Membrane Transport Proteins Part A What distinguishes facilitated diffusion from simple diffusion? No energy is used to move molecules across the membrane. Membrane proteins help move molecules across the membrane. Molecules move from a region of higher concentration to a region of lower concentration. Molecules move from a region of lower concentration to a region of higher concentration.… Read More »

Part A This animation illustrates the functioning of a _____ protein. To view the animation, click here. Then click on the image to start the animation. receptor contractile structural protein gene regulatory transport Correct The protein is transporting a substance across the cell membrane. Part B Arrow A is indicating a(n) _____ protein. transport enzyme signal structural receptor Correct… Read More »

Part A Which molecule is not a carbohydrate? Starch Glycogen Lipid Cellulose Correct A lipid is a hydrophobic polymer, not a carbohydrate. Part B Which of the following statements about monosaccharide structure is true? Aldoses and ketoses differ in the position of their hydroxyl groups. A six-carbon sugar is called a pentose. All monosaccharides contain carbon, hydrogen, oxygen, and nitrogen… Read More »

Part A Which of these is NOT a lipid? wax cholesterol phospholipid RNA steroids Correct RNA is a nucleic acid Part B This figure is an example of a(n) _____. nucleic acid saturated fat unsaturated fat steroid protein Correct The fatty acid tails lack double bonds. Part C Which of these is a phospholipid? Answer Correct Phospholipids are… Read More »

Part A Proteins are polymers of _____. glycerol nucleotides amino acids hydrocarbons CH2O units Correct Proteins are polymers of amino acids. Part B What type of bond joins the monomers in a protein’s primary structure? ionic hydrophobic hydrogen peptide S – S Correct The amino acids of a protein are linked by peptide bonds. Part C Which of… Read More »

Part A If a strand of DNA has the nitrogen base sequence 5′-ATTTGC-3′, what will be the sequence of the matching strand? 3′-GCAAAT-5′ 3′-ATTTGC-5′ 3′-UAAACG-5′ 3′-TUUUCG-5′ 3′-TAAACG-5′ Correct Adenine pairs with thymine and guanine pairs with cytosine. Part B If a DNA double helix is 100 nucleotide pairs long and contains 25 adenine bases, how many guanine bases… Read More »

Condensation and Hydrolysis Reactions Part A Which polymers are composed of amino acids? Monomers Carbohydrates Proteins Nucleic acids Correct Proteins are composed of amino acids joined together. Part B Which of the following is not attached to the central carbon atom in an amino acid? A side chain (“R group”) An oxygen A carboxyl functional group An amino functional group… Read More »

Functional Groups Part A Which one of these is an amino group? B D E A C Correct This is an amino group, NH2. Part B Which of these is a phosphate group? F A C E B Correct Of the choices, this is the only one that contains phosphorus. Part C Which of these is a hydroxyl… Read More »

Isomers Part A L-dopa is used to treat _____. muscle sprains laryngitis Marfan’s syndrome Parkinson’s disease Alzheimer’s disease Correct People with Parkinson’s disease lack dopamine. Part B What kind of effect does R-dopa have on Parkinson’s disease? It alleviates the symptoms. It makes the symptoms of Parkinson’s disease worse. At first it makes the symptoms worse but over… Read More »

Diversity of Carbon-Based Molecules Part A How do these hydrocarbons differ? One of these hydrocarbons is longer than the other. One of these hydrocarbons has a ring structure. These hydrocarbons are identical. One of these hydrocarbons is branched. One of these hydrocarbons has a double bond. Correct The hydrocarbon on the right is longer than the hydrocarbon on… Read More »