Question 1

Phenotype is ____.
A) only expressed in a heterozygous organism
B) an observable property or expression of a trait in an organism
C) the specific genetic constitution of an organism
D) the variation of genes
E) cannot be determined by knowing genotype

Accepted Answer

Phenotype refers to the observable traits and characteristics of an organism, such as its physical appearance or behavior. It is a result of both genetic and environmental factors and can be influenced by both. Phenotype can be observed in both homozygous and heterozygous organisms.

Question 2

Pedigrees ____.
A) are usually constructed using the phenotypic information of one generation
B) cannot determine whether a trait has a dominant or recessive pattern
C) use squares to represent females and circles to represent males on their diagrams
D) are not useful in deducing the genotypes of parents
E) provide information on the patterns of inheritance of a trait

Accepted Answer

Pedigrees provide information on the patterns of inheritance of a trait, such as whether it is dominant or recessive, and can be used to determine the probability of a person inheriting the trait. They typically use squares to represent males and circles to represent females on their diagrams, and are usually constructed using the phenotypic information of multiple generations, allowing for the deduction of genotypes.

Question 3

In codominant inheritance,____.
A) there is partial phenotypic expression of one member of a gene pair in the homozygous condition
B) there is full phenotypic expression of both members of a gene pair in the heterozygous condition
C) the interaction of two or more non-allelic genes controls a single phenotype
D) two recessive alleles interact and express themselves as a single dominant trait 
E) the phenotype of a heterozygote is intermediate to those of the parents

Accepted Answer

In codominant inheritance, both alleles in the heterozygous condition are fully expressed in the phenotype, resulting in a unique phenotype that shows characteristics of both alleles. This is in contrast to incomplete dominance where the heterozygote phenotype is intermediate or a blend of the two homozygous phenotypes.

Question 4

Mendel chose to study pea plants because they have a long life cycle that offers ample time for analysis.

Accepted Answer

Mendel chose pea plants because they have a short life cycle and distinct, easily observable traits, which allowed for quick and clear analysis of inheritance patterns.

Question 5

Recessive traits are expressed only in the homozygous state.

Accepted Answer

Recessive traits require two copies of the recessive allele to be expressed, meaning the individual must be homozygous for that trait. If an individual is heterozygous (having one dominant and one recessive allele), the dominant allele will mask the expression of the recessive allele, resulting in the dominant trait being expressed.

Question 6

Independent assortment means that the ____.
A) phenotypes are often a blending of two independent genotypes
B) segregation of one gene pair depends on the segregation of another gene pair
C) gametes produced must be heterozygous in all cases
D) segregation of one gene pair occurs as if no other gene pair was present
E) phenotypic ratio in F2 will be the same for dihybrid and monohybrid crosses

Accepted Answer

Independent assortment means that the segregation of one gene pair occurs as if no other gene pair was present. This means that the inheritance of one trait is not dependent on the inheritance of another trait.

Question 7

In a monohybrid cross with complete dominance,the F2 offspring should contain ____.
A) two different phenotypes and two different genotypes
B) two different phenotypes and three different genotypes
C) three different phenotypes and two different genotypes
D) three different phenotypes and three different genotypes
E) two different phenotypes and one genotype

Accepted Answer

In a monohybrid cross involving complete dominance, the F2 generation typically displays two different phenotypes (dominant and recessive) and three different genotypes (homozygous dominant, heterozygous, and homozygous recessive).

Question 8

Alternate forms of a gene are called ____.
A) homologues
B) loci
C) alleles
D) homozygous
E) heterozygous

Accepted Answer

Alternate forms of a gene are called alleles. Homologues refer to chromosomes that come in pairs and contain the same genes at the same location. Loci refer to the specific location of a gene on a chromosome. Homozygous refers to having two of the same alleles for a particular gene, while heterozygous refers to having two different alleles for a particular gene.

Question 9

People with albinism carry two copies of the dominant allele (AA)and cannot make a pigment called melanin.

Accepted Answer

People with albinism carry two copies of a recessive allele (aa), not a dominant allele (AA). They cannot make melanin due to a lack of function of the enzyme tyrosinase.

Question 10

Gregor Mendel was a completely self-trained scientist and never attended university.

Accepted Answer

Gregor Mendel attended the University of Olomouc and later the University of Vienna, where he studied under notable scientists, receiving formal education in science and mathematics.

Question 11

When analyzing a cross involving two traits,each trait is analyzed separately,and then the frequencies of each are combined to yield the observed phenotypic ratios.

Accepted Answer

This statement describes the principle of independent assortment, which states that the alleles for different traits segregate independently of one another during gamete formation. This allows for the separate analysis of each trait, and the combination of their frequencies to predict the phenotypic ratios in the offspring.

Question 12

In a P1 cross involving incomplete dominance,____.
A) the dominant phenotype is expressed in the F1
B) the recessive phenotype is expressed in the F1
C) Mendelian inheritance does not apply
D) the phenotypic ratio and genotypic ratio in the F1 are identical
E) heterozygotes will express the parental phenotype

Accepted Answer

In a P1 cross involving incomplete dominance, the F1 generation will exhibit a phenotype that is intermediate between the two parental phenotypes. This results in the phenotypic ratio being identical to the genotypic ratio in the F1 generation, as each genotype corresponds to a unique phenotype.

Question 13

Chi-square tests are used to determine whether a cross has been correctly constructed and analyzed.

Accepted Answer

Chi-square tests are used to determine if there is a significant difference between the expected and observed frequencies in one or more categories, not to verify the construction and analysis of a cross.

Question 14

A locus is ____.
A) an alternate form of a gene
B) the chromosome location of the centromere
C) the location of a gene on a chromosome
D) a mutation of a gene to an alternate state
E) the site of crossing over

Accepted Answer

A locus refers to a specific location on a chromosome where a gene is located. It is not an alternate form of a gene (allele), the location of the centromere, a mutation, or the site of crossing over.

Question 15

Methylmalonic acidemia (MMA)is caused by the inability to metabolize amino acids and fats.

Accepted Answer

MMA is a genetic disorder that affects the metabolism of certain amino acids and fats, leading to the buildup of toxic compounds such as methylmalonic acid. This leads to a range of symptoms and complications, including developmental delay, neurological damage, and metabolic acidosis. Therefore, option A is correct.

Question 16

In his monohybrid crosses,Mendel deduced that one trait was recessive because that trait was ____.
A) not present in the F1 and did not reappear in the F2
B) present in the F1 and in the F2
C) not present in the F1 and reappeared in the F2
D) present only in the parents
E) present only in the F2

Accepted Answer

Mendel deduced that a trait was recessive because it was not visible in the F1 generation (which displayed the dominant trait) but reappeared in the F2 generation, indicating that the trait was masked in the F1 but still carried and expressed in some of the F2 individuals.

Question 17

Incomplete dominance is the expression of a phenotype that is intermediate to those of the parents.

Accepted Answer

In incomplete dominance, the heterozygous genotype results in a phenotype that is a blend of the two homozygous phenotypes, rather than one being dominant over the other.

Question 18

Pedigree construction can be a difficult task.

Accepted Answer

Pedigree construction involves tracing the inheritance of genes or traits within a family, which can be challenging due to incomplete or inaccurate family records and the complexity of genetic inheritance.

Question 19

In a cross between a true-breeding plant bearing the dominant traits of smooth,yellow seeds and a true-breeding plant bearing the recessive traits of wrinkled,green seeds,the offspring (F1)are all smooth and yellow and their genotype is ____.
A) SSYY
B) ssyy
C) SsYy
D) ssYY
E) SSyy

Accepted Answer

Based on the given information, the dominant traits are smooth and yellow, which are represented by S and Y respectively. The recessive traits are wrinkled and green, represented by s and y respectively. Since the parents are true-breeding for each trait, the genotype of the smooth, yellow parent would be SSYY and the genotype of the wrinkled, green parent would be ssyy. In the F1 generation, all the offspring are smooth and yellow, indicating that they have inherited one dominant allele for smoothness and one dominant allele for yellowness from each parent. Therefore, the genotype of the F1 offspring would be SsYy.

Question 20

If a dihybrid cross is begun with a P1 generation of a true-breeding plant that produces smooth and yellow peas (smooth and yellow are both dominant traits),crossed with a plant that produces wrinkled green peas (wrinkled and green are both recessive traits),the F1 plants will all be smooth and yellow.

Accepted Answer

This is because both dominant traits, smooth and yellow, are present in the P1 plant and will be passed on to all of the F1 offspring. The recessive traits, wrinkled and green, will be masked by the dominant traits.

Quiz 3: Transmission of Genes from Generation to Generation

Phenotype is ____.

Pedigrees ____.

In codominant inheritance,____.

Mendel chose to study pea plants because they have a long life cycle that offers ample time for analysis.

Recessive traits are expressed only in the homozygous state.

Independent assortment means that the ____.

In a monohybrid cross with complete dominance,the F2 offspring should contain ____.

Alternate forms of a gene are called ____.

People with albinism carry two copies of the dominant allele (AA)and cannot make a pigment called melanin.

Gregor Mendel was a completely self-trained scientist and never attended university.

When analyzing a cross involving two traits,each trait is analyzed separately,and then the frequencies of each are combined to yield the observed phenotypic ratios.

In a P1 cross involving incomplete dominance,____.

Chi-square tests are used to determine whether a cross has been correctly constructed and analyzed.

A locus is ____.

Methylmalonic acidemia (MMA)is caused by the inability to metabolize amino acids and fats.

In his monohybrid crosses,Mendel deduced that one trait was recessive because that trait was ____.

Incomplete dominance is the expression of a phenotype that is intermediate to those of the parents.

Pedigree construction can be a difficult task.

In a cross between a true-breeding plant bearing the dominant traits of smooth,yellow seeds and a true-breeding plant bearing the recessive traits of wrinkled,green seeds,the offspring (F1) are all smooth and yellow and their genotype is ____.