Exam 14: Mendel and the Gene Idea

Use the following information to answer the questions below. Tay-Sachs disease is an inherited genetic disorder in which the gene sequence codes for an enzyme involved in lipid metabolism.Accumulation of lipids in the brain leads to seizures,blindness,loss of neural function,and early death.People can be carriers of this disease and only homozygotic offspring will die from this disorder. -How can you reconcile these conclusions?

In humans,ABO blood types refer to glycoproteins in the membranes of red blood cells.There are three alleles for this autosomal gene: IA,IB,and i.The IA allele codes for the A glycoprotein,the IB allele codes for the B glycoprotein,and the i allele doesn't code for any membrane glycoprotein.IA and IB are codominant,and i is recessive to both IA and IB.People with type A blood have the genotypes IAIA or IAi,people with type B blood are IBIB or IBi,people with type AB blood are IAIB,and people with type O blood are ii.If a woman with type AB blood marries a man with type O blood,which of the following blood types could their children possibly have?

Which of the following is an example of polygenic inheritance?

Why did Mendel continue some of his experiments to the F₂ or F₃ generation?

Use the information given here to answer the following questions. Feather colour in budgies is determined by two different genes,Y and B,one for pigment on the outside and one for the inside of the feather.YYBB,YyBB,or YYBb is green; yyBB or yyBb is blue; YYbb or Yybb is yellow; and yybb is white. -Two blue budgies were crossed.Over the years,they produced 22 offspring,5 of which were white.What are the most likely genotypes for the two blue budgies?

In the cross AaBbCc × AaBbCc,what is the probability of producing the genotype AABBCC?

Use the following pedigree shown below for a family in which dark-shaded symbols represent individuals with one of the two major types of colon cancer.Numbers under the symbols are the individual's age at the time of diagnosis. -In each generation of this family after generation I,the age at diagnosis is significantly lower than would be found in nonfamilial (sporadic)cases of this cancer (~ 63 years).What is the most likely reason?

Use the following information to answer the questions below. A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative.Rh positive is a trait that shows simple dominance over Rh negative and is designated by the alleles R and r,respectively.A third gene for the MN blood group has codominant alleles M and N. -Which of the following is a possible phenotype for the father?

Use the following information to answer the questions below. Skin colour in a certain species of fish is inherited via a single gene with four different alleles. -How many different types of gametes would be possible in this system?

Use the following information to answer the questions below. Drosophila (fruit flies)usually have long wings (+)but mutations in two different genes can result in bent wings (bt)or vestigial wings (vg). -If a homozygous bent wing fly is mated with a homozygous vestigial wing fly,which of the following offspring would you expect?

Refer to the following information to answer the questions below. Humanoids on the newly explored planet Brin (in a hypothetical galaxy in ~50 years from the present)have a gene structure similar to our own,but many very different plants and animals. -If the environmental parameters,such as temperature,humidity,atmosphere,sunlight,and so on,are mostly Earthlike,which of the following do you expect of its types of leaves,stems,and flowers?

Two plants are crossed,resulting in offspring with a 3:1 ratio for a particular trait.What does this suggest?

Use the following information to answer the questions below. Tallness (T)in snapdragons is dominant to dwarfness (t),while red (R)flower colour is dominant to white (r).The heterozygous condition results in pink (Rr)flower colour. -A dwarf,red snapdragon is crossed with a plant homozygous for tallness and white flowers.What are the genotype and phenotype of the F₁ individuals?

Which of the following provides an example of epistasis?

Use the following information to answer the questions below. Radish flowers may be red,purple,or white.A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring.The part of the radish we eat may be oval or long,with long being the dominant characteristic. -If true-breeding red long radishes are crossed with true-breeding white oval radishes,the F₁ will be expected to be which of the following?

Use the following pedigree shown below for a family in which dark-shaded symbols represent individuals with one of the two major types of colon cancer.Numbers under the symbols are the individual's age at the time of diagnosis. -From this pedigree,how does this trait seem to be inherited?

Mendel accounted for the observation that traits which had disappeared in the F₁ generation reappeared in the F₂ generation by proposing that

Use the following information to answer the questions below. A certain (hypothetical)organism is diploid,has either blue or orange wings as the consequence of one of its genes on chromosome 12,and has either long or short antennae as the result of a second gene on chromosome 19,as shown in this figure. -If a female of this species has one chromosome 12 with a blue gene and another chromosome 12 with an orange gene,and has both number 19 chromosomes with short genes,she will produce which of the following egg types?

Which of the following differentiates between independent assortment and segregation?

Refer to the following information to answer the questions below. Gene S controls the sharpness of spines in a type of cactus.Cacti with the dominant allele,S,have sharp spines,whereas homozygous recessive ss cacti have dull spines.At the same time,a second gene,N,determines whether or not cacti have spines.Homozygous recessive nn cacti have no spines at all. -A cross between a true-breeding sharp-spined cactus and a spineless cactus would produce