Anatomy and Physiology Exam 1 Practice Questions & Answers Correct 100%

Define Atom - Answer Smallest stable unit of matter Atoms of the same element (protons) that have different numbers of neutrons are called - Answer Isotopes How is it possible for two samples of molecular hydrogen to contain the same number of atoms, yet have different molecular weights? - Answer Isotopes contain different numbers of neutrons, but the same number of protons Defina a chemical bond and identify several types of chemical bonds - Answer -Attractive force acting between two atoms that may be strong enough to hold them together in a molecule or compound -Covalent and Ionic Bond Which kind of bond holds atoms in a water molecule together? What attracts water molecules to one another? - Answer -The atoms in a water molecule are held together by polar covalent bonds -Water molecules are attracted to another by hydrogen bonds Both Oxygen and Neon are gases at room temperature. Oxygen combines readily with other elements, but neon does not. Why? - Answer -Atoms combine with each other to gain a complete set of electrons in their outer energy level -Oxygen atoms do not have a full energy outer level, so they readily react with many other elements to attain the stable arrangement -Neon already has a full outer energy level, so it cannot combine with other elements When using the result for chemical notation, how is an ion's electrical charge represented? - Answer Numerical number its a + or - in the top right corner Using the rules for chemical notation, write the molecular formula for glucose, a compound composed of 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms - Answer C6H12O6 Identify and describe the three types of chemical reactions important to human physiology - Answer 1) Decomposition- breaking a molecule down into smaller fragments 2) synthesis- making compounds in the body 3) Exchange In cells, glucose, a 6-carbon molecule, is converted into two three-carbon molecules by a reaction that releases energy. How would you classify this reaction? - Answer This reaction involves a large molecule being broken down into smaller pieces, so it is a decomposition reaction What is an enzyme? - Answer An enzyme is a protein that promotes chemical reactions by lowering the activation energy requires. In doing so, they make it possible for chemical reactions t proceed under conditions compatible with life Why are enzymes needed in our cells? - Answer Without enzymes, chemical reactions would proceed only under conditions cells could not tolerate (high temp). By lowering the activation energy, enzymes make it possible for chemical reactions to rapidly proceed under conditions compatible with life Organic Compounds - Answer Always contain hydrogen and carbon Inorganic Compounds - Answer Do not contain carbon and hydrogen together Explain how the chemical properties of water make life possible - Answer Solubility- its strong polarity enables it to be used as an efficient solvent Reactivity- it participates in many chemical reactions High heat-capacity- it absorbs and releases heat slowly Serves as a lubricant Define ph, and explain how the pH scale relates to acidity and alkalinity. - Answer -pH is described as the measure of hydrogen concentration in moles/liters in fluids. -The lower the pH, the more acidic. 7 is described as neutral. Values below 7 indicate acidic solutions, and values above 7 indict alkaline solutions. What is the significance of pH in physiological systems? - Answer If the body is to remain at homeostasis, the pH of different body fluids must remain within a fairly narrow range. 7.35-7.45 is normal The maintenance of a constant and optimal internal environment in an organism is termed - Answer Homeostasis When body temperature rises, a center in the brain initiates physiological changes to decrease the body temperature. This is an example of - Answer negative feedback The most important high energy compound in cells is - Answer ATP Which of the following substances would be least acidic? - Answer Biggest number, most basic Water molecules and small ions enter a cell through - Answer channels in some integral membrane proteins Which of the following lists the four main categories of tissues? - Answer muscle, nervous, epithelial, connective Dead skin cells are shed in sheets because they are held together by strong intercellular connections that resist mechanical stress named - Answer Desmosomes All of the following are true of the pigment melanin, except that it - Answer decreases in concentration within cells during exposure to the sun. Which of the following is formed by intramembrous ossification? - Answer Both the roof of the skull and the clavicle, but not the carpal bones. The lacunae of osseous tissue contain - Answer Osteocytes How does an antacid help decrease stomach discomfort? - Answer Antacids contain a weak base that neutralizes the excess acid in the stomach, raising the pH. It is a buffer, because it stabilizes the pH of a solution by removing or replacing hydrogen ions. A food contains organic molecules with the elements C, H and O, in a ratio of 1:2:1. What class of compounds do these molecules belong to, and what are their major functions in the body? - Answer a. This is a carbohydrate. b. The body uses carbohydrates mainly as an energy source Describe Lipids - Answer a. Lipids are a diverse group of compounds that include fatty acids, glycerides, steroids, phospholipids, and glycolipids. b. They are organic compounds that contain carbon, hydrogen and oxygen in a ratio that does not approximate 1:2:1. Which lipids would you find in human plasma membranes? - Answer It contains mainly phospholipids, with small amounts of cholesterol and glycolipids. Describe a protein - Answer a. Proteins are organic compounds formed from amino acids, which contain a central carbon atom, a hydrogen atom, an amino group, a carboxyl group, and an R group or variable side chain. b. Proteins function in support, movement, transport, buffering, metabolic regulation, coordination and control, and defense. How does boiling a protein affect its structural and functional properties? - Answer a. The heat of boiling breaks bond that maintain the proteins structure. The resulting structural change, known as denaturation, affects the ability of the protein molecule to perform its normal biological functions. All organic compounds in the human body contain all of the following elements except: - Answer Calcium A substance containing atoms of different elements that are bonded together is called - Answer Compound All the chemical reactions that occur in the human body are collectively referred as - Answer Metabolism The speed, or rate, of a chemical reaction is influenced by: - Answer -Presence of catalyst -The temperature -The concentrations of the reactants A pH of 7.8 in the human body typifies a condition known as - Answer Alkalosis A is a solute that dissociates to release hydrogen ions, and a is a solute that removes hydrogen ions from solution - Answer Acid and base Special catalytic molecules called control chemical reactions in the human body. - Answer Enzymes