Bio 181 Exam 3 Study Guide PDF

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Completed study guide for what is to be covered for exam 3....

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Bio 181 Exam 3 Study Guide 1. What are chromosomes made of? - DNA molecules and protein 2. What are somatic cells? Gamete cells? - Somatic: Diploids cells that make up your body, 46 chromosomes - Gamete: Reproductive cells (sperm and egg) haploid cells, 23 chromosomes 3. What does diploid (2n) mean? Haploid (n)? - Diploid: Containing two complete sets of chromosomes, one from each parent. - Haploid: An organism or cell having only one complete set of chromosomes. 4. What number and type of cells are produced in mitosis? In meiosis? - Mitosis: 2 cells, daughter cells (diploid), sister chromatids - Meiosis: 4 cells,(haploid) sister chromatids and homologous chromosomes 5. What is the role of the centrosome? - Organize microtubules and provide structure for the cell, as well as work to pull chromatids apart during cell division. 6. How is cytokinesis different in plant and animal cells? - Animal: Cleavage furrows - Plant: Cell plate 7. What are the stages of mitosis and what happens at each stage? - Prophase: Chromosome formation - Metaphase: Chromosomes live up on metaphase pole - Anaphase: split sister chromatids - Telophase: chromatin, nuclear envelope forming - Cytokinesis: cytoplasm division 8. What is density-dependent inhibition? - Crowded cells stop dividing - Density-dependent inhibition and anchorage dependence check the growth of cells at an optimal density 9. Medications that are used for treating cancer should target what type of cells? - Localized tumors may be treated with high-energy radiation, which damages the DNA in the cancer cells - To treat metastatic cancers, chemotherapies that target the cell cycle may be used 10. What are the phases of interphase and what happens at each phase? - G1 phase (first gap): Cell growth - S phase: duplicate chromosomes - G2: cell growth 11. How many chromosomes in a human cell after mitosis? After meiosis? - After Mitosis: 46 - After Meiosis: 23 12. What is the genome? - The entire set of genetic material (DNA) in an organism 13. What is the difference between sexual and asexual reproduction? - Sexual reproduction: 2 parents, mitosis AND meiosis, offspring have genetic variation

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Asexual reproduction: 1 parent, mitosis (binary fission), offspring genetically identical (clone) What happens during fertilization? - A sperm cell unites with an egg cell and a zygote is formed What organisms use alternation of generations? - Plants and some algae What are homologous chromosomes and what characteristics do they have in common? - Matching pair, same length, same centromere location, same traits. In humans what are the roles of the X and Y chromosomes? - Sex chromosomes What is a karyotype? - Display of chromosomes Which cells of the body are normally diploid and which are normally haploid? - Body: diploid - haploid: gametes What is crossing over and when does it normally occur? - Homologous chromosomes swap DNA - Crossing over produces recombinant chromosomes, which combine DNA inherited from each parent - Crossing over contributes to genetic variation by combining DNA from two parents into a single chromosome Be able to identify the different phases of mitosis and meiosis by images.

22. What is genotype? Phenotype? - Genotype: Combination of alleles - Phenotype: Physical characteristics 23. What is dominant allele? Recessive allele? - Dominant allele: can mask recessive allele (A), one allele - Recessive allele: two alleles (a)

24. What does homozygous mean? Heterozygous? - Same dominant or recessive alleles - different 25. Be able to do Punnett squares! a. Monohybrid crosses b. Test cross c. Sex-linked 26. What is pleiotropy? - Gene has many phenotype effects - *Cystic fibrosis or sickle cell 27. What is polygenic inheritance? - 2 or more genes→ 1 phenotype - an additive effect of two or more genes on a single phenotype - *skin color 28. What is epistasis? - 1 gene affects expression of a second gene - *animal coat color 29. What is incomplete dominance? - Situation in which one allele is not completely dominant over another allele, - heterozygous mixture of a phenotypes - *RR=Red, Rr=pink, rr=white 30. What is codominance? - 2 dominant alleles - *ABO blood types: I^A I^A= type A, I^B I^B=type B, I^A I^B= type AB 31. What is multiple alleles? - More than 2 alleles - *ABO blood types: ii=type O, I^A i= type A, I^Bi= type B 32. Why are males affected more by X-linked traits than female? - Because they have only 1 X chromosome 33. Why are all calico(tortoiseshell) cats female? - The gene that codes for coloration is found on the X chromosome. - This 'color gene' will code for a specific color such as black, orange, etc. - Each individual receives an X chromosome from its mother. - 1 X chromosome in each cell “turns off”--> barr body - mosaic phenotype - carrier or heterozygous for trait 34. Men with an x-linked gene can only pass it on to whom? - daughter 35. What is linkage and how does recombination frequency affect linkage? - Close together on chromosome and usually inherited together - genes on the same chromosome - increase distance, increases likelihood of crossover and recombination frequency - genes that are close together, less to cross over 36. What is recombination? - Offspring with nonparental phenotypes (new combinations of traits)

37. What is nondisjunction and how does that impact chromosome number? - pairs of homologous chromosomes do not separate normally during meiosis - One gamete receives two of the same type of chromosome, and another gamete receives no copy 38. What is translocation? Deletion? Inversion? Duplication - Translocation: A segment from another chromosome - Deletion: Missing segment - Inversion: Reverses the orientation of the segment - Duplication: Repeated segment 39. What is genomic imprinting? - Variation in phenotype depending on whether an allele is inherited from the male or female parent. 40. What is monosomy and an example? - Has only one copy of a chromosome - Turner Syndrome 41. What is trisomy and an example? - Has three copies of chromosome - Down Syndrome 42. What is polyploidy and what types of organisms exhibit polyploidy? -

More than two sets of chromosomes - Plants...