Question 1

In the ABO multiple allele system, there are the following combinations of genotypes and phenotypes:
A) 4 genotypes, 4 phenotypes
B) 4 genotypes, 6 phenotypes
C) 6 genotypes, 6 phenotypes
D) 6 genotypes, 4 phenotypes
E) 3 genotypes, 4 phenotypes

Accepted Answer

There are 6 genotypes (AA, AO, BB, BO, AB, OO) and 4 phenotypes (A, B, AB, O) in the ABO blood group system.

Question 2

Alternate forms of a gene are best described as _____.
A) homologues
B) loci
C) alleles
D) homozygous
E) heterozygous

Accepted Answer

Alleles refer to the alternate forms of a gene, which are responsible for producing different versions of a trait. Homologues are pairs of chromosomes that carry the same genes in the same order but may have different alleles. Loci refer to the specific location of a gene on a chromosome. Homozygous refers to having two identical alleles for a particular gene, while heterozygous refers to having two different alleles for the same gene.

Question 3

Methylmalonic acidemia is caused by _____.
A) an overdose of ethylene glycol
B) fat accumulation in white blood cells
C) defective liver enzymes
D) the inability to metablolize amino acids and fats
E) destruction of myelin sheaths surrounding nerves

Accepted Answer

Methylmalonic acidemia is characterized by the inability to properly metabolize amino acids and fats, specifically converting the amino acid methionine and the fatty acid derivative propionic acid into usable energy. This is due to a deficiency in the enzyme methylmalonyl-CoA mutase, which normally converts methylmalonyl-CoA into succinyl-CoA. Without this conversion, levels of methylmalonic acid build up in the body, leading to symptoms such as developmental delay, low muscle tone, poor feeding, and vomiting.

Question 4

The phenotype is _____.
A) controlled by the genotype
B) the expression of a trait in an organism
C) the result of inheritance from both parents
D) never homozygous
E) all of these

Accepted Answer

The phenotype is the expression of a trait in an organism.

Question 5

Why did Mendel choose pea plants to experiment on?
A) Offspring of pea plants are fertile.
B) They have a number of different distinct traits.
C) They are self-fertilizing.
D) They have a relatively short life cycle.
E) All of theses are reasons Mendel chose pea plants to experiment on.

Accepted Answer

Mendel chose pea plants to experiment on because offspring of pea plants are fertile, they have a number of different distinct traits, they are self-fertilizing, and they have a relatively short life cycle.

Question 6

Mendel's principle of segregation is directly related to an event that occurs in ______ of meiosis.
A) prophase I
B) metaphase I
C) anaphase I
D) prophase II
E) metaphase II

Accepted Answer

The principle of segregation refers to the separation of homologous chromosomes during anaphase I of meiosis, which results in the segregation of alleles into different gametes. Thus, the correct choice is C, which represents the stage of meiosis where this segregation occurs.

Question 7

In a cross between a true-breeding plant bearing smooth, yellow seeds and a true-breeding plant with wrinkled, green seeds, the offspring were all smooth and yellow. What is the genotype of the F₁ plants?
A) SSYY
B) ssyy
C) SsYy
D) ssYY
E) SSyy

Accepted Answer

This is an example of a monohybrid cross, where only one trait (seed texture and color) is studied. In this case, the parental plants are true-breeding, so they can be represented by homozygous genotypes: SSYY for the smooth yellow-seeded plant and syy for the wrinkled green-seeded plant. The F1 generation shows a dominant phenotype: all plants are smooth and yellow. This means that the allele for smooth texture (S) and the allele for yellow color (Y) are dominant over the alleles for wrinkled texture (s) and green color (y), respectively. Therefore, the genotype of the F1 plants must be heterozygous for both traits: SsYy.

Question 8

Mendel's principle of independent assortment is directly related to an event that occurs in _____ of meiosis.
A) prophase I
B) metaphase I
C) anaphase I
D) prophase II
E) metaphase II

Accepted Answer

Mendel's principle of independent assortment states that the segregation of alleles for one gene is independent of the segregation of alleles for another gene. This occurs during metaphase I of meiosis when homologous chromosomes line up randomly at the equator of the cell, creating multiple possible combinations of alleles in the resulting gametes.

Question 9

Free earlobes are dominant to attached ear lobes and brown eyes are dominant to blue eyes. Ricardo has brown eyes and attached ear lobes. Ricardo's mother has blue eyes and free ear lobes. Ricardo's partner, Shanteel, has blue eyes and free ear lobes. Shanteel's mother has brown eyes and attached ear lobes. What is the probability that Ricardo and Shanteel will have a child who has blue eyes and attached ear lobes?
A) 100 percent
B) 75 percent
C) 50 percent
D) 25 percent
E) 0 percent

Accepted Answer

According to the given information, Ricardo is heterozygous for both traits (BbEe), while Shanteel is homozygous recessive for eye color and heterozygous for earlobe attachment (bbEe). 
The Punnett Square for their offspring is:

|   | B | b |
|---|---|---|
| e |Be |be |
| e |Be |be |

Therefore, there is a 25% probability that their child will have blue eyes and attached earlobes.

Question 10

In a 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 F2 are identical
E) heterozygotes have a phenotype like one of the parents

Accepted Answer

In incomplete dominance, the heterozygotes have a phenotype that is a blend of the two parental phenotypes, leading to identical phenotypic and genotypic ratios in the F2 generation.

Question 11

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

Accepted Answer

Mendel observed that the recessive trait disappeared in the F1 generation but reappeared in the F2 generation, indicating it was masked by the dominant trait in the F1.

Question 12

A locus is best defined as _____.
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 the specific location of a gene on a chromosome.

Question 13

Independent assortment means that _____.
A) monohybrid crosses will show segregation and independent assortment
B) the segregation of one gene pair depends on the segregation of another gene pair
C) the gametes produced must be heterozygous in all cases
D) the segregation of one gene pair occurs as if no other gene pair was present
E) the 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 suggests that the inheritance of one trait does not depend on the inheritance of another trait, and that the assortment of alleles for one gene is independent of the assortment of alleles for another gene.

Question 14

A pea plant with yellow peas is crossed with a pea plant that has green peas. The offspring include both yellow-pea and green-pea plants. The original plant with yellow peas must, therefore, have what genotype?
A) YY
B) Yy
C) yy
D) It cannot be determined: YY or Yy
E) It cannot be determined: Yy or yy

Accepted Answer

This is a classic example of a cross between two heterozygous individuals (one with Yy and one with yy). The Punnett square for this cross would result in 50% Yy (yellow) and 50% yy (green) offspring. Therefore, the original plant with yellow peas must have had a genotype of Yy.

Question 15

In a pedigree, a person whose symbol is filled in and who is associated with the roman numeral II _____.
A) is affected by the trait and in the second generation
B) is not affected by the trait and in the second generation
C) is affected by the trait and is the second-oldest child in the family
D) is not affected by the trait and is the second-oldest child in the family
E) is affected by the trait and has an identical twin

Accepted Answer

A person whose symbol is filled in and associated with the roman numeral II is in the second generation of the pedigree. If the symbol is filled in, it means that the person is affected by the trait. Therefore, the best choice is A, which states that the person is affected by the trait and in the second generation.

Question 16

The offspring resulting from the cross of two red flowered plants are 3/4 red and 1/4 white. The most likely genotype of the red flowered plants is _____ .
A) homozygous dominant
B) heterozygous
C) homozygous recessive
D) impossible to tell from this information

Accepted Answer

The fact that the offspring are 3/4 red and 1/4 white suggests that one parent was homozygous dominant (RR) and the other was heterozygous (Rr). When the two are crossed, the Punnett square predicts that the offspring will be 3/4 red (RR or Rr) and 1/4 white (rr). Therefore, the most likely genotype of the red flowered plants is heterozygous (Rr). Option A (homozygous dominant) would result in all red offspring, while option C (homozygous recessive) would result in all white offspring, neither of which match the observed ratio. Option D (impossible to tell) is incorrect, as the observed ratio provides enough information to make a reasonable inference about the parent genotype.

Question 17

In a situation with codominant inheritance _____.
A) there is no recessive phenotype
B) each allele is fully and completely expressed
C) the principles of Mendelian inheritance are intact
D) independent assortment can predict the genotypes and phenotypes of the offspring
E) all of these are true

Accepted Answer

All of the choices are true. In codominant inheritance, both alleles are fully expressed, so there is no recessive phenotype. The principles of Mendelian inheritance are intact, and independent assortment can predict the genotypes and phenotypes of the offspring.

Question 18

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) none of these

Accepted Answer

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

Question 19

Pedigrees _____.
A) provide information on the patterns of inheritance of a trait
B) can identify those at risk for a disease
C) can identify those at risk for transmitting a disease
D) can be used to deduce the genotypes of parents
E) have all of these characteristics

Accepted Answer

Pedigrees provide information on the patterns of inheritance of a trait, can identify those at risk for a disease, can identify those at risk for transmitting a disease, and can be used to deduce the genotypes of parents. Therefore, all of these characteristics are true for pedigrees.

Question 20

A chi square test is done to determine _____.
A) whether an organism with a dominant phenotype is homozygous or heterozygous
B) whether an allele exhibits complete or incomplete dominance
C) what the predicted outcome of a dihybrid cross will be
D) how closely actual results of a cross match the expected results
E) whether a trait is determined by one gene or many genes

Accepted Answer

A chi square test is used to determine whether the actual results of a cross match the expected results, which can help to determine how closely the observed data fits the theoretical patterns. This test is commonly used in genetics to test hypotheses about the inheritance of traits and to determine whether the results are statistically significant. The other choices are all related to genetic concepts, but they are not directly tested using a chi square analysis.

Quiz 3: Transmission of Genes From Generation to Generation

In the ABO multiple allele system, there are the following combinations of genotypes and phenotypes:

Alternate forms of a gene are best described as _____.

Methylmalonic acidemia is caused by _____.

The phenotype is _____.

Why did Mendel choose pea plants to experiment on?

Mendel's principle of segregation is directly related to an event that occurs in ______ of meiosis.

In a cross between a true-breeding plant bearing smooth, yellow seeds and a true-breeding plant with wrinkled, green seeds, the offspring were all smooth and yellow. What is the genotype of the F₁ plants?

Mendel's principle of independent assortment is directly related to an event that occurs in _____ of meiosis.

In a cross involving incomplete dominance _____.

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

A locus is best defined as _____.

Independent assortment means that _____.

A pea plant with yellow peas is crossed with a pea plant that has green peas. The offspring include both yellow-pea and green-pea plants. The original plant with yellow peas must, therefore, have what genotype?

In a pedigree, a person whose symbol is filled in and who is associated with the roman numeral II _____.

The offspring resulting from the cross of two red flowered plants are 3/4 red and 1/4 white. The most likely genotype of the red flowered plants is _____ .

In a situation with codominant inheritance _____.

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

Pedigrees _____.

A chi square test is done to determine _____.