Carbon Atoms Answers

UNIT 3 1. Carbon atoms form the framework of biological molecules. 2. Molecules consisting only of carbon and hydrogen are calledhydrocarbons. 3. Carbon-oxygen and carbon-nitrogen bonds are described as which of the following? Polar covalent and formed by an unequal sharing of electrons. 4. This is the structural formula for the phosphate group. 5. Select all statements that aretrueaboutstructural isomers. They are composed of the same number and type of atoms. They differ in the actual structure of their carbon skeleton. They have the same molecular formula. 6. The framework or backbone of biological molecules consists predominantly of which of the following atoms? Carbon 7. A molecule that has mirror-image versions is called a chiral molecule. It is also known as an enantiomer. 8. Proteins are composed of monomers called amino acids nucleic acids are composed of monomers called nucleotides , and carbohydrates are composed of monomers called Monosaccharide (for example, glucose). 9. Biological polymers are often made using dehydration (or condensation) reactions. During these dehydration reactions which of the following occurs (choose all that apply)? A molecule of water is removed from the reactants. Two separate molecules are joined together by a covalent bond. An H atom is removed from one molecule and an -OH group is removed from another molecule. 10.Select the characteristics of a hydrolysis reaction. A large molecule is broken down into two smaller molecules. Water is added to the reaction. 11.Which of the following statements about enantiomers aretrue? They are mirror images of each other. They have the same carbon skeleton but differ in how the groups attached to the skeleton are arranged in space. 12. All carbohydrates contain the elements carbon, hydrogen, and oxygen in the approximate molar ratio of which of the following? 1:2:1 13. Which of the following describes the D and L forms of an organic molecule? 14. They differ in how they rotate a plane of polarized light. They are mirror images of each other. They are enantiomers. 15.Glucose and galactose can be described as which of the following? Stereoisomer 16.Which polysaccharides function primarily to store energy? Amylose, Amylopectin and Glycogen 17.In a hydrolysis reaction, water is added to break a specific covalent bond in a macromolecule. 18.When a six-carbon sugar is dissolved in water, it generally forms a ring. 19.The two classes of nucleic acids are deoxyribonucleic acid and ribonucleic acid. 20. 21. Cytosine is a pyrimidine Adenine is a purine 22.ATP is often referred to as the "energy currency of the cell. 23.Of the following list, choose the functions of proteins in living cells. They play a key role in moving materials within cells. They help the body recognize and destroy foreign microbes and cancer cells. They catalyze chemical reactions. They transport oxygen in the blood of vertebrates. 24.Which describes purines? They are double-ring molecules. They are found in both DNA and RNA. They are nitrogenous bases. 25.Identify functions of ATP. To power transport across cell membranes To drive energetically unfavorable reactions To power the movement of cells 26.What are the two major functional groups found in an amino acid, which allow it to form a peptide bond with another amino acid? Amino group and a carboxyl group. 27.How are DNA and RNA molecules similar? Both have nitrogenous bases. Both are composed of nucleotides. Both use phosphodiester bonds to link the nucleotides in a single strand together. 28. Which of the following accurately describes the chemical structure of a typical amino acid found in a protein? A central carbon atom is bound to an amino group, carboxyl group, a side chain, and a hydrogen atom. 29. Select amino acids that are most likely to be found in the interior of a protein. Leucine, Valine and Phenylalanine 30. A protein that is composed of multiple polypeptides is said to have aquaternary level of protein structure. 31. Select examples of protein domains. The region of a protein that activates transcription The region of a protein that binds to DNA 32. In general, where are nonpolar and polar amino acids found in a folded protein? Non-polar interior; Polar exterior. 33. How can scientists use protein motifs? To predict the function of the protein. 34. A protein is initially driven into its tertiary structure by what type of interactions? Hydrophobic exclusion 35. Functional units within the larger structure of a protein are called domians. 36. You are studying a protein and notice that it contains two regions made of beta-sheets connected by an alpha-helix. This type of recurring structure that can be found in proteins with very different functions is called a motif. 37. What is the function of chaperone proteins? Help other proteins fold correctly. 38. If a single protein carries out multiple functions, such as binding DNA and activating transcription, then each function may be carried out by a specific region of the protein calleddomain. 39. Trans fats are bad. 40. Common steroid: Oestrogen, testosterone and cholesterol 41. Most unsaturated fatty acids found in nature have double bonds with acis configuration where the carbon chain is on the same side before and after the double bond. 42. The presence ofdoublebonds between some of the carbon atoms in the hydrocarbon chains of a fat influences whether it is a solid or liquid at room temperature. 43. Which of the following describes the structure of a phospholipid? A polar head and two long, nonpolar tails 44. Terpenes- Long-chain lipids that are part of many biologically important pigments 45. Steroids- Composed of four carbon rings; some function as hormones 46. Prostaglandins- Act as local chemical messengers in many vertebrate tissues 47. Phosphate