AP LECTURE

Compare and contrast the major types of chemical reactions and discuss their importance.

A chemical reaction occurs whenever chemical bonds are formed, rearranged, or broken. Notice that in equations, a number written as a subscript indicates that the atoms are joined by chemical bonds. But a number written as a prefix denotes the number of unjoined atoms or molecules. All chemical reactions are potentially reversible. If chemical bonds can be made, they can be broken, and vice versa. Once chemical equilibrium is reached, there is no further net change in the amounts of reactants and products unless more of either are added to the mix. Product molecules are still formed and broken down, but the balance established when equilibrium was reached (such as greater numbers of product molecules) remains unchanged. Synthesis Reactions: Bond formation. A + B → AB. Anabolic reactions in which atoms or molecules combine and energy is absorbed for bond formation. Ie., Amino acids make proteins. Decomposition Reactions: AB → A+B. Catabolic reactions in which bonds break and chemical energy is released. Ie., Digestion, our body's process of breaking down food and using the nutrients for energy. Ie., Proteins are broken down into amino acids. Displacement/Exchange Reaction: Both synthesis and decomposition reactions. Bonds are both made and broken.Parts of the reactant molecules change partners, so to speak, producing different product molecules. AB+C → AC+B and AB+CD → AD+CB Energy Flow in Chemical Reactions: Because all chemical bonds represent stored chemical energy, all chemical reactions ultimately result in net absorption or release of energy. Reactions that release energy are exergonic reactions. These reactions yield products with less energy than the initial reactants, along with energy that can be harvested for other uses. With a few exceptions, catabolic and oxidative reactions are exergonic. In contrast, the products of energy-absorbing, or endergonic reactions contain more potential energy in their chemical bonds than did the reactants. Anabolic reactions are typically endergonic reactions. In the body, endergonic reactions are usually coupled to exergonic reactions. For example, the energy released when fuel molecules are broken down (oxidized) is captured in ATP molecules and then used to synthesize the complex biological molecules the body needs to sustain life.

Define homeostasis and explain its significance.

A dynamic state of equilibrium, or balance, in which internal conditions vary, but always within relatively narrow limits. In general, the body is in homeostasis when its needs are adequately met and it is functioning smoothly. Virtually every organ system plays a role in maintaining the constancy of the internal environment. Adequate blood levels of vital nutrients must be continuously present, and heart activity and blood pressure must be constantly monitored and adjusted so that the blood is propelled to all body tissues. Also, wastes must not be allowed to accumulate, and body temperature must be precisely controlled. A wide variety of chemical, thermal, and neural factors act and interact in complex ways.

Summarize the cell theory.

All living organisms are composed of cells.Cells are the most basic and smallest unit of life. Cells come from pre-existing cells. An organisms functions depend on the cells/group of collective cells functions. Biochemical activities of cells are dictated by their specific sub-cellular structures.

Explain why chemical reactions in the body are often irreversible.

Although all chemical reactions are reversible, many biological reactions show so little tendency to go in the reverse direction that they are irreversible for all practical purposes. Chemical reactions that release energy will not go in the opposite direction unless energy is put back into the system. For example, when our cells break down glucose during cellular respiration to yield carbon dioxide and water, some of the energy released is trapped in the bonds of ATP. Because the cells then use ATP's energy for various functions (and more glucose will be along with the next meal), this particular reaction is never reversed in our cells. Furthermore, if a product of a reaction is continuously removed from the reaction site, it is unavailable to take part in the reverse reaction. This situation occurs when the carbon dioxide that is released during glucose breakdown leaves the cell, enters the blood, and is eventually removed from the body by the lungs.

Predict the atomic structure of an atom and determine its stability.

Amount of electrons in valence shell greatly determines stability: Atoms with a full valence shell will be more stable and less reactive because they do not need to make bonds to form a full shell Atoms without a full valence shell will be more reactive and less stable because they want to form bonds to create a full valence shell

Use the Periodic Table to identify the number of protons, neutrons, electrons, atomic number, and atomic mass.

Atomic number = Protons = indirectly electrons Ex: 2He Mass Number= Protons + Neutrons 4He. Nearly all known elements have two or more structural variations called isotopes. Isotopes: have the same number of protons and electrons (and so have the same chemical properties), but they differ in the number of neutrons they contain. Carbon has several isotopes. The most abundant of these are 12C, 13C, and 14C. Each of the carbon isotopes has six protons (otherwise it would not be Carbon), but 12C has six neutrons, 13C has seven, 14C has eight. Isotopes can also be written with the mass number following the symbol: C-14, for example. Radioisotopes: The heavier isotopes of many elements are unstable, and their atoms decompose spontaneously into more stable forms. This process of atomic decay is called radioactivity, and isotopes that exhibit this behavior are called radioisotopes. The disintegration of a radioactive nucleus may be compared to a tiny explosion. It occurs when subatomic alpha (ɑ) particles (packets of 2p + 2n), beta (β) particles (electron-like particles), or gamma (𝛾) rays (electromagnetic energy) are ejected from the atomic nucleus. The important point is that the dense nuclear particles are composed of even smaller particles called quarks that associate in one way to form protons and in another way to form neutrons. The "glue" that holds these nuclear particles together is weaker in the heavier isotopes. When radioisotopes disintegrate, the element usually transforms into a different element. Radioactive isotopes share the same chemistry as their more stable isotopes, radioisotopes are valuable tools for biological research and medicine. Most radioisotopes used in the clinical setting are used for diagnosis, that is, to localize and illuminate damaged or cancerous tissues.All radioisotopes, regardless of the purpose for which they are used, damage living tissue, and they all gradually lose their radioactive behavior. The time required for a radioisotope to lose one-half of its activity is called its half-life. The half-lives of radioisotopes vary dramatically from hours to thousands of years. Alpha emission is easily blocked outside the body, but if absorbed, it causes considerable damage. Gamma emission has the greatest penetrating power. Radium-226, cobalt-60, and certain other radioisotopes that decay by gamma emission are used to destroy localized cancers. Contrary to what some believe, ionizing radiation does not damage organic molecules directly. Instead, it knocks electrons out of other atoms and sends them flying, like bowling balls smashing through pins all along their path. It is the electron's energy and the unstable molecules left behind that do the damage. Atomic Weight/Mass An average of the weights (mass numbers) of all the isotopes of an element, taking into account their relative abundance in nature. As a rule, the atomic weight of an element is approximately equal to the mass number of its most abundant isotope.

In order from simplest to most complex, the major levels of organization in the human organism.

Atoms Molecules Organelle Tissue Organ Organ System Organism

Use correct anatomical terms to describe body regions, planes, or sections.

Axial region: head, neck, and trunk. Appendicular region: limbs/extremities/appendages. Superior/inferior: above/below. Anterior/posterior: front/back. Medial/lateral: toward the midline/away from the midline. Cephalad (cranial)/caudal: toward the head/toward the tail. Ventral/dorsal: belly side/backside. Proximal/distal: nearer the trunk or attached end/farther from the trunk or point of attachment. Superficial (external)/deep (internal): toward or at the body surface/away from the body surface.

Cardiovascular System

Blood vessels transport blood, which carries oxygen, carbon dioxide, nutrients, wastes, etc. The heart pumps blood. Heart Blood vessels

Identify the monomer and polymer form(s) of each of the four major types of macromolecules.

Carbohydrates- Monomer: Monosaccharides: Glucose Fructose Galactose Deoxyribose Ribose Idek- Disaccharides: Sucrose = Glucose + Fructose Maltose = Glucose + Glucose Lactose = Glucose + Galactose Polymer- Polysaccharides: Starch Glycogen Lipids- Monomer: Glycerol & fatty acid chains Polymer: Triglyceride Proteins- Monomer: Amino acids. Polymer- Polypeptides Proteins Nucleic Acids-Monomer: Nucleotides Polymer: DNA& RNA

Describe the structure and function of the four major types of macromolecules and provide examples of each.

Carbohydrates: Carbohydrates, a group of molecules that includes sugars and starches, represent l-2% of cell mass. Carbohydrates contain carbon, hydrogen, and oxygen, and generally the hydrogen and oxygen atoms occur in the same 2: 1 ratio as in water. This ratio is reflected in the word carbohydrate ("hydrated carbon"). A carbohydrate can be classified according to size and solubility as a monosaccharide ("one sugar"), disaccharide ("two sugars"), or polysaccharide ("many sugars"). Monosaccharides are the monomers, or building blocks, of the other carbohydrates. In general, the larger the carbohydrate molecule, the less soluble it is in water. Monosaccharides: Monosaccharides, or simple sugars, are single-chain or single-ring structures containing from three to seven carbon atoms. Usually carbon, hydrogen, and oxygen atoms occur in the ratio 1:2:1, so a general formula for a monosaccharide is (CH2O)n where n is the number of carbons in the sugar. Glucose, for example, has six carbon atoms, and its molecular formula is C6H12O6. Ribose, with five carbons, is C5H10O5. Monosaccharides are named generically according to the number of carbon atoms they contain. Most important in the body are the pentose (five-carbon) and hexose (six-carbon) sugars. The pentose deoxyribose is part of DNA, and glucose, a hexose, is blood sugar. Two other hexoses, galactose and fructose, are isomers of glucose. That is, they have the same molecular formula (C6H12O6,), but their atoms are arranged differently, giving them different chemical properties. Disaccharide: A disaccharide,or double sugar, is formed when two monosaccharides are joined by dehydration synthesis. Important disaccharides in the diet are: Sucrose, which is cane or table sugar. Lactose, found in milk. Maltose, also called malt sugar. Disaccharides are too large to be transported through cell membranes, so they must be hydrolyzed to monosaccharides before the digestive tract can absorb them. A water molecule is added as each bond is broken, releasing monosaccharides that can be absorbed from the digestive tract into the blood. Polysaccharide: Polysaccharides are polymers of simple sugars linked together by dehydration synthesis. Because polysaccharides are large, fairly insoluble molecules, they are ideal storage products. Another consequence of their large size is that they lack the sweetness of the simple and double sugars. Only two polysaccharides are of major importance to the body: Starch and Glycogen. Both are polymers of glucose. Only their degree of branching differs. Starch is the storage carbohydrate formed by plants. The number of glucose units composing a starch molecule is high and variable. When we eat starchy foods such as grain products and potatoes, the starch must be digested for its glucose units to be absorbed. We are unable to digest cellulose, another polysaccharide of carbs found in all plant products. However, it is important in providing the bulk (one form of fiber) that helps move feces through the colon. Glycogen, the storage carbohydrate of animals tissues, is stored primarily in skeletal muscle and liver cells. Like starch, it is highly branched and is a very large molecule. Since each branch can be attacked by an enzyme, many glucose molecules can be released simultaneously when cells need glucose for fuel. Skeletal muscles use their glycogen for themselves, but liver cells use their stored glycogen to maintain blood sugar (glucose) levels. This allows the body's cells to get the fuel they need. Carbohydrate Functions: The major function of carbohydrates in the body is to provide a ready, easily used source of cellular fuel. Most cells can use only a few types of simple sugars, and glucose is at the top of the cellular "menu." As described in earlier discussion of oxidation-reduction reactions, glucose is broken down and oxidized within cells.During these reactions, electrons are transferred, releasing the bond energy stored in glucose. This energy is used to synthesize ATP. When ATP supplies are sufficient, dietary carbohydrates are converted to glycogen or fat and stored. Only small amounts of carbohydrates are used for structural purposes. For example, some sugars are found in our genes. Others are attached to the external surfaces of cells where they act as identity molecules to guide cellular interactions. Lipids: Lipids are insoluble in water but dissolve readily in other lipids and in organic solvents such as alcohol and ether. Like carbohydrates, all lipids contain carbon, hydrogen, and oxygen, but the proportion of oxygen in lipids is much lower. In addition, phosphorus is found in some of the more complex lipids. Lipids include triglycerides, phospholipids, steroids, and a number of other lipoid substances. Triglycerides: Triglycerides are commonly known as fats when solid or oils when liquid. Triglycerides are large molecules, often consisting of hundreds of atoms. They provide the body's most efficient and compact form of stored energy, and when they are oxidized, they yield large amounts of energy. A triglyceride is composed of two types of building blocks, fatty acids and glycerol, in a 3:I ratio of fatty acids to glycerol. Fatty acids are linear chains of carbon and hydrogen atoms (hydrocarbon chains) with an organic acid group (-COOH) at one end. Glycerol is a modified simple sugar (a sugar alcohol). Fat synthesis involves attaching three fatty acid chains to a single glycerol molecule by dehydration synthesis. The result is an E-shaped molecule. The glycerol backbone is the same in all triglycerides, but the fatty acid chains vary, resulting in different kinds of fats and oils. Their hydrocarbon chains make triglycerides nonpolar, molecules. Because polar and nonpolar molecules do not interact (oil and water do not mix), digestion and absorption of fats is complicated, and ingested fats and oils must be broken down into their building blocks. Triglycerides are found mainly beneath the skin, where they insulate the deeper body tissues from heat loss and protect them from mechanical trauma. The length of a triglyceride's fatty acid chains and their degree of saturation with H atoms determine how solid the molecule is at a given temperature. Fatty acid chains with only single covalent bonds between carbon atoms are referred to as saturated. Their fatty acid chains are straight and, at room temperature, the molecules of a saturated fat are packed closely together, forming a solid. Longer fatty acid chains and more saturated fatty acids are common in animal fats such as butter- fat and the fat of meat, which are solid at room temperature. Fatty acids that contain one or more double bonds between carbon atoms are said to be unsaturated. The double bonds cause the fatty acid chains to kink so that they cannot be packed closely enough to solidify. As a result, triglycerides with short fatty acid chains or unsaturated fatty acids are oils (liquid at room temperature) and are typical of plant lipids. Examples include olive and peanut oils (rich in monounsaturated fats) and corn, soybean, and safflower oils, which contain a high percentage of polyunsaturated fatty acids. Of the two types of fatty acids, the unsaturated variety, olive oil for example, is said to be more "heart healthy."Trans fats, common in many margarines and baked products, are oils that have been solidified by the addition of H atoms at sites of carbon double bonds. They increase the risk of heart disease even more than the solid animal fats. Conversely, the omega-3 fatty acids, found naturally in cold-water fish, appear to decrease the risk of heart disease and some inflammatory diseases. Phospholipids: Phospholipids are modified triglycerides. Specifically, they have two, rather than three, fatty acid chains. The third chain is replaced by a phosphate group (PO4) with an attached nitrogen-containing group. The two fatty acid "tails" make one end of the phospholipid molecule nonpolar and hydrophobic. These nonpolar tails interact only with other nonpolar molecules. The rest of the molecule, including the phosphate group, form the head- the polar, hydrophilic region of the molecule. The head interacts with other polar or charged particles, such as water or ions. Having both hydrophilic and hydrophobic ends makes phospholipids ideally suited to be the chief building material for cellular membranes. Steroids: Structurally, steroids differ quite a bit from fats and oils. Steroids are basically flat molecules made of four interlocking hydrocarbon rings. Like triglycerides, steroids are fat soluble and contain little oxygen. The single most important molecule in our steroid chemistry is cholesterol. We ingest cholesterol in animal products such as eggs, meat, and cheese, and our liver produces some. Cholesterol has a bad reputation because of its role in atherosclerosis, but it is essential for human life. Cholesterol is found in cell membranes and is the raw material for synthesis of vitamin D, steroid hormones, and bile salts. Although steroid hormones are present in the body in only small quantities, they are vital to homeostasis. Without sex hormones, reproduction would be impossible, and a total lack of the corticosteroids produced by the adrenal glands is fatal. Eicosanoids: The eicosanoids are diverse lipids chiefly derived from a 20-carbon fatty acid (arachidonic acid) found in all cell membranes. Particularly important are the prostaglandins, which play roles in various body processes including blood clotting, regulation of blood pressure, inflammation, and labor contractions. Their synthesis and inflammatory actions are blocked by NSAIDs (nonsteroidal anti-inflammatory drugs; e.g., ibuprofen). Proteins: Protein composes I0-30o/o of cell mass and is the basic struc- tural material of the body. However, not all proteins are con- struction materials. Many play vital roles in cell function. Proteins, which include enzymes (biological catalysts), hemo- globin of the blood, and contractile proteins of muscle, have the most varied functions of any molecules in the body. These and other selected roles of proteins are shown in Amino Acids and Peptide Bonds: The building blocks of proteins are molecules called amino acids, of which there are 20 common types. All amino acids have two important functional groups: a basic group called an amine group (-NH2) an organic acid group (-COOH). An amino acid may therefore act either as a base (proton acceptor) or an acid (proton donor). All amino acids are identical except for a single group of atoms called their R group .It is differences in the R group that make each amino acid chemically unique. All amino acids contain carbon, oxygen, hydrogen, and nitrogen, and two contain sulfur as well. Proteins are long chains of amino acids joined together by dehydration synthesis, with the acid end of one amino acid linked to the amine end of the next. The resulting bond produces a characteristic arrangement of linked atoms called a peptide bond. Two united amino acids form a dipeptide, three a tripeptide, and ten or more a polypeptide. Although polypeptides containing more than 50 amino acids are called proteins, most proteins are macromolecules containing from l00 to over l0,000 amino acids. Because each type of amino acid has distinct properties, the sequence in which they are bound together produces proteins that vary widely in both structure and function. We can think of the 20 run ino acids as a 20-letter "alphabet" used in specific combinations to form "words" (proteins). Just as a change in one letter can produce a word with an entirely different meaning, changes in the kinds or positions of amino acids can yield proteins with different functions or proteins that are nonfunctional. Nevertheless, there are thousands of different proteins in the body, each with distinct functional properties, and all constructed from different combinations of the 20 common amino acids. Structural Levels of Proteins: Proteins can be described in terms of four structural levels: Primary Secondary Tertiary Quaternary The linear sequence of amino acids composing the polypeptide chain is the primary structure of a protein. This structure, which resembles a strand of amino acid "beads," is the backbone of the protein molecule. Proteins do not normally exist as simple, linear chains of amino acids. Instead, they twist or bend upon themselves to form a more complex secondary structure. The most common type of secondary structure is the alpha (α)-helix, which resembles a coiled spring. The α-helix is formed by coiling the primary chain. It is stabilized by hydrogen bonds formed between NH and CO groups in amino acids in the primary chain that are about four amino acids apart. Hydrogen bonds in α-helices always link different parts of the same chain together. In another type of secondary structure, the beta (β)-pleated sheet, the primary polypeptide chains do not coil, but are linked side by side by hydrogen bonds to form a pleated, ribbonlike structure that resembles an accordion. Notice that in this type of secondary structure, the hydrogen bonds may link together different polypeptide chains as well as different parts of the same chain that has folded back on itself. A single polypeptide chain may exhibit both types of secondary structure at various places along its length. Many proteins have tertiary structure, the next higher level of complexity, which is superimposed on secondary structure and involves the amino acids' R-groups. Tertiary structure is achieved when α-helical or β-pleated regions of the polypeptide chain fold upon one another to produce a compact ball-like, or globular, molecule. Hydrophobic R groups are on the inside of the molecule and hydrophilic R groups are on its outside. Their interactions plus those reinforced by covalent and hydrogen bonds help to maintain the unique tertiary shape. When two or more polypeptide chains aggregate in a regular manner to form a complex protein, the protein has quaternary structure. The transthyretin molecule with its four identical globular subunits represents this level of structure (Transthyretin transports thyroid hormone in the blood.) Although a protein with tertiary or quaternary structure looks a bit like a clump of congealed pasta, the ultimate overall structure of any protein is very specific and is dictated by its primary structure. In other words, the types (hydrophilic versus hydrophobic) and relative positions of amino acids in the protein backbone determine the complex three-dimensional structure of the folded protein. Proteins fold so that hydrophilic amino acids are near the surface and hydrophobic amino acids are buried in the protein's core. Fibrous and Globular Proteins: The overall structure of a protein determines its biological function. In general, proteins are classified according to their overall appearance and shape as either fibrous or globular. Fibrous proteins, also known as structural proteins, form long strands. Some exhibit only secondary structure, but most have tertiary or even quaternary structure as well. For example, collagen is made of helical tropocollagen molecules packed together side by side to form a strong ropelike structure. Fibrous proteins are insoluble in water, and very stable-qualities ideal for providing mechanical support and tensile strength to the body's tissues. Besides structural proteins like collagen (the single most abundant protein in the body), the fibrous proteins include certain contractile proteins. Globular proteins, also called functional proteins, are compact, spherical proteins that have at least tertiary structure. Some also exhibit quaternary structure. The globular proteins are water-soluble, chemically active molecules, and they play crucial roles in virtually all biological processes. Some (anti-bodies) help to provide immunity, others (protein-based hor- mones) regulate growth and development, some are transport proteins, and still others (enzymes) are catalysts that oversee just about every chemical reaction in the body. Protein Denaturation: Fibrous proteins are stable, but globular proteins are quite the opposite. The activity of a protein depends on its specific three-dimensional structure. Intramolecular bonds, particularly hydrogen bonds, are important in maintaining that structure. However, hydrogen bonds are fragile and easily broken by many chemical and physical factors, such as excessive acidity or temperature. Although individual proteins vary in their sensitivity to environmental conditions, hydrogen bonds begin to break when the pH drops or the temperature rises above normal (physiological) levels. When this happens, proteins unfold and lose their specific three-dimensional shape. Such a protein is said to be denatured. The disruption is reversible in most cases, and the "scram- bled" protein regains its native structure when desirable condi- tions are restored. However, if the temperature or pH change is so extreme that protein structure is damaged beyond repair, the protein is irreversibly denatured. The coagulation of egg white (primarily albumin protein) that occurs when you boil or fry an egg is an example of irreversible protein denaturation. There is no way to restore the white, rubbery protein to its original translucent form. When globular proteins are denatured, they can no longer perform their physiological roles. For example, an enzyme's function depends on the presence of specific arrangements of atoms where catalytic activity occurs, called active sites. Active sites are regions that fit and interact chemically with other molecules of complementary shape and charge. Because atoms contributing to an active site in the folded protein may actually be far apart in the primary chain, disruption of intramolecular bonds separates them and destroys the active site. The globular transport protein hemoglobin becomes totally unable to bind and transport oxygen when blood pH is too acidic, because the structure needed for its function has been destroyed. One group of proteins, enzymes, is intimately involved in the normal functioning of all cells, so we will consider these incredibly complex molecules here. Nucleic Acids: The nucleic acids, composed of carbon, oxygen, hydrogen, nitrogen, and phosphorus, are the largest molecules in the body. The nucleic acids include two major classes of molecules, deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Roles of DNA & RNA: DNA and RNA have different roles in the cell. Typically, DNA is found in the nucleus (control center) of the cell, where it constitutes the genetic material, also called the genes, or more recently the genome. DNA has two fundamental roles: It replicates (reproduces) itself before a cell divides, ensuring that the genetic information in the descendant cells is identical and it provides the basic instructions for building every protein in the body. Although we have said that enzymes govern all chemical reactions, remember that enzymes, too, are proteins formed at the direction of DNA. By providing the information for protein synthesis, DNA determines what type of organism you will be and directs your growth and development. It also accounts for your uniqueness. DNA fingerprinting can help solve forensic mysteries, identify badly burned or mangled bodies after a disaster, and establish or disprove paternity. DNA fingerprinting analyzes tiny samples of DNA taken from blood, semen, or other body tissues and shows the results as a "genetic barcode" that distinguishes each of us from all others. RNA is located chiefly outside the nucleus and can be considered a "molecular slave" of DNA. That is, RNA carries out the orders for protein synthesis issued by DNA. [Viruses in which RNA (rather than DNA) is the genetic material are an exception to this generalization.] There are three major varieties of RNA (messenger RNA, ribosomal RNA, and transfer RNA) that are distinguished by their relative size and shape. Each has a specific role to play in carrying out DNA's instructions for protein synthesis. In addition to these three RNAs, there are several types of small RNA molecules, including microRNAs. Structure of DNA & RNA: The structural units of nucleic acids, called nucleotides, are quite complex. Each nucleotide consists of three components: A nitrogen-containing base. A pentose sugar. A phosphate group. The synthesis of a nucleotide involves the attachment of a base and a phosphate group to the pentose sugar. Five major varieties of nitrogen-containing bases can contribute to nucleotide structure: Adenine (A) Guanine (G) Cytosine © Thymine (T) Uracil (U) Adenine and guanine are large, two-ring bases (called purines), whereas cytosine, thymine, and uracil are smaller, single-ring bases (called pyrimidines). DNA is a long, double-stranded polymer, a double chain of nucleotides. The bases in DNA are A, G, C, and T, and its pentose sugar is deoxyribose. Its two nucleotide chains are held together by hydrogen bonds between the bases, so that a ladderlike molecule is formed. Alternating sugar and phosphate components of each chain form the backbones or "uprights" of the "ladder," and the joined bases form the "rungs." The whole molecule is coiled into a spiral staircase-like structure called a double helix. Bonding of the bases is very specific: A always bonds to T. G always bonds to C. A and T are therefore called complementary bases, as are C and G. RNA molecules are single strands of nucleotides. RNA bases include A, G, C, and U (U replaces the T found in DNA), and its sugar is ribose instead of deoxyribose.

Define and identify organic and inorganic compounds.

Chemicals in the body fall into one of two major classes: organic or inorganic compounds. Organic compounds: Contain carbon and are made by living things. All organic compounds are covalently bonded molecules, and many are large. Inorganic compounds: All other chemicals in the body are considered inorganic compounds. These include water, salts, and many acids and bases. (SALTS ELECTROLYTES) Are generally defined as compounds that lack carbon. Should be aware of a few exceptions to this generalization: Carbon dioxide and carbon monoxide, for example, contain carbon but are considered to be inorganic compounds. **Organic and inorganic compounds are equally essential for life.

Provide specific examples to demonstrate how organ systems respond to maintain homeostasis.

Communication is accomplished chiefly by the nervous and endocrine systems, which use neural electrical impulses or bloodborne hormones, respectively, as information carriers. Endocrine system: The endocrine system is equally important in maintaining homeostasis. A good example of a hormonal negative feedback mechanism is the control of blood sugar (glucose) by insulin. As blood sugar rises, receptors in the body sense this change, and the pancreas (the control center) secretes insulin into the blood. This change in turn prompts body cells to absorb more glucose, removing it from the bloodstream. As blood sugar falls, the stimulus for insulin release ends. Urinary system: Rids the body of waste and toxins, also directly involved in maintaining proper blood pressure. Kidneys play a role in storing the right water and salt content in the body, and red blood cell production (EPO- stimulates RBC production) Nervous system: Regulation of body temperature is only one of the many ways the nervous system maintains the constancy of the internal environment. Another type of neural control mechanism is seen in the withdrawal reflex mentioned earlier, in which the hand is jerked away from a painful stimulus such as broken glass.

Distinguish between a compound and a mixture.

Compound: When two or more different kinds of atoms bind, they form molecules.Compounds are chemically pure, and all of their molecules are identical.A molecule is the smallest particle of a compound that still has the specific characteristics of the compound. This concept is important because the properties of compounds are usually very different from those of the atoms they contain. Water, for example, is very different from the elements hydrogen and oxygen. Mixture: Substances composed of two or more components physically intermixed. Most matter in nature exists in the form of mixtures, but there are only three basic types: solutions, colloids, and suspensions.

Locate and name the major body cavities and their subdivisions and associated membranes, and list the major organs contained within them.

Dorsal body cavity: Cranial cavity: Contains the brain. Vertebral (spinal) cavity: Contains the spinal cord. Ventral body cavity: Thoracic cavity: Separated from the rest of the ventral cavity by the diaphragm. Heart and lungs protected by the rib cage. Abdominopelvic cavity: Superior abdominal cavity: Stomach, intestines, liver and other. Inferior pelvic cavity: Partially enclosed by the bony pelvis. Reproductive organs, bladder, and rectum.**The walls of the ventral body cavity and the outer surfaces of the organs it contains are covered with a very thin, double-layered membrane called the serosa or serous membrane. Space between parietal and visceral serosa is the cavity. Ie., pleural cavity. These membranes produce a thin lubricating fluid that allows the visceral organs to slide over one another or to rub against the body wall with minimal friction. Also, compartmentalize the various organs to prevent infection in one organ from spreading to others. Parietal serosa= part of the membrane lining the cavity walls Visceral serosa= covering the external surface of the organs within the cavity. Parietal/Visceral Peritoneum= abdominal cavity Parietal/Visceral Pleura= lungs Parietal/Visceral Pericardium= heart. Oral cavity: commonly called the mouth, contains the tongue and teeth. Continuous with the rest of the digestive tube, which opens to the exterior at the anus. Nasal cavity: located within and posterior to the nose, the nasal cavity is part of the passages of the respiratory system. Orbital cavities: house the eyes and present them in an anterior position. Middle ear cavities: each middle ear cavity lies just medial to an eardrum and is carved into the skull. These cavities contain tiny bones that transmit sound vibrations to the hearing receptors in the inner ears. Synovial cavities: are joint cavities-- enclosed within fibrous capsules that surround the freely moveable joints of the body, such as the vertebrae and the knee and hip joints. Like the serous membranes of the ventral body cavity, the membranes lining the synovial cavities secrete a lubricating fluid that reduces friction as the encloses structures move across one another.

Discuss how enzymes function as molecular catalysts.

Enzymes: Enzymes are globular proteins that act as biological catalysts. Catalysts are substances that regulate and accelerate the rate of biochemical reactions but are not used up or changed in those reactions. More specifically, enzymes can be thought of as chemical traffic cops that keep our metabolic pathways flowing. Enzymes cannot force chemical reactions to occur between molecules that would not otherwise react. They can only increase the speed of reaction, and they do so by staggering amounts. Without enzymes, biochemical reactions proceed so slowly that for practical purposes they do not occur at alI. Characteristics of Enzymes: Some enzymes are purely protein. In other cases, the functional enzyme consists of two parts: an apoenzyme (the protein portion). and a cofactor. Together, these two parts form a holoenzyme. Depending on the enzyme, the cofactor may be an ion of a metal element such as copper or iron, or an organic molecule needed to assist the reaction in some way. Most organic cofactors are derived from vitamins (especially the B complex vitamins). In this case the type of cofactor is more precisely called a coenzyme. Each enzyme is chemically specific. Sorne enzymes control only a single chemical reaction. Others can regulate a small group of related reactions by binding with molecules that differ only slightly. The substance on which an enzyme acts is called a substrate. As mentioned earlier, catalytic activity occurs at the active site. The presence of specific enzymes determines not only which reactions will be speeded up, but also which reactions will occur, no enzyme no reaction. This also means that unwanted or unnecessary chemical reactions do not occur. Most enzymes are named for the type of reaction they catalyze. Hydrolases add water during hydrolysis reactions and oxidases oxidize reactants by adding oxygen or removing hydrogen. In many cases, enzymes are part of cellular membranes.They are often grouped together so that the product of one enzyme-catalyzed reaction becomes the substrate of the neighboring enzyme, and so on. Some enzymes are produced in an inactive form and must be activated in some way before they can function, often by a change in the pH of their surroundings.For example, digestive enzymes produced in the pancreas are activated in the small intestine, where they actually do their work. If they were produced in active form, the pancreas would digest itself. Sometimes, enzymes are inactivated immediately after they have performed their catalytic function. This is true of enzymes that promote blood clot formation when the wall of a blood vessel is damaged. Once clotting is triggered, those enzymes are inactivated. Otherwise, you would have blood vessels full of solid blood instead of one protective clot. Enzyme Action: enzymes perform their catalytic role by having every chemical reaction requires that a certain amount of energy, called activation energy, be absorbed to prime the reaction. The activation energy is needed to alter the bonds of the reactants so that they can be rearranged to become the product. It is present when kinetic energy pushes the reactants to an energy level where their random collisions are forceful enough to ensure interaction. Activation energy is needed regardless of whether the overall reaction is ultimately energy absorbing or energy releasing. One way to increase kinetic energy is to increase the temperature, but this is not possible in the body because higher temperatures would denature proteins. Enzymes allow reactions to occur at normal body temperature by decreasing the amount of activation energy required. An enzyme speeds up a reaction by lowering the barrier. Think of a runner slowly climbing a 12-foot wall versus one that is running over hurdles. Due to structural and electrostatic factors, they decrease the randomness of reactions by binding to the reacting molecules temporarily and presenting them to each other in the proper position for chemical interaction (bond making or breaking) to occur. 1. Substrate(s) bind to the enzyme's active site, temporarily forming an enzyme-substrate complex. Substrate binding causes the active site to change shape so that the substrate and the active site fit together precisely, and in an orientation that favors reaction. Although enzymes are specific for particular substrates, other (nonsubstrate) molecules may act as enzyme inhibitors if their structure is similar enough to occupy or block the enzyme's active site. 2. The enzyme-substrate complex undergoes internal rearrangements that form the product(s). 3. The enzyme releases the product(s) of the reaction. If the enzyme became part of the product, it would be a reactant and not a catalyst. The enzyme is not changed and returns to its original shape, available to catalyze another reaction. Because enzymes are unchanged by their catalytic role and can act again and again, cells need only small amounts of each enzyme. Catalysis occurs with incredible speed. Most enzymes can catalyze millions of reactions per minute. ATP Transfers Energy To Other Compounds: Glucose is the most important cellular fuel, but none of the chemical energy contained in its bonds is used directly to power cellular work. Instead, energy released during glucose. Catabolism is coupled to the synthesis of adenosine triphosphate (ATP). In other words, some of this energy is captured and stored as small packets of energy in the bonds of ATP. ATP is the primary energy-transferring molecule in cells and it provides a form of energy that is immediately usable by all body cells. It is the dollar of the cell's metabolic economy.Structurally, ATP is an adenine-containing RNA nucleotide to which two additional phosphate groups have been added. Chemically, the triphosphate tail of ATP can be compared to a tightly coiled spring ready to uncoil with tremendous energy when the catch is released. Actually, ATP can store energy because its three negatively charged phosphate groups are closely packed and repel each other.When its terminal (third) high-energy phosphate bond is broken (hydrolyzed), the chemical "spring'' relaxes and the molecule as a whole becomes more stable. Cells tap ATP's bond energy during coupled reactions. An enzyme transfers the terminal phosphate group from ATP to another molecule in a process called phosphorylation. These newly phosphorylated molecules temporarily become more energetic and capable of performing some type of cellular work. In the process of doing that work, they lose the phosphate group. The amount of energy released and transferred during ATP hydrolysis corresponds closely to that needed to drive most biochemical reactions. As a result, cells are protected from excessive energy release that might be damaging, and energy squandering is kept to a minimum. Breaking the terminal phosphate bond of ATP yields a molecule with two phosphate groups, adenosine diphosphate (ADP) and an inorganic phosphate group, indicated by (Pi ) accompanied by a transfer of energy. As ATP is hydrolyzed to provide energy for cellular needs, ADP accumulates. Breaking the terminal phosphate bond of ADP liberates a similar amount of energy and produces adenosine monophosphate (AMP). The cell's ATP supplies are replenished as glucose and other fuel molecules are oxidized and their bond energy is released. The same amount of energy that is liberated when ATP 's terminal phosphates are split off must be captured and used to reverse the reaction to reattach phosphates and reform the energy-transferring phosphate bonds. Without ATP, molecules cannot be made or degraded, cells cannot transport substances across their membranes, muscles cannot shorten to tug on other structures, and life processes cease

Describe the structure of water and the unique properties of water.

High heat capacity: Water has a high heat capacity. It absorbs and releases large amounts of heat before changing appreciably in temperature itself. This property of water prevents sudden changes in temperature caused by external factors, such as sun or wind exposure, or by internal conditions that release heat rapidly, such as vigorous muscle activity. As part of blood, water redistributes heat among body tissues, ensuring temperature homeostasis. High heat of vaporization: Requires that large amounts of heat be absorbed to break the hydrogen bonds that hold water molecules together. This property is extremely beneficial when we sweat. As sweat (mostly water) evaporates from ours kin, large amounts of heat are removed from the body, providing efficient cooling. Polar solvent properties: Water is the universal solvent. Biological molecules do not react chemically unless they are in solution, and virtually all chemical reactions in the body depend on water's solvent properties. Because water molecules are polar, they orient themselves with their slightly negative ends toward the positive ends of the solutes, and vice versa, first attracting the solute molecules, and then surrounding them. This polarity of water explains why ionic compounds and other small reactive molecules (such as acids and bases) dissociate in water, their ions separating from each other and becoming evenly scattered in the water, forming true solutions. Water also forms layers of water molecules, called hydration layers, around large charged molecules such as proteins, shielding them from the effects of other charged substances in the vicinity and preventing them from settling out of solution. Such protein-water mixtures are biological colloids. Blood plasma and cerebrospinal fluid (which surrounds the brain and spinal cord) are colloids. Water is the body's major transport medium because it is such an excellent solvent. Nutrients, respiratory gases, and metabolic wastes carried throughout the body are dissolved in blood plasma, and many metabolic wastes are excreted from the body in urine, another watery fluid. Lubricants (e.g., mucus) also use water as their dissolving medium. Reactivity: Water is an important reactant in many chemical reactions. For example, foods are broken down into their building blocks by adding a water molecule to each bond as it is broken.. Cushioning: Water is not compressible, but it can flow. These properties allow water to form resilient cushions around certain body organs, helping to protect them from physical trauma. The cerebrospinal fluid surrounding the brain exemplifies water's cushioning role.

Describe the role of pH buffers in biological systems.

Homeostasis of acid-base balance is carefully regulated by the kidneys and lungs and by chemical systems (proteins and other types of molecules) called buffers. Buffers resist abrupt and large swings in the pH of body fluids by releasing hydrogen ions (acting as acids) when the pH begins to rise and by binding hydrogen ions (acting as bases) when the pH drops. Buffers can do this because they consist of a combination of a weak acid and a corresponding weak base. The first important concept is that the acidity of a solution reflects only the free hydrogen ions, not those still bound to anions. Consequently, acids that dissociate completely and irreversibly in water are called strong acids, because they dramatically change the pH of a solution. Examples are hydrochloric acid and sulfuric acid. Acids that do not dissociate completely, like carbonic acid and acetic acid are weak acids. Weak acids dissociate in a predictable way, and molecules of the intact acid are in dynamic equilibrium with the dissociated ions. Normally, blood pH varies within a very narrow range (7.35 to 7.45). If the pH of blood varies from these limits by more than a few tenths of a unit, it may be fatal. Although there are other chemical blood buffers, the bicarbonate buffer system is a major one. In this buffer system, the weak acid is carbonic acid (H2O3). It dissociates reversibly, releasing its corresponding weak base, bicarbonate ions (HCO3- ), and protons (H+). The chemical equilibrium between carbonic acid and bicarbonate ion resists changes in blood pH by shifting to the right or left as H+ ions are added to or removed from the blood. As blood pH rises (becomes more alkaline due to the addition of a strong base), the equilibrium shifts to the right, forcing more carbonic acid to dissociate. Similarly, as blood pH begins to drop (become more acidic due to the addition of a strong acid), the equilibrium shifts to the left as more bicarbonate ions begin to bind with protons. Strong bases are replaced by a weak base (bicarbonate ion) and protons released by strong acids are tied up in a weak one (carbonic acid). In either case, the blood pH changes much less than it would in the absence of the buffering system.

Describe a person in anatomical position

In the anatomical position, the body is erect with feet slightly apart. This position is easy to remember because it resembles "standing at attention," except that the palms face forward and the thumbs point away from the body.

Discuss types of chemical bonding: covalent, ionic and hydrogen.

Ionic Bonds (strongest): A chemical bond between atoms formed by the transfer of one or more electrons from one atom to the other. Electrons can be transferred from one atom to another, and when this happens, the precise balance of + and - charges is lost so that charged particles called ions are formed. Anion: negatively charged (electron acceptor) Cation: positively charged (electron donor) Both anions and cations are formed whenever electron transfer between atoms occurs. Because opposite charges attract, these ions tend to stay close together, resulting in an ionic bond. Most ionic compounds fall in the chemical category called salts. In the dry state, salts such as sodium chloride do not exist as individual molecules. Instead, they form crystals, large arrays of cations and anions held together by ionic bonds. Sodium chloride is an excellent example of the difference in properties between a compound and its constituent atoms. Sodium is a silvery white metal, and chlorine in its molecular state is a poisonous green gas used to make bleach. However, sodium chloride is a white crystalline solid that we sprinkle on our food. Covalent Bonds (intermediate): Electrons do not have to be completely transferred for atoms to achieve stability. Instead, they may be shared so that each atom is able to fill its outer electron shell at least part of the time. Electron sharing produces molecules in which the shared electrons occupy a single orbital common to both atoms. The shared electron pair orbits around the molecule as a whole, satisfying the stability needs of each atom. The electrons orbit and "belong to" the whole molecule, ensuring the stability of each atom. When 2 atoms share 1 pair of electrons, a single covalent bond is formed. In some cases, atoms share two or three electron pairs, resulting in double or triple covalent bonds. Polar & Nonpolar Covalent: The molecules formed are electrically balanced and are called nonpolar molecules (because they do not have separate + and - poles of charge). Such electrical balance is not always the case. When covalent bonds are formed, the resulting molecule always has a specific three-dimensional shape, with the bonds formed at definite angles. A molecule's shape helps determine what other molecules or atoms it can interact with. It may also result in unequal electron pair sharing, creating a polar molecule, especially in non symmetrical molecules containing atoms with different electron-attracting abilities. In general, small atoms with 6 or 7 valence shell electrons, such as oxygen, nitrogen, and chlorine, are electron-hungry and attract electrons very strongly, a capability called electronegativity. On the other hand, most atoms with only one or two valence shell electrons tend to be electropositive. In other words, their electron-attracting ability is so low that they usually lose their valence shell electrons to other atoms. Potassium and sodium, each with one valence shell electron, are good examples of electropositive atoms. Carbon dioxide and water illustrate how, molecular shape and the relative electron-attracting abilities of atoms determine whether a covalently bonded molecule is nonpolar or polar. In carbon dioxide (CO2), carbon shares four electron pairs with two oxygen atoms (two pairs are shared with each oxygen). Oxygen is very electronegative and so attracts the shared electrons much more strongly than does carbon. However, because the carbon dioxide molecule is linear and symmetrical, the electron-pulling ability of one oxygen atom offsets that of the other, like a standoff between equally strong teams in a game of tug-of-war. As a result, the shared electrons orbit the entire molecule and carbon dioxide is a nonpolar compound. In contrast, a water molecule (H2O) is bent, or Y shaped. The two electropositive hydrogen atoms are located at the same end of the molecule, and the very electronegative oxygen is at the opposite end. This arrangement allows oxygen to pull the shared electrons toward itself and away from the two hydrogen atoms. In this case, the electron pairs are not shared equally, but spend more time in the vicinity of oxygen. Because electrons are negatively charged, the oxygen end of the molecule is slightly more negative (the charge is indicated with a delta and minus as 𝛿- ) and the hydrogen end slightly more positive (indicated by 𝛿+). Because water has two poles of charge, it is a polar molecule, or dipole. Polar molecules orient themselves toward other dipoles or toward charged particles (such as ions and some proteins), and they play essential roles in chemical reactions in body cells. Hydrogen Bonding (weakest): Unlike the stronger ionic and covalent bonds, hydrogen bonds are more like attractions than true bonds. Forms when a hydrogen atom, already covalently linked to one electronegative atom (usually nitrogen or oxygen), is attracted by another electron-hungry atom, so that a "bridge'' forms between them. Hydrogen bonding is common between dipoles (such as water molecules) because the slightly negative oxygen atoms of one molecule attracts the slightly positive hydrogen atoms of other molecules. Hydrogen bonding is responsible for the tendency of water molecules to cling together and form films, referred to as surface tension. This tendency helps explain why water beads up into spheres when it sits on a hard surface and why water striders can walk on a pond's surface. Although hydrogen bonds are too weak to bind atoms together to form molecules, they are important intramolecular bonds (literally, bonds within molecules), which hold different parts of a single large molecule in a specific three-dimensional shape. Some large biological molecules, such as proteins and DNA, have numerous hydrogen bonds that help maintain and stabilize their structures.

Explain the pH scale and compare and contrast acids and bases (inorganic compounds).

Like salts, acids and bases are electrolytes.They ionize and dissociate in water and can then conduct an electrical current. pH: Acid-Base Concentration: The more hydrogen ions in a solution, the more acidic the solution is. Conversely, the greater the concentration of hydroxyl ions (the lower the concentration of H+), the more basic, or alkaline the solution becomes. The relative concentration of hydrogen ions in various body fluids is measured in concentration units called pH units. The pH scale that resulted is based on the concentration of hydrogen ions in a solution, expressed in terms of moles per liter, or molarity. The pH scale runs from 0 to 14 and is logarithmic. In other words, each successive change of one pH unit represents a tenfold change in hydrogen ion concentration. The pH of a solution is defined as the negative logarithm of the hydrogen ion concentration [H+] in moles per liter, or -log[H+]. Brackets [ ] indicate the concentration of a substance. At a pH of 7 the solution is neutral-neither acidic nor basic. The number of hydrogen ions exactly equals the number of hydroxyl ions (pH = pOH). Absolutely pure (distilled) water has a pH of 7. Solutions with a pH below 7 are acidic. The hydrogen ions outnumber the hydroxyl ions. The lower the pH, the more acidic the solution. A solution with a pH of 6 has ten. many hydrogen ions as a solution with a pH of 7. Solutions with a pH higher than 7 are alkaline, and the relative concentration of hydrogen ions decreases by a factor of 10 with each higher pH unit. Acids: Acids have a sour taste. Acid is a substance that releases hydrogen ions (H+) in detectable amounts. Because a hydrogen ion is just a hydrogen nucleus, which consists of a single "naked" proton, acids are also defined as proton donors. When acids dissolve in water, they release hydrogen ions (protons) and anions. It is the concentration of protons that determines the acidity of a solution. HCI → H+ (proton) + Cl- (anion) Bases: Bases have a bitter taste, feel slippery, and are proton acceptors. That is, they take up hydrogen ions (H+) in detectable amounts. Common inorganic bases include hydroxides. Like acids, hydroxides dissociate when dissolved in water, but in this case hydroxyl ions (OH-) and cations are liberated. For example, ionization of sodium hydroxide (NaOH) produces a hydroxyl ion and a sodium ion, and the hydroxyl ion then binds to (accepts) a proton present in the solution. This reaction produces water and simultaneously reduces the acidity (hydrogen ion concentration) of the solution. NaOH → Na+ + OH- and then OH- + H+ → H2O Bicarbonate ion (HCO3- ), an important base in the body, is particularly abundant in blood. Ammonia (NH3), a common waste product of protein breakdown in the body, is also a base. It has one pair of unshared electrons that strongly attracts protons. By accepting a proton, ammonia becomes an ammonium ion: NH3 + H+ → NH4+ Neutralization: When acids and bases are mixed they react with each other in displacement reactions to form water and a salt. This type of reaction is called a neutralization reaction, because the joining of H+ and OH- to form water neutralizes the solution. Although the salt produced is written in molecular form remember that it actually exists as dissociated ions when dissolved in water.

List the functional characteristics necessary to maintain life in humans.

Maintaining boundaries: Internal environment remains distinct from the external. In single-celled organisms, the external boundary is a limiting membrane that encloses its contents and lets in needed substances while restricting entry of potentially damaging or unnecessary substances. Plasma membrane in cells-- separates intracellular fluid inside cells from extracellular fluid outside. Part of the extracellular fluid, plasma, is enclosed in blood vessels. That remainder, the interstitial fluid, surrounds and bathes all of our other cells. Integumentary system. Movement: Includes the activities promoted by the muscular system. Also occurs when substances such as blood, foodstuffs, and urine are propelled through internal organs of the cardiovascular, digestive, and urinary systems. On a cellular level, the muscle cell's ability to move by shortening is more precisely called contractility. Responsiveness or excitability:The ability to sense changes (stimuli) in the environment and then respond to them. Because nerve cells are highly excitable and communicate rapidly with each other via electrical impulses, the nervous system is most involved with responsiveness. However, all body cells are excitable to some extent. Digestion:The breaking down of ingested foodstuffs to simple molecules that can be absorbed into the blood. The blood is then distributed to all body cells by the cardiovascular system. Metabolism: A broad term that includes all chemical reactions that occur within body cells. Includes breaking down substances into simpler building blocks (catabolism), synthesizing more complex substances from simpler building blocks (anabolism), and using nutrients and oxygen to produce (via cellular respiration) ATP, the energy-rich molecules that power cellular activities. Depends on the digestive and respiratory systems to make nutrients and oxygen available to the blood, and on the cardiovascular system to distribute them throughout the body. Regulates largely by hormones secreted by endocrine system glands. Excretion:The process of removing wastes, or extreta, from the body. If the body is to operate as we expect it to, it must get rid of non useful substances produced during digestion and metabolism. Several organ systems participate in this: Digestive: indigestible food residues in feces. Urinary: disposes of nitrogen-containing metabolic wastes, urine. Respiratory: CO2. Reproduction: Occurs at the cellular rate and the organism level. Cellular: Original cell divides, producing two identical daughter cells that may then be used for body growth or repair. Organism: Sperm + egg. Growth: An increase in size of a body part of the organism as a whole. Usually accomplished by increasing the number of cells. However, individual cells also increase in size when not dividing. For true growth to occur, constructive activities must occur at a faster rate than destructive ones.

Define the terminology used in basic chemistry.

Matter: Anything that occupies space and has mass. With some exceptions, it can be seen, smelled, and felt. The mass of an object is equal to the actual amount of matter in the object, and it remains constant wherever the object is. In contrast, weight varies with gravity. Solid: Have a definite shape and volume. Liquid: Have a definite volume, but they conform to the shape of their container. Gaseous: Have neither a definite shape nor a definite volume. Energy: The capacity to do work, or to put the matter into motion. It has no mass, does not take up space, and we can measure it only by its effects on matter. The greater the work done, the more energy is used doing it. Matter and energy are inseparable. Matter is the substance, and energy is the mover of the substance. All living things are composed of matter and they all require energy to grow and function. The release and use of energy by living systems gives us the elusive quality we call life. Kinetic: Energy in action.Evidence of kinetic energy in the constant movement of the tiniest particles of matter (atoms) as well as in larger objects (a bouncing ball). Kinetic energy does work by moving objects, which in turn can do work by moving or pushing on other objects. Potential: Stored energy, that is, inactive energy that has the potential to do work but is not presently doing so.Your leg muscles have potential energy when you sit still on the couch. When potential energy is released, it becomes kinetic energy and so is capable of doing work. Chemical: The form stored in the bonds of chemical substances. When chemical reactions occur that rearrange the atoms of the chemicals in a certain way, the potential energy is unleashed and becomes kinetic energy, or energy in action. For example, some of the energy in the foods you eat is eventually converted into the kinetic energy of your moving arm. However, food fuels cannot be used to energize body activities directly. Instead, sorne of the food energy is captured temporarily in the bonds of a chemical called adenosine triphosphate (ATP) Later, ATP's bonds are broken and the stored energy is released as needed to do cellular work. Chemical energy in the form of ATP is the most useful form of energy in living systems because it is used to run almost all functional processes. Electrical: Results from the movement of charged particles. In your body, electrical currents are generated when charged particles (ions) move along or across cell membranes. The nervous system uses electrical currents, called nerve impulses (or action potentials), to transmit messages from one part of the body to another. Electrical currents traveling across the heart stimulate it to contract (beat) and pump blood. (This is why a strong electrical shock, which interferes with such currents, can cause death.) Mechanical: Is energy directly involved in moving matter. When you ride a bicycle, your legs provide the mechanical energy that moves the pedals. Radiant/ Electromagnetic: The energy that travels in waves. These waves, which vary in length, are collectively called the electromagnetic spectrum. They include radio waves, microwaves, infrared waves, visible light, ultraviolet waves, and X rays. Light energy, which stimulates the retinas of our eyes, is important in vision. Ultraviolet waves cause sunburn, but they also stimulate your body to make vitamin D. Converting Forms of Energy: With few exceptions, energy is easily converted from one form to another. Energy conversions are quite inefficient. Some of the initial energy supply is always "lost" to the environment as heat. It is not really lost because energy cannot be created or destroyed, but that portion given off as heat is at least partly unusable. Ex: Electrical energy is converted into light energy in a lightbulb. But if you touch a lit bulb, you will soon discover that some of the electrical energy is producing heat instead. All energy conversions in the body liberate heat.This heat helps to maintain our relatively high body temperature, which influences body functioning. For example, when matter is heated, the kinetic energy of its particles increases and they begin to move more quickly. The higher the temperature, the faster the body's chemical reactions occur

Describe how macromolecules are built and broken down and apply it to a given scenario.

Molecules unique to living systems, carbohydrates, lipids (fats), proteins, and nucleic acids all contain carbon. No other small atom is so precisely electroneutral. The consequence of its electroneutrality is that carbon never loses or gains electrons. Instead, it always shares them. Furthermore, with four valence shell electrons, carbon forms four covalent bonds with other elements, as well as with other carbon atoms. As a result, carbon can help form long, chainlike molecules (common in fats), ring structures (typical of carbohydrates and steroids), and many other structures that are uniquely suited for specific roles in the body. Many biological molecules (carbohydrates and proteins for example) are macromolecules, large complex molecules containing thousands of atoms. Most macromolecules are polymers, which are chainlike molecules made of many smaller, identical or similar subunits (monomers). Monomers are joined together by a process called dehydration synthesis. During dehydration synthesis, a hydrogen atom is removed from one monomer and a hydroxyl group is removed from the monomer it is to be joined with. As a covalent bond unites the monomers, a water molecule is released. This removal of a water molecule at the bond site occurs each time a monomer is added to the growing polymer chain. The opposite reaction in which molecules are degraded is called hydrolysis (water splitting). In these reactions, a water molecule is added to each bond that is broken, thereby releasing its building blocks (smaller molecules) For the most part, organic molecules are very large molecules, but their interactions with other molecules typically involve only small, reactive parts of their structure called functional groups (acid groups, amines, and others).

List the survival needs of the body.

Nutrients: Taken via diet, contain the chemical substances used for energy and cell building.Plant-derived foods are rich in carbs, vitamins, and minerals. Animal-derived foods are rich in proteins and fats. Carbs are the major energy fuel for body cells. Proteins, and to a lesser extent fats, are essential for building cell structures. Fats also provide a reserve of energy-rich fuel. Selected minerals and vitamins are required for the chemical reactions that go on in cells and for oxygen transport in the blood. The mineral calcium helps to make bones hard and is required for blood clotting. Oxygen: All the nutrients in the world are useless unless oxygen is also available. The chemical reactions that release energy from foods are oxidative reactions that require oxygen. The cooperative efforts of the respiratory and cardiovascular systems make oxygen available to the blood and body cells. Water: The single most abundant chemical substance in the body.Provides a watery environment necessary for chemical reactions and the fluid base for body secretions and excretions. We obtain water from ingested foods and liquids. We lose it from the body by evaporation from the lungs and skin and in body excretions. Normal body temperature: If chemical reactions are to continue at life-sustaining rates, a normal body temperature must be maintained (37 °C or 98.6 °F). As body temperature drops, metabolic reactions become slower and slower and finally stop. When body temperature is too high, chemical reactions occur at a frantic pace and body systems stop functioning. At their extreme, death occurs. The activity of the muscular system generates most body heat. Appropriate atmospheric pressure: The force that air exerts on the surface of the body. Breathing in and gas exchange in the lungs depend on appropriate atmospheric pressure. At high altitudes, where atmospheric pressure is lower and the air is thin, gas exchange may be inadequate to support cellular metabolism. ** The mere presence of these survival factors is not sufficient to sustain life. They must be present in the proper amounts.

List the four major elements that make up 96% of the human body.

Oxygen: A component of both organic (carbon-containing) and inorganic (non-carbon- containing) molecules. As a gas, it is needed for the production of cellular energy (ATP). Carbon: A component of all organic molecules, which include carbohydrates, lipids (fats and oils), proteins, and nucleic acids. Hydrogen: A component of all organic molecules. As an ion (proton), it influences the pH of body fluids. Nitrogen: A component of proteins and nucleic acids (genetic material).

Lymphatic System

Picks up fluid leaked from blood vessels and returns it to blood. Disposes of debris in the lymphatic stream. Houses white blood cells (lymphocytes) involved in immunity. The immune response mounts the attack against foreign substances within the body. Thymus Lymphatic vessels Thoracic duct Spleen Lymph nodes Red Bone marrow

Compare and contrast positive and negative feedback in terms of the relationship between stimulus and response.

Positive feedback: The initial response enhances the original stimulus so that further responses are even greater. "Positive" because that change that results proceeds in the same direction as the initial change, causing the variable to deviate further and further from its original value or range. Usually controls infrequent events that do not require continuous adjustments. Typically, they set off a linked sequence of events, like a cascade. Ex: Blood clotting, Labor Are likely to race out of control, so they are rarely used to promote moment-to-moment well-being of the body. Some may have only local effects, like blood clotting, but does not normally spread to the entire circulation. Negative feedback: Most homeostatic control mechanisms. Maintain some physiological function. The output shuts off the original effect of the stimulus or reduces its intensity. These mechanisms cause the variable to change in a direction opposite to that of the initial change, returning to its "ideal" value. Regulation of temperature @ hypothalamus. Neural control mechanism @ withdrawal reflex. Endocrine system @ control of blood sugar (glucose) by insulin. As blood sugar rises, receptors in the body sense this change, and the pancreas (the control center) secretes insulin into the blood. This change in turn prompts body cells to absorb more glucose, removing it from the bloodstream. As blood sugar falls, stimulus for insulin release ends. All negative feedback mechanisms have the same goal: preventing severe changes within the body.

Skeletal System

Protects and supports body organs, and provides a framework the muscles use to cause movement. Blood cells are formed within bones. Bones store minerals. Bones & Joints

nine abdominopelvic regions and list the major organs located in each.

Right Hypochondriac Region: Liver. Small intestines Right kidney. Gallbladder Epigastric Region: Liver Stomach. Pancreas. Duodenum. Spleen. Adrenal glands. Left Hypochondriac Region: Left Kidney Spleen Pancreas. Colon. Right Lumbar Region: Gallbladder. Liver. Right colon. Umbilical Region: Umbilicus (navel). Parts of small intestine. Duodenum. Left Lumbar Region: Left kidney. Bottom colon. Right Iliac Region: Appendix. Cecum. Hypogastric Region: Urinary bladder. Sigmoid colon. Female reproductive organs. Left Iliac Region: Descending colon. Sigmoid colon.

Describe the location of the four abdominopelvic quadrants

Right Upper Quadrant: Liver. Gallbladder. Transverse Colon. Left Upper Quadrant: Spleen. Stomach. Pancreas Right Lower Quadrant: Small intestine. Ascending colon. Appendix Left Lower Quadrant: Descending colon. Sigmoid colon.

Compare solutions, colloids and suspensions.

Solutions: Homogeneous mixtures of components that may be gases, liquids, or solids. A sample taken from any part of the mixture has the same composition (in terms of the atoms or molecules it contains) as a sample taken from any other part of the mixture. The substance present in the greatest amount is called the solvent (or dissolving medium). Solvents are usually liquids. Substances present in smaller amounts (dissolved in the solvent) are called solutes. Water is the body's chief solvent. Most solutions in the body are true solutions containing gases, liquids, or solids dissolved in water. True solutions are usually transparent. The solutes of true solutions are very small, usually in the form of individual atoms and molecules. Consequently, they are not visible to the naked eye, do not settle out, and do not scatter light. In other words, if a beam of light is passed through a true solution, you will not see the path of light. Colloids: Also called emulsions, are heterogeneous mixtures, which means that their composition is dissimilar indifferent areas of the mixture. Colloids often appear translucent or milky and although the solute particles are larger than those in true solutions, they still do not settle out. However, they do scatter light, so the path of a light beam shining through a colloidal mixture is visible. Colloids have many unique properties, including the ability of some to undergo sol-gel transformations, that is, to change reversibly from a fluid (sol) state to a more solid (gel) state. Cytosol, the semifluid material in living cells, is also a colloid, largely because of its dispersed proteins. Its sol-gel transforma- tions underlie many important cell activities, such as cell divi- sion and changes in cell shape. Suspensions: Are heterogeneous mixtures with large, often visible solutes that tend to settle out. So is blood, in which the living blood cells are suspended in the fluid portion of blood (blood plasma). If left to stand, the suspended cells will settle out unless some means-mixing, shaking, or circulation in the body-keeps them in suspension.**All three types of mixtures are found in both living and nonliving systems. In fact, living material is the most complex mixture of all, since it contains all three kinds of mixtures interacting with one another.

Describe factors that impact chemical reaction rates.

Temperature: Higher temperatures increase the kinetic energy of particles and the force of their collisions, increasing the rate of chemical reactions. Concentration: High concentrations of reacting particles increase the chances of successful collisions, and reactions progress faster. Lowering concentrations slows reactions. Unless reactants are added or products removed, chemical equilibrium will eventually occur. Particle size: The smaller the reacting particles, the faster the chemical reaction. Smaller particles move faster than larger ones (at the same temperature) and so collide more frequently and forcefully. Catalysts: At normal body temperature, most chemical reactions would proceed far too slowly to maintain life were it not for the presence of catalysts. Catalysts are substances that increase the rate of chemical reactions without themselves being chemically changed or part of the product. Biological catalysts are called enzymes.

Explain the "fluid mosaic" model of the plasma membrane.

The fluid mosaic model is the model used for describing the plasma membrane. The model describes the plasma membrane as a "mosaic" of components, phospholipids, cholesterol, proteins, and carbohydrates, that gives the membrane a fluid like movement and behavior. It is constantly moving and is flexible but is stable enough to protect and hold the cell.

Illustrate and describe the components of the plasma membrane.

The plasma membrane is the phospholipid barrier that separates the inside of the cell to the outside atmosphere. The membrane provides protection for the inners of the cell as well as a stable environment. The main components of the plasma membrane are lipids (phospholipids and cholesterol), proteins, and carbohydrates that are attached to some of the lipids and proteins.

Physiology

The study of body function

List the components of a feedback loop and explain the function of each.

The variable: the factor or event being regulated. All homeostatic control mechanisms are processes involving at least three components that work together to regulate the variable. (ie., body temp, blood sugar, heart rate, blood pressure, rate and depth of breathing, blood levels of O2, CO2, and minerals). The receptor: a sensor that monitors the environment. It responds to stimuli (changes) by sending information (input) along the afferent pathway to the second component, the control center. The control center: determines the set point. Which is the level (or range of levels) at which a variable is to be maintained. It analyzes the input it receives by comparing it to the set point and determines the appropriate response. Information (output) then flows from the control center along the efferent pathway to the third component, the effector. The effector: carries out the control center's response to the stimulus. The results of the response then feed back to influence the effect of the stimulus, either reducing it so that the whole control process is shut off, or enhancing it so that the whole process continues at an even faster rate.

Regional anatomy

all structures in a particular region of the body examined at the same time. ex: all structures in the leg are examined at the same time.

Muscular System

allows manipulation of the environment, locomotion, and facial expression. Maintains posture, and produces heat. Skeletal muscles

nervous system

as the last-acting control system of the body, it responds to internal and external changes by activating appropriate muscles and glands. Brain Spinal cord Nerves

Systemic anatomy

body system is studied structure by structure. ex: cardiovascular system is studied through the heart and blood vessels

Digestive System

breaks down food into absorbable units that enter the blood for distribution to body cells. Indigestible foodstuffs are eliminated as feces. Oral Cavity Esophagus Liver Stomach Small intestine Large intestine Rectum Anus

Embryology

concerns developmental changes that occur before birth.

Renal physiology

concerns kidney function and urine production

Microscopic anatomy

deals with structures too small to be seen with the naked eye.

Urinary System

eliminates nitrogenous wastes from the body. Regulates water, electrolyte, and acid-base balance of the blood. Kidney Ureter Urinary bladder Urethra

Cardiovascular physiology

examines the operation of the heart and blood vessels

Neurophysiology

explains the workings of the nervous system

Integumentary System

forms the external body covering, and protects deeper tissues from injury. Synthesizes vitamin D, and houses cutaneous (pain, pressure, etc.) receptors, and sweat and oil glands. Hair, Skin, Nails

Endocrine System

glands secrete hormones that regulate processes such as growth, reproduction, and nutrient use (metabolism) by body cells. Pineal gland Pituitary gland Thyroid gland Thymus Adrenal gland Pancreas Ovary Testis

Respiratory System

keeps blood constantly supplied with oxygen and removes carbon dioxide. These exchanges occur through the walls of the air sacs of the lungs. Nasal cavity Pharynx Larynx Trachea Bronchus Lung

Female Reproductive System

ovaries produce eggs and female sex hormones. The remaining female structures serve as sites for fertilization and development of the fetus. Mammary glands of female breasts produce milk to nourish the newborn. Mammary Glands Uterus Uterine Tube Vagina

Male Reproductive System

overall function is production of offspring.Testes produce sperm and male sex hormone, and male ducts and glands aid in delivery of sperm to the female reproductive tract Prostate Penis Testis Scrotum Ductus Deferens

Anatomy

structure of body parts

Cytology

study of cells

Histology

study of tissues

Surface anatomy

the study of internal structures as they relate to the overlying skin surface.

Gross or macroscopic anatomy

the study of large body structures visible to the naked eye.

Developmental Anatomy

traces structural changes that occur in the body throughout the life span