genetics Flashcards
The acquisition of traits by their transmission from parent to offspring is called
inheritance or heredity
The concept of __ inheritance suggested that the determinants of hereditary traits are transmitted in discrete units from one generation to the next.
Particulate
Particulate inheritance was first proposed by the monk
Gregor/Gregory Mendel
The unit of heredity is the
gene
Most of Mendel’s experiments were conducted using __ plants.
pea or garden pea
True or false: Inheritance is the acquisition of traits by their transmission from offspring to parent.
False
What explanation of inheritance suggests that hereditary traits are determined by discrete units that are transmitted from one generation to the next?
Particulate inheritance
Mendel used the garden pea to study inheritance because the pea plants were:
easy to cross
Who suggested particulate inheritance in the 1860s?
Mendel
Match each term with the correct definition: Character
A general feature of an organism
Match each term with the correct definition: Trait
A specific variant of a feature of an organism
Match each term with the correct definition: gene
A genetic determinant that is passed intact from one generation to the next
Match each term with the correct definition: allele
A variant form of a genetic determinant
What is broadly defined as a unit of heredity?
A gene
Flower color is an example of a(n) __ in pea plants. Purple and white flower colors are examples of __.
Blank 1: character, characteristic, or phenotype
Blank 2: traits, trait, variants, or phenotypes
What type of plant did Mendel use for most of his work?
Pea
Each character that Mendel selected to study was found in exactly __ discrete variants.
2
The acquisition of traits by their transmission from parent to offspring is called
inheritance or heredity
Which of the following properties of the garden pea were advantageous for Mendel’s studies of inheritance?
- Pea plants have relatively few chromosomes.
- True-breeding strains were available.
- Many varieties with different traits were available.
- Pea plants can be self-fertilized or cross-fertilized.
True-breeding strains were available.
Many varieties with different traits were available.
Pea plants can be self-fertilized or cross-fertilized.
A variant form of a character is called a(n) ______, and a variant form of a gene is called a(n) ______.
trait; allele
When two P generation individuals are crossed, the offspring constitute the
F1 generation.
A general feature of an organism, such as plant height or flower color, is called a(n) ______.
character
A single-factor cross is one in which an experimenter follows
the variants of only one character.
Mendel chose to study characters of pea plants that occurred in:
two discrete variants
The offspring of two true-breeding parents that differ in a single character are called single-character hybrids, or
monohybrids or monohybrid
True or false: Inheritance is the acquisition of traits by their transmission from offspring to parent.
False
What ratio did Mendel observe in the F2 offspring in monohybrid crosses between true-breeding lines for dominant and recessive traits?
3 dominant : 1 recessive
Mendel used the garden pea to study inheritance because the pea plants were:
easy to cross
Match these terms describing alleles with their definitions: dominant
trait is displayed
Match these terms describing alleles with their definitions: recessive
trait is masked
Plants from two different true-breeding P generation lines are crossed to one another and produce offspring. These offspring are allowed to self-fertilize, which results in production of the:
F2 generation
A cross in which only one character is studied is called a(n) __-__ cross.
Blank 1: single or mono
Blank 2: factor or hybrid
Mendel’s “unit factors” are now called __, and their variant forms are referred to as __.
Blank 1: genes
Blank 2: alleles
Consider two true-breeding individuals that differ in a single character. If these mate, their offspring are
monohybrids
By convention, dominant alleles are written with a(n) __ letter.
capital, capitalized, uppercase, or upper-case
In Mendel’s experiments, he observed a 3:1 ratio between dominant and recessive traits in
the F2 generation of monohybrid crosses.
When two true-breeding plants that differ in a single character are crossed, the monohybrids display the __ trait, and the __ trait is masked.
Blank 1: dominant
Blank 2: recessive
True or false: Of the gametes produced by a heterozygous individual, half will contain the dominant allele and half will contain the recessive allele.
True
When two P generation individuals are crossed, the offspring constitute the
F1 generation.
Mendel proposed that a unit factor, now called a __, codes for a character, and each individual carries two variant forms, now called __, of the unit factor for a given character.
Blank 1: gene or genes
Blank 2: alleles
Each parent carries __ alleles of a gene that will segregate from each other during gamete formation.
2
Lowercase letters are used to represent __ alleles.
recessive
Mendel’s law of __ is the idea that the two alleles of a gene separate during the formation of eggs and sperm so that every gamete receives only one allele.
segregation or law of segregation
What ratio did Mendel observe in the F2 offspring in monohybrid crosses between true-breeding lines for dominant and recessive traits?
3 dominant : 1 recessive
The term __ describes the genetic composition of an individual for a particular gene.
genotype
A heterozygous individual will have ______ numbers of gametes carrying the dominant allele and recessive allele.
equal
Plants from two different true-breeding P generation lines are crossed to one another and produce offspring. These offspring are allowed to self-fertilize, which results in production of the:
F2 generation
In pea plants, round seeds are dominant to wrinkled seeds, and the round and wrinkled alleles are represented with R and r, respectively. What genotypes will have round seeds?
RR and Rr
According to Mendel’s law of segregation, the alleles of a gene segregate during gamete formation so that each gamete receives:
one allele
What does Mendel’s law of segregation state?
Alleles of a gene segregate during gamete formation so that half the gametes receive one allele and half receive the second allele.
In pea plants, the allele T codes for tall plants and the allele t codes for short plants. If a plant is short, this would be considered its:
phenotype
The combination of alleles that an individual has for a particular gene is the individual’s:
genotype
using T and t: Match these genotypes with the correct genetic symbols: homozygous dominant
TT
Using T and t: Match these genotypes with the correct genetic symbols: heterozygous
Tt
Using T and t: Match these genotypes with the correct genetic symbols: homozygous recessive
tt
True or false: Of the gametes produced by a heterozygous individual, half will contain the dominant allele and half will contain the recessive allele.
True
An individual who is homozygous for a given gene carries:
two identical alleles of the gene
If “T” is a dominant allele for “tall,” which of these would phenotypically describe a heterozygote (Tt)?
Tall
An individual who carries two different alleles of a gene is termed __ with respect to that gene.
heterozygous or heterozygote
Each parent carries __ alleles of a gene that will segregate from each other during gamete formation.
2
What is a phenotype?
The observable characteristic of an organism
The combination of alleles that an individual possesses, such as Tt or TT, is the individual’s
genotype
A(n) __ square can be used to predict the outcome of a simple genetic cross.
Punnett
In pea plants, yellow seeds are dominant to green seeds, and the yellow and green alleles are represented with Y and y, respectively. Match each genotype with the correct description of alleles: YY
Homozygous for the yellow allele
In pea plants, yellow seeds are dominant to green seeds, and the yellow and green alleles are represented with Y and y, respectively. Match each genotype with the correct description of alleles: Yy
Heterozygous for the yellow and green alleles
In pea plants, yellow seeds are dominant to green seeds, and the yellow and green alleles are represented with Y and y, respectively. Match each genotype with the correct description of alleles: yy
Homozygous for the green allele
An individual with two identical alleles of a gene of a particular trait has a(n) __ genotype with respect to that gene.
homozygous
A two-factor cross is one in which an experimenter follows the inheritance of
two different characters.
A heterozygous individual carries:
two different alleles of a given gene
In pea plants, purple flowers are dominant to white flowers, and axial flowers are dominant to terminal flowers. If a true-breeding plant with purple, axial flowers is crossed with a true-breeding plant with white, terminal flowers, what proportion of the F2 offspring will have purple, terminal flowers?
3/16
The characteristics of an organism that are the result of the expression of its genes is referred to as its
phenotype
A 9:3:3:1 ratio is obtained in the F2 generation of a dihybrid cross when alleles assort __ from one another.
independently, separately, distinctly, autonomously, or individually
Which of these is commonly used to predict the results of simple genetic crosses?
Punnett square
Which of Mendel’s laws states that alleles of different genes assort independently of each other during gamete formation?
Law of independent assortment
A Punnett square for a single trait should be set up as a ______ square (Not counting the squares for parental gametes).
2 x 2
A cross that follows the simultaneous inheritance of two different characters is called a(n) __-__ cross.
Blank 1: two, 2, or di
Blank 2: factor or hybrid
A true-breeding pea plant with smooth green pods is crossed with a true-breeding plant with constricted yellow pods. The F1 offspring all have smooth green pods. If these F1 individuals are cross-fertilized, what proportion of the F2 offspring are expected to have smooth green pods?
9/16
What ratio is obtained in the F2 generation of a dihybrid cross when alleles assort independently from one another?
9:3:3:1
The __ theory of inheritance states that inheritance patterns of traits can be explained by the transmission of chromosomes during meiosis and fertilization.
chromosome or chromosomal
The law of independent assortment states that:
alleles of different genes assort independently during gamete formation
According to the chromosome theory of inheritance, Mendel’s laws can be explained by:
the behavior of chromosomes during meiosis
A two-factor cross is one in which an experimenter follows the inheritance of
two different characters.
Homologous chromosomes separate from one another during:
meiosis I
In pea plants, purple flowers are dominant to white flowers, and axial flowers are dominant to terminal flowers. If a true-breeding plant with purple, axial flowers is crossed with a true-breeding plant with white, terminal flowers, what proportion of the F2 offspring will have purple, terminal flowers?
3/16
What theory states that the inheritance patterns of traits can be explained by the transmission of chromosomes during meiosis and fertilization?
The chromosome theory of inheritance
The separation of homologous chromosomes during meiosis I explains:
the law of segregation
Which of Mendel’s laws states that alleles of different genes assort independently of each other during gamete formation?
Law of independent assortment
The random alignment of different pairs of homologs during meiosis I explains:
the law of independent assortment
Which of the following are principles of the chromosome theory of inheritance?
- Chromosomes are replicated and passed from parent to offspring and from cell to cell.
- The nucleus of a diploid cell contains homologous pairs of chromosomes.
- Genes are found in the chromosomes.
- During meiosis, the homologous pairs segregate independently and haploid gametes are produced.
- The DNA in chromosomes is wound around proteins to form nucleosomes, which are further coiled and compacted.
- Gametes are haploid cells that combine to form a diploid cell during fertilization.
Chromosomes are replicated and passed from parent to offspring and from cell to cell.
The nucleus of a diploid cell contains homologous pairs of chromosomes.
Genes are found in the chromosomes.
During meiosis, the homologous pairs segregate independently and haploid gametes are produced.
Gametes are haploid cells that combine to form a diploid cell during fertilization.
Match the separation of chromosomes in meiosis I and II: meiosis I
homologous pairs segregate
Match the separation of chromosomes in meiosis I and II: meiosis II
sister chromatids separate
A true-breeding pea plant with smooth green pods is crossed with a true-breeding plant with constricted yellow pods. The F1 offspring all have smooth green pods. If these F1 individuals are cross-fertilized, what proportion of the F2 offspring are expected to have smooth green pods?
9/16
Independent assortment of alleles of different genes can be explained by the random alignment of homologous pairs of __ during meiosis I.
chromosomes or chromatids
What aspect of chromosome behavior during meiosis explains Mendel’s law of segregation?
Separation of homologous chromosomes during meiosis I
