Author: Biology Junction Team

Chapter 15 – Chromosomal Basis of Heredity Objectives

 

Chapter 15     Chromosomal Basis of Heredity
Objectives
Relating Mendelian Inheritance to the Behavior of Chromosomes

1.  Explain how the observations of cytologists and geneticists provided the basis for the chromosome theory of inheritance.

2.  Explain why Drosophila melanogaster is a good experimental organism for genetic studies.

3.  Explain why linked genes do not assort independently.

4.  Distinguish between parental and recombinant phenotypes.

5.  Explain how crossing over can unlink genes.

6.  Explain how Sturtevant created linkage maps.

7.  Define a map unit.

8.  Explain why Mendel did not find linkage between seed color and flower color, despite the fact that these genes are on the same chromosome.

9.  Explain how genetic maps are constructed for genes located far apart on a chromosome.

10. Explain the effect of multiple crossovers between loci.

11. Explain what additional information cytogenetic maps provide.

Sex Chromosomes

12. Describe how sex is genetically determined in humans and explain the significance of the SRY gene.

13. Distinguish between linked genes and sex-linked genes.

14. Explain why sex-linked diseases are more common in human males.

15. Describe the inheritance patterns and symptoms of color blindness, Duchenne muscular dystrophy, and hemophilia.

16. Describe the process of X inactivation in female mammals. Explain how this phenomenon produces the tortoiseshell coloration in cats.

Errors and Exceptions in Chromosomal Inheritance

17. Explain how nondisjunction can lead to aneuploidy.

18. Define trisomy, triploidy, and polyploidy. Explain how these major chromosomal changes occur and describe possible consequences.

19. Distinguish among deletions, duplications, inversions, and translocations.

20. Describe the type of chromosomal alterations responsible for the following human disorders: Down syndrome, Klinefelter syndrome, extra Y, triple-X syndrome, Turner syndrome, cri du chat syndrome, and chronic myelogenous leukemia.

21. Define genomic imprinting. Describe the evidence that suggests that the Igf2 gene is maternally imprinted.

22. Explain why extranuclear genes are not inherited in a Mendelian fashion.
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Chapter 16 – Molecular Basis of Inheritance

 

Chapter 16   Molecular Basis of Inheritance
Objectives
DNA as the Genetic Material
1. Explain why researchers originally thought protein was the genetic material.
2. Summarize the experiments performed by the following scientists that provided evidence that DNA is the genetic material:
a. Frederick Griffith
b. Oswald Avery, Maclyn McCarty, and Colin MacLeod
c. Alfred Hershey and Martha Chase
d. Erwin Chargaff
3. Explain how Watson and Crick deduced the structure of DNA and describe the evidence they used. Explain the significance of the research of Rosalind Franklin.
4. Describe the structure of DNA. Explain the base-pairing rule and describe its significance.
DNA Replication and Repair
5. Describe the semiconservative model of replication and the significance of the experiments of Matthew Meselson and Franklin Stahl.
6. Describe the process of DNA replication, including the role of the origins of replication and replication forks.
7. Explain the role of DNA polymerases in replication.
8. Explain what energy source drives the polymerization of DNA.
9. Define antiparallel and explain why continuous synthesis of both DNA strands is not possible.
10. Distinguish between the leading strand and the lagging strand.
11. Explain how the lagging strand is synthesized even though DNA polymerase can add nucleotides only to the 39 end. Describe the significance of Okazaki fragments.
12. Explain the roles of DNA ligase, primer, primase, helicase, topoisomerase, and single-strand binding proteins.
13. Explain why an analogy can be made comparing DNA replication to a locomotive made of DNA polymerase moving along a railroad track of DNA.
14. Explain the roles of DNA polymerase, mismatch repair enzymes, and nuclease in DNA proofreading and repair.
15. Describe the structure and function of telomeres.
16. Explain the possible significance of telomerase in germ cells and cancerous cell.

 
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Chapter 17 AP Objectives

 

Chapter 17    From Gene to Protein
Objectives
The Connection Between Genes and Proteins
1. Explain why dwarf peas have shorter stems than tall varieties.
2. Explain the reasoning that led Archibald Garrod to first suggest that genes dictate phenotypes through enzymes.
3. Describe Beadle and Tatum’s experiments with Neurospora and explain the contribution they made to our understanding of how genes control metabolism.
4. Distinguish between the “one geneÐone enzyme” hypothesis and the “one geneÐone polypeptide” hypothesis and explain why the original hypothesis was changed.
5. Explain how RNA differs from DNA.
6. Briefly explain how information flows from gene to protein.
7. Distinguish between transcription and translation.
8. Compare where transcription and translation occur in prokaryotes and in eukaryotes.
9. Define codon and explain the relationship between the linear sequence of codons on mRNA and the linear sequence of amino acids in a polypeptide.
10. Explain the early techniques used to identify what amino acids are specified by the triplets UUU, AAA, GGG, and CCC.
11. Explain why polypeptides begin with methionine when they are synthesized.
12. Explain what it means to say that the genetic code is redundant and unambiguous.
13. Explain the significance of the reading frame during translation.
14. Explain the evolutionary significance of a nearly universal genetic code.
The Synthesis and Processing of RNA
15. Explain how RNA polymerase recognizes where transcription should begin. Describe the promoter, the terminator, and the transcription unit.
16. Explain the general process of transcription, including the three major steps of initiation, elongation, and termination.
17. Explain how RNA is modified after transcription in eukaryotic cells.
18. Define and explain the role of ribozyme.
19. Describe the functional and evolutionary significance of introns.
The Synthesis of Protein
20. Describe the structure and functions of tRNA.
21. Explain the significance of wobble.
22. Explain how tRNA is joined to the appropriate amino acid.
23. Describe the structure and functions of ribosomes.
24. Describe the process of translation (including initiation, elongation, and termination) and explain which enzymes, protein factors, and energy sources are needed for each stage.
25. Describe the significance of polyribosomes.
26. Explain what determines the primary structure of a protein and describe how a polypeptide must be modified before it becomes fully functional.
27. Describe what determines whether a ribosome will be free in the cytosol or attached to the rough endoplasmic reticulum.
28. Describe two properties of RNA that allow it to perform so many different functions.
29. Compare protein synthesis in prokaryotes and in eukaryotes.
30. Define point mutations. Distinguish between base-pair substitutions and base-pair insertions. Give examples of each and note the significance of such changes.
31. Describe several examples of mutagens and explain how they cause mutations.
32. Describe the historical evolution of the concept of a gene.

 
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Chapter 18 – AP Objectives

 

Chapter 18    Genetics of Viruses & Bacteria
Objectives
The Genetics of Viruses
1. Recount the history leading up to the discovery of viruses. Include the contributions of Adolf Mayer, Dimitri Ivanowsky, Martinus Beijerinck, and Wendell Stanley.
2. List and describe the structural components of viruses.
3. Explain why viruses are obligate intracellular parasites.
4. Explain how a virus identifies its host cell.
5. Describe bacterial defenses against phages.
6. Distinguish between the lytic and lysogenic reproductive cycles, using phage lambda as an example.
7. Describe the reproductive cycle of an enveloped virus. Explain the reproductive cycle of the herpesvirus.
8. Describe the reproductive cycle of retroviruses.
9. List some characteristics that viruses share with living organisms and explain why viruses do not fit our usual definition of life.
10. Describe the evidence that viruses probably evolved from fragments of cellular nucleic acids.
11. Define and describe mobile genetic elements.
12. Explain how viral infections in animals cause disease.
13. Describe the best current medical defenses against viruses. Explain how AZT helps to fight HIV infections.
14. Describe the mechanisms by which new viral diseases emerge.
15. Distinguish between the horizontal and vertical routes of viral transmission in plants.
16. Describe viroids and prions.
17. Explain how a non-replicating protein can act as a transmissible pathogen.
The Genetics of Bacteria
18. Describe the structure of a bacterial chromosome.
19. Compare the sources of genetic variation in bacteria and humans.
20. Compare the processes of transformation, transduction, and conjugation.
21. Distinguish between generalized and specialized transduction.
22. Define an episome. Explain why a plasmid can be an episome.
23. Explain how the F plasmid controls conjugation in bacteria.
24. Describe the significance of R plasmids. Explain how the widespread use of antibiotics contributes to R plasmid-related disease.
25. Explain how transposable elements may cause recombination of bacterial DNA.
26. Distinguish between an insertion sequence and a transposon.
27. Describe the role of transposase in the process of transposition.
28. Briefly describe two main strategies that cells use to control metabolism.
29. Explain the adaptive advantage of genes grouped into an operon.
30. Using the trp operon as an example, explain the concept of an operon and the function of the operator, repressor, and corepressor.
31. Distinguish between structural and regulatory genes.
32. Describe how the lac operon functions and explain the role of the inducer, allolactose.
33. Explain how repressible and inducible enzymes differ and how those differences reflect differences in the pathways they control.
34. Distinguish between positive and negative control and give examples of each from the lac operon.
35. Explain how cyclic AMP and catabolite activator protein are affected by glucose concentration.
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Chapter 19 AP Objectives

 

Chapter 19    Eukaryotic Genomes
Objectives
The Structure of Eukaryotic Chromatin

1.  Compare the structure and organization of prokaryotic and eukaryotic genomes.

2.  Describe the current model for progressive levels of DNA packing in eukaryotes.

3.  Explain how histones influence folding in eukaryotic DNA.

4.  Distinguish between heterochromatin and euchromatin.

The Control of Gene Expression

5.  Explain the relationship between differentiation and differential gene expression.

6.  Describe at what level gene expression is generally controlled.

7.  Explain how DNA methylation and histone acetylation affect chromatin structure and the regulation of transcription.

8.  Define epigenetic inheritance.

9.  Describe the processing of pre-mRNA in eukaryotes.

10. Define control elements and explain how they influence transcription.

11. Distinguish between general and specific transcription factors.

12. Explain the role that promoters, enhancers, activators, and repressors may play in transcriptional control.

13. Explain how eukaryotic genes can be coordinately expressed and give some examples of coordinate gene expression in eukaryotes.

14. Describe the process and significance of alternative RNA splicing.

15. Describe factors that influence the life span of mRNA in the cytoplasm. Compare the longevity of mRNA in prokaryotes and in eukaryotes.

16. Explain how gene expression may be controlled at the translational and post-translational level.

The Molecular Biology of Cancer

17. Distinguish between proto-oncogenes and oncogenes. Describe three genetic changes that can convert proto-oncogenes into oncogenes.

18. Explain how mutations in tumor-suppressor genes can contribute to cancer.

19. Explain how excessive cell division can result from mutations in the ras proto-oncogenes.

20. Explain why a mutation knocking out the p53 gene can lead to excessive cell growth and cancer. Describe three ways that p53 prevents a cell from passing on mutations caused by DNA damage.

21. Describe the set of genetic factors typically associated with the development of cancer.

22. Explain how viruses can cause cancer. Describe several examples.

23. Explain how inherited cancer alleles can lead to a predisposition to certain cancers.

Genome Organization at the DNA Level

24. Describe the structure and functions of the portions of eukaryotic DNA that do not encode protein or RNA.

25. Distinguish between transposons and retrotransposons.

26. Describe the structure and location of Alu elements in primate genomes.

27. Describe the structure and possible function of simple sequence DNA.

28. Using the genes for rRNA as an example, explain how multigene families of identical genes can be advantageous for a cell.

29. Using a-globin and b-globin genes as examples, describe how multigene families of nonidentical genes may have evolved.

30. Define pseudogenes. Explain how such genes may have evolved.

31. Describe the hypothesis for the evolution of a-lactalbumin from an ancestral lysozyme gene.

32. Explain how exon shuffling could lead to the formation of new proteins with novel functions.

33. Describe how transposition of an Alu element may allow the formation of new genetic combinations while retaining gene function.

 
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