Inheritance (17) Flashcards
What is the basic unit of heredity?
Gene
True or False: Alleles are different forms of a gene.
True
What is the phenotype of an organism?
The observable characteristics of an organism.
What does the term ‘homozygous’ mean?
Having two identical alleles for a particular gene.
What does the term ‘heterozygous’ mean?
Having two different alleles for a particular gene.
Fill in the blank: The physical expression of a genotype is called __________.
phenotype
What is a genotype?
The genetic makeup of an organism.
True or False: Dominant alleles are always expressed in the phenotype.
True
What is a recessive allele?
An allele that is only expressed in the phenotype when two copies are present.
What is a Punnett square used for?
To predict the possible genotypes of offspring from a genetic cross.
What does the term ‘sex-linked’ refer to?
Traits that are associated with genes located on sex chromosomes.
What is the role of a test cross?
To determine the genotype of an individual with a dominant phenotype.
What is the expected phenotypic ratio of a monohybrid cross?
3:1
What is the expected phenotypic ratio of a dihybrid cross?
9:3:3:1
What is codominance?
A situation where both alleles in a heterozygote are fully expressed.
Fill in the blank: The ABO blood group system is an example of __________ inheritance.
codominant
What is the purpose of a pedigree chart?
To trace the inheritance of traits across generations.
True or False: Autosomal recessive traits can skip generations.
True
What is epistasis?
The interaction between genes where the effect of one gene is modified by another gene.
What is the function of the SRY gene?
It determines male sex characteristics.
What is a polygenic trait?
A trait that is controlled by multiple genes.
What is the definition of genetic linkage?
The tendency of genes located close together on a chromosome to be inherited together.
Fill in the blank: The process of random assortment occurs during __________.
meiosis
What are linked genes?
Genes that are located on the same chromosome and tend to be inherited together.
True or False: Crossing over increases genetic variation.
True
What is the significance of the Hardy-Weinberg principle?
It describes the genetic variation of a population that is not evolving.
What are the conditions for Hardy-Weinberg equilibrium?
No mutations, random mating, no natural selection, large population size, and no gene flow.
What is the formula for calculating allele frequencies in a population?
p + q = 1
In the Hardy-Weinberg equation, what does ‘p²’ represent?
The frequency of the homozygous dominant genotype.
In the Hardy-Weinberg equation, what does ‘2pq’ represent?
The frequency of the heterozygous genotype.
In the Hardy-Weinberg equation, what does ‘q²’ represent?
The frequency of the homozygous recessive genotype.
What is the role of mutations in evolution?
They introduce new genetic variation into a population.
True or False: Natural selection can lead to changes in allele frequencies over time.
True
What is genetic drift?
A random change in allele frequencies in a population.
What is gene flow?
The transfer of alleles or genes from one population to another.
What is a carrier in genetics?
An individual who has one copy of a recessive allele but does not express the trait.
What is the difference between a genotype and a phenotype?
Genotype is the genetic makeup, while phenotype is the observable characteristics.
Fill in the blank: The law of segregation states that allele pairs separate during __________.
gamete formation
What is a dominant trait?
A trait that is expressed in the phenotype even when only one allele is present.
What is the role of the chromosome in inheritance?
Chromosomes carry genes and determine genetic traits.
True or False: All traits are determined by single genes.
False
What is incomplete dominance?
A form of inheritance where the phenotype of a heterozygote is intermediate between the two homozygotes.
What is a monohybrid cross?
A genetic cross between individuals that differ in one trait.
What is a dihybrid cross?
A genetic cross between individuals that differ in two traits.
What does the term ‘phenotypic ratio’ refer to?
The ratio of different phenotypes produced in a genetic cross.
What is the expected genotypic ratio of a monohybrid cross?
1:2:1
Fill in the blank: The observable characteristics of an organism are referred to as its __________.
phenotype
What is a test cross used for?
To determine the genotype of an organism with a dominant phenotype.
What is the significance of crossing over during meiosis?
It increases genetic variation by exchanging genetic material between homologous chromosomes.
What is a hybrid organism?
An organism that has two different alleles for a trait.
True or False: The environment can influence the expression of genes.
True
What is the role of sex chromosomes in inheritance?
They determine the sex of an organism and carry sex-linked traits.
What is a chromosome map?
A representation of the arrangement of genes on a chromosome.
What is the expected outcome of a test cross involving a homozygous recessive individual?
The offspring will show the phenotype of the homozygous recessive individual if the tested individual is homozygous dominant.
What is the difference between qualitative and quantitative traits?
Qualitative traits are categorical, while quantitative traits are measurable and can vary continuously.
Fill in the blank: Genetic __________ is the study of how traits are passed from one generation to the next.
inheritance
What is Mendel’s law of independent assortment?
The law stating that genes for different traits are inherited independently of each other.
What is the role of the X chromosome in sex-linked inheritance?
It carries genes that can affect traits in both males and females.
What is a linkage map?
A diagram that shows the relative positions of genes on a chromosome.
True or False: The Y chromosome is smaller than the X chromosome.
True
What is a sex-linked trait?
A trait associated with a gene located on a sex chromosome.
What is the expected phenotypic ratio for a dihybrid cross involving two heterozygous parents?
9:3:3:1
What does ‘P generation’ refer to in genetics?
The parental generation in a genetic cross.
What does ‘F1 generation’ refer to in genetics?
The first filial generation, offspring of the P generation.
What does ‘F2 generation’ refer to in genetics?
The second filial generation, offspring of the F1 generation.
What is the significance of the law of dominance?
It states that in a heterozygote, one allele may mask the expression of another.
What is the role of genetic recombination in evolution?
It increases genetic diversity within a population.
