Question 1

Knight followed up on attempts of English farmers to improve varieties of agriculture with his studies on garden peas. When he crossed two true-breeding varieties, he found all of the following: Check all that apply.

Accepted Answer

When Knight crossed two true-breeding varieties, all F1 offspring exhibited the dominant trait. In the F2 generation, both dominant and recessive traits appeared, with more offspring showing the dominant trait.

Question 2

Sometimes, when Mendel crossed two purple-flowered pea plants with each other, he obtained a phenotypic ratio of 3:1 (purple-flowered pea plants to white-flowered pea plants). These results are consistent with which of the following sets of parents?

Accepted Answer

The 3:1 phenotypic ratio is typical of a monohybrid cross between two heterozygous individuals, where the dominant trait (purple) is expressed in 3 out of 4 offspring.

Question 3

A person who has lost a large amount of blood but is still alive is found in a wrecked automobile under a highway bridge. Several people are helping the paramedics load the victim into the ambulance. After the ambulance has departed for the hospital, you overhear the following conversation from the persons who helped the paramedics. "I am certain that when that guy gets to the hospital, they will transfuse him with any blood that they have in the blood bank since he has lost so much blood." The other person says, "Yeah, I bet you're right!" Having had a biology course, you know which blood could be safely given to anyone. Select it below.

Accepted Answer

Blood type O negative is considered the universal donor and can be safely given to anyone in an emergency situation.

Question 4

In white tigers, the absence of fur pigmentation is caused by a recessive allele. This allele also causes the tigers to be cross-eyed. If two tigers heterozygous for this allele mate, what do you expect to see among the offspring?

Accepted Answer

The recessive allele causes both white fur and cross-eyedness. If two heterozygous tigers mate, each parent will contribute one dominant allele and one recessive allele. The offspring will have a 1/4 chance of inheriting two recessive alleles, which will result in both white fur and cross-eyedness.

Question 5

A scientist has a pea plant that produces yellow seeds. Since yellow is dominant to green, she wants to determine if the plant is homozygous or heterozygous. In order to be certain that she will get conclusive results from a single cross, what is the BEST choice of plant to cross her pea plant with?
A. A green-seeded pea plant
B. A yellow-seeded pea plant
C. A pea plant that produces both green and yellow seeds
D. Itself

Accepted Answer

The answer of A scientist has a pea plant that...

Question 6

In humans, sickle-cell disease is due to a defect in a single gene and is inherited in an autosomal recessive manner. If 2 people without sickle-cell disease have a daughter who has this disease, what is the probability that their next child will be a boy with sickle-cell disease?

Accepted Answer

Both parents must be carriers (heterozygous) for their daughter to have sickle-cell disease. The probability of having a child with the disease is 1/4, and the probability of having a boy is 1/2. Therefore, the probability of having a boy with sickle-cell disease is 1/4 * 1/2 = 1/8.

Question 7

In watermelons, the gene for green color is dominant over its allele for striped color. At another gene locus, the gene for short shape is dominant over its allele for long shape. These two allele pairs assort independently. If a plant with long, striped fruit is crossed with a plant that is heterozygous for both of these traits, what percentage of the offspring do you expect will be short and green? ( Enter the number only without the percent sign. For example, enter 100% as 100 and enter 12.5% as 12.5 )

Accepted Answer

The answer of In watermelons, the gene for green color...

Question 8

In rabbits, there is a dominant gene "T" for long ears and its recessive allele "t" for short ears. At another gene locus, there are alleles "B" for black coat and "W" for white coat. Neither allele is dominant and BW produces a gray coat. These two allele pairs assort independently. If a gray rabbit that is heterozygous at the gene locus controlling ear length is mated with a white rabbit that is also heterozygous at the gene locus controlling ear length, what is the probability that their first offspring will be gray with long ears?

Accepted Answer

The answer of In rabbits, there is a dominant gene...

Question 9

In rabbits there is a dominant gene "T" for long ears and its recessive allele "t" for short ears. At another gene locus, there are alleles "B" for black coat and "W" for white coat. Neither allele is dominant and BW produces a gray coat. These two allele pairs assort independently. If a gray rabbit that is heterozygous at the gene locus controlling ear length is mated with a white rabbit that is also heterozygous at the gene locus controlling ear length, what proportion of the long-eared offspring will be homozygous for that trait?

Accepted Answer

The answer of In rabbits there is a dominant gene...

Question 10

Within the human body, different cells have different characteristics or phenotypes. For example, neurons look and behave very differently from hepatocytes (liver cells). How can this be explained considering that all cells within a person were derived from the same starting cell?

Accepted Answer

Different cell types express different sets of proteins, which are determined by the specific genes that are active or inactive in each cell type. All cells contain the same DNA, but differential gene expression leads to the production of different proteins, resulting in different cell characteristics or phenotypes.

Quiz 11: Patterns of Inheritance

Knight followed up on attempts of English farmers to improve varieties of agriculture with his studies on garden peas. When he crossed two true-breeding varieties, he found all of the following: Check all that apply.

Sometimes, when Mendel crossed two purple-flowered pea plants with each other, he obtained a phenotypic ratio of 3:1 (purple-flowered pea plants to white-flowered pea plants) . These results are consistent with which of the following sets of parents?

In white tigers, the absence of fur pigmentation is caused by a recessive allele. This allele also causes the tigers to be cross-eyed. If two tigers heterozygous for this allele mate, what do you expect to see among the offspring?

In humans, sickle-cell disease is due to a defect in a single gene and is inherited in an autosomal recessive manner. If 2 people without sickle-cell disease have a daughter who has this disease, what is the probability that their next child will be a boy with sickle-cell disease?

Within the human body, different cells have different characteristics or phenotypes. For example, neurons look and behave very differently from hepatocytes (liver cells) . How can this be explained considering that all cells within a person were derived from the same starting cell?