CELLULAR CHEMISTRY 1 O H E N C C H C OH OH OH OH H C C C. 1. Which of these molecules would be used when making a protein?

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1 CELLULAR CHEMISTRY 1 Functional groups to macromolecules 1. Biologically important macromolecules are assembled by polymerizing small subunit molecules using condensation reactions. (T/F) 2. Chemical reactions involving the combination of smaller building-block molecules with the removal of water molecules are hydrolysis reactions. (T/F) 3. The carbon atom can form so many different chemical compounds because a. its outer energy level contains four electrons. b. its electron shells are stable. c. it tends to give up electrons to electron acceptors. d. it can form both ionic and covalent bonds. Matching. A B C O H H H H H H H H H H H H C C C C C C C C C C C C C CH 3 HO H H H H H H H H H H H H O H H H O C E N C C H H H OH H C OH H D H C C C HO C H H H H H C OH H O H H C C C H H C OH OH OH OH H C OH H H 1. Which of these molecules would be used when making a protein? 2. Which of these molecules would be used when a plant makes cellulose? 3. & 4. Which TWO of these molecules are used when making a phospholipid? 5. Which of these molecules is a ketone? 6. Which of these molecules has an aldehyde functional group? 7. Which of these molecules, when put into water, would have both a positive and a negative charge? 8. Which of these molecules has the MOST hydrophobic character? 9. & 10. Which TWO of these molecules have hydroxyl groups? 11. Which of these molecules would participate in the formation of a disaccharide?

2 CELLULAR CHEMISTRY 2 Proteins 1. Proteins denature when heated due to the fragile bonds of their 1 structure. (T/F) 2. Quaternary structure of proteins is the tendency of polypeptides to fold into globular shapes. (T/F) 3. The bond between two adjacent amino acids in a protein molecule is a peptide bond. (T/F) 4. Some proteins play a structural role by forming tough fibers which help form things like hair and fingernails. (T/F) 5. Proteins that function as catalysts speed up chemical reactions but must be rapidly replaced because they are destroyed in the process. (T/F) 6. Protein denaturation is usually due to the loss of secondary structure when the proteins are exposed to high heat or very acidic ph. (T/F) 7. A particular protein passes through a membrane such that part of it is inside the cell and part of it is outside the cell. The amino acids making contact with the inner part of the membrane would mostly likely a. be composed of fatty acids b. possess phosphate groups c. have nonpolar side chains d. have multiple hydroxyl groups 8. The conformation of a protein molecule depends on several different types of bond and group interactions. Which of these will most likely remain intact when a protein is denatured? a. peptide bonds b. ionic bonds c. hydrophobic interactions d. H bonds 9. Some protein possess which are crucial, permanent parts of the protein but are not composed of amino acids. a. side kicks b. R groups c. prosthetic groups d. stanchions 10. The amino acid cysteine contains which allows it to participate in the formation of 3 and 4 structure. a. an extra carboxyl group b. an extra amine group c. a nonpolar side group c. a sulfhydryl group 11. Heat denaturation of a protein involves a loss of normal 3-D structure, especially structure a. 1 b. 2 c. 4 d. any or all of the above

3 CELLULAR CHEMISTRY In order to pass through a cell membrane, H+ must pass through a protein channel. You would expect this channel to have amino acids in the center forming the channel and amino acids on the outside in contact with the membrane a. charged / charged b. charged / nonpolar c. nonpolar / nonpolar d. nonpolar / charged 13. Some amino acids are classified as being charged amino acids due to the presence of in their side groups. a. aldehyde groups b. amine groups c. carboxyl groups d. b or c e. a, b or c 14. Some proteins possess which are permanent parts of the protein even though they are not composed of amino acids. a. side groups b. R groups c. prosthetic groups d. cofactors 15. Amino acids can be classified (on the basis of their side chains) as all these below EXCEPT a. polar b. amphibolic c. nonpolar d. charged 16. The quaternary structure of proteins is dependent on the amino acid cysteine and its ability to form. a. disulfide bonds b. ionic bonds c. hydrophobic interactions d. a, b and c Matching. The following questions deal with the 4 levels of protein structure. A. Primary B. Secondary C. Tertiary D. Quaternary 1. structure formed when multiple polypeptides are brought together 2. structure held together essentially by only hydrogen bonds 3. structure s comprised of the sequence of amino acids 4. structure is held together strictly by peptide bonds 5. structure is frequently in the form of an alpha helix 6. structure is usually globular in nature 7. structure requires the use of disulfide bonds 8. structure may be in the form of a relatively flat surface

4 CELLULAR CHEMISTRY 4 Fill in the blank Proteins must attain a particular 3 dimensional conformation in order to function. This conformation is comprised of 4 levels of structure. The 1 level is composed of the linear sequence of. 2 structure is composed of coiling (alpha helix) and folding (pleated sheet) and is held together by. In 3 structure, the coils and folds are themselves folded over resulting in most proteins having a roughly shape. Both 3 and 4 structure may be held in place by bonds which require that two cysteines be brought into the correct alignment. Short Answer Compare and contrast 2 and 3 protein structure including the how the effect the shape of the protein and what types of bonds hold them together. Briefly describe the primary, secondary, tertiary and quaternary structures of proteins. Which of these levels is most dependent on the use of disulfide bonds? Which level of structure would be the MOST difficult to disrupt? Nucleic acids 1. DNA is composed of polymers of the 20 different nucleotides. (T/F) 2. The paired strands of DNA are held together by hydrogen bonds. (T/F) 3. DNA is the macromolecule used to contain the information necessary for synthesizing proteins. (T/F) 4. The parallel strands of DNA are held together by H bonds. (T/F) 5. ATP can be used a. as one of the nucleotides for making DNA. b. as one of the nucleotides for making RNA c. as a source of energy for driving chemical reactions d. a and b are both correct e.. a, b and c are all correct 6. Both DNA and RNA. a. are single-stranded molecules b. contain the same four nucleotide bases c. are polymers of amino acids d. have the same five-carbon sugar e. contain phosphate groups

5 CELLULAR CHEMISTRY 5 7. DNA is usually double stranded, with the strands being held together by a. disulfide bonds b. peptide bonds c. ionic bonds d. hydrogen bonds 8. The backbone of DNA is composed of repeating units of a. nitrogenous bases b. glucose and phosphate c. ribose and phosphate d. glucose and nitrogenous bases 9. DNA and RNA serve in the information flow within the cell when a. DNA is converted into RNA. b. RNA is converted into DNA. c. DNA serves as a template for guiding the synthesis of RNA. d. old age sets in and the cell can't get it done any other way. 10. Which of the following is NOT part of a nucleic acid? a. phosphate group b. fatty acid c. ribose (5 carbon sugar) d. nitrogenous base 11. In DNA, you would expect to find a. adenine hydrogen bonded with thymine b. adenine hydrogen bonded with cytosine c. adenine hydrogen bonded with guanine d. adenine hydrogen bonded with uracil Lipids 1. Which of the following is NOT NECESSARILY a component of a phospholipid? a. glycerol b. 5 carbon sugar c. fatty acid d. phosphate group 2. Phospholipids are crucial for the construction of a. genes. b. polypeptides. c. cell membranes. d. polysaccharides 3. Phospholipids a. are composed of glycerol, polysaccharides and phosphate groups. b. have both hydrophobic and hydrophilic regions. c. possess extensive numbers of hydroxyl groups. d. make extensive use of aldehyde rather than hydroxyl functional groups. Fill in the blank Lipids are key molecules in the formation of cell membranes. These particular lipids are formed by reactions between 2 which have long, hydrophobic tails and the 3 carbon compound which serves as the backbone of the molecule. In addition, a group is attached to the 3rd carbon of the backbone molecule which gives it a polar head.

6 CELLULAR CHEMISTRY 6 Short Answer Briefly describe the characteristics of phospholipids that allow them to spontaneously form membranes in water. Carbohydrates 1. Sucrose (table sugar) is a disaccharide composed of two molecules of glucose. (T/F) 2. The bonds connecting the simple-sugar units of starch can be broken by hydrolysis. (T/F) 3. Glycogen, starch and cellulose are all a. easily digested food materials. b. structural components of woody plants c. polymers of glucose d. assembled using peptide bonds 4. Sugars contain either or functional groups. a. aldehyde or ketone b. carboxyl or hydroxyl c. amine or carboxyl d. hydroxyl or sulfhydryl 5. Table sugar (also called ) is a disaccharide composed of glucose and fructose. a. sucrose b maltose c. arabinose d. lactose 6. Which of the following functional groups would you LEAST expect to find as part of a sugar? a. hydroxyl b. phosphate c. ketone d. aldehyde