BIO 313 Exam 3 Review
Ch. 16, 17, 21, 5-7
Supplemental Instruction
Iowa State University
Leader:
Course:
Instructor:
Date:
Laura
Bio 313
Dr. Tuggle
10/25/15
1. Which of the following is not a level of gene regulation?
a. Alteration of DNA structure
b. mRNA processing
c. Posttranslational modification
d. Rate of replication
2. DNA binding motif that is characterized by two alpha helices is known as
a. Leucine Zipper
b. Zinc Finger
c. Helix-turn-Helix
d. Helix-loop-Helix
3. Draw the basic structure of an operon:
See Figure 16.3
4. Continuously expressed genes under normal cellular conditions running the
factory building is known as
a. Positive control
b. Constitutive expressed
c. Negative control
d. Inducibly regulated
5. 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
 Allosterically activate
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
6. The lac operon is a ________ _________ operon
a. Negative repressible
b. Positive repressible
c. Negative inducible
d. Positive inducible
7. In the presence of allolactose, the lac repressor
a. Binds the operator
b. Binds the promoter
c. Cannot bind the operator
d. Binds to the regulatory gene
8. What is the effect of high levels of glucose on the lac operon
a. Transcription is stimulated
b. Little transcription takes place
c. Transcription is not affected
d. Transcription may be stimulated or inhibited, depending on the levels of
lactose
9. In trp operon, what happens to the trp repressor in the absence of tryptophan?
a. It binds to the operator and represses transcription
b. It cannot bind to the operator and transcription takes place
c. It binds to the regulator gene and represses transcription
d. It cannot bind to the regulator gene and transcription takes place
10. Molecules that influence the formation of secondary structures in mRNA
a. Ribozymes
b. Riboswitches
c. Antisense RNA
d. Molecular chaperons
11. Chromatin structure is controlled by all of the following except
a. DNase I hypersensitivity
b. Histone modification
c. DNA methylation
d. DNA binding proteins
12. What is the function of an insulator?
a. To enhance the effect of an enhancer
b. To block all effects of the enhancer
c. To block long range effects of the enhancer
d. To enhance only a specific enhancer
13. Match the term to the definition
Term
_D__Complete dominance
Definition
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
_B_Penetrance
__C__Expressivity
C. The degree to which a character is
expressed; strength of phenotype
D. Phenotype of the heterozygote is the
same as the phenotype of one of the
homozygotes
E. Phenotype of the heterozygote includes
the phenotypes of both homozygotes
14. A child has type A blood. The genotypes of the parents could be any of the
following except:
a. IAIA x IBi
b. IAIB x ii
c. ii x IBii
d. IAIB x IAIB
15. Match the term to the definition
Term
_D__Sex-linked characteristic
Definition
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
D. Genes located on the sex chromosome
_E_Genetic material maternal effect
E. Nuclear genotype of the maternal parent
_C_Cytoplasmic inheritance
__B_Genomic imprinting
F. Genes on autosomal chromosomes that
are more readily expressed in one sex
16. Epigenetics effects all of the following except
a. Stress levels
b. Cognition
c. Metabolism
d. Likelihood of having twins
17. Which of the following is a disadvantage of humans of experimental subjects
a. Enormous biological info
b. Extensive genetic records
c. Long generation time
d. Large family size
18. What inheritance pattern is seen below?
Autosomal Recessive
19. Why do you have twin studies? What is their purpose?
To help distinguish between genetic and environmental influences on phenotype
20. 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.
21. 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