AP Biology

Reading Guide

Chapter 10 – From DNA to Protein: Gene Expression

Chapter 10 – From DNA to Protein: Gene Expression

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QUESTIONS – Section 10.1: The Function of Genes

Go to the website Here you will find an excellent series of tutorials for Chapters 8-12 of our book. Explore panels 21-28 to guide you through this chapter. Be sure to click on the animation and problem links to get the complete info.

  1. What is a gene?
  1. Refer to the following hypothetical pathway to answer the following question:

1 2 3

A  B  C  D

After irradiation with X-rays, Neurospora spores were allowed to on various minimal media plates supplemented with one the metabolites in the pathway above. While the spores were able to grow on minimal media supplemented with metabolite D, but not on plates supplemented with either A, B, or C. Which enzyme is defective?

  1. Explain the one gene-one enzyme hypothesis.
  1. Why was this later refined to the one gene-one polypeptide hypothesis?
  1. Compare the structure and composition of RNA and DNA.

RNA / DNA
Sugar
Bases
Structure
  1. Why doesn’t DNA directly control protein synthesis?
  1. Describe the function of the various classes of RNA.

rRNA
mRNA
tRNA
  1. Define codon.
  1. Summarize the flow of genetic information from DNA to protein (the central dogma).

QUESTIONS – Section 10.2: Transcription

  1. Where does transcription occur in a eukaryotic cell?
  1. Define template strand. Define noncoding strand.
  1. Which direction is mRNA synthesized?
  1. Define promoter. What is the significance of the promoter?
  1. What signals RNA polymerase to stop transcription?

Eukaryotic mRNA Processing

  1. List the three modifications that are made to the primary mRNA transcript in eukaryotes before it is considered a mature mRNA and leaves the nucleus.
  1. What functional significance does the 5’-cap and poly-A tail serve?
  1. Define intron and exon.
  1. Do prokaryotes have introns?
  1. Describe the biological relevance of introns.

QUESTIONS – Section 10.3: The Genetic Code

  1. Why did scientists believe the genetic code was a triplet code?
  1. Explain the significance of each of the following statements regarding the genetic code:
  2. The genetic code is redundant but not ambiguous
  1. The genetic code is universal
  1. Define genetic mutation. What are possible sources of mutations?
  1. Can a mutation in the DNA of your skin cell be passed on to your offspring? Why or why not?
  1. Distinguish between a point mutation and a frameshift mutation. Which would be more severe?
  1. The occurrence of a point mutation can have one of three effects on the final protein product; missense, nonsense, or silent mutation. Using Fig 10.12, distinguish between these scenarios.

QUESTIONS – Section 10.4: Translation

  1. Where does translation take place in a eukaryotic cell?
  1. Sketch a tRNA below. Label the 5’ and 3’ ends, the anticodon loop and the point at which the amino acid attaches.
  1. What is aminoacyl-tRNA synthetase? How many aminoacyl-tRNA synthetases should exist in a cell? What high-energy molecule is required for this reaction?
  1. Describe the structure of the ribosome.
  1. Summarize the events that occur during the various stages of translation:

Initiation
Elongation
Termination
  1. Explain the difference between the E site, P site and A site of the large ribosomal subunit.
  1. Which amino acid does every protein start with? What is its codon?
  1. Which direction does translation occur?
  1. Which direction (N or C-terminal) are new amino acids added?
  1. Explain this statement: Peptide bond formation attaches the peptide chain to the newly arrived amino acid.
  1. When does the ribosome ‘know’ to terminate protein synthesis?
  1. Define polyribosome.
  1. Use Table 10.1 to compare/contrast transcription and translation between prokaryotes and eukaryotes.

QUESTIONS – Section 10.5: Post-Translational Protein Modification

  1. What determines if a protein will be synthesized in the cytosol or by a ribosome associated with the ER?
  1. What are three ways a post-translational modification may alter protein structure and function?

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