Download Molecular Genetics

Molecular Genetics
Chapters 16-21
Chapter 16: The Molecular Basis of Inheritance
1. The first half of this century was an exciting time for molecular geneticists as they
hurried to be the first to elucidate the structure of DNA. Describe the early
experiments that paved the way for the discovery of DNA and relate it to the
theme of “science as a process.” (Be sure to discuss Griffith’s, Avery’s, Hershey
& Chase’s, and Chargaff’s work)
2. Watson & Crick are credited with discovering the structure of DNA. What
crucial piece did they need to solve the puzzle? Describe their work.
3. Examine Figure 16.6. What holds the nitrogenous bases of DNA together? Draw
each base pair and label the number and type of bonds between each base.
4. Watson & Crick were special. After discovering the structure of DNA, they set
their sights on how DNA gets replicated. Describe the model they proposed.
What is this process called?
5. Describe the Messelson and Stahl experiments. What did they prove?
6. DNA replication has different mechanisms in prokaryotes and eukaryotes.
Describe how replication begins in each of these types of cells.
7. What role does DNA polymerase play in replication? What type of molecule is a
polymerase?
8. How is energy ATP different than the ATP used in DNA synthesis?
9. DNA strands are antiparallel. What does this mean using 5’ and 3’ in your
answer. How does this affect replication (discuss lagging strand)?
10. What role does DNA ligase serve?
11. DNA polymerase can only elongate DNA, not begin a new strand. What enzyme
can begin a new strand?
12. What is the role of helicases and single-stranded binding proteins?
13. Mistakes happen, but with DNA, a mistake can be quite costly. How can
enzymes proofread DNA and repair damage along the way?
14. Examine Figure 16.16. With at least ½ a page, copy the drawing and label it by
hand.
15. Now write a brief summary of DNA replication from beginning to end, be sure to
use all of the enzymes.
16. What is the end region of DNA called? What problem does this region pose in
terms of replication?
17. The above regions have been the subject of recent research. Describe how they
have implications for aging and cancer.
Chapter 17: From Gene to Protein
1. What is the connection between a gene and a protein? Relate this to the one geneone polypeptide hypothesis.
2. Review: List the main differences between DNA and RNA.
3. Provide the definitions of transcription and translation. What does each make and
where do they occur?
4. There are 3 types of RNA. Please describe these in relation to their functions.
5. There are 4 DNA nucleotides and 20 amino acids. How can we relate these
languages to each other? In other words, describe the mathematical reasoning
behind needing 3 nucleotides to code for an amino acid and not two.
6. DNA has 2 strands. What is the name of the strand with the code for a protein?
What is a codon?
7. What is meant by “reading frame?”
8. What information does the genetic code provide?
9. What is the role of RNA polymerase?
10. Describe how the promoter, transcription factors, and the TATA box help initiate
transcription. Do you like the TATA box?
11. RNA polymerase elongates the growing RNA strand until it reaches what? What
happens then?
12. After RNA is released from the DNA template, many modifications are made.
Describe what is meant by a poly(A) tail and RNA splicing. Describe and copy
Figure 17.9 in your answer.
13. What is a spliceosome (other than one of the coolest words known to man)?
Describe the difference between an exon and an intron.
14. What is a ribozyme? Explain this in relation to the sentence “All biological
catalysts are proteins.”
15. Translation involves “translating” from one biological language to another. What
am I talking about?
16. How are codons and anticodons related? What molecule has the codon and which
has the anticodon?
17. A tRNA is shaped like what letter? Draw a tRNA molecule and describe how it
functions as the translator.
18. What is an aminoacyl-tRNA synthetase? How does it function?
19. What is a ribosome made of? Distinguish between the P, A, and E site of a
ribosome.
20. How does translation get initiated?
21. Describe how a polypeptide gets elongated during translation.
22. Discuss how a polypeptide chain gets terminated and released from the ribosome.
23. Like transcription, after translation finishes the product continues to get modified.
These modifications occur in the endoplasmic reticulum. Describe how signal
peptides and signal recognition particles help the young, maturing protein enter
the E.R. to receive its modifications.
24. Bacteria are slightly different in that they do not have a nucleus. What
implication does this have for their transcription and translation?
25. What is a mutation? Specifically, describe what a point mutation is.
26. There are 3 types of point mutations. List them and describe what happens.
27. What is a mutagen? Provide examples of mutagens.
Chapter 18: Microbial Models: The Genetics of Bacteria and Viruses
1.
2.
3.
4.
5.
Describe how scientists discovered viruses.
What is a virus? Discuss the structure of a virus and include a drawing of one.
What is a bacteriophage?
Discuss how viral replication occurs. What does the virus need to reproduce?
Discuss the differences between the lytic and lysogenic cycles. Which one is the
“bad” one?
6. What is a viral envelope and what is its function?
7. How can viruses be classified? Give examples. Hint: See Table 18.1
8. What is a retrovirus? How do they work? Give an example.
9. What is a vaccine and how do they protect you?
10. Is their a relationship between viruses and cancer? Explain.
11. Why are plant viruses a problem?
12. Distinguish between viroids and prions. What can they do?
13. Viruses exist “in the semantic fog between life and nonlife.” Explain.
14. Why are bacteria great organisms to use in research?
15. What is a bacterial nucleoid?
16. Distinguish between transformation and transduction. What can be accomplished
through each method?
17. What is bacterial conjugation (aka bacterial sex) and how does it work?
18. What is a plasmid? Describe how the F plasmid works?
19. What is an R plasmid and how can it lead to antibiotic resistance?
20. Why should we worry about antibiotic resistance?
21. What is a transposon and what role do they play in bacterial genetics?
22. Bacteria can regulate the expression of their genes with an operon. What is an
operon and describe how they function?
23. Distinguish between an operator, a promoter, and a repressor. What roles do they
serve?
24. Distinguish between an inducible and a repressible operon. What is an inducer?
25. Describe the example of positive gene regulation at the end of the chapter.
26. Draw an operon with a repressor, promoter, operator, and inducer. Explain in
your own words how these work to regulate gene expression.
Chapter 19: The Organization and Control of Eukaryotic Genomes
1. What is chromatin?
2. DNA gets tightly packet in order to fit all 6.5 feet of it in every cell’s nucleus.
Describe Figure 19.1 in relation to DNA packing. Be sure to discuss what
nucleosomes are.
3. What is repetitive DNA (aka junk DNA)? How much of the human genome is
repetitive? Distinguish between tandemly and interspersed repetitive DNA.
4. What is a multigene family and what does this say about evolution?
5. What is a pseudogene?
6. Describe how gene amplification, loss, or rearrangement can alter a cell’s
genome.
7. What is a transposon and how much of a human genome do they make up?
8. Explain what is meant by cell differentiation. How does this impact what genes
are expressed in that cell?
9. Figure 19.7 demonstrates the many opportunities for control of gene expression in
eukaryotes. Study this figure closely because it sets the stage for the next several
pages. What does it mean to “express a gene?” Why is it important that we
regulate the expression of our genes?
10. What is DNA methylation and why does it occur?
11. What is histone acetylation and why does it occur?
12. What role do transcription factors have in regulating gene expression? Be sure to
discuss enhancers, promoters, and activators.
13. What is meant by coordinately controlled genes?
14. Alternative mRNA splicing is really quite nifty. What happens?
15. Explain how regulating the degradation of mRNA helps to control gene
expression.
16. How is translation controlled?
17. How can protein processing and degradation help regulate gene expression?
18. Distinguish between oncogenes and protooncogenes.
19. What role do tumor-suppressing genes serve?
20. Explain the normal function of the ras and p53 genes. What happens when these
genes do not function correctly?
21. Cancer is said to have genetic causes. Explain how multiple mutations can cause
cancer.
22. Explain how viruses can cause cancer. In what percent of human cancers are
viruses said to be the main cause?
Chapter 20: DNA Technology
1. Distinguish between genetic engineering and biotechnology.
2. Examine Figure 20.1. List the 6 steps for gene cloning. What possible uses does
this technique have?
3. What are restriction enzymes and what are they used for? What is a sticky end?
What brings DNA back together again (DNA glue)?
4. What is the Polymerase Chain Reaction? Why do we use it?
5. What is gel electrophoresis? How does it work and what does it accomplish?
6. What are RFLPs?
7. What was the Human Genome Project?
8. How can biotechnology be used for human gene therapy? What could the
potential results be?
9. Explain how DNA technology is used in forensics. Be sure to discuss DNA
fingerprinting.
10. Explain how DNA technology can be used for environmental uses.
11. Explain how DNA technology can be used in agriculture.
12. What is meant by “DNA technology raises important safety and ethical
questions”? How do you feel about the use of this technology?
Chapter 21: The Genetic Basis of Development (EXTRA CREDIT!)
Using the Chapter 21 outline on page 388, read the chapter and make 5 bullets of
information for each main bullet on the outline. Your bullets can include definitions or
examples of the statements on the outline. Finish by writing ONE paragraph
summarizing what you learned from the chapter.