Question 1

A person who has type O blood has

Accepted Answer

A person with type O blood has no A or B surface antigens on their red blood cells, but they do have both anti-A and -B antibodies in their plasma. This means that if they were to receive a blood transfusion with A, B, or AB blood, their antibodies would recognize the foreign antigens and attack the donated blood cells, causing a potentially fatal reaction. Therefore, people with type O blood are often called "universal donors" because their blood can be donated to people with any blood type, but they can only receive transfusions from other type O donors.

Question 2

Which of the following phenotypic ratios show independent assortment?

Accepted Answer

The answer of Which of the following phenotypic ratios show...

Question 3

If two or more forms of the same gene exist,the different forms are called

Accepted Answer

Different forms of the same gene are called alleles.

Question 4

The phenotypic ratio 3:1 may indicate

Accepted Answer

The phenotypic ratio 3:1 is a classic ratio observed in Mendelian inheritance and is typically associated with complete dominance. This means that one allele (the dominant allele) completely masks the expression of the other allele (the recessive allele) in heterozygous individuals.

Question 5

When the same gene is related to respiratory problems and sterility,it can be described as

Accepted Answer

Pleiotropy occurs when a single gene affects multiple traits or phenotypes. In this case, the gene is related to both respiratory problems and sterility, indicating pleiotropy. Codominance, incomplete dominance, complete dominance, and penetrance and expressivity do not describe this specific scenario.

Question 6

Which of these is not an example of a continuous trait?

Accepted Answer

Phenylketonuria (PKU) is a genetic disorder that follows an autosomal recessive pattern of inheritance. It is not a continuous trait as it is a binary trait, either the individual has the disorder or not. Age at death, human skin color, birth weight of mice, and plant height are all examples of continuous traits.

Question 7

The blood groups A,B,and O are different types of

Accepted Answer

Blood groups A, B, and O are determined by different versions of a gene (alleles) that codes for a protein marker on the surface of red blood cells. Each individual has two copies of this gene, one inherited from each parent, and the combination of alleles determines their blood type.

Question 8

The phenotypic ratio 9:3:4 may indicate

Accepted Answer

The phenotypic ratio of 9:3:4 is indicative of epistasis, where one gene's expression masks or modifies the effect of another gene.

Question 9

Temperature sensitive (ts)alleles of the Drosophila shibire gene were isolated by David Suzuki.Under permissive conditions,what is the phenotype of flies homozygous for the ts alleles?

Accepted Answer

Under permissive conditions, the phenotype of flies homozygous for the ts alleles is indistinguishable from wild-type.

Question 10

Which of the following ratios indicates a lethal gene?

Accepted Answer

A 2:1 ratio in offspring typically indicates the presence of a lethal gene, where one genotype is lethal and does not survive to be counted, leading to the observed deviation from the expected Mendelian ratios.

Question 11

Which of the following ratios demonstrate gene interaction?

Accepted Answer

The ratio 9:3:4 demonstrates gene interaction, specifically the ratio observed in a dihybrid cross between two individuals who are heterozygous for two different genes that are involved in the same pathway or trait. This type of gene interaction is called epistasis, where one gene masks or affects the expression of another gene. The other answer choices are not specifically associated with gene interaction.

Question 12

The phenotypic ratio 1:2:1 may indicate

Accepted Answer

The 1:2:1 phenotypic ratio is typical of codominance, where both alleles in a heterozygote are fully expressed, resulting in a distinct phenotype for each genotype.

Question 13

People may inherit a specific genotype that predisposes them to cancer.However,not everyone with this genotype develops cancer;the occurrence of cancer in these individuals is dependent on environment.This is an example of:

Accepted Answer

Incomplete penetrance is the term used when individuals with a specific genotype do not express the phenotype associated with that genotype. In this example, individuals with a genotype that predisposes them to cancer may not necessarily develop cancer because the occurrence of cancer is also dependent on environmental factors.

Question 14

Which of the following ratios show codominance?

Accepted Answer

The ratio 1:2:1 is the only option that suggests codominance where two alleles are equally expressed in the phenotype of the individual. The other ratios suggest either complete dominance, incomplete dominance, or sex-linked inheritance.

Question 15

A _____________ results whenever the nucleotide sequence is changed.

Accepted Answer

A mutation is a change in the nucleotide sequence of DNA. The other answer choices refer to broader concepts. Phenotype refers to the observable traits of an organism, genotype refers to the genetic makeup of an individual, trait is an observable characteristic of an organism, and character is a broader term that refers to any aspect of an organism (such as behavior or morphology). Therefore, C is the best choice.

Question 16

Which of the following monohybrid ratios can describe incomplete dominance and codominance?

Accepted Answer

The 1:2:1 ratio can describe both incomplete dominance and codominance. In incomplete dominance, the heterozygous phenotype is intermediate between the homozygous dominant and homozygous recessive phenotypes, resulting in a 1:2:1 ratio. In codominance, both alleles contribute to the phenotype equally, resulting in a 1:2:1 ratio as well. The other ratios (2:1, 3:1, 1:3, and 4:1) do not accurately describe incomplete dominance or codominance.

Question 17

Another name for a normal gene is

Accepted Answer

A wild-type gene refers to the most common or normal version of a gene in a population. It is usually the dominant allele and is reflected in the phenotype of most individuals in the population. The other options (B-D) do not refer to a normal gene but rather to different types of inheritance patterns or characteristics of genes. Option E refers to a gene that is masked by a dominant allele and is not necessarily normal.

Question 18

The phenotypic ratio 2:1 may indicate

Accepted Answer

The phenotypic ratio of 2:1 often indicates a recessive lethal situation, where individuals homozygous for the recessive allele do not survive, thus not appearing in the phenotypic ratio.

Question 19

The blood groups A,B,and O show

Accepted Answer

The ABO blood group system exhibits complete dominance (A and B alleles are dominant over O), recessiveness (O is recessive), and codominance (A and B alleles are codominant with each other, leading to the AB blood type).

Question 20

The phenotypic ratio 9:7 may indicate

Accepted Answer

The answer of The phenotypic ratio 9:7 may indicate
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Quiz 1: Mendels Principles of Heredity