Texas BIO 311 – Cell cycle mitosis meiosis

11 Jun Texas BIO 311 – Cell cycle mitosis meiosis

Question
Study Guide for Exam #3
What follows is a list of questions on topics that we have covered in class since Exam #2, which includes Chaps. 12 (Cell cycle, Lecture 13 slides), 13, 16, 17 and 18 (Gene regulation, Lecture 17 slides) (please see your syllabus). If you can provide good responses to these topics, then you should be well prepared for the third exam. Please realize we have emphasized some topics more than others. This will be reflected on the exam. I highly recommend that you read the chapters in the textbook as support for the discussions of material in class. While there will not be any questions on the exam about topics that were not covered in class, the book is an excellent reflection of the class material and can provide a great deal of insight.

Cell cycle/mitosis/meiosis: (Chaps. 12 & 13)

Define genome, chromosome, chromatin, somatic cell and gamete.

If shown diagrams of non-replicated and replicated chromosomes (with 2 sister chromatids), be sure you can identify the centromere(s) and chromatid(s).

What is the difference between the terms centromere and kinetochore?

Draw the cell cycle identifying interphase, mitotic phase, mitosis, G1, S, G2 and cytokinesis. What is the order, and what characterizes each phase?

Be prepared to describe the events of mitosis. What do we mean by nuclear division? What are the main stages?

Describe the role of the spindle, asters, centrosomes, and kinetochore and nonkinetochore microtubules during mitosis.

How is cytokinesis different in animals and plants and why?

What is binary fission and in what organisms does it occur? How does binary fission differ from mitosis?

How is the cell cycle regulated? Know the role of cyclins and cdks using MPF as an example. What is the role of checkpoints? How are growth factors involved?

Describe some characteristics of normal cells that change when they become cancer cells. What are two main features that control cell growth that become unregulated in cancer cells?

Distinguish between autosomes and sex chromosomes. Distinguish between diploid and haploid.

How are the terms gene, gene loci and alleles related to one another? What are homologous chromosomes? What is a karyotype?

Define meiosis and fertilization and their roles in sexual reproduction. What is a zygote?

What are the three main types of sexual life cycles and how do they differ?

Describe the events of meiosis. What are the key steps? What is the overall purpose of Meiosis I? Meiosis II? What is crossing over and when does it occur?

What are the implications of errors during meiosis?

Be able to compare and contrast meiosis and mitosis.

How and when is genetic variation generated? Give a description of variation due to independent assortment, crossing over, and random fertilization. How does this variation relate to dominate and recessive alleles and the concepts of genotypes and phenotypes?

DNA structure/replication: (Chap. 16)

Outline the past experiments that resulted in identifying DNA as the key molecule containing hereditary information. What is the approach and underlying concept behind each experiment?

What are Chargaff’s rules? How did they help determine the structure of DNA?

What are the main parts of the DNA molecule? (overall structure, nucleotide components, and bases) How do the complementary base pairs bond together?

Explain how the structure of DNA is well-suited for replication and its function.

What is meant by semi-conservative replication? Explain the experiment that confirmed this model of replication.

What is an origin of replication? What is a replication fork?

Know the roles of helicase, single stranded binding protein, topoisomerase, primase, DNA polymerase, and ligase.

Why does DNA synthesis between the leading strand and lagging strand differ? Explain. What are Okasaki fragments? Be prepared to draw a replication fork with all of these components.

What are the roles of proofreading, mismatch repair, and nucleotide excision repair?

What is a telomere and what is its purpose?

Describe how eukaryotic DNA is organized into chromatin. Be sure you know the roles of histones and nucleosomes. What is the difference between euchromatin and heterochromatin, both structurally and functionally?

Genetic code/Gene expression: (Chap. 17)

Explain what is meant by the central dogma. What are the mechanisms of each stage involved in gene expression (transcription, translation)? What is different about gene expression between prokaryotes and eukaryotes?

What is a codon? Describe the features of the genetic code. What is meant by reading frame?

What is the function of RNA polymerase? How does RNA polymerase know where to start transcription? What is a promoter? What is a transcription factor and what role does it play?

How is a primary transcript processed in the eukaryotic nucleus? What are the roles of the 5′ cap and poly A tail? What is the difference between an intron and an exon?

What is the role of spliceosomes? What are ribozymes? What are the implications of alternate processing? Why is alternate processing important for differential cell function?

What does tRNA do? Explain the functions of the three tRNA binding sites on the ribosome.

What is an anticodon? What is wobble?

What is an aminoacyl-tRNA synthetase? What is peptidyl-tRNA? What does it bind to?

Outline the steps of translation initiation, elongation and termination.

How do polyribosomes (polysomes) speed up translation?

After translation, what else is often required to make a functional protein?

How is a protein localized to the endomembrane system? How do free ribosomes differ from bound ribosomes?

What are the roles of signal peptides and signal recognition particles?

What are the various ways a point mutation (substitution mutation, insertion, deletion) can change the way a gene leads to a gene product?

Genes can be defined in several ways depending on the context–incorporating what we covered in this chapter, what is a detailed definition of a gene?

Gene regulation: (Chap. 18)

How do bacteria regulate gene expression and the activity of gene products? What is the relationship between feedback inhibition of enzymes and the regulation of gene expression? Which is a more rapid response?

Define a regulatory gene. What is an operator and an operon? What are the roles of a repressor and a corepressor?

How do repressible operons function verses inducible operons? What is an example of each?

What is an inducer?

What is an example of positive gene regulation in prokaryotes? How does cAMP-CAP regulate the lac operon?

What meant by the term “differential gene expression” in multicellular organisms?

What are the different stages of gene regulation possible in eukaryotic cells? Name at least one way that genes can be regulated at each stage.

How does chromatin organization influence differential gene expression? What is histone acetylation and how does it affect gene expression? What are the effects of DNA methylation?

How do transcription factors regulate eukaryotic genes? What are proximal control elements and distal control elements (enhancers)? Explain the roles of general transcription factors (essential for all protein-coding genes) and specific transcription factors (the control elements).

What are some mechanisms of post-transcriptional regulation?

How are proteins marked for degradation? What are the roles of ubiquitin and the proteasome?

What are noncoding RNAs? What are some roles that they play in controlling gene expression?

Describe the role of cytoplasmic determinants and induction in cell differentiation and morphogenesis.

How is cancer related to gene regulation? What is an oncogene? What is a proto-oncogene? What is a tumor suppressor gene? How do mutations of these cause cancer?

Explain the roles of the ras oncogene and the p53 tumor suppressor.