Unit 5

A certain species of plant has four unlinked genetic loci W,X,Y,Z. Each genetic locus has one dominant allele and one recessive. For a plant with the genotype WwXxYyZz. What is the probability that the plant will produce a gamete with a haploid genotype of Wxyz.

1/16

If an organism has 60 chromosomes in each cell prior to meiosis, how many chromosomes will be present in each of their gametes?

30

(Pedigree) One of the affected males from the third generation has a child with a female who is a carrier. For the pedigree shown, which of the following best expressed the probability that the couple's first son will be affected

50%

The figure above shows a map of four genes on a chromosome. Between which two genes would you expect the highest frequency of recombination?

A and G

A man who carries an X-linked allele will pass it on to...

All of his daughters

(Pedigree) What is the mode of inheritance

Autosomal Recessive

Individuals with an inherited autosomal recessive disorder called PCD often have severe respiratory problems due to defective cilia. Males with PCD are often sterile because they produce sperm with defective flagella. Which of the following most likely explains the effect?

Cells do no produce functional motor proteins

F1 population comes out all one phenotype and F2 is a 3:1 ration. Which is true

Completely plated phenotype is controlled by the dominant allele

(Tables) Based on the data in table 1, which of the following best explains why no individuals have constricted pods in the F₁ generation

Inflated pod shape is dominant to constricted pod shape

You have in your possession a microscope slide of meiotic cells and a light microscope. What could u look for if you want to identify metaphase cells in the slide?

Homologous chromosomes (tetrads) lined up at the middle of the cell

Which of the following provides an example of epistasis?

In rabbits, and many other mammals, one genotype (cc) prevents any fur color from developing

What describes the ABO blood group system?

Multiple Alleles

Which may lead to genetic variation?

Mutations in the genome

If individual IV-7 were to marry a man with no family history of the disease, which would be true?

None of the children will have the disease

(Tables) The ratio of phenotypes in the offspring from testcross F₁ plants suggest that color of pod and shape are ________

On different chromosomes

Blue and pink flowers, how do you prove that the flower color is due primarily to soil conditions?

Plant under controlled conditions that vary only in regard to soil pH

The frequency of crossing over between any two linked genes will be which of the following?

Proportional to the distance between them

F1 is broad leaved, white flowered by narrow leaved, purple flowered. The offspring all vary from the parental phenotype, why?

Recombination between the leaf shape and flower color genes resulted in chromosomes carrying a dominant allele of both genes.

In cattle, roan coat color (mixed red/white hairs) occurs in the heterozygous (Rr) offspring of red (RR) and white (rr) homozygotes. Which cross would produce offspring in the ratio of 1 red: 2 roan: 1 white?

Roan * Roan

Eye pigment in a particular strain of fly is determined by 2 genes. An autosomal gene that controls the color of the pigments in the eye has 2 alleles: a dominant allele(R) that results in red eyes and a recessive allele (r) that results in sepia eyes. A sex-linked gene that controls the expression of colored pigments also has 2 alleles: a dominant allele (T) that allows the expression of the colored pigments and a recessive allele (t) that does not allow for the expression of the colored pigments. Individuals without a T allele have white eyes regardless of the alleles of other eye-color genes.

RrXtXt * RrXTY

Which of the following provides the best justification for an assumption in the computer simulation (table 2)

The purple allele is dominant to the white allele because offspring from purple and white cross had purple flowers

50% frequency of recombination means that

The two genes are located on different chromosomes

An obstetrician knows that one of her patients is a pregnant woman whose fetus is at risk for a serious disorder that is detectable biochemically in fetal cells that are 15 weeks old. The obstetrician would most reasonably offer which of the following procedures to her patient.

amniocentesis

Couple 1- A and A Couple 2- A and B Couple 3- B and O Baby 1- B Baby 2- O Baby 3- AB

couple I with baby 2, Couple II with baby 3, couple III with baby 1

The process is best summarized by which of the following descriptions

during meiosis crossing over occurs, leading to recombination of alleles between homologous chromosomes

A student in bio class crossed a male Drosophila Melanogaster having a gray body and long wings with a female D. Melanogaster having a black body and apterous wings. The following distribution of traits was observed in the offspring: Phenotype Gray Body, Long wings (42) Black Body, apterous wings(41) Gray body, apterous wings(9) Black body, long wings(8)

genes for the two traits are close together on the same chromosome, and crossing over occurred

After telophase 1 of meiosis the chromosome makeup of each daughter cell is

haploid, # of chromosomes are consisting of 2 chromatids

High blood cholesterol can lead to cardiovascular problems such as atherosclerosis and heart attack. Exercise and monitoring of diet can often control cholesterol. Both peoples levels are also higher than average. A physician has suggested they get tested for the HC allele. Which of the following is a valid e

if both have the allele for HC, should an insurance company raise their rates because of the results of the test.

The process illustrated in the models depicted all result in which of the following

in increase in genetic variation

Independent assortment of chromosomes occur

in meiosis 1 only

The human X and Y chromosomes

include genes that determine sex

All of the following statements regarding polyploid are true except one. Select the exception.

it is caused by the breakage of chromosome

Which of the following is not an example of aneuploidy?

polyploidy

Which occurs in meiosis but not mitosis?

synapsis of chromosomes

The diagram depicts a karyotype of an individual human. Which of the following statements concerning the karyotype in the diagram is true.

the diagram illustrates the results of nondisjunction during gamete formation

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

traits can be dominant or recessive, and the recessive traits were obscured by the dominant ones in the F1 generation

One possible result of chromosomal breakage is for a fragment to join non-homologous chromosome. What is this alteration called.

translocation

A genetic counselor is consulted by a young man who is worried about developing huntington's disease and the news has caused him to consider his own risk for developing the disorder. Which of the following questions will best help the genetic counselor to evaluate the risk of the young man developing huntington's disease and transmitting it to his children.

were your grandparents or parents ever diagnosed with huntington's disease

In fruit flies, the allele for vestigial wings is recessive to the allele for wild type wings and for white eyes is recessive to the allele for red eyes. The gene containing wild type is located on an autosome whereas the gene for eye color is located on the X chromosome. A true breeding female with wild type and white eyes is crossed with a vestigial wing and red eyes

½