Workshop #8

MOLECULAR GENETICS

1.     Make a diagram of a DNA molecule (include: nucleotides drawn like this. Draw three nucleotides per strand - any sequence is fine, and label where the covalent and hydrogen bonds are, and label the three parts of one of the nucleotides.)

DNA Molecule diagram

2.     Why are the American, James Watson, and the Englishman, Francis Crick, important in the field of molecular genetics?

3.     What is a nucleotide?

        What is a nitrogenous base?

       Compare DNA and RNA in the following ways:
 
 
                 DNA                                                RNA
      Function in cell: 
      Number of strands: 
     Type of sugar: 
     Types of nitrogenous bases present: 

4.    A.   What is a gene (as defined by molecular biologists)?

       B.   Explain how a Mendelian geneticist (from the first half of the 20th Century) would define a "gene" and then compare that with your definition above from the molecular biologist.

5.    A.   How and when during the cell cycle does DNA replication occur?

       B.   Explain why the process of DNA replication had to evolve 3 billion years ago in the primordial soup and why it is necessary for all asexually and sexually reproducing organisms on earth today to be able to do this.

6.    Considering that all the cells in your body have the same genes, what is it that allows cells to become different from each other or specialized (such as muscle cell, nerve cell, etc.)?

7.    List, in order, the sequence of events that take place when a DNA message is used to code for an enzyme or other protein. Include both transcription and translation stages. Number your steps.

8.    Describe the function of "termination codes".

9.    What are codons and anticodons?

10.   A.   What is a mutation (explain in chemical terms)?

         B.   How have mutations been important to the history of life on earth?

11.    Discuss the difference between sickle hemoglobin and normal hemoglobin. What are the symptoms present in a person who is homozygous for the recessive sickle hemoglobin gene and therefore has sickle cell anemia?

12.    Why is it so important to the survival of the cell (and ultimately the organism) that the cell be able to correctly make protein molecules? Use an example of a human genetic disorder (other than sickle cell anemia) in your answer.

13.     What is meant by the famous saying "ONE GENE --> ONE PROTEIN"?

14.     Explain how a change in a DNA molecule in a cell would affect the functioning of that cell (be specific).

15.     Explain in molecular terms how an organism's "genotype" affects his/her phenotype." For example: a plant is homozygous for red flowers, explain the chemical connection between the genotype (RR) and the resulting phenotype (red).

          How does a knowledge of molecular genetics explain what Mendel actually saw?

16.    Scenario: You are the brown-eyed parent of a brown-eyed fifth grade boy. He asks you to explain how he got his brown eye gene and how it works in his eye cells to make them brown. (You have taken Biology so you know that brown eye pigment is made in the cell as a result of an enzyme-catalyzed reaction.)

        Your task: Explain clearly to him the answer to his two questions. Include some proper terminology (such as names of molecules. etc.) but in such a way that he can easily understand what is going on. If you'll need a diagram to help explain, include it here. Use only this space below for your answer.