Chemistry of Life

Chemistry of Life TYPE IN YOUR ANSWERS USING A DIFFERENT COLOR! Define: (43 points) [HOMEOSTASIS] – Process which organisms maintain a relatively stable internal environment [ENERGY] – Ability to do work [METABOLISM] – A set of chemical reactions in the body [VIRUS] – Ultramicroscopic infectious agent that replicates itself only within cells of living hosts [PRION] - Proteinaceous infectious particle that lacks nucleic acids and replicates by converting similar normal proteins into new prions. [ELEMENT] – Pure substance that consists of one type of atom [MATTER] – Anything that takes up space [ATOM] – The basic unit of matter [PROTON] – Determine the element; positively charged and located in the nucleus [ELECTRON] – Negatively charged particle; (located in space around the nucleus) [NEUTRON] – Neutral charge; located in the nucleus [NUCLEUS] – Center of an atom (contains protons and neutrons) [COVALENT BOND] – A bond between atoms in which the electrons are shared [MOLECULE] – Smallest unit of most compounds that displays all types of that compound [ORGANIC] – Compound that contain both hydrogen and carbon [INORGANIC] – Compound that do not contain both hydrogen and carbon [CARBOHYDRATE] – Compound made up of carbon, hydrogen, and oxygen atoms; type of nutrient that is the major source of energy for the body [PROTEIN] – Macromolecule that contains hydrogen, oxygen, nitrogen, and carbon [LIPIDS]- Macromolecule made mostly from carbon and hydrogen atoms (fats, oil, and waxes) [NUCLEIC ACIDS] – Macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorous [MACROMOLECULES] – Giant molecule formed by the joining of smaller molecules normally by a condensation reaction (polysaccharides, proteins, and nucleic acids) [MONOMER] – Small chemical unit that makes up a polymer [POLYMER] – Molecules composed of many monomers; makes up macromolecules [MONOSACCHARIDE] – Simple sugar molecule [AMINO ACID] – Compound with an amino group on one end and a carboxyl group on the other end [NUCLEOTIDE] – Sunbunit of which nucleic acids are composed; made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base [CELL] – Membrane bound structure that is the basic unit of life [CELL MEMBRANE] – the lipid bilayer that forms the outer boundary of cell [PHOSPHOLIPID] – A bilayer of the cell membrane [HYDROPHOBIC] – Repelling, tending not to combine with water; nonpolar [HYDROPHILIC] – Dissolves in water; polar [POLAR MOLECULE] – Molecule with an unequal distribution of charge, resulting in molecules having a positive and negative end [HYDROGEN BOND] – Weak attraction between a hydrogen atom and another atom [COHESION] – Attraction between molecules of the same substance [ADHESION] – Force of attraction between different kinds of molecules [SOLVENT] – Dissolving substance in a solution [SOLUTE] – Substance that is dissolved in a solution [SOLUTION] – Type of mixture in which all the components are evenly distributed [IONIC BOND] – Chemical bond formed when 1+ electrons are transferred from one to another [ION] – Atom that has a positive or negative charge [pH] – abbreviation meaning "potential for hydrogen."; a scale used to define the levels of hydrogen (H) or hydroxide (OH) ions in a solution. Ranges from 0 (acidic) to 14 (basic/alkaline), with 7 being neutral [ACID] – Compound that forms hydrogen ions (H+) in solution; a solution with a pH of less than 7 [BASE] – Compound that produces hydroxide ions (OH-) in solution; pH level more than 7 Answer. (46 points total) 1. List the five characteristics inherent to all living things. (5) a. Growth b. Reproduction c. Homeostasis d. Respond to Stimuli e. Obtain and Use Energy 2. Why must living organisms be able to reproduce? (1) a. Reproduction is important because it prevents the organisms being extinct 3. Why is homeostasis an important characteristic of living things? (1) a. Because it regulates its internal environment 4. What do you think it means to sense and respond to stimuli? (1) a. Basically being aware of your surrounding and being able to respond to it 5. What are the possible sources of energy for living organisms? (2) a. Sun b. Chemical 6. Why is it essential that living things be able to use energy? (1) a. Energy can break down and build up molecules and transport it through the membranes 7. A friend asks you about viruses: Specifically, she wants to know if they are alive. You explain that viruses consist of genetic material (RNA or DNA) surrounded by a protein coat, which may or may not be enclosed in a small membrane. When a virus infects a cell, the genetic material in the virus “overwrites” the cell's genetic instructions, and the cell produces more of the components of the virus and assembles the components for it. (5 points) a. Does a virus grow? a. Yes the virus grow b. Does a virus reproduce? a. Yes, virus can reproduce c. Does a virus maintain a stable internal environment? a. No d. Does a virus sense and respond to stimuli? a. Yes e. Does a virus obtain and use energy? a. For it to be reproduce it uses the energy from the host cell 8. Keeping these characteristics in mind, what is your answer? Is a virus alive? (1) a. I believe that virus is alive with the relation they have with host cells 9. What makes carbon such an important part of life’s molecules? (1) a. Carbon is consider the building blocks of life; all living organisms contain carbon 10. What kind of chemical bonds does a carbon atom typically make with other atoms? (1) a. Covalent Bond 11. Up to how many bonds can a carbon atom form? (1) a. Up to 4 bonds 12. What characterizes organic molecules? (1) a. Carbon atoms in rings that are attached to other atoms like oxygen and hydrogen etc. 13. Is the compound methane (four hydrogen attached to a central carbon) organic? (1) a. Yes this compound is organic 14. For each of the below descriptions, write down which of the four molecules of life it is describing: (protein, carb, lipid, or nucleic acid) (1 point each = 13) a. when “complex,” they contain many subunits in straight or branching chains o Carbohydrate b. do not have repeating subunits o Lipid c. subunits are amino acids o Protein d. some are used to speed up chemical reactions o Protein e. used for storing, transmitting, and executing genetic information o Nucleic Acid f. subunits are composed of a nitrogenous base, five-carbon sugar, and phosphate group o Nucleic Acid g. subunits are joined to each other with peptide bonds o Protein h. some function as hormones o Lipid i. subunits are called monosaccharides o Carbohydrate j. subunits each have the same core structure, but they differ in the side chains they contain o Protein k. the three-dimensional shape of the molecule is essential for it to function correctly o Protein l. some are useful as padding or insulation o Lipid m. subunits usually consist of carbon rings o Carbohydrate n. the two types of molecules in this class differ based on whether they consist of a single chain of subunits or two chains of subunits o Nucleic Acid o. some of them are a major component of cell membranes o Lipid p. subunits are nucleotides o Nucleic Acid 15. What are two basic components of the cell membrane? (2) a. Phospholipid Bilayer b. Proteins 16. Why is the cell membrane important? (1) a. It regulates what comes in and out; 17. Are the atoms in water covalently or ionically bonded? How do you know? (2) a. Covalent bonded; Hydrogen atoms share electrons with the oxygen atom 18. Why is water a polar molecule? (1) a. One is positive charged end and one negative charge end; the different charges cancel each other out 19. What does being polar have to do with being a good solvent? (1) a. Being polar the substance has to have different ends one positive and the other negative which makes it dissolves 20. What is hydrogen bonding and how does it affect water bonding with itself and other substances? (2) a. attraction between a highly electronegative atom in one polar bond and a slightly positive hydrogen atom in another polar bond b. High Heat capacity 21. How does hydrogen bonding affect the heat capacity of water? (1) a. Heat capacity of water is the property that is caused by hydrogen bonding 22. Explain why water is important for life. (1) a. Due to water flowing, water gives an efficient way to transfer substance from a cell to cell’s environment Review Questions (Highlight the correct answer) (1 point each = 11) 1. Which of the following is not a characteristic of all living things? A. growth B. reproduction C. using energy D. breathing E. acquiring energy 2. True or False: Evidence of life on Mars will definitely fit within our definition of life on Earth. 3. The simplest kind of carbohydrate molecule is called a _____. Carbohydrates are primarily important because they can be used to _____. A. monosaccharide / store energy B. amino acid / carry out various cellular functions C. nucleotide / store genetic information D. fatty acid / store energy E. amino acid / store genetic information 4. Which type of biological macromolecule is not made of chains of linked monomers? A. Complex Carbohydrates B. Lipids C. Proteins D. Nucleic Acids E. None of the above; all are made of chains of monomers 5. All of the following are types of lipids except _____. A. Nucleic acids B. Fatty acids C. Triglycerides D. Sterols E. Phospholipids 6. The tails of phospholipids are A. Hydrophobic. B. Hydrophilic. C. Neutral. 7. The heads of phospholipids are A. Hydrophobic. B. Hydrophilic. C. Neutral. 8. What part of a phospholipid in the cell membrane interacts with the inside environment of the cell? A. Head B. Tail C. Neither 9. Water molecules attracted to each other by hydrogen bonds will be connected by bonds between _____ A. the positive (hydrogen) side of one molecule and the negative (oxygen) side of the other. B. the positive (hydrogen) side of one molecule and the positive (hydrogen) side of the other. C. the negative (oxygen) side of one molecule and the negative (oxygen) side of the other. D. Both B and C E. None of the above. 10. Which of the following pairs of terms apply to a single water molecule’s structure? A. polar, covalent bond B. nonpolar, covalent bond C. polar, hydrogen bond D. nonpolar, hydrogen bond 11. Waxes are a kind of lipid. Why does water form beads on wax paper? A. B. C. D. Wax is hydrophobic; water will be attracted to itself by cohesion but not to the wax. Wax is hydrophilic; water will be attracted to the wax paper by adhesion but not to itself. Wax is hydrophobic; water will be attracted to the wax paper by adhesion but not to itself. Wax is hydrophilic; water will be attracted to itself by cohesion but not the wax.