BIOD 210 Exam 2 genetics/Questions & Answers

Which of the following statements is correct? Mendel’s work demonstrated that genes are linked to similar genes. Dominant genes are usually linked to the male sex chromosomes. Mendel’s label of “unit factors” are wha ...

Which of the following statements is correct? Mendel’s work demonstrated that genes are linked to similar genes. Dominant genes are usually linked to the male sex chromosomes. Mendel’s label of “unit factors” are what we now refer to as genes. Corrrreecctt!! Genetic characteristics are controlled by unit factors that exist as individual entities. Question 2 2 / 2 pts True or False: A dominant gene will always cause the expression of a dominant phenotype in the case of complete dominance. Corrrreecctt!! True False Question 3 2 / 2 pts People with sickle-cell disease can become very sick under what conditions? Desert environments Corrrreecctt!! High altitude Low altitude Humid environments Question 4 0 / 4 pts Your Answer: A homozygous long-haired cat is bred with a homozygous shorthaired cat. Assuming that the gene for long hair is completely dominant, what are the chances of the F1 offspring being shorthaired? 0% 0%; All offspring will be heterozygous long-haired. Question 5 0 / 4 pts Your Answer: A dog breeder is looking to cross a long-haired female dog with a short-haired male dog. The gene for hair length has incomplete dominance. By crossing the F1 offspring, what percentage of the F2 generation are predicted to be medium-haired? 25% 50%; A 1:2:1 ratio predicts 50% of the offspring to be heterozygotes, or medium- haired. Question 6 0 / 6 pts Your Answer: Consider 3 genes that assort independently in squirrels. A gene for brown color is dominant (D), a gene for a bushy tail is dominant (B), and a gene for reflux after eating acorns is recessive (a). Use the product law to predict the likelihood of producing a squirrel (from parents that are heterozygous for each trait individually) that is brown, skinny-tailed, but feels ok after eating lots of acorns. 3/64 that feels okay after eating lots of acorns,but brown and bushy tail (3/4) x (1/4) x (3/4) = 9/64 probability of brown, skinnytailed, and with no reflux. Question 7 6 / 9 pts Your Answer: Two individuals with widow’s peaks have a child with a straight hairline. A. True or False: The gene for a widow’s peak is likely dominant? B. True or False: Assuming no codominance, you can conclude that the parents are heterozygous for a widow’s peak. C. If the child with the straight hairline someday marries a person with a straight hairline, can you predict whether their offspring will have a widow’s peak? A.true B.true C. no because the other parent could be heterozygous or homozygous for a straight hairline so either could be made A. True B. True C. You could predict that if the straight hairline is recessive (ww), then both parents will pass along a ‘w’ gene, thus making the child ww, and they will not have a widow’s peak. Question 8 2 / 2 pts Alternate forms of a gene are termed: Dominant Genotypes Corrrreecctt!! Alleles Epistates Loci Question 9 14 / 14 pts Match the terms on the left with their best definition on the right. Gamete Sex cells that carry chromosomes. Corrrreecctt!! Phenotype The physical manifestation of any trait. Corrrreecctt!! Heterozygous Containing two different alleles for a specific gene. Corrrreecctt!! Wild-type The allele that is predominantly expressed. Corrrreecctt!! Corrrreecctt!! Codominance Both genes can produce two independent gene products. Genotype The two alleles carried for a given trait (i.e., Dd, DD or dd). Corrrreecctt!! Chromosome The structure on which genes are organized. Corrrreecctt!! Question 10 6 / 6 pts Your Answer: Give a brief description of a karyotype and explain why it has such utility in diagnosing genetic disorders. What type of cells are used for deriving the chromosomes? its a snapshot of the chromosomes within the cell, it is a utility in diagnosing genetics disorders because they can be organized into homologous pairs to detect genetic abnormalities that may appear in some as they age. white blood cells are used for deriving chromosomes