BIOL 112 Lecture Notes - Lecture 18: Okazaki Fragments, Dna Mismatch Repair, Dna Ligase

Question 4

Using the terms provided, complete the statements below. Some terms may apply more than once, while others may not apply at all. (15 points)

Watson and Crick determined that DNA exists in the form of a _______________, where two antiparallel chains of nucleotides wind around each other. The nitrogenous bases project to the interior where they hydrogen bond in specific pairs, ___________ with __________ and _____________ with ____________.Meselson and Stahl demonstrated that DNA is replicated by the _______________ model in which the parent molecule unwinds and each strand serves as a template for synthesis of a new strand. Synthesis of DNA is carried out by _________________, which builds the new strands in the ___________ direction. While the ______________ grows continuously; the _______________ is built in short sections called _________________, which will eventually be joined together by __________________. Eukaryotic __________________ is composed of DNA and _____________ proteins that bind together forming ________________________, the basic units of DNA packaging.

Question 5

In the table below, predict (yes or no) whether or not the E. coli lac operon will be transcriptionally active in the presence or absence of glucose or lactose as indicated and respond to questions "a" and "b."

Explain each of your answers in terms of the molecular mechanisms that are known to underlie the regulation of the lac operon. Which mechanism is considered to be negative control and which is considered to be positive control? Explain.

Question 6

Use the genetic code table in your textbook to aid you in answering the questions below. (15 points)

a.) Use the genetic code table to deduce the amino acid sequence of a protein encoded by the mRNA shown here:

5’AUGAUUGGAGGUUUGAUCGGGCAAUAGGGGUUUCAGUAAAUG3’

b.) Explain how the above sequence in "a" illustrates that redundancy of the genetic code.

c.) Explain what would happen if a mutational event caused the underlined "G" to be changed to a "U"? What is the name for this kind of mutation?

QUESTION 2. Bacterial cells use DNA replication to:

QUESTION 3. Choose the true statement about the genetic code.

QUESTION 4. Of the following enzymes, which are correctly matched with their function? To be marked correct, you'll need to select all correctly matched statements, as there may be more than one correct answer.

QUESTION 5. Which of the following contributes to DNA replication accuracy? To be marked correct, you'll need to select all true statements, as there may be more than one correct answer.