D Flashcards
(25 cards)
What is the definition of a dominant trait?
A dominant trait is a genetic characteristic that is expressed in the phenotype even when only one allele is present.
True or False: A dominant allele can mask the effect of a recessive allele.
True
Fill in the blank: In a heterozygous genotype, the dominant allele is represented by a ______ letter.
capital
What is the symbol used to represent a dominant allele?
A capital letter
Which of the following is an example of a dominant trait in humans? A) Blue eyes B) Brown hair C) Attached earlobes
B) Brown hair
In a Punnett square, how can you identify a dominant phenotype?
A dominant phenotype can be identified when at least one dominant allele is present in the genotype.
True or False: Dominant traits can skip generations.
False
What is the relationship between dominant and recessive alleles?
Dominant alleles express their trait over recessive alleles in a heterozygous condition.
What does it mean for an organism to be homozygous dominant?
It means the organism has two identical dominant alleles for a trait.
Fill in the blank: A phenotypic ratio of 3:1 in offspring indicates that the parents were ______ for a trait.
heterozygous
Which of the following genotypes would produce a dominant phenotype? A) aa B) Aa C) AA
B) Aa and C) AA
True or False: A dominant trait will always appear in every generation.
False
What is an example of a dominant genetic disorder?
Huntington’s disease
Fill in the blank: In genetics, a trait that is not expressed in the presence of a dominant allele is called a ______ trait.
recessive
What is the expected phenotypic ratio from a monohybrid cross involving two heterozygous parents?
3:1
True or False: Dominance is always complete and does not vary.
False
What is incomplete dominance?
A situation where the phenotype of heterozygotes is intermediate between the phenotypes of the two homozygotes.
Which of the following best describes codominance? A) Blending of traits B) Both traits expressed fully C) One trait is masked
B) Both traits expressed fully
What is the purpose of a test cross?
To determine the genotype of an organism showing a dominant phenotype.
Fill in the blank: In a dihybrid cross, the expected phenotypic ratio is ______.
9:3:3:1
True or False: All dominant traits are beneficial.
False
What does it mean if a trait is sex-linked dominant?
It means the trait is located on a sex chromosome and is expressed when at least one dominant allele is present.
Which is NOT a characteristic of dominant alleles? A) They can mask recessive alleles B) They are always more common than recessive alleles C) They are represented by capital letters
B) They are always more common than recessive alleles
What is the term for the observable characteristics of an organism?
Phenotype
