BIOL 1103 1st EditionExam # 3 Study Guide Lectures: 14 - 18Lecture 14 (October 3)What are phenotype, genotype, allele, homozygous, heterozygous?Phenotype refers to the physical traits and behaviors of an organism whereas genotype refers to the genetic makeup of an organism. An allele is a variation of a gene and genes usuallyhave two alleles. Homozygous organisms have two identical alleles of a gene for a given character and heterozygous organisms have differing alleles.What are Mendel’s Laws?Mendel’s first law states that differing characters in organisms result from two genetic elementsthat separate during gamete formation so that each gamete gets only one of two alleles (LAW OF SEGREGATION). Mendel’s second law states that during gamete formation gene pairs assort independently of each other (LAW OF INDEPENDENT ASSORTMENT). Lecture 15 (October 8) What is incomplete dominance? What is codominance?Incomplete dominance is a genetic condition in which the heterozygous phenotype is intermediate between the homozygous phenotypesCodominance is when two alleles of a given gene have different phenotypic effects with both effects manifesting in organisms that are heterozygous for the geneWhat is polygenic inheritance? Why is it represented in a bell curve?Polygenic inheritance is the inheritance of a genetic character that is determined by the interaction of multiple genes with each gene having a small additive effect on the character; thisproduces all the human diversity. Polygenic inheritance is represented by a bell curve to more accurately express the continuing variation of species.Lecture 16 (October 10)What is sex linkage? What are three sex-linked traits in humans? What are the effects of these traits?Sex linkage is the association of certainalleles with sex chromosomes that cause traits to appear in certain genders more often than others.Three sex-linked traits in humans are hemoplilia, Duchenne muscular dystrophy, and red-green color blindness. Hemophilia causes faulty blood clotting, Duchenne muscular dystrophy causes atrophy of muscles, and red-green colorblindness prevents people from being able to distinguishshades of red from greenWhat is the relationship between Queen Victoria and the Russian Revolution of 1917?Queen Victoria was a carrier of hemophilia and through ancestral transference a son, Alexis, was born with the disease. He was the son of Czar Nicholas II. Alexis’ mother took him to Rasputin, a purported healer, and had no luck. The disease and the falsified healer were all factors leading to the decline of the Royal Russian family and the Russian Revolution in 1917.Lecture 17 (October 15)What are genes and what do they do?Genes are information segments made of DNA that lie on chromosomes. They carry the information via DNA for making proteins.How does DNA replicate?DNA strand unwinds and free-floating nucleotides join both strands and this forms two new DNA strands made of old and new contents.What are three ways DNA differs from RNA?The sugar in RNA is just ribose as opposed to deoxyribose found in DNA. Adenine bonds with uricil in RNA as opposed to bonding with thymine. Lastly, RNA is single-stranded and does not take on the double helical shape that DNA does. Lecture 18 (October 17)What are DNA plasmids? What is recombinant DNA?DNA plasmids are ring-like structures found in prokaryotes that contain the cell’s DNA. Recombinant DNA is made through a process called polymerase chain reaction that clips a segment of DNA and then seals it into a new segment of DNA. Recombinant DNA is important now because it is being inserted into prokaryotes’ plasmids so that they can reproduce the desired gene more rapidly than could eukaryotes.Why do stem cells have so much potential?Embryonic stem cells can form every type of cell found in an adult human body. Adult stem cells are becoming more diverse are able to vary in the types of cells they produce, as