Exam 4: BIO1201/ BIO 1201 (Latest 2024/ 2025 Update) | Questions and Verified Answers| 100% Correct| Grade A – LSU

Exam 4: BIO1201/ BIO 1201 (Latest 2024/ 2025 Update) | Questions and Verified Answers| 100% Correct| Grade A – LSU Q: what makes a specific locus homozygous? Answer: if both homologous chromosomes carry the same allele at a given gene locus (also called true-breeding) Q: what makes a specific locus heterozygous? Answer: if 2 homologous chromosomes carry different alleles at a given gene locus (also called hybrid) Q: what is the punnett square method? Answer: a prediction of the possible offspring genotypes and phenotypes from combinations of parental gametes Q: how do you make a punnett square? Answer: 1) assign letter to the differet alleles of the characteristic under consideration (uppercase for dominant and lowercase for recessive) 2) determine the possible gametes from both parents 3) write the gametes from each parent, along each side of a 2 x 2 grid 4) fill in the gentotypes of each pair of combined gametes in the grid 5) determine the genotypic ration based on the outcome of the punnett square 6) based on which traits are dominant and which are recessive, calculate the predicted phenotypic ratio Q: what type of organism did mendel use for his experiment? Answer: pea plants Q: when an organism is homozygous for a particular characteristic, what type of phenotype do they produce? Answer: the same phenotype (if a plant is homozygous for purple flowers, it will always produce offspring with purple flowers) Q: what does the term "true-breeding" mean? Answer: organisms that are homozygous for a characteristic Q: what does the term "genetic crossing" mean in reference to pea plants? Answer: the mating of pollen and eggs from the same or different parents Q: what happens when you cross a true-breeding purple flower plant with a true-breeding white-flower plant (P generation)? Answer: the F1 generation is composed of all purple-flowered plants Q: what is a genotype? Answer: the particular combination of the 2 alleles carried by an individual (which controls the phenotype) Q: what is a phenotype? Answer: the physical expression of the genotype (you can change physical appearance without changing genes, like dying hair, etc) Q: what is a test cross? Answer: it is used to deduce whether an organism with a dominant phenotype is homozygous or heterozygous Q: what dictates gender? Answer: chromosomes Q: what set of chromosomes do females have? Answer: 2 X chromosomes