Study Guide: ;Molecular Genetics

Introduction Cartoon:

In the comic, an mRNA strand glares at a smug looking DNA strand. The mRNA says "I'm telling you, Carol. I'm DONE being this guy's messenger boy. He can leave the nucleus and do it himself for all I care!"  What differences between DNA and RNA can you learn from the comic? Why is the mRNA calling itself a "messenger?" What message does it carry?

Learning Objectives: 

By the end of this week you should be able to 

• • Understand the role of Nucleic Acids What are they made of? what roles do they fill for living organisms)? What are chromosomes, genes, alleles,  mRNA, ribosomes?
  • Explain the relationship between DNA, RNA and proteins. How does the DNA get transcribed into RNA? How does the RNA get translated into protein? What is the relationship between the DNA sequence of a gene and the mRNA sequence and the protein amino acid sequence? What is the relationship between proteins amino acid sequence, protein folding and protein function? 
  • Assess the impact of a mutation on protein structure and function.  Given a DNA sequence and the genetic code, be able to transcribe this into mRNA, translate the mRNA into a protein's amino acid sequence.  Given the same sequence but with a  mutation, be able to transcribe and translate. This could be a point mutation or an insertion/deletion mutation. 
  • Explain the flow of information from DNA --> RNA--> Protein --> Phenotype

Study Guide Questions. 

Some of these questions will be used for your the short answer portion of your exam. The others will be converted into multiple choice questions.  

1.Explain the relationship between DNA sequence of a gene and the traits of an organism. This should include 

• • • Description and explanation of what are genes.
    • Explain the relationship between DNA->  RNA --Protein
      • making sure to explain amino acid sequence and protein folding
    • Explain the relationship between protein shape and function and phenotype. 

2. Explain the process of transcription. Make sure to use the following vocabulary: DNA, chromosome, gene, RNA polymerase, nucleotides, ATP, mRNA, nucleus

3. Explain the process of translation.  Make sure to use the following vocabulary: mRNA, ribosome, amino acids, tRNA, ATP, genetic code, protein folding.

4. Explain why a  mutation might have no impact, a small impact or a large impact on a protein's structure and function.  To answer this question you will need to 

• • • • explain the structure and function of DNA and  mRNA
      • explain what codons are and how they code for amino acids
      • explain about the difference in amino acid side chains and how the sequence of amino acids leads to different shaped proteins ( don't skimp on details!)
      • explain what a mutation is
      • show an example of a mutation that has no effect, a small effect, and a large effect.

5.  Given a DNA sequence, be able to transcribe it into the correct mRNA sequence and translate it into the correct amino acid sequence.

(Transcription and Translation Practice Assignment will help with Questions #4 and #5) 

6. Fill in the following table

7. On your Lecture Exam II, you answered a short answer question: Explain how a protein is made, modified and exported from the cell.

Take your answer to this question and a) make any corrections suggested and b) add details about how the ribosome makes proteins from what we learned this week. 

Class Powerpoints.