Chapter 4 The Outsiders S.E. Hinton

Proteins are used to build cells, & they act as enzymes! 55. What are the 4 main elements making up proteins? How many covalent bonds does each of these elements form? - Carbon forms four covalent bonds - Hydrogen forms one covalent bond - Oxygen forms two covalent bonds - Nitrogen forms three covalent bonds 56. Sketch these two amino acids --- glycine & alanine. Circle the center carbon, place a triangle around the amino group, and put a box around the carboxyl group. For glycine and alanine, draw a carbon atom and attach a hydrogen atom to it. Circle the carbon atom. Around the carbon atom, draw a triangle to represent the amino group (-NH2) and a box to represent the carboxyl group (-COOH) 57. What are the monomers of proteins called? How many are there? Name the 4 things bonded to the center carbon of this monomer. The monomers of proteins are called amino acids. There are 20 different amino acids commonly found in proteins. The four things bonded to the center carbon of this monomer are: - Amino group (-NH2) Carboxyl group (-COOH) Hydrogen atom (H) Variable R-group (side chain) 58. The main difference among amino acids is their ____R-____ group. What is the R-group on glycine? on alanine? The R-group on glycine is a hydrogen atom, while the R-group on alanine is a methyl group (-CH3) 59. Differences in R-groups give different proteins different ________structures and functions______. 60. How does a dipeptide form? Sketch the dipeptide formed from glycine and alanine. What molecule had to be removed to join these 2 amino acids? A dipeptide forms through a dehydration synthesis reaction, where the amino group of one amino acid reacts with the carboxyl group of another, releasing a water molecule. 61. What do you call the covalent bonds that hold amino acids together? Put a box around these bond in the sketch you did on question 60. The covalent bonds that hold amino acids together are called peptide bonds 62. Long chains of amino acids are called ___polypeptides_______ and these join together to make a _____protein_______. 63. Hydrogen bonding among individual amino acids in a chain cause what effect on the protein's shape? Hydrogen bonding among individual amino acids in a chain can cause the protein to fold into a specific shape or conformation 64, What is the effect of temperature on protein shape? Give an example of this. Temperature can affect protein shape. For example, high temperatures can denature proteins, causing them to unfold or lose their shape, and consequently, their function 65. Most proteins act as catalysts or _____enzymes ________ inside of cells. 66. The substance an enzyme is acting upon is called the _substrate___ and it must __bind ___ into a place called the active site on the enzyme. 67. When a substrate joins with an enzyme, what effect does this have on chemical bonding of that substrate? Is the enzyme affected temporarily or permanently? How is it affected? When a substrate joins with an enzyme, it forms an enzyme-substrate complex. This interaction temporarily weakens certain chemical bonds in the substrate, facilitating the reaction. The enzyme is not permanently affected by this interaction 68. When chemical bonds in a substrate are weakened, what effect does this have on activation energy needed to start the reaction? When chemical bonds in a substrate are weakened, it lowers the activation energy needed to start the reaction 69. After the reaction, what happens to the products? Can the enzyme be re-used & why? After the reaction, the products are released from the active site of the enzyme. Yes, the enzyme can be reused because it is not consumed or altered during the reaction 70. Besides temperature, what else can effect how an enzyme works by changing the enzyme's shape? Can the reaction still take place? Besides temperature, factors such as pH, substrate concentration, and the presence of inhibitors can affect how an enzyme works by changing its shape. If the enzyme's shape is significantly altered, the reaction may not take place efficiently or at all