Practice Exam 1 (Chapter 1-5)[1419]

Practice Exam 1 Please note, Dr. Harvill’s exams are normally 50-60 questions in length and have a short free response section associated with them. This practice exam is only designed for extra practice. Use it as a gauge for how well you know the material. I hope it helps! Anything in blue are little side notes that you should know as well that are related to the question! Try to cover them when taking the exam because they could give away the answer. A localized group of organisms that belong to the same species is called a Biosystem Community Population Ecosystem Family (know order of the biological hierarchy) The element present in all organic molecules is Hydrogen Oxygen Carbon Nitrogen Phosphorus (also know CHON makes up 96%) Which of the following are nitrogenous bases of the purine type? Cytosine and guanine Guanine and adenine Adenine and thymine Thymine and uracil Uracil and cytosine Purines (aggies- A, G- two rings) Pyrimidines (T, C, U- one ring) Which of these classes of biological molecules consist of both small molecules and macromolecular polymers? Lipids Carbohydrates Proteins Nucleic acids Lipids, carbohydrates, proteins, and nucleic acids all consist of only macromolecular polymers (disaccharides- small two-unit molecules and polysaccharides) The slight negative charge at one end of one water molecule is attracted to the slight positive charge of another water molecule. What is this attraction called? A covalent bond A hydrogen bond An ionic bond A hydrophilic bond A van der Waals interaction (know order of strongest to weakest and what is intermolecular and what is intramolecular) Which of the following statements best summarizes the differences between DNA and RNA? DNA encodes hereditary information, whereas RNA does not. The bases in DNA for base-paired duplexes, whereas the bases in RNA do not. DNA nucleotides contain a different sugar than RNA. DNA contains the base uracil, whereas RNA contains the base thymine. DNA encodes hereditary information, whereas RNA does not; the bases in DNA form base-paired duplexes, whereas the bases in RNA do not; and DNA nucleotides contain a different sugar than RNA nucleotides. (please know the three things required to make a single nucleotide- 1. Base (pyrimidine or purine) 2. Sugar (ribose or deoxyribose) 3. 1-3 phosphate groups. ) Why is each element unique and different from other elements in chemical properties? Each element has a unique atomic mass. Each element has a unique atomic weight. Each element has a unique number of protons in its nucleus. Each element has a unique number of neutrons in its nucleus. Each element has different radioactive properties. (also know the charges and masses associated with electrons, protons, and neutrons) Which of the following is not a polymer? Glucose Starch Cellulose Chitin DNA (please understand that glucose is a monomer but has the ability to function by itself and plays important roles in metabolic functions (cellular respiration and photosynthesis) —other monomers for other macromolecules usually do not have this function and must be in polymer form to be useful- an exception to this would be ATP which is a nucleotide and serves as an immediate energy source) The main source of energy for producers in an ecosystem is Light energy Kinetic energy Thermal energy Chemical energy ATP Which of the following descriptions best fits the class of molecules known as nucleotides? A nitrogenous base and a phosphate group A nitrogenous base and a pentose sugar A nitrogenous base, a phosphate group, and a pentose sugar A phosphate group and an adenine or uracil A pentose sugar and a purine or pyrimidine Which of the following best summarizes the relationship between dehydration reactions and hydrolysis? Dehydration reactions assemble polymers, and hydrolysis reactions break down polymers. Dehydration reactions eliminate water from lipid membranes, and hydrolysis makes lipid membranes water permeable. Dehydration reactions can occur only after hydrolysis. Hydrolysis creates monomers, and dehydration reactions break down polymers. Dehydration reactions ionize water molecules and add hydroxyl groups to polymers; hydrolysis reactions release hydroxyl groups from polymers. (Please be able to calculate the molecular formula of polymer that is bonded together after losing waters—we did this in SI) Stanley Miller’s 1953 experiments supported the idea that Life arose on Earth from simple inorganic molecules. Organic molecules can be synthesized abiotically under conditions that may have existed on early Earth. Life arose on Earth from simple organic molecules, with energy from lightning and volcanoes. The conditions on early Earth were conducive to the origin of life. The conditions on early Earth were conducive to the abiotic synthesis of organic molecules. Which of the following effects is produced by the high surface tension of water? Lakes don’t freeze solid in winter, despite low temperatures. A water strider can walk across the surface of a small pond. Organisms resist temperature changes, although they give off heat due to chemical reactions. Evaporation of sweat from the skin helps to keep people from overheating. Water flows upward from the roots to the leaves in plants. (HYDROGEN BONDING, HYDROGEN BONDING, HYDROGEN BONDING!!!- gives water its emergent properties) Which of the following explains most specifically the attraction of water molecules to one another? Nonpolar covalent bond Polar covalent bond Ionic bond Hydrogen bond Hydrophobic interaction How many electron pairs does carbon share in order to complete its valence shell? 1 2 3 4 8 (please know the different between the valence shell and the VALENCE (bonding capacity) of an atom- see figure 4.4 in textbook) One of the primary functions of RNA molecules is to Transmit genetic information to offspring. Function in the synthesis of proteins. Make a copy of itself, thus ensuring genetic continuity. Act as a pattern or blueprint to form DNA. Form the genes of higher organisms. A molecule with the chemical formula C6H12O6 is probably a Carbohydrate Lipid Monosaccharide Carbohydrate and lipid only Carbohydrate and monosaccharide only (carbohydrate monomers usually have a molecular formula that contains some variation of C, H, and O) Which of the following takes place as an ice cube cools a drink? Molecular collisions in the drink increase. Kinetic energy in the drink decreases. A calorie of heat energy is transferred from the ice to the water of the drink. The specific heat of the water in the drink decreases. Evaporation of the water in the drink increases. (know the difference/relationship between thermal energy, temperature, kinetic energy, Calorie, kilocalorie, and calorie) A covalent chemical bond is one in which Electrons are removed from one atom and transferred to another atom so that the two atoms become oppositely charged. Protons and neutrons are shared by two atoms so as to satisfy the requirements of both atoms. Outer-shell electrons of two atoms are shared so as to satisfactorily fill the outer electron shells of both atoms. Outer-shell electrons of one atom are transferred to fill the inner electron shell of another atom. An electron occupies a hybrid orbital located between the nuclei of two atoms. (must know the difference between the 4 types of bonds- covalent( polar/nonpolar), ionic, hydrogen bonding (H-NOFCLS), and Van Der Waals) What is the term used for a protein molecule that assists in the proper folding of other proteins? Tertiary protein Chaperonin Enzyme protein Renaturing protein Denaturing protein (also know the different kinds of bonding that we see in each level of protein structure) The nutritional information on a cereal box shows that one serving of a dry cereal has 200 kilocalories. If one were to burn one serving of the cereal, the amount of heat given off would be sufficient to raise the temperature of 20 kg of water how many degrees Celsius? 0.2°C 1.0°C 2.0°C 10.0°C 20.0°C (be able to do it in case he throws it in there) Van der Waals interactions result when Hybrid orbitals overlap. Electrons are not symmetrically distributed in a molecule. Molecules held by ionic bonds react with water. Two polar covalent bonds react. A hydrogen atom loses an electron. Which of the following types of cells utilize deoxyribonucleic acid (DNA) and their genetic material but do not have their DNA encased within a nuclear envelope? Animal Plant Archaea Fungi Protists (archaea are the really weird guys that scientists don’t really understand very well—so whenever something looks out of place.. go with archaea) Why are hydrocarbons insoluble in water? The majority of their bonds are polar covalent carbon-to-hydrogen linkages. The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages. They are hydrophilic. They exhibit considerable molecular complexity and diversity. They are lighter than water. (understand polar (hydrophilic) and nonpolar (hydrophobic)—LIKE DISSOLVES LIKE) Humans can digest starch but not cellulose because The monomer of starch is glucose, while the monomer of cellulose is galactose. Humans have enzymes that can hydrolyze the ? glycosidic linkages of starch but not the ? glycosidic linkages of cellulose. Humans have enzymes that can hydrolyze the ? glycosidic linkages of starch but not the ? glycosidic linkages of cellulose. Humans harbor starch-digesting bacteria in the digestive tract. The monomer of starch is glucose, while the monomer of cellulose is glucose with a nitrogen-containing group The reactivity of an atom arises from The average distance of the outermost electron shell from the nucleus. The existence of unpaired electrons in the valence shell. The sum of the potential energies of all the electron shells. The potential energy of the valence shell. The energy difference between the s and p orbitals. (answer this: is helium reactive? Why or why not? Are noble gases reactive? No, because they have a full octet) Once labor begins in childbirth, contractions increase in intensity and frequency until delivery. The increasing labor contractions of childbirth are an example of which type of regulation? A bioinformatic system Positive feedback Negative feedback Feedback inhibition Enzymatic catalysis Which of the following is (are) true of natural selection? It requires genetic variation. It results in descent with modification It involves differential reproductive success. It results in descent with modification and involves differential reproductive success. It requires genetic variation, results in descent with modification, and involves differential reproductive success. What results from an unequal sharing of electrons between atoms? A nonpolar covalent bond A polar covalent bond An ionic bond A hydrogen bond A hydrophobic interaction Which of the following statements correctly describes cis-trans isomers? They have variations in arrangement around a double bond. They have an asymmetric carbon that makes them mirror images. They have the same chemical properties. They have different molecular formulas. Their atoms and bonds are arranged in different sequences. (please know the diagrams including isomers in your textbook! You will see them on the test!) Which level of protein structure do the ? helix and the ? pleated sheet represent? Primary Secondary Tertiary Quaternary All of the above A controlled experiment is one in which The experiment is repeated many times to ensure that the results are accurate. The experiment proceeds at a slow pace to guarantee that the scientist can carefully observe all reactions and process all experimental data. There are at least two groups, one of which does not receive the experimental treatment. There are at least two groups, one differing from the other by two or more variables. There is one group for which the scientist controls all variables. Which of the following is a false statement concerning amino groups? They are basic in pH. They are found in amino acids. They contain nitrogen. They are nonpolar. They are components of urea. (know the base structure of an amino acid—they will always have an amino (NH2) and carboxyl (COOH) group—also know the main characteristics of the R-side chains—polar, nonpolar, acidic, and basic) Which of the following is the best description of a control for an experiment? The control group is kept in an unchanging environment. The control is left alone by the experimenters. The control group is matched with the experimental group except for the one experimental variable. The control group is exposed to only one variable rather than several. Only the experimental group is tested or measured. Why does ice float in liquid water? The high surface tension of liquid water keeps the ice on top. The ionic bonds between the molecules in ice prevent the ice from sinking. Ice always has air bubbles to keep it afloat. Hydrogen bonds stabilize and keep the molecules of ice farther apart than the water molecules of liquid water. The crystalline lattice of ice causes it to be denser than liquid water. (HYDROGEN BONDING—When is water most dense?- 4 degrees Celsius—THIS IS ONE OF THE MOST UNIQUE PROPERTIES OF ALL COMPOUNDS) Which of the following best describes a model organism? It is often pictured in textbooks and easy for students to imagine. It lends itself to many studies that are useful to beginning students. It is well studied, easy to grow and results are widely applicable. It is small, inexpensive to raise, and lives a long time. It has been chosen for study by the earliest biologists. The two molecules shown in the figure above are best described as Optical isomers. Enantiomers. Structural isomers. Cis-Trans isomers. Chain length isomers. Liquid water’s high specific heat is mainly a consequence of the Small size of the water molecules. High specific heat of oxygen and hydrogen atoms. Absorption and release of heat when hydrogen bonds break and form. Fact that water is a poor heat conductor. Higher density of liquid water than solid water. One difference between carbon-12 and carbon 14, is that carbon-14 has: Two more protons than carbon-12. Two more electrons than carbon-12. Two more neutrons than carbon-12. Two more protons and the more neutrons than carbon-12. Two more electrons and two more neutrons than carbon-12 (please understand the difference between isomers and isotopes! Don’t get them confused. Isomers- molecules with same chemical formula but different arrangement of atoms Isotopes- elements with different number of neutrons from the parent element—used for radiometric dating) Hydrophobic substances such as vegetable oil are Nonpolar substances that repel water molecules. Nonpolar substances that have an attraction for water molecules. Polar substances that repel water molecules. Polar substances that have an affinity for water. Charged molecules that hydrogen-bond with water molecules. (“hydrogenated” substances are also known as saturated fats (all single bonds) and solid at room temp. Unsaturated fats have double bonds or “kinks” in their tails that makes them liquid at room temp.) Which bonds are created during the formation of the primary structure of a protein? Peptide bonds Hydrogen bonds Disulfide bonds Phosphodiester bonds Peptide bonds, hydrogen bonds, and disulfide bonds What is the name of the functional group shown in the figure above? Carbonyl Ketone Aldehyde Carboxyl Hydroxyl (please be able to do this with all the functional groups!) Which of the following statements is true about buffer solutions? They maintain a constant pH when bases are added to them but not when acids are added to them. They maintain a constant pH when acids are added to them but not when bases are added to them. They maintain a relatively constant pH of approximately 7 when either acids or bases are added to them. They maintain a relatively constant pH when either acids or bases are added to them. They are found only in living systems are biological fluids. (look at the SI worksheet over chapter 3 to get a good definition of buffers!) Which of the following is an example of qualitative data? The temperature decreased from 20 degrees to 15 degrees. The plant’s height is 25 centimeters. The fish swam in a zigzag motion. The six pairs of robins hatched an average of three chicks. The contents of the stomach are mixed every 20 seconds. How many molecules of glycerol (molecular mass = 92) would be present in 1 L of a 1 M glycerol solution? 1 x 106 14 x 6.02 x 1023 92 x 6.02 x 1023 6.02 x 1026 6.02 x 1023 What do elements in the same column of the periodic table have in common? They have the same number of protons. They have the same number of neutrons. They have the same number of electrons. They have the same number of electrons in their valence shell. They have the same number of electron shells. (same row- same number of shells ex: 1st row has one shell, 2nd row has two shells, 3rd row has three shells) According to Darwinian theory, which of the following exhibits the greatest fitness for evolutionary success? The species with the longest life The individuals within a population that have the greatest reproductive success The phylum with members that occupy the greatest number of habitats The community of organisms that is capable of living in the most nutrient-poor biome The organism that produces its own nutrients most efficiently (Dr. Harvill LOVES Darwin ;) ) Which of the lists below correctly lists the chemical interactions from strongest to weakest? Covalent bonds, ionic bonds, hydrogen bonds, Van der Waals interactions Ionic bonds, covalent bonds, hydrogen bonds, Van der Waals interactions Hydrogen bonds, Van der Waals interactions, ionic bonds, covalent bonds Van der Waals interactions, hydrogen bonds, ionic bonds, covalent bonds About 25 of the 92 natural elements are known to be essential to life. Which four of these 25 elements make up approximately 96% of living matter? Carbon, sodium, hydrogen, nitrogen Carbon, oxygen, phosphorus, hydrogen Oxygen, hydrogen, calcium, nitrogen Carbon, hydrogen, nitrogen, oxygen Carbon, oxygen, nitrogen, calcium The atomic mass of an element is made up of the mass of which of the following? The number of protons in the element The number of electrons in the element The number of the electrons and the neutrons in the element The number of protons, neutrons, and electrons in the element The number of protons, and neutrons in the element What is the pH of a solution with a hydroxyl ion [OH-] concentration of 10-12 M? pH 2 pH 4 pH 10 pH 12 pH14 (this is always just trying to add to a total pH of 14—it’s a balancing act- Ex: pH=4 pOH=10) Which of the groups shown above is a functional group that helps stabilize proteins by forming covalent cross-links within or between protein molecules? A B C D E (Disulfide bridges in the tertiary structure) Which of the following solutions would require the greatest amount of base (OH) to be added to bring the solution to neutral pH? Gastric juice at pH 2 Vinegar at pH 3 Tomato juice at pH 4 Black coffee at pH 5 Household bleach at pH 12 (Neutral pH equals 7) Which of the following statements is true for the class of biological molecules known as lipids? They are insoluble in water. They are made from glycerol, fatty acids, and phosphate. They contain less energy than proteins and carbohydrates. They are made by dehydration reactions. They contain nitrogen. (Remember that lipids are not true macromolecules and therefore the don’t have true monomer and polymers) Thalidomide and L-dopa are examples of pharmaceutical drugs that occur as enantiomers, or molecules that Have identical three-dimensional shapes. Are mirror images of one another. Are structural isomers. Are mirror images of one another and have the same biological activity. Are cis-trans isomers. What aspects of protein structure are stabilized or assisted by hydrogen bonds? Primary structure Secondary structure Tertiary structure Quaternary structure Secondary, tertiary, and quaternary structure, but not primary structure Label the following amino acid as nonpolar, polar, acidic, or basic based on the property of its side chain. Then fill out the chart indicating the number of each functional group present. Functional Group Total Found Hydroxyl Carbonyl Carboxyl Amino Sulfhydryl Phosphate Methyl Type of Amino Acid: PLEASE KNOW YOUR MACROMOLECULE CHEAT SHEET AS WELL