Biology

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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.

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

Describe how DNA packaged when it is in this form.

Gene for hemoglobin in a Red Blood Cell

YES / NO

Yes / NO

Gene for hemoglobin in a skin cell

Yes / NO

Yes / NO

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?

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?

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 _________________________________

amino acid sequence _________________________________

Mutation

Effect on amino acid sequence

i. Substitution of T for G at position 8.

B. Mutated template strand: 3( TAC GCA ATC AAT ACC GAC GAA 5(

mRNA _________________________________

tRNA _________________________________

amino acid sequence _________________________________

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?

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

Types of control

a. The gene or DNA itself

b. The mRNA product of the

gene

c. The protein product of the

mRNA

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.

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?

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.

image1.jpg

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.

image2.jpg

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