Chapter 2: Biological Molecules

 Biological Molecules

Introduction

1.     Define biochemistry.

2.     Name the six most common elements in the bodies of living organisms.

3.     What percentage of the human body by weight is made up of hydrogen and oxygen?

Fundamental biological molecules

4.     List the four main types of compounds present in a cell.

5.     Explain why carbon plays an important role in forming organic compounds.

6.     Differentiate between organic and inorganic compounds with examples from the text.

7.     Why are proteins considered the most abundant organic compounds in the cell?

8.     Compare the percentage of DNA in bacterial cells and mammalian cells.

9.     Explain the importance of enzymes and hormones in a cell.

10.  Identify two components that are present in a higher percentage in mammalian cells compared to bacterial cells.

11.  Define polymer and monomer as given in the text.

12.  List the four major classes of biological macromolecules.

13.  What is the monomer unit of nucleic acids?

14.  Produce a Table and match each polymer with its correct monomer and give one example for each.

Condensation and hydrolysis  

15.  Name the process in which monomers are joined together to form polymers.

16.  Give an example of a condensation reaction.

17.  Explain the difference between condensation and hydrolysis reactions.

18.  Describe the role of enzymes in hydrolysis and condensation processes.

19.  Why are proteins considered polymers? Support your answer with examples from the text.

Biological importance of water

20.  How does the structure of water contribute to its polar nature?

21.  Explain why water is called the “universal solvent” according to the text.

22.  State the importance of adhesion and cohesion to explain how water moves upward in plant xylem.

23.  Define specific heat capacity of water.

24.  What is the significance of water’s high specific heat for living organisms?

25.  At what temperature does water freeze and boil under normal atmospheric pressure?

26.  Explain why water can absorb or release large amounts of heat without large changes in its own temperature.

27.  Describe how the high specific heat of water benefits aquatic organisms during seasonal temperature changes.

28.  Why is ice less dense than liquid water, and how is this property important for aquatic life?

29.  Predict what might happen to life in polar regions if ice sank instead of floating.

30.  If water had a low specific heat, explain how it would affect the body temperature regulation of mammals.

31.  Apply the concept of hydrogen bonding to explain why evaporation of water has a cooling effect on the human body

32.  Why does water’s high specific heat make it a good temperature buffer for living organisms?

33.  How do hydrogen bonds influence the physical properties of water?

34.  Why is the property of water having a high latent heat of vaporization important for plants?

Carbohydrates

35.  Name the two functional groups present in glucose.

36.  Give the general formula of monosaccharides.

37.  Differentiate between monosaccharides, disaccharides, and polysaccharides using examples.

38.  From your understanding of carbohydrate classification, classify lactose and explain why it fits that category.

39.  How does the presence of hydroxyl groups in glucose influence its chemical reactivity?

40.  Define monosaccharides and give two examples.

41.  What is the general formula of monosaccharides?

42.  Name the three-carbon sugars.

43.  What is fructose? Which functional group is present in it?

44.  Write the molecular formula of glucose.

45.  Explain the difference between aldose and ketose sugars with examples.

46.  Describe the difference between triose, pentose, and hexose sugars.

47.  Why are glucose and fructose considered structural isomers?

48.  What is the significance of pentose sugars in nucleic acids?

49.  Describe the process of disaccharide formation from two monosaccharides.

50.  Identify the bond formed between two monosaccharides in a disaccharide.

51.  What would happen to sucrose if hydrolyzed in the presence of enzymes like sucrase.

52.  Based on the structural formula, determine if galactose is an aldose or ketose and justify your answer.

53.  Why are monosaccharides considered the simplest form of carbohydrates?

54.  Why is glucose the most abundant monosaccharide in nature?

55.  Define disaccharides and give three examples.

56.  Name the monosaccharides that form sucrose, lactose, and maltose.

57.  What type of bond links the monosaccharides in a disaccharide?

58.  Define polysaccharides and give two examples.

59.  State one storage function and one structural function of polysaccharides.

60.  Explain how a glycosidic bond is formed between two monosaccharides.

61.  Describe the difference between storage polysaccharides and structural polysaccharides.

62.  How is cellulose different from starch in terms of function and structure?

63.  Why can’t most animals digest cellulose?

64.  Explain the role of glycogen in animals.

65.  Compare the glucose arrangement in cellulose and starch.

66.  What is hydrolysis? What would result from the hydrolysis of maltose.

67.  Explain how the presence of different glycosidic bonds affects the properties of polysaccharides.

68.  Why polysaccharides are considered macromolecules?

69.  How does the branching in glycogen benefit animals metabolically?

70.  What is the significance of storing carbohydrates as polysaccharides rather than monosaccharides in cells?

Proteins

71.  Define amino acids.

72.  Name the four basic components of an amino acid structure.

73.  What does the R group in an amino acid represent?

74.  Give the full names and abbreviations for Gly, Lys, and Phe.

75.  Which functional group gives amino acids their acidic property?

76.  Explain why amino acids are considered the building blocks of proteins.

77.  Describe how the R group affects the properties of amino acids.

78.  Why are amino acids with different R groups important for protein diversity?

79.  Compare the side chains of glycine and phenylalanine in terms of complexity.

80.  Describe the general chemical composition of proteins.

81.  What would happen to a protein’s function if one amino acid in its sequence was replaced by another with a very different R group.

82.  Identify which of the given amino acids is nonpolar and explain your reasoning.

83.  How amino acids bond together to form polypeptides.

84.  Why is the R group called the “variable” part of an amino acid?

85.  How do the chemical properties of the R group influence protein shape?

86.  How can proteins have such a wide variety of functions in living organisms?

87.  Define a peptide bond.

88.  What two functional groups are involved in peptide bond formation?

89.  What are the two main types of protein shapes?

90.  Give one example of a fibrous protein and one example of a globular protein.

91.  Explain how dipeptides are formed.

92.  Describe the role of hemoglobin in red blood cells.

93.  How does the sequence of amino acids affect protein function?

94.  Differentiate between fibrous and globular proteins in terms of structure and solubility.

95.  Why does sickle cell anemia cause red blood cells to have reduced oxygen-carrying capacity?

96.  List four functions of proteins in living organisms.

97.  Explain how proteins act as structural components in living organisms.

Lipids

98.  Define lipids.

99.  Name the two components that form an acylglycerol.

100. Differentiate between saturated and unsaturated fatty acids.

101. Why are lipids insoluble in water but soluble in organic solvents?

102. Compare the structure of saturated and unsaturated fatty acids and relate this to their state at room temperature.

103. Apply the difference between saturated and unsaturated fats to explain why vegetable oils remain liquid at room temperature.

104. Why is the hydrophobic nature of lipids important for living cells?

105. Define phospholipids.

106. Name the two parts of a phospholipid molecule.

107. Give two examples of steroids.  Write their function.

108. What are terpenoids, and where are they found?

109. Which steroid helps maintain male and female characteristics?

110. Explain how the structure of phospholipids makes them suitable for forming cell membranes.

111. Describe the role of cholesterol in the human body.

112. Explain why terpenoids are considered important plant products.

113. Discuss how testosterone and oestrogen differ in their functions.

114. Explain why steroids can easily pass through cell membranes.

115. Analyze the health risks associated with high cholesterol levels.

116. Suggest possible uses of terpenoids in medicines based on their plant origins.

117. Why do phospholipids arrange themselves in a bilayer in water?

118. How does the presence of cholesterol affect the fluidity of cell membranes?

119. Why are steroids classified as lipids even though they do not contain fatty acids?

Nucleic acids

120. Define nucleotides.

121. Name the three components of a nucleotide.

122. What is a nucleoside?

123. List the main types of nitrogenous bases.

124. Give two examples each of purines and pyrimidines.

125. What type of bond joins the phosphate group to the sugar in a nucleotide?

126. Explain the difference between a nucleotide and a nucleoside.

127. Describe the phosphodiester bond and its role in nucleic acid structure.

128. How do DNA and RNA differ in their sugar components?

129. Explain the role of ATP as a nucleotide derivative.

130. Describe the structural difference between purines and pyrimidines.

131. Explain why ATP is called an energy currency molecule.

132. How does the presence of a phosphate group affect the chemical properties of nucleotides?

133. Why is ATP considered a high-energy molecule?

134. How does the chemical difference between ribose and deoxyribose influence RNA and DNA function?

135. Define a dinucleotide and give an example.

136. What is ATP and what does it stand for?

137. Write the full forms of NAD and NADP.

138. List the three components of ATP.

139. State the amount of energy released when ATP is hydrolyzed to ADP and Pi.

140. How are polynucleotides formed from nucleotides?

141. Differentiate between DNA and RNA in terms of their sugar and nitrogenous bases.

142. Name the four types of nucleotides present in DNA.

143. What is the diameter of the DNA molecule?

144. Give the chemical names for the nucleotides represented as dAMP, dTMP, dGMP, and dCMP.

145. List the three main types of RNA.

146. Differentiate between the sugar present in DNA and RNA.

147. Describe the role of each type of RNA (mRNA, tRNA, rRNA).

DNA as Hereditary material

148. Who conducted the first experiment showing that DNA is the genetic material?

149. Name the two types of bacteria used in Griffith’s experiment.

150. Which scientists proved that DNA is responsible for the virulence of Pneumococcus?

151. State the contribution of Hershey and Chase in proving that DNA is the hereditary material.

152. Define a gene.

153. What is meant by a triplet code in DNA?

154. Explain the process by which Griffith demonstrated the transfer of genetic material.

155. Describe how Avery, McLeod, and McCarty’s work supported Griffith’s findings.

156. Using the bacteriophage experiment, explain how Hershey and Chase confirmed that DNA is the genetic material.

157. Explain why DNA is called the “data bank” of living organisms.

158. What is genetic code?

159.