Principles of Inheritance and Variation XII Flashcards
Comprehensive Study and Memorization of Material
What is the basic unit of heredity?
Gene
True or False: Alleles are different forms of a gene.
True
What does the term ‘homozygous’ mean?
Having two identical alleles for a specific gene.
What is a phenotype?
The observable characteristics or traits of an organism.
Fill in the blank: The physical expression of a trait is known as its __________.
phenotype
What is the difference between dominant and recessive alleles?
Dominant alleles express their trait even in the presence of a recessive allele, while recessive alleles express their trait only when homozygous.
In a Punnett square, what do the letters on the top and side represent?
The alleles contributed by each parent.
What is the expected phenotypic ratio of a monohybrid cross?
3:1
True or False: A test cross is used to determine the genotype of an individual with a dominant phenotype.
True
What is the purpose of a dihybrid cross?
To study the inheritance of two different traits simultaneously.
Fill in the blank: The genetic makeup of an organism is referred to as its __________.
genotype
What is codominance?
A situation in which both alleles in a heterozygous individual fully express their traits.
What is incomplete dominance?
A situation where the phenotype of a heterozygote is intermediate between the phenotypes of the two homozygotes.
What is the role of sex-linked genes?
They are located on the sex chromosomes and can affect traits related to sex.
True or False: All traits are determined by a single gene.
False
What is polygenic inheritance?
A type of inheritance where multiple genes determine a single trait.
What is Mendel’s Law of Segregation?
The law stating that the two alleles for a trait separate during gamete formation.
What does Mendel’s Law of Independent Assortment state?
The alleles for different traits segregate independently of one another during gamete formation.
Fill in the blank: The observable traits of an organism are influenced by both __________ and __________ factors.
genetic, environmental
What is the significance of the F1 generation in genetics?
It is the first filial generation resulting from a cross of two parental (P) generations.
What is a carrier in genetics?
An individual who has one copy of a recessive allele for a trait but does not express that trait.
True or False: Genetic variation is essential for the process of evolution.
True
What is a pedigree chart used for?
To trace the inheritance of traits through generations in a family.
What is the probability of obtaining a homozygous recessive offspring from a cross between two heterozygous parents?
25%
