Download assignmentschapters16-19and11-1

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Chapter 16- The Molecular Basis of Inheritance
1. A fly has the following percentage of Adenine (A) nucleotides: 21%. Using Chargaff’s rule,
predict the percentage of the other nucleotides in this fly.
Thymine (T)Guanine (G)Cytosine (C)-
2. Why can DNA Pol III add nucleotides to the 3’ end of a growing strand of DNA but cannot add
nucleotides to the 5’ end??
3. List the order in which the enzymes and proteins used to make a new strand of DNA are
utilized during the process of DNA replication. Briefly describe their function.
Enzyme or Protein
Function
1.
2.
3.
4.
5.
6.
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4. Compare and contrast the synthesis of the leading strand and the lagging strand.
Leading strand
Lagging strand
Directionality of synthesis
(5’  3’ or 3’ to 5’)
Direction of synthesis
(toward or away from
replication fork?)
Continuous or
Discontinuous synthesis?
5. Euchromatic vs. Heterocchromatic DNA
Euchromatic
Heterochromatic
Gene for hemoglobin in a
Red Blood Cell
YES / NO
Yes / NO
Gene for hemoglobin in a
skin cell
Yes / NO
Yes / NO
Describe how DNA
packaged when it is in this
form.
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Chapter 17-From Gene to Protein
1. Given your understanding of transcription and translation, fill in the blanks below and
indicate the 5 and 3 ends of each nucleotide sequence. Assume no RNA processing occurs.
Nontemplate strand of DNA:
5 A T G T A T G C C A A T G C A 3
Template strand of DNA:
__ T _ _ _ _ _ _ _ _ _ _ _ _ _ _ __
mRNA:
__ A _ _ _ _ U _ _ _ _ _ _ _ _ _ __
Anticodons on complementary tRNA: __ _ _ _ / _ _ _ / _ _ _ / _ _ _ / _ _ _ / __
Amino acids
_____ / _____ / _____ / _____ / _____ /
2. How does RNA polymerase “know” where to start transcribing a gene…
in prokaryotes?
in eukaryotes?
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3. A number of different types of RNA exist in prokaryotic and eukaryotic cells. List the three
main types of RNA involved in transcription and translation. Answer the questions to complete
the chart.
a. Types of RNA:
b. Where are they
produced?
c. Where and how do they
function in cells?
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4. The chart lists a point mutation that may occur in the original strand of DNA. What happens
to the amino acid sequence or protein produced as a result of this mutation? (Note: Position 1
refers to the first base at the 3 end of the transcribed strand. The last base in the DNA strand,
at the 5 end, is at position 21.)
A. Original template strand: 3 TAC GCA AGC AAT ACC GAC GAA 5
mRNA
_________________________________
tRNA
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amino acid sequence
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Mutation
i. Substitution of T for G at position 8.
Effect on amino acid sequence
B. Mutated template strand: 3 TAC GCA ATC AAT ACC GAC GAA 5
mRNA
_________________________________
tRNA
_________________________________
amino acid sequence
_________________________________
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Chapter 18- Regulation of Gene Expression
1. Lac Operon Function- For each of the conditions listed in the first column of the table below,
indicate whether it occurs when the Lac operon is “OFF” of when it is “ON”.
Conditions
Lac Operon “OFF”
Lac Operon “ON”
RNA Polymerase binds to the
promoter
Lactose is present
The Lac genes are transcribed
and translated
The repressor protein binds to
the operator located within the
promoter
The Lac I regulatory gene,
located upstream of the Lac
operon, is transcribed and
translated into the repressor
protein
Lactose binds to the repressor
protein, changing the
repressor protein shape
2. List the genes that are found within the Lac Operon:
3. What function do the proteins made from these genes serve?
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Human genes cannot all be active at the same time. If they were, all the cells in our bodies
would look the same and have the same function(s). For specialization to occur, some genes or
gene products must be active while others are turned off or inactive.
4. In eukaryotes, gene expression or gene product expression can be controlled at several
different levels. Indicate what types of control might occur at each level of gene or gene
product expression.
Note: The table presents a representative sample of the various types of control mechanisms. It
does not include all possible mechanisms of control.
Level
a. The gene or DNA itself
Types of control
b. The mRNA product of the
gene
c. The protein product of the
mRNA
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Chapter 19- Viruses
1. Name the 2 major components of a virus.
2. “A virus is a living organism.” Support of refute this statement.
3. What type of organism does a bacteriophage infect?
4. Compare the effect on the host cell of a lytic phage and a lysogenic phage.
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Chapter 11- Cell Communication
1. Describe a signal transduction pathway that you observe in your everyday life. Include the
three parts of a signal transduction pathway: Reception, Transduction, and Response.
Reception
Transduction
Response
2. Nerve growth factor (NGF) is a water-soluble signaling molecule. Would you expect the
receptor for NGF to be intracellular or in the plasma membrane? WHY?
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3. Using the figure below, determine whether epinephrine is a water-soluble or lipid-soluble
hormone. How can you tell?
Describe the signal transduction pathway initiated by epinephrine in a liver cell. Include a
description of all three steps of the signal transduction pathway.
4. Using the figure below, determine whether estradiol is a water-soluble or lipid-soluble
hormone. How can you tell?
Describe the signal transduction pathway initiated by estradiol in a bird’s liver cell. Include a
description of all three steps of the signal transduction pathway.
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