Simple Patterns of Inheritance Chaper 16

Hemophilia A is an X-linked recessive genetic condition. In humans it is due to a mutation in the F8 gene, which encodes a protein called coagulation factor VII. Coagulation factors are proteins important in blood clotting. Individuals with hemophilia, when injured, bleed longer than a normal, healthy individual; the inability to normally clot blood can be life threatening. Hemophilia is much more common in males than in females. Which of the following does NOT explain why this is so?

Males have to receive a defective allele only from their father to get hemophilia A

How can you determine the genotype of a plant showing the dominant phenotype of red color?

Cross the red plant with a white plant to see if any white plants appear.

For mechanisms of sex determination, which of the following is incorrectly paired?

1n-2n, pea plant

Consider the human population. With regards to the ABO blood groups there are _____ alleles, ____ possible genotypes, and _____ possible phenotypes.

3, 6, 4

A male is heterozygous for the trait that produces freckles on the skin, and he has freckles. If he marries a woman who is also heterozygous for freckles, ______ percent of their children are predicted to be freckled. Also, of all their children, ______ percent are predicted to be heterozygous.

75%, 50%

What is the difference between the blood types, A, B, and O?

A and B individuals have different modifications made to their carbohydrate tree. O individuals have no modifications made to their carbohydrate tree.

What is a testcross?

A cross between an organism of unknown genotype with a homozygous recessive individual

Hemophilia is a sex-linked recessive condition that results in deficient blood clotting. The disease causes excessive bleeding which occurs spontaneously or upon slight injury. In dogs (as in humans) hemophilia is caused by a defect in a gene on the X chromosome. What will be the results of mating between a normal, non-carrier female dog and a male dog with hemophilia?

All of the offspring will be normal, but all females will be carriers.

Eyelash length is an inherited trait. In the human population, there is an eyelash length gene. There are two possible variants of this gene - an allele for long eyelashes (> 1cm) and an allele for short eyelashes (1 cm or less). The allele for long eyelashes is dominant (L) and the allele for short eyelashes is recessive (l). An individual who is heterozygous for eyelash length would produce which of the following gametes?

Half of the gametes would have the L allele and half of the gametes would have the l allele.

In Thomas Hunt Morgan's experiments, the ratio of red-eyed flies to white-eyed flies appeared to follow a simple Mendelian pattern of inheritance. What observation(s) did he make that led to his conclusion that the white-eyed trait was actually not a simple Mendelian trait?

He was able to correlate the expression of white eyes to the inheritance of an X chromosome because only F2 males had white eyes and the trait is recessive.

_________ occurs when 50% of a protein produces a different phenotype than that produced by 100% or 0% of the protein.

Incomplete dominance

Eyelash length is an inherited trait. In the human population, there is an eyelash length gene. There are two possible variants of this gene - an allele for long eyelashes (> 1cm) and an allele for short eyelashes (1 cm or less). The allele for long eyelashes is dominant (L) and the allele for short eyelashes is recessive (l). An individual who is heterozygous for eyelash length would have which of the following genotypes?

Ll

A person who is homozygous for a mutation of the phenylalanine hydroxylase gene

can lead a normal life if the environment is controlled.

The single-factor crosses performed by Mendel support the observation that

the two alleles for a given gene are distributed randomly among an individual's gametes. Correct

You discover a new sunflower that has blue flowers instead of yellow. When you cross this blue variety with a common yellow variety you get blue and yellow speckled flowers. What type of inheritance pattern does this gene exhibit?

codominance

In mammals, males are ______ for genes on their sex chromosomes, and females can be ______ or heterozygous for genes on their sex chromosomes.

hemizygous, homozygous

If a pink snapdragon is self-fertilized, the offspring are red, pink, or white. What type of inheritance pattern does flower color exhibit in this example?

incomplete dominance

Imagine that horn color in Hodags (folkloric creatures of Wisconsin) is controlled by a single gene. You mate a Hodag homozygous for a bright orange horns (COCO) with a Hodag homozygous for ivory horns (CICI). Numerous offspring are produced, all with pale orange horns. This pattern of inheritance of horn color can best be described as

incomplete dominance.

The color of petunia flower can be changed from red to blue by altering the pH of the soil. This is an example of

norm of reaction.

When a single-gene mutation can have phenotypic effects at multiple stages of development, it is

pleiotropic

A white cow was mated with a red cow, and they had an offspring who was roan - the calf had an even mixture of white hairs and red hairs covering her body. What is the most likely explanation of the inheritance of the roan coat?

red and white are codominant

Human males produce

sperm, half contain an X chromosome, half contain a Y chromosome. Correct

A woman visits her doctor's office complaining of pattern baldness. Her mother and father do not have pattern baldness, but her brother does. The doctor is concerned that she may have the serious condition of __, and he immediately orders blood tests to check her ________ levels.

tumor of the adrenal gland, 5-dihydrotestosterone

Color blindness is a recessive X-linked trait. A normal couple has a color-blind child. Who else in this family is probably color blind?

the child's maternal grandfather

An X-linked gene is

a gene on the X chromosome.

What features of meiosis allow for independent assortment of chromosomes?

Random alignment of homologous chromosome pairs on the metaphase plate

Which of the following inheritance patterns is matched with an inaccurate molecular basis?

Simple Mendelian inheritance: The protein produced by a single allele cannot produce the dominant phenotype.