AP BIOLOGY
GENETICS
GENE EXPRESSION & CONTROL
Name __________________________________# ____
Date _________________ Period __________________
GENE EXPRESSION IN EUKARYOTES
5 Levels of Processing
Transcription Factors
mRNA Processing
mRNA Transport
Translation
Protein Processing
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A FEW OUTCOMES OF EUKARYOTIC GENE CONTROL
PROKARYOTIC GENE CONTROL
Promoter
Repressor
Operon
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TRP OPERON
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LAC OPERON
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QUESTIONS AND LEARNING OBJECTIVES
1. Listed below are descriptions and examples of the different types of recombination in bacteria. Classify each
type as:
A) transformation
B) transduction
C) conjugation
D) transposons
______ Bacteria assimilate genetic material from surroundings
______ Bacteria take up DNA from environment
______ Gene transfer from one bacterium to another via bacteriophage
______ Direct transfer of genes between two bacterial temporarily joined by sex pili
______ Jumping genes first described by Barbara McClintock
______ Pieces of DNA move from one location to another location in cell’s genome
______ A DNA segment is moved from one location to another
______ DNA is transferred from one bacterium to another by a virus
______ A plasmid is exchanged between two bacteria through a pilus
______ Bacterial strains A and B are growing together in a colony that has been infected with viruses. After a short
period of time, a new strain of bacteria is detected that is very similar to strain A, but has a few characteristics of B.
______ The conversion of live R strain Streptococcus pneumoniae into S strain when heat-killed S strain is
added to R strain
______ E. coli bacteria are induced to take up the pBLU plasmid
2. Match the description/function with the correct term.
A. Corepressor genes with related functions
C. Operon into several polypeptides
E. Promoter
G. Repressor
______ Regulated cluster of adjacent structural
B. Operator
D. Polycistronic mRNA
F. Regulatory Genes
H. Structural gene
______ Gene that codes for polypeptide
______ Transcript of several genes; translated
______ RNA segment between promoter & structural genes; controls access of RNA polymerase to
structural gene
______ Specific protein that binds to operator and blocks transcription
______ Genes that code for repressor or regulators of other genes gene
______ RNA polymerase binding site
______ Molecule that binds to repressor protein; complex then binds to operator
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3. Explain how the trp operon works:
a. If tryptophan is absent from the cell.
b. If tryptophan is present in the cell
4. Explain how tryptophan acts as a corepressor.
5. Match these components of the lac operon with their functions.
______ β-galactosidase
A. is inactivated when attached to lactose
______ cAMP-CAP complex
B. codes for synthesis of repressor
______ lactose
C. hydrolyzes lactose
______ operator
D. stimulates gene expression
______ promoter
E. repressor attaches here
______ regulator gene
F. RNA polymerase attaches here
______ repressor
G. acts as inducer that inactivates repressor
______ structural gene
H. codes for an enzyme
6. Listed below are characteristics of repressible and inducible enzymes. Identify each of the following as true of
Repressible or Inducible enzymes.
______ genes are switched off until a specific metabolite inactivates the repressor
______ genes are switched on until a specific metabolite activates the repressor
______ Generally function in anabolic pathways
______ Usually function in catabolic pathways
______ Pathway end product switches off its own production
______ Enzyme synthesis is switched on by the nutrient in used in the pathway
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