Exam 2 Genetic Study Guide Fall 2024 PDF

**Exam 2 covers lecture material from Sept. 26 -- Oct. 25 and Labs 6, 7, and 8.** Class notes are in Canvas - Module 3. Create a study plan: Practice working through problems done in class, practice homework problem sets, and quizzes 3 and 4 are also good practice for some of these topics. Practi...

**Exam 2 covers lecture material from Sept. 26 -- Oct. 25 and Labs 6, 7, and 8.** Class notes are in Canvas - Module 3. Create a study plan: Practice working through problems done in class, practice homework problem sets, and quizzes 3 and 4 are also good practice for some of these topics. Practice writing out answers. 1\. **Cell structure** - Know the three Domains and types of cells that are characteristic of each Domain. - Be able to describe similarities and differences among prokaryotic and eukaryotic cells. - Know names of the parts of the cell that we covered in lecture: cell wall, plasma membrane, nucleus & nuclear envelope (eukaryotes only), nucleolus (eukaryotes only), nucleoid (prokaryotes only), mitochondrion (mitochondria), chloroplast, cytoskeleton (microtubules & microfilaments), ribosomes, and plasmids. Know the primary functions of these parts and in what kinds of cells (eg, prokaryotic vs eukaryotic; animal vs plant vs fungal) they would be found. - Locations of DNA within different types of cells and whether the DNA molecules are linear or circular. - Basic structure of DNA, RNA, proteins, and chromosomes. How are DNA and RNA similar vs. different? How are proteins different from nucleic acids such as DNA and RNA? What are chromosomes made of? 2\. **Mitosis** - Mitotic cell cycle: G~1~, S, G~2~, mitosis. - Basic results of mitosis: 2 new, genetically identical cells; same chromosome number as original cell and genetically identical to original cell. - Basic structure of a chromosome: DNA + proteins; centromere. - Difference between a replicated and an unreplicated chromosome; - Difference between chromosome, sister chromatids, non-sister chromatids, homologous chromosomes, non-homologous chromosomes - Diploid vs. haploid chromosome number (ploidy level) - Functions of mitosis (other than for asexual reproduction). - Details of the stages of mitosis: - prophase, prometaphase, metaphase, anaphase, telophase - Differences between animal and plant cells in the formation of their spindles. - Terms: centrosome, aster, microtubules, spindle fibers, mitotic spindle, kinetochore. - Cytokinesis: - how this works in animal vs plant cells. - Terms: cleavage, cleavage furrow, phragmoplast, cell plate. 3\. **Asexual vs sexual life cycles** - Types of asexual reproduction and genetic consequences (offspring are genetic clones of parents). - Sexual life cycles for animals, fungi, and plants. You should be able to sketch the basic life cycle and apply all of the following terms: diploid (2n), haploid (n), meiosis, mitosis, gametes (sperm and egg), fertilization, zygote. - In sexual reproduction, what are the two processes involved? How do these processes contribute to genetic variability in offspring? 4\. **Meiosis** - The basic outcome and its genetic consequences: 4 cells produced, each with half the number of chromosomes of the original cell, and all genetically unique. - Important terms: haploid, diploid, homologous chromosomes, synapsis, crossing over, independent alignment of homologous pairs, segregation of homologs. - Meiosis I: In addition to details of spindle formation and the movement of chromosomes during each stage, be sure to understand - synapsis of homologous chromosomes; how crossing over works and when it happens. - the concept of segregation of homologs during Anaphase I, the genetic consequences (segregation of alleles at a gene - Mendel's first principle), and the chromosomal consequences (reduction in ploidy level from diploid to haploid). - the concept of independent alignment of different homologous pairs and the genetic consequences (independent assortment of alleles at different genes - Mendel's second principle). - that chromatids [do not] separate during this stage. - Meiosis II: Chromosome behavior much like mitosis, but be sure to remember to begin with replicated chromosomes that retain any genetic recombination that occurred in Meiosis I. 5\. **Mendelian genetics** - Single gene crosses: gene, allele, genotype, phenotype, heterozygote (heterozygous genotype), dominant, recessive, homozygote (homozygous genotype), true-breeding line, the three most important crosses (AA x aa, Aa x Aa, Aa x aa) and what they tell you about dominance and allelic segregation. - Two-gene crosses: be able to work crosses using two unlinked genes. Be able to make predictions about what you would expect to see if genes are linked (on the same chromosome) vs. unlinked (genes located on non-homologous chromosomes) - Theories and Laws (be able to explain) - **Cell theory** - **Particulate theory of inheritance** - ***Mendel's law of segregation*:** Mendel's principle of segregation: [During meiosis, the two alleles at a gene segregate from one another into separate cells.] Be able to clearly explain the connection between chromosome behavior in meiosis and this principle. You should also be able to give examples using genes and alleles and draw a meiotic cell that shows segregation occurring. - *Mendel's principle of independent assortment*: [During meiosis, the alleles at one gene segregate independently of the alleles at other genes.] Genes that are on separate chromosomes will exhibit independent assortment of their alleles. You should be able to explain this clearly using alleles from two genes, and draw or recognize a meiotic cell that shows independent assortment occurring. - Solving genetic problems: Use Punnett squares or rules of probability (multiplication rule and addition rule) to work forwards or backwards to determine genotypes, phenotypes, and their expected proportions. - Mendelian genetics and hypothesis testing: - Figuring out the pattern of inheritance requires developing hypotheses, predictions, and testing those predictions by doing genetic crosses (review material from labs 7 and 8) - You should understand how to diagram a cross to show the expected (predicted) outcome. Diagramming a cross includes defining the allelic notation, writing the genotypes and phenotypes of the parents, writing the genotypes and phenotypes of the offspring. - You should be able to interpret actual (observed) genetic data to determine whether or not it agrees with your predictions (expectations) and to determine whether or not the data support your genetic hypothesis. - Know when to use a test cross and a reciprocal cross and predictions from each - Variations on single-gene crosses: sex-linked traits (X-linked in mammals), multiple alleles at a gene, dominance hierarchies, incomplete dominance, co-dominance.