Concept explainers
For each of the terms in the left column, choose the best matching phrase in the right column.
a. |
1. having two identical alleles of a given gene |
b. alleles | 2. the allele expressed in the phenotype of the heterozygote |
c. independent | 3. alternate forms of a gene assortment |
d. gametes | 4. observable characteristic |
e. gene | 5. a cross between individuals both heterozygous for two genes |
f. segregation | 6. alleles of one gene separate into gametes randomly with respect to alleles of other genes |
g. heterozygous | 7. reproductive cells containing only one copy of each gene |
h. dominant | 8. the allele that does not contribute to the phenotype of the heterozygote |
i. F1 | 9. the cross of an individual of ambiguous genotype with a homozygous recessive individual |
j. testcross | 10. an individual with two different alleles of a gene |
k. genotype | 11. the heritable entity that determines a characteristic |
l. recessive | 12. the alleles an individual has |
m. dihybrid cross | 13. the separation of the two alleles of a gene into different gametes |
n. homozygote | 14. offspring of the P generation |
a.
To determine:
The phrase that describes “phenotype” among the options given below.
1. Having two identical alleles of a given gene
2. The allele expressed in the phenotype of the heterozygote
3. Alternate forms of a gene assortment
4. Observable characteristic
5. A cross between individuals both heterozygous for two genes
6. Alleles of one gene separate into gametes randomly with respect to alleles of other genes
7. Reproductive cells containing only one copy of each gene
8. The allele that does not contribute to the phenotype of the heterozygote
9. The cross of an individual of ambiguous genotype with a homozygous recessive individual
10. An individual with two different alleles of a gene
11. The heritable entity that determines a characteristic
12. The alleles an individual has
13. The separation of the two alleles of a gene into different gametes
14. Offspring of the P generation
Introduction:
Gene is the basic unit of biological information. The way genes transmit physiological, anatomical, and behavioral traits from parents to offspring is termed as heredity.
Answer to Problem 1P
Correct answer:
Phenotype: Observable characteristic
Explanation of Solution
The observable physical properties of an organism such as appearance, development, and behavior are termed as phenotypes. The phenotype of an individual is determined by its genotype.
b.
To determine:
The phrase that describes “alleles” among the options given below.
1. Having two identical alleles of a given gene
2. The allele expressed in the phenotype of the heterozygote
3. Alternate forms of a gene assortment
4. Observable characteristic
5. A cross between individuals both heterozygous for two genes
6. Alleles of one gene separate into gametes randomly with respect to alleles of other genes
7. Reproductive cells containing only one copy of each gene
8. The allele that does not contribute to the phenotype of the heterozygote
9. The cross of an individual of ambiguous genotype with a homozygous recessive individual
10. An individual with two different alleles of a gene
11. The heritable entity that determines a characteristic
12. The alleles an individual has
13. The separation of the two alleles of a gene into different gametes
14. Offspring of the P generation
Introduction:
Genetics is the science of heredity in which a precise explanation of the biological structures and mechanisms that determine inheritance are studied.
Answer to Problem 1P
Correct answer:
Alleles: alternate forms of a gene assortment
Explanation of Solution
A variant form of a gene is termed as an allele. The genes have a variety of different forms, which are located at the same position, or genetic locus, on a chromosome.
c.
To determine:
The phrase that describes “independent” among the options given below.
1. Having two identical alleles of a given gene
2. The allele expressed in the phenotype of the heterozygote
3. Alternate forms of a gene assortment
4. Observable characteristic
5. A cross between individuals both heterozygous for two genes
6. Alleles of one gene separate into gametes randomly with respect to alleles of other genes
7. Reproductive cells containing only one copy of each gene
8. The allele that does not contribute to the phenotype of the heterozygote
9. The cross of an individual of ambiguous genotype with a homozygous recessive individual
10. An individual with two different alleles of a gene
11. The heritable entity that determines a characteristic
12. The alleles an individual has
13. The separation of the two alleles of a gene into different gametes
14. Offspring of the P generation
Introduction:
Gregor Mendel was the scientist who explained the fundamental laws of inheritance. His studies on pea plants exposed that genes come in pairs and are inherited as distinct units, one from each parent.
Answer to Problem 1P
Correct answer:
Independent: Alleles of one gene separate into gametes randomly with respect to alleles of other genes
Explanation of Solution
Gregor Mendel stated that the alleles for separate traits are passed to the next generation independent of each other. The selection of one allele is independent of the selection of the other trait.
d.
To determine:
The phrase that describes “gametes” among the options given below.
1. Having two identical alleles of a given gene
2. The allele expressed in the phenotype of the heterozygote
3. Alternate forms of a gene assortment
4. Observable characteristic
5. A cross between individuals both heterozygous for two genes
6. Alleles of one gene separate into gametes randomly with respect to alleles of other genes
7. Reproductive cells containing only one copy of each gene
8. The allele that does not contribute to the phenotype of the heterozygote
9. The cross of an individual of ambiguous genotype with a homozygous recessive individual
10. An individual with two different alleles of a gene
11. The heritable entity that determines a characteristic
12. The alleles an individual has
13. The separation of the two alleles of a gene into different gametes
14. Offspring of the P generation
Introduction:
Gametes are known as sex cells which is produced through the process of meiosis.
Answer to Problem 1P
Correct answer:
Gametes: Reproductive cells containing only one copy of each gene
Explanation of Solution
Gametes are the reproductive cells of an individual. A gamete is a haploid cell that fuses with another haploid cell during fertilization in an individual during sexual reproduction. The two gametes usually look different from each other.
e.
To determine:
The phrase that describes “gene” among the options given below.
1. Having two identical alleles of a given gene
2. The allele expressed in the phenotype of the heterozygote
3. Alternate forms of a gene assortment
4. Observable characteristic
5. A cross between individuals both heterozygous for two genes
6. Alleles of one gene separate into gametes randomly with respect to alleles of other genes
7. Reproductive cells containing only one copy of each gene
8. The allele that does not contribute to the phenotype of the heterozygote
9. The cross of an individual of ambiguous genotype with a homozygous recessive individual
10. An individual with two different alleles of a gene
11. The heritable entity that determines a characteristic
12. The alleles an individual has
13. The separation of the two alleles of a gene into different gametes
14. Offspring of the P generation
Introduction:
Gene is the basic unit of hereditary information. They are present in the fixed position on a chromosome.
Answer to Problem 1P
Correct answer:
Gene: the heritable entity that determines a characteristic
Explanation of Solution
Gene is termed as a single functional sequence of a DNA or RNA. The different traits of an organism are coded by different functional genes.
f.
To determine:
The phrase that describes “segregation” among the options given below.
1. Having two identical alleles of a given gene
2. The allele expressed in the phenotype of the heterozygote
3. Alternate forms of a gene assortment
4. Observable characteristic
5. A cross between individuals both heterozygous for two genes
6. Alleles of one gene separate into gametes randomly with respect to alleles of other genes
7. Reproductive cells containing only one copy of each gene
8. The allele that does not contribute to the phenotype of the heterozygote
9. The cross of an individual of ambiguous genotype with a homozygous recessive individual
10. An individual with two different alleles of a gene
11. The heritable entity that determines a characteristic
12. The alleles an individual has
13. The separation of the two alleles of a gene into different gametes
14. Offspring of the P generation
Introduction:
Gregor Mendel is the father of genetics and he explained the fundamental laws of inheritance. His studies on pea plants exposed that genes come in pairs and are inherited as distinct units, one from each parent.
Answer to Problem 1P
Correct answer:
Segregation: the separation of the two alleles of a gene into different gametes
Explanation of Solution
According to Gregor Mendel’s law of segregation, the two alleles corresponding to a trait separate from each other during meiosis and segregate into the different gametes.
g.
To determine:
The phrase that describes “heterozygous” among the options given below.
1. Having two identical alleles of a given gene
2. The allele expressed in the phenotype of the heterozygote
3. Alternate forms of a gene assortment
4. Observable characteristic
5. A cross between individuals both heterozygous for two genes
6. Alleles of one gene separate into gametes randomly with respect to alleles of other genes
7. Reproductive cells containing only one copy of each gene
8. The allele that does not contribute to the phenotype of the heterozygote
9. The cross of an individual of ambiguous genotype with a homozygous recessive individual
10. An individual with two different alleles of a gene
11. The heritable entity that determines a characteristic
12. The alleles an individual has
13. The separation of the two alleles of a gene into different gametes
14. Offspring of the P generation
Introduction:
Genes come in pairs and each pair is present in a specific position or locus on a chromosome. If the locus has two identical alleles, they are homozygous; if the locus has two different alleles, they are heterozygous.
Answer to Problem 1P
Correct answer:
Heterozygous: An individual with two different alleles of a gene
Explanation of Solution
An individual carrying two different alleles of a single gene is termed as a heterozygote. In case of heterozygote, one allele is dominant, and the other gene is recessive.
h.
To determine:
The phrase that describes “dominant” among the options given below.
1. Having two identical alleles of a given gene
2. The allele expressed in the phenotype of the heterozygote
3. Alternate forms of a gene assortment
4. Observable characteristic
5. A cross between individuals both heterozygous for two genes
6. Alleles of one gene separate into gametes randomly with respect to alleles of other genes
7. Reproductive cells containing only one copy of each gene
8. The allele that does not contribute to the phenotype of the heterozygote
9. The cross of an individual of ambiguous genotype with a homozygous recessive individual
10. An individual with two different alleles of a gene
11. The heritable entity that determines a characteristic
12. The alleles an individual has
13. The separation of the two alleles of a gene into different gametes
14. Offspring of the P generation
Introduction:
Dominant and recessive alleles present in a trait that has two different forms at the gene level.
Answer to Problem 1P
Correct answer:
Dominant: the allele expressed in the phenotype of the heterozygote
Explanation of Solution
In genetics, dominance defines the relationship between alleles of one gene. Dominant allele masks the contribution of the recessive allele in the phenotype of any gene.
i.
To determine:
The phrase that describes “F1” among the options given below.
1. Having two identical alleles of a given gene
2. The allele expressed in the phenotype of the heterozygote
3. Alternate forms of a gene assortment
4. Observable characteristic
5. A cross between individuals both heterozygous for two genes
6. Alleles of one gene separate into gametes randomly with respect to alleles of other genes
7. Reproductive cells containing only one copy of each gene
8. The allele that does not contribute to the phenotype of the heterozygote
9. The cross of an individual of ambiguous genotype with a homozygous recessive individual
10. An individual with two different alleles of a gene
11. The heritable entity that determines a characteristic
12. The alleles an individual has
13. The separation of the two alleles of a gene into different gametes
14. Offspring of the P generation
Introduction:
F1 is also termed as filial 1 generation.
Answer to Problem 1P
Correct answer:
F1: offspring of the P generation
Explanation of Solution
F1 generation comes as an offspring formed due to sexual reproduction between parents. F1 generation is obtained by the fusion of male and female gametes.
j.
To determine:
The phrase that describes “testcross” among the options given below.
1. Having two identical alleles of a given gene
2. The allele expressed in the phenotype of the heterozygote
3. Alternate forms of a gene assortment
4. Observable characteristic
5. A cross between individuals both heterozygous for two genes
6. Alleles of one gene separate into gametes randomly with respect to alleles of other genes
7. Reproductive cells containing only one copy of each gene
8. The allele that does not contribute to the phenotype of the heterozygote
9. The cross of an individual of ambiguous genotype with a homozygous recessive individual
10. An individual with two different alleles of a gene
11. The heritable entity that determines a characteristic
12. The alleles an individual has
13. The separation of the two alleles of a gene into different gametes
14. Offspring of the P generation
Introduction:
Testcross is a very important method to determine the zygosity of the individual.
Answer to Problem 1P
Correct answer:
Testcross: The cross of an individual of ambiguous genotype with a homozygous recessive individual
Explanation of Solution
Testcross involves the breeding of a recessive individual with an individual having unknown zygosity.
k.
To determine:
The phrase that describes “genotype” among the options given below.
1. Having two identical alleles of a given gene
2. The allele expressed in the phenotype of the heterozygote
3. Alternate forms of a gene assortment
4. Observable characteristic
5. A cross between individuals both heterozygous for two genes
6. Alleles of one gene separate into gametes randomly with respect to alleles of other genes
7. Reproductive cells containing only one copy of each gene
8. The allele that does not contribute to the phenotype of the heterozygote
9. The cross of an individual of ambiguous genotype with a homozygous recessive individual
10. An individual with two different alleles of a gene
11. The heritable entity that determines a characteristic
12. The alleles an individual has
13. The separation of the two alleles of a gene into different gametes
14. Offspring of the P generation
Introduction:
The part of the genetic makeup of an organism is called the genotype. It determines the characteristics of an organism.
Answer to Problem 1P
Correct answer:
Genotype: the alleles an individual has
Explanation of Solution
The pair of alleles responsible for the expression of a particular phenotype is known as the genotype. It can consist of a pair of homologous or heterologous alleles.
l.
To determine:
The phrase that describes “recessive” among the options given below.
1. Having two identical alleles of a given gene
2. The allele expressed in the phenotype of the heterozygote
3. Alternate forms of a gene assortment
4. Observable characteristic
5. A cross between individuals both heterozygous for two genes
6. Alleles of one gene separate into gametes randomly with respect to alleles of other genes
7. Reproductive cells containing only one copy of each gene
8. The allele that does not contribute to the phenotype of the heterozygote
9. The cross of an individual of ambiguous genotype with a homozygous recessive individual
10. An individual with two different alleles of a gene
11. The heritable entity that determines a characteristic
12. The alleles an individual has
13. The separation of the two alleles of a gene into different gametes
14. Offspring of the P generation
Introduction:
Dominant and recessive alleles present in a trait that has two different forms at the gene level.
Answer to Problem 1P
Correct answer:
Recessive: The allele that does not contribute to the phenotype of the heterozygote
Explanation of Solution
A recessive trait is a specific form of a trait that does not express itself in the presence of a dominant allele. This trait expresses itself in a pair of homologous recessive alleles.
m.
To determine:
The phrase that describes “dihybrid cross” among the options given below.
1. Having two identical alleles of a given gene
2. The allele expressed in the phenotype of the heterozygote
3. Alternate forms of a gene assortment
4. Observable characteristic
5. A cross between individuals both heterozygous for two genes
6. Alleles of one gene separate into gametes randomly with respect to alleles of other genes
7. Reproductive cells containing only one copy of each gene
8. The allele that does not contribute to the phenotype of the heterozygote
9. The cross of an individual of ambiguous genotype with a homozygous recessive individual
10. An individual with two different alleles of a gene
11. The heritable entity that determines a characteristic
12. The alleles an individual has
13. The separation of the two alleles of a gene into different gametes
14. Offspring of the P generation
Introduction:
The cross between two different lines or genes that vary in two observed traits is termed as dihybrid cross.
Answer to Problem 1P
Correct answer:
Dihybrid cross: A cross between individuals both heterozygous for two genes
Explanation of Solution
Dihybrid cross explains the mating experiment between two individuals that are identically hybrid for two traits.
n.
To determine:
The phrase that describes “homozygote” among the options given below.
1. Having two identical alleles of a given gene
2. The allele expressed in the phenotype of the heterozygote
3. Alternate forms of a gene assortment
4. Observable characteristic
5. A cross between individuals both heterozygous for two genes
6. Alleles of one gene separate into gametes randomly with respect to alleles of other genes
7. Reproductive cells containing only one copy of each gene
8. The allele that does not contribute to the phenotype of the heterozygote
9. The cross of an individual of ambiguous genotype with a homozygous recessive individual
10. An individual with two different alleles of a gene
11. The heritable entity that determines a characteristic
12. The alleles an individual has
13. The separation of the two alleles of a gene into different gametes
14. Offspring of the P generation
Introduction:
The degree of similarity between the alleles for a trait in an organism is known as zygosity.
Answer to Problem 1P
Correct answer:
Homozygote: having two identical alleles of a given gene
Explanation of Solution
Homozygote is an individual who has two identical alleles of a particular gene or genes.
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