1.
If a pea plant were homozygous recessive for height, how would its alleles be represented?
Correct Answer
C. Tt
Explanation
The correct answer is "tt" because in genetics, uppercase letters represent dominant alleles and lowercase letters represent recessive alleles. Since the pea plant is homozygous recessive for height, it means that both of its alleles for height are recessive, so they would be represented by lowercase letters "t".
2.
A plant that is homozygous for red flowers (rr) is crossed with a plants that is homozygous for white flowers (ww). In the case of incomplete dominance, the flowers of the offspring will be ___.
Correct Answer
D. Pink only
Explanation
When a plant that is homozygous for red flowers (rr) is crossed with a plant that is homozygous for white flowers (ww) in the case of incomplete dominance, the flowers of the offspring will be pink only. In incomplete dominance, neither allele is completely dominant over the other, resulting in a blending of traits. In this case, the red and white alleles blend together to produce pink flowers in the offspring.
3.
The term for a cross that involves just one trait, such as flower color, is ___.
Correct Answer
C. A monohybrid cross
Explanation
A monohybrid cross refers to a cross between two individuals that differ in only one trait, such as flower color. In this type of cross, the individuals being crossed are both homozygous for the trait being studied. The purpose of a monohybrid cross is to study the inheritance patterns of a single trait and determine the genotypes and phenotypes of the offspring.
4.
Hair color and eye color are examples of a person's
Correct Answer
D. pHenotype.
Explanation
Hair color and eye color are examples of a person's phenotype. Phenotype refers to the observable characteristics or traits of an individual, which are determined by both their genetic makeup (genotype) and environmental factors. Hair color and eye color are influenced by multiple genes and can vary among individuals. Therefore, they are considered as part of an individual's phenotype rather than being solely determined by dominant alleles or recessive traits.
5.
What do the letters inside the grid of a Punnett square represent?
Correct Answer
B. Genotypes of offspring
Explanation
The letters inside the grid of a Punnett square represent the genotypes of the offspring. A Punnett square is a tool used in genetics to predict the possible combinations of alleles that offspring can inherit from their parents. Each letter in the grid represents a different allele, and by combining the letters, we can determine the genotypes of the offspring. This helps in understanding the inheritance patterns and predicting the traits that the offspring may possess.
6.
Which law states that organisms inherit two copies of each gene and donate one copy to each of their offspring?
Correct Answer
B. Law of segregation
Explanation
The law of segregation states that organisms inherit two copies of each gene and donate one copy to each of their offspring. This means that during the formation of gametes, the two copies of a gene separate from each other, so that each gamete only carries one copy. This ensures that each offspring receives one copy of each gene from each parent, maintaining genetic diversity and allowing for the inheritance of specific traits.
7.
Recessive alleles may not be expressed because they are
Correct Answer
A. Masked by the dominant allele.
Explanation
Recessive alleles may not be expressed because they are masked by the dominant allele. This means that when an individual has both a dominant and recessive allele for a particular trait, only the dominant allele will be visible or expressed in the organism's phenotype. The recessive allele is still present in the individual's genotype, but its expression is suppressed by the dominant allele. As a result, the dominant allele determines the observable trait while the recessive allele remains hidden or "masked."
8.
Two parents have the genotype Gg for a genetic disorder caused by a dominant allele. What is the chance that any of their children will inherit the disorder?
Correct Answer
C. 75%
Explanation
Since both parents have the genotype Gg, it means that they each have one dominant allele (G) and one recessive allele (g). The disorder is caused by a dominant allele, so there is a 50% chance that each parent will pass on the dominant allele to their child. Therefore, the chance that any of their children will inherit the disorder is 50% + 50% = 100%.
9.
For an XX female to express a recessive sex-linked trait, she must have
Correct Answer
C. Two recessive alleles.
Explanation
In order for an XX female to express a recessive sex-linked trait, she must have two recessive alleles. This is because females have two X chromosomes, and for a recessive trait to be expressed, both copies of the gene must carry the recessive allele. The presence of a Y chromosome is not necessary for the expression of a recessive sex-linked trait in females. An inactivated allele refers to X-inactivation, which is a process that occurs in females to balance gene expression between the two X chromosomes, but it does not determine the expression of a recessive trait.
10.
Any of the alternative forms of a gene that occurs at a specific place on a chromosome are known as ___.
Correct Answer
A. Alleles
Explanation
Alleles are alternative forms of a gene that occur at a specific location on a chromosome. They can vary in their DNA sequence and can result in different traits or characteristics. Alleles are responsible for genetic diversity and can be dominant or recessive, influencing the expression of traits in an individual.
11.
A chart or "family tree" that tracks which members of a family have a particular trait is called a ___.
Correct Answer
A. Pedigree
Explanation
A chart or "family tree" that tracks which members of a family have a particular trait is called a pedigree. This term is commonly used in genetics to visually represent the inheritance of traits within a family lineage. It helps to identify patterns of inheritance and determine the likelihood of passing on certain traits to future generations. A pedigree can provide valuable information for genetic counseling and understanding the genetic basis of certain conditions.
12.
___ studied traits of pea plants and discovered the two fundamental laws of genetics.
Correct Answer
A. Mendel
Explanation
Mendel is the correct answer because he is widely recognized as the father of modern genetics. He conducted experiments with pea plants in the 19th century and discovered the two fundamental laws of inheritance, known as Mendel's Laws. His work laid the foundation for the field of genetics and revolutionized our understanding of how traits are passed down from generation to generation.