BIO 313 Exam 3 Review
Ch. 16, 17, 21, 5-7
Supplemental Instruction
Iowa State University / Leader: / Laura
Course: / Bio 313
Instructor: / Dr. Tuggle
Date: / 10/25/15
  1. Which of the following is not a level of gene regulation?
  2. Alteration of DNA structure
  3. mRNA processing
  4. Posttranslational modification
  5. Rate of replication
  1. DNA binding motif that is characterized by two alpha helices is known as
  2. Leucine Zipper
  3. Zinc Finger
  4. Helix-turn-Helix
  5. Helix-loop-Helix
  1. Draw the basic structure of an operon:

See Figure 16.3

  1. Continuously expressed genes under normal cellular conditions running the factory building is known as
  2. Positive control
  3. Constitutive expressed
  4. Negative control
  5. Inducibly regulated
  1. Fill in the important characteristics of each

Negative inducible
  • Tx typically off
  • Repressor bound to operator
WANT TO:
  • Turn tx ON
  • Allosterically inhibit repressor so it can’t bind to operator
/ Positive inducible
  • Tx typically off
  • Inactive activator not bound to operator
WANT TO:
  • Turn tx ON
  • Allostericallyactivate activator so it can bind to operator

Negative repressible
  • Tx typically On
  • Repressor not bound to operator
WANT TO:
  • Turn tx OFF
  • Allosterically activate repressor so it can bind to operator
/ Positive repressible
  • Tx typically off
  • Activator bound to operator
WANT TO:
  • Turn tx ON
  • Allosterically inhibit activator so it can’t bind to operator

  1. The lac operon is a ______operon
  2. Negative repressible
  3. Positive repressible
  4. Negative inducible
  5. Positive inducible
  1. In the presence of allolactose, the lac repressor
  2. Binds the operator
  3. Binds the promoter
  4. Cannot bind the operator
  5. Binds to the regulatory gene
  1. What is the effect of high levels of glucose on the lac operon
  2. Transcription is stimulated
  3. Little transcription takes place
  4. Transcription is not affected
  5. Transcription may be stimulated or inhibited, depending on the levels of lactose
  1. In trp operon, what happens to the trp repressor in the absence of tryptophan?
  2. It binds to the operator and represses transcription
  3. It cannot bind to the operator and transcription takes place
  4. It binds to the regulator gene and represses transcription
  5. It cannot bind to the regulator gene and transcription takes place
  1. Molecules that influence the formation of secondary structures in mRNA
  2. Ribozymes
  3. Riboswitches
  4. Antisense RNA
  5. Molecular chaperons
  1. Chromatin structure is controlled by all of the following except
  2. DNase I hypersensitivity
  3. Histone modification
  4. DNA methylation
  5. DNA binding proteins
  1. What is the function of an insulator?
  2. To enhance the effect of an enhancer
  3. To block all effects of the enhancer
  4. To block long range effects of the enhancer
  5. To enhance only a specific enhancer
  1. Match the term to the definition

Term / Definition
_D__Complete dominance / A. Phenptype of the heterozygote is intermediate (Falls within the range) between the phenotype of the two homozygotes
__A_Incomplete dominance / B. The percentage of individuals having a particular genotype that express the expected phenotype
_E__Codominance / C. The degree to which a character is expressed; strength of phenotype
_B_Penetrance / D. Phenotype of the heterozygote is the same as the phenotype of one of the homozygotes
__C__Expressivity / E. Phenotype of the heterozygote includes the phenotypes of both homozygotes
  1. A child has type A blood. The genotypes of the parents could be any of the following except:
  2. IAIA x IBi
  3. IAIB x ii
  4. ii x IBii
  5. IAIB x IAIB
  1. Match the term to the definition

Term / Definition
_D__Sex-linked characteristic / A. Autosomal genes whose expression is limited to one sex
__F_Sex-influenced characteristic / B. Genes whose expression is affected by the sex of the transmitting parent
_A_Sex-limited characteristic / C. Cytoplasmic genes, which are usually inherited entirely from only one parent
_E_Genetic material maternal effect / D. Genes located on the sex chromosome
_C_Cytoplasmic inheritance / E. Nuclear genotype of the maternal parent
__B_Genomic imprinting / F. Genes on autosomal chromosomes that are more readily expressed in one sex
  1. Epigenetics effects all of the following except
  2. Stress levels
  3. Cognition
  4. Metabolism
  5. Likelihood of having twins
  1. Which of the following is a disadvantage of humans of experimental subjects
  2. Enormous biological info
  3. Extensive genetic records
  4. Long generation time
  5. Large family size
  1. What inheritance pattern is seen below?

Autosomal Recessive

  1. Why do you have twin studies? What is their purpose?

To help distinguish between genetic and environmental influences on phenotype

  1. What are Mendel’s 2 laws? Include the definitions!

law of independent assortment. the principle, originated by Gregor Mendel, stating that when two or more characteristics are inherited, individual hereditary factors assort independently during gamete production, giving different traits an equal opportunity of occurring together.

law of segregation. the principle stating that during the production of gametes the two copies of each hereditary factor segregate so that offspring acquire one factor from each parent.

  1. What would be the gametes from the F1 generation? Indicate which ones would be recombinants.

Recombinants :

Pr+ vg and Pr vg+

Non-recombinants :

Pr+ vg+ and Pr vg