+ Cl- Valency When atoms bond together they attempt to achieve stability in the outer shell They gain / lose / share electrons during the bonding process Should an atom gain electrons it acquires a negative charge or becomes and anion / a negative ion If an atom loses an electron it becomes positively charged or becomes a cation / a positive ion IDENTIFY THE MAJOR CATIONS AND ANIONS FOUND IN THE BODY. CATIONS: Na is #1 / others include K / Ca / H ANIONS: Cl is #1 / others include HCO3 / OH / PO / SO IDENTIFY THE MAJOR FUNCTIONS OF SODIUM / POTASSIUM / CALCIUM. SODIUM Na+ Major extracellular cation Session Two - The Chemical Basis of Life Very important in water balance / conduction of nerve impulses / muscle contractions POTASSIUM K+ Necessary for nerve impulses / conduction of muscle contraction / cardiac function Ca+ Found as salts in bones and teeth Required for muscle contraction / nerve impulse conduction / blood clotting IDENTIFY THE PRIMARY ROUTE OF ELECTROLYTE INTAKE AND LOSS IN THE BODY. An electrolyte balance exists when the quantities of the various electrolytes gained by the body are equal to those lost INTAKE Primarily food Beverages Water secondary source a gain in electrolytes as a by product from metabolic reactions usually they are attained through hunger and thirst a deficiency can result in “cravings” OUTPUT Some lytes are lost through perspiration / quantity varies with the amount of “sweat” / increasing with warmer days and strenuous exercise Some loss occurs with stool / dependent on the quality and quantity of same The greatest electrolyte loss is renally IDENTIFY THE CHEMICAL COMPOSITION OF EXTRACELLULAR AND INTRACELLULAR FLUID. ECF contains from the most to the least is: Na / Cl / HCO3 / K / Ca / Mg / PO4 / SO4 ICF contains form the most to the least is: K / PO4 / Mg / SO4 / Na / Cl / HCO3 / Ca RECOGNIZE THE RELATIONSHIP BETWEEN WATER AND ELECTROLYTE BALANCE. Electrolytes are dissolved in water therefore their balance is interdependent DIFFERENTIATE BETWEEN ACIDS AND BASES. Recall what an electrolyte is Session Two - The Chemical Basis of Life Acids and bases are also are electrolytes They ionize / dissociate in water and can conduct an electrical current Some substances dissociate in water and specifically form hydrogen ions – ACIDS They also will release some anions during that chemical process If we look at the ionization of hydrochloric acid, the equation looks like this: HCl → H+ + Cl- other substances dissociate in water and form hydroxyl ions (OH-) and are called BASES if we look at the compound NaOH (sodium hydroxide) NaOH → Na + OH acid release hydrogen molecules bases release hydroxyl molecules DEFINE THE TERM pH. Continually we have reactions ongoing in our body Very often these reactions can be the result of hydrogen and hydroxyl ion concentration within our body fluids These reactions play a very important role in the regulation of BP and RR The amount of these ions in our body are measured in units called pH Definition of pH: the measurement of the hydrogen ion concentration used to indicate the acid or alkaline condition of a solution In the body we monitor the balance between hydrogen and hydroxyl ions / pH reflects the concentration of these ions DESCRIBE THE pH SCALE. Scale ranges from 0 → 14 7 is the midpoint where hydrogen ions and hydroxyl ions are equal in concentration if the concentration of hydrogen increases more than the hydroxyl ions and has a pH of less than 7 then the solution is acid if the concentration of hydrogen decreases and has a pH of greater then 7 then the solution is alkaline or base any small shift in pH reflect a significant change b/c there is tenfold difference between the numbers on the scale EXPLAIN THE RELATINSHIP BETWEEN ACIDS, BASES AND pH. Answered in previous outcome EXPLAIN WHY SMALL SHIFTS IN pH ARE SIGNIFICANT. Session Two - The Chemical Basis of Life Recall the tenfold difference Living cells are very sensitive to even the slightest shift changes in pH When pH changes more than a few tenths, death will likely ensure When pH decreases or blood becomes more acidic, the amount of oxygen that the blood can carry becomes dangerously low When our cells are deprived of oxygen they cannot make ATP which is the body’s source of energy IDENTIFY THE HOMEOSTATIC RANGE OF SERUM pH. 7.35 to 7.45 slightly alkaline EXPLAIN THE IMPORTANCE OF MAINTAINING SERUM pH. pH levels vary from place to place in the body recall that living cells are very sensitive to even the slightest changes in pH for us to survive it is imperative to maintain the pH of the blood within the normal homeostatic range recall that human blood is 7.35 to 7.45 / slightly alkaline if the pH drops below 7.4 than the blood is becoming acidotic if the pH rises above 7.4 than the blood is becoming alkalotic without medical intervention and if the pH is lower than 6.8 or higher that 8.0 then death would ensue fluctuation above or below normal affect the rate of metabolism IDENTIFY THE PRIMARY MACHANISM RESPONSIBLE FOR MAINTAINING pH. The # 1 defense the body has against shifts in serum pH is BUFFERS / chemical substances The # 2 mechanism that works to control pH is the lungs and the # 3 control is the renal system NAME THE MAIN BLOOD BUFFER SYSTEM. The main / #1 blood buffers are bicarbonate ions (HCO3) and carbonic acid (H2CO3) EXPLAIN HOW BUFFERS WORK. Definition: a substance that can react with a strong acid or base to form a weaker one Biochemical reactions are very sensitive to any changes in pH The homeostasis of our acid / base balance is imperative Recall the systems that are in place to maintain pH homeostasis BUFFERS are specific molecules work to resist sudden and large swings within the pH of our body fluids Session Two - The Chemical Basis of Life As our pH increases buffers release hydrogen ions and when the pH decreases buffers bind with hydrogen All of this is directed at maintaining the pH between the narrow limit of 7.35 – 7.45 To understand the concept of how buffers work it is important to understand what strong acids and bases are The acidity of a solution is directly related only the free hydrogen ions that are not bound to anions Acids that dissociate completely and irreversibly are called strong acids b/c of these free floating hydrogen ions they can dramatically change the pH of a solution Acids that do not dissociate completely do not release all their hydrogen ions are called weak acids Recall what a base is Should a base be added to a liquid hydroxyl ions would attract hydrogen ions This will attempt to decrease pH back within normal homeostatic levels Blood buffers are chemicals that are extremely effective in maintaining our pH on a second to second basis IDENTIFY THE TWO BODY SYSTEMS WHICH ASSIST IN THE MAINTENANCE OF SERUM pH. If blood buffers cannot maintain pH then there is a back up system The respiratory system (lungs) is the second line of defense The renal system (kidneys) is the third line of defense DESCRIBE THE STRUCTURE OF CARBOHYDRATES, LIPIDS. PROTEINS AND NUCLEIC ACIDS. Carbohydrates – CHO Contain carbon / hydrogen / oxygen Usually the H and O occur in the ratio of 2:1 2 hydrogen to 1 oxygen carbohydrate means hydrated carbon glucose = C6H12O6 they are classified according to their size and solubility monosaccharide / one sugar disaccharide / double sugar monosaccharide are the structural units the larger the molecule the less soluble the CHO is lipids fats have two types of building blocks fatty acids / glycerol also composed of C, H, O oxygen is in smaller proportions each glycerol molecule is combined with 3 fatty acids chains = triglyceride Session Two - The Chemical Basis of Life protein contains C, H, O and N (nitrogen) amino acids are the building blocks 20 different kinds of amino acids occurs commonly in proteins all amino acids contain an amine group (NH2) and an acid group (COOH) additionally amino acids contain another portion bonded to the basic structure creating each specific amino acid nucleic acids the most fundamental compounds of the cell DNA / RNA Play a vital role in cellular activities Make up genes which provide the blueprint for life Direct growth and development Dictates protein synthesis Contains C, O , H, N, phosphorus Building blocks are nucleotides Each contain a sugar / phosphate group and one of several organic bases Sugars – ribose (RNA) and deoxyribose (DNA) NAME THREE TYPES OF FAT. Triglycerides The building blocks of fat are a triglyceride which is a glycerol and 3 fatty acid chains In other fats the glycerol portion stays the same but the fatty acids vary creating different fats What differs is the length of the carbon chain and how they bond SATURATED FATS Single carbon - carbon bonds Each carbon atom is saturated with as many H atoms “happy” UNSATURATED Double bonds between the carbon atoms Creating opportunity for elements to rebond POLYUNSATURATED Many double carbon bonds Unsaturated fats are liquid at room temp (peanut / corn oils ) Saturated are solid at room temperature / animal fats / butter Phospholipids Similar in structure of lipids Glycerol / fatty acid chains with one fatty acid chain being replaced with a phosphate group Session Two - The Chemical Basis of Life Important building block of cellular structures Steroids Structure includes four rings of carbon Includes cholesterol, Vit D, bile, various hormones IDENTIFY THE PRIMARY SOURCE OF SATURATED FAT) AND UNSATURATED FAT AND EXPLAIN THEIR RELATIONSHIP TO CHOLESTEROL. Cholesterol is ingested with animal products ( eggs / meat / cheese ) Is known to play a role in the development of arteriosclerosis We need some cholesterol in our bodies for the structure of bile salts / steroid hormones / Vitamin D / plasma cell membranes 15% comes from our diet 85% is converted in the liver for our own needs serum levels are measured in: HDL – high density lipoproteins LDL – low density lipoproteins HDL are the good ones b/c they collect cholesterol for breakdown in the liver LDL tend to be deposited against the artery wall DIFFERENTIATE BETWEEN ESSENTIAL / NON ESSENTIAL AMINO ACIDS AND COMPLETE / INCOMPLETE PROTEINS. Proteins are digested to amino acids and absorbed into the circulatory system The venous blood from the digestive system circulates through the liver where amino acids are processed Whatever amino acids are remaining are left to continue to circulated with the blood to the body cells These cells quickly pick up these amino acids for their own use (protein synthesis) The cells take in as many amino acids as they can to maintain their own supply / “cellular greed” Cells need all 20 amino acids so they can build proteins 8 of these amino acids are termed “essential” meaning they cannot be made or synthesized by our body cells and must be ingested amino acids that can be synthesized by our body cells are called non essential amino acids there are two sources of non essential / diet / body production there is only one source of essential / diet all proteins are made up of both essential and non essential amino acids the amino acid pool must contain both types if protein synthesis is to take place body proteins have 2 primary functions they provide structural components of all body cells specialized functions / enzymes / hormones proteins are rated to their content Session Two - The Chemical Basis of Life foods containing all of the 8 essential amino acids are called complete proteins / animal proteins are complete proteins foods that contain only limited amounts of or improper amounts of the essential amino acids are called incomplete proteins and are often found in the plant group of foods vegetarians must be knowledgeable about what sources contain so the right combination can be ingested to make complete proteins EXPLAIN THE CONCEPT OF NITROGEN BALANCE. Usually in healthy adults the rate of protein synthesis = the rate of breakdown and loss The homeostasis of this is reflected in one’s nitrogen balance The body is said to be in nitrogen balance when the amount of protein ingested = the amount excreted in the stool / urine DIFFERENTIATE BETWEEN POSITIVE AND NEGATIVE NITROGEN BALANCE. Positive nitrogen balance is when protein synthesis is greater than the rate of breakdown and loss Growing children / pregnancy / tissues being rebuilt following illness or surgery A positive nitrogen balance always indicates that the amount of protein being incorporated into the tissues is greater than the amounts being broken down and used for energy Negative nitrogen balance indicates that the protein breakdown exceeds the use of protein for building structural or functional proteins People are likely to be in a negative nitrogen balance during physical or emotional stress / when dietary protein is poor or unavailable The tissues lose protein faster than it is replaced