| Which polymers are composed of amino acids? | Proteins |
| Which of the following is not attached to the central carbon atom in an amino acid? | An oxygen. The central carbon atom in an amino acid is bonded to an amino functional group, a carboxyl functional group, a side chain, and hydrogen. |
| Which part of an amino acid is always acidic? | Carboxyl functional group. The carboxyl group (COOH) contains two oxygen atoms that tend to pull electrons away from the hydrogen atom, so this group tends to lose a proton and is acidic. |
| Which monomers make up RNA? | Nucleotides |
| Which of the following statements about the formation of polypeptides from amino acids is true? | A bond forms between the carboxyl functional group of one amino acid and the amino functional group of the other amino acid. A hydroxyl group is removed from the carboxyl group of one amino acid and hydrogen is removed from the amino group of the other amino acid, allowing a bond to form between the two groups. |
| True or false? Enzymes in the digestive tract catalyze hydrolysis reactions. | True |
| Which molecule is not a carbohydrate? | Lipid |
| Which of the following statements about monosaccharide structure is true? | Monosaccharides can be classified according to the spatial arrangement of their atoms. |
| True or false? Peptidoglycan is a polysaccharide found only in bacteria. | True |
| Which complex carbohydrate contains only a-1,4-glycosidic linkages? | Amylose |
| Which of the following complex carbohydrates is listed with its correct function? | Cellulose: structural component of plant cell walls |
| Which polysaccharide contains a modified monosaccharide? | Peptidoglycan. The N-acetylglucosamine and N-acetylmuramic acid units that make up peptidoglycan are composed of modified glucose monomers. |
| Which of these is NOT a lipid? | RNA |
| Saturated fat | Fatty acids lack double bonds |
| Phospholipid structure | Phospholipids are composed of a phosphate group, a glycerol, and fatty acids. |
| Which of these is rich in unsaturated fats? | olive oil |
| A function of cholesterol that does not harm health is its role | as a component of animal cell membranes |
| What do fats, steroids, and waxes have in common? | Low solubility in water |
| Dr. Haxton told one of his students, "To move in the bloodstream, fats need the help of phospholipids." What would a good student say? | Yes. Nonpolar molecules aren't compatible with water. Water rejects nonpolar molecules such as fats, so fats travel inside particles that are coated with polar parts of phospholipids and proteins. |
| Proteins are polymers of | amino acids |
| What type of bond joins the monomers in a protein's primary structure? | peptide |
| Which of these illustrates the secondary structure of a protein? | Alpha helices and beta pleated sheets are characteristic of a protein's secondary structure. |
| The secondary structure of a protein results from | Hydrogen bonds. Electronegative oxygen and nitrogen atoms leave hydrogen atoms with partial positive charges. |
| Tertiary structure is NOT directly dependent on | peptide bonds |
| Which of the following statements is an accurate description of proteins? | The primary structure of a protein is the order of amino acids in a polypeptide, as coded for in the DNA of a gene. |
| Identify the level(s) of protein structure present in this molecule. | This protein illustrates all four levels of protein structure. primary: the order of amino acids in the polypeptide chain secondary: localized regions of alpha helices and beta pleated sheets tertiary: the overall three-dimensional shape of a polypeptide, stabilized by interactions between R groups quaternary: the association of more than one polypeptide subunit into a functional protein. |
| What could happen if a mutation in a gene caused a hydrophobic amino acid in a polypeptide to be replaced by a hydrophilic amino acid? | The new amino acid would not form the same interactions with hydrophobic R groups, and the protein's shape would likely be affected. |
| If a strand of DNA has the nitrogen base sequence 5'-ATTTGC-3', what will be the sequence of the matching strand? | 3'-TAAACG-5; Adenine pairs with thymine and guanine pairs with cytosine. |
| If a DNA double helix is 100 nucleotide pairs long and contains 25 adenine bases, how many guanine bases does it contain? | 75; 100 nucleotide pairs are a total of 200 nucleotides. Because of base pairing, if there are 25 adenine there must also be 25 thymine. This leaves 200-50 = 150 nucleotides to be divided evenly between guanine and cytosine. |
| The two strands of a DNA double helix are held together by _____ that form between pairs of nitrogenous bases. | hydrogen bonds |
| A nucleotide is composed of a(n) | phosphate group, a nitrogen-containing base, and a five-carbon sugar |
| RNA nucleotides contain __________ than DNA nucleotides. | more oxygen |
| The orange unit with two linked rings in this diagram represents | A purine. Purines have two linked rings. |
| How likely is it that the next base, out of sight at the top of this polymer, is uracil? | Not a chance, since this is a DNA molecule, not an RNA molecule. |
| Which statement helps to explain how DNA stores hereditary information? | DNA contains four kinds of nitrogenous bases. |
| DNA and mRNA differ with respect to | the kind of sugar they contain |
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