Genetics And Inheritance Flashcards
(26 cards)
What is the basic unit of heredity?
Gene
What do we call the physical expression of a gene?
Phenotype
What term describes the genetic makeup of an organism?
Genotype
In a Punnett square, what does each box represent?
A possible genotype of the offspring
What is the difference between dominant and recessive alleles?
Dominant alleles express their trait even if only one copy is present, while recessive alleles require two copies to express the trait.
What is the probability of getting a homozygous recessive offspring from two heterozygous parents (Aa)?
25%
What is the term for an organism’s genetic makeup?
Genotype
What is a phenotype?
The observable characteristics of an organism.
What is an allele?
Different forms of a gene.
What is the law of segregation?
The principle that during the formation of gametes, the two alleles for a trait separate from each other.
Who is known as the father of genetics?
Gregor Mendel
What is a dihybrid cross?
A cross that examines the inheritance of two different traits.
In humans, what are the sex chromosomes for males?
XY
What is incomplete dominance?
A form of inheritance where the phenotype of heterozygotes is intermediate between the phenotypes of the two homozygotes.
What do we call traits that are controlled by multiple genes?
Polygenic traits
What is a test cross?
A cross between an individual with an unknown genotype and a homozygous recessive individual.
What is the expected phenotypic ratio of a monohybrid cross?
3:1
What is a carrier?
An individual who has one copy of a recessive allele but does not express the trait.
What is a pedigree chart?
A diagram that shows the occurrence of a genetic trait in several generations of a family.
What does the term ‘homozygous’ mean?
Having two identical alleles for a particular gene.
What is the role of DNA in genetics?
DNA carries the genetic instructions used in the growth, development, and reproduction of organisms.
What is the definition of a mutation?
A change in the DNA sequence of a gene.
What are linked genes?
Genes that are located close together on the same chromosome and tend to be inherited together.
What is a genetic disorder?
A disease caused by abnormalities in an individual’s DNA.
