Question 1

-The illustration above shows the F₂phenotypes from a monohybrid cross in snapdragons.What type of inheritance produces such an outcome? A) complete dominance B) incomplete dominance C) multiple alleles D) continuous variation E) epistasis

Accepted Answer

Incomplete dominance occurs when the phenotype of the heterozygote is intermediate between the phenotypes of the homozygotes, which is typical in snapdragons where red and white flowers produce pink offspring.

Question 2

The pea plant was an excellent choice for Mendel's experiments because
A) true-breeding varieties were available.
B) the plant can self-fertilize.
C) it can be cross-fertilized.
D) true-breeding varieties were available, and it can be cross-fertilized.
E) true-breeding varieties were available, the plant can self-fertilize, and it can be cross-fertilized.

Accepted Answer

The pea plant was an excellent choice for Mendel's experiments because it had all three qualities: true-breeding varieties were available, the plant can self-fertilize, and it can also be cross-fertilized. This allowed Mendel to easily control and manipulate the genetics of the pea plants in his experiments.

Question 3

-Which offspring in the illustration above are homozygous recessive for both traits?
A) A
B) B
C) C
D) D
E) none of these

Accepted Answer

D

Question 4

-A gene that produces multiple effects is called
A) a multiple allele.
B) an autosome.
C) an epistatic gene.
D) a pleiotropic gene.
E) an incompletely dominant gene.

Accepted Answer

A pleiotropic gene is one that influences multiple phenotypic traits.

Question 5

For Mendel's explanation of inheritance to be correct,
A) the genes for the traits he studied have to be located on the same chromosome.
B) the combination of gametes at fertilization has to be due to chance.
C) genes cannot be transmitted independently of each other.
D) only diploid organisms demonstrate inheritance patterns.
E) none of these apply.

Accepted Answer

Mendel's explanation of inheritance relies on the random combination of gametes at fertilization, which is due to chance. The other options are not necessary for his explanation to be correct.

Question 6

An individual with a genetic makeup of aa BB is called
A) true-breeding.
B) recessive.
C) hybrid.
D) dihybrid.
E) heterozygous.

Accepted Answer

The answer of An individual with a genetic makeup of...

Question 7

-The F₂ phenotypic ratio of 9:3:4 is a result of a cross involving A) two genes expressing complete dominance. B) a gene expressing dominance and another gene expressing codominance. C) two genes expressing codominance. D) epistasis, in which one gene modifies the expression of the other gene. E) multiple alleles.

Accepted Answer

The 9:3:4 ratio is typical of recessive epistasis, where one gene's recessive alleles mask or modify the expression of another gene.

Question 8

The most accurate description of an organism with genotype AaBb is
A) homozygous dominant.
B) heterozygous.
C) heterozygous dominant.
D) homozygous recessive.
E) heterozygous recessive.

Accepted Answer

An organism with the genotype AaBb has two different alleles for each gene, making it heterozygous for both traits.

Question 9

Mendel's dihybrid crosses, but not his monohybrid crosses, show that
A) some genes are linked together.
B) the two alleles controlling a trait are divided equally among the gametes.
C) alleles for different traits are inherited independently.
D) one of the pair of alleles is dominant to the other.
E) the crossing of two different homozygous forms will not produce any offspring in the first generation that will look like either of the parents.

Accepted Answer

Mendel's dihybrid crosses showed that alleles for different traits are inherited independently. This is known as the principle of independent assortment, which states that the segregation of one set of alleles for a trait is independent of the segregation of another set of alleles for a different trait. This is why Mendel was able to observe a 9:3:3:1 ratio in his dihybrid crosses, indicating that the inheritance of one trait did not affect the inheritance of the other trait.

Question 10

The ABO blood types are controlled by
A) pleiotropy.
B) multiple alleles.
C) incomplete dominance.
D) codominance.
E) multiple alleles and codominance.

Accepted Answer

The ABO blood types are controlled by multiple alleles (A, B, O) and exhibit codominance, where both A and B alleles are expressed in the phenotype.

Question 11

The CFTR protein product is responsible for:
A) pumping chloride ions out of the cell.
B) pumping water out of the cell.
C) pumping chloride ions into the cell.
D) fighting off bacterial infections.
E) regulating gene expression.

Accepted Answer

The CFTR protein product is a chloride channel protein that pumps chloride ions out of the cell. This function is important in maintaining proper fluid balance and electrolyte levels in various tissues and organs in the body, including the lungs, pancreas, and digestive tract. Defects in the CFTR gene can lead to the development of cystic fibrosis.

Question 12

Multiple effects of a single gene is
A) expressivity.
B) penetrance.
C) codominance.
D) pleiotropy.
E) multiple alleles.

Accepted Answer

Pleiotropy refers to when a single gene has multiple effects on an individual's phenotype. This can manifest in a variety of ways, such as a gene that affects both hair color and eye color, or one that affects both height and susceptibility to a certain disease.

Question 13

Where would the CFTR gene not be heavily expressed?
A) Lungs.
B) Reproductive system.
C) Intestines.
D) Brain.
E) Skin.

Accepted Answer

The CFTR gene is primarily expressed in epithelial tissues, including the lungs, intestines, and reproductive tract. It is not heavily expressed in the brain or skin.

Question 14

Which of the following is NOT TRUE of cystic fibrosis?
A) It produces sticky mucus.
B) It leads to increased bacterial lung infections.
C) The amino acid affected is phenylalanine.
D) It causes insufficient water to leave the cells.
E) All of these are true.

Accepted Answer

All the statements provided are true regarding cystic fibrosis. It produces sticky mucus, leads to increased bacterial lung infections, involves the deletion of phenylalanine in the CFTR protein, and causes insufficient water to leave the cells.

Question 15

-Genes at one locus that affect the expression of genes at a different locus are said to be
A) epistatic.
B) linked.
C) codominant.
D) penetrant.
E) alleles.

Accepted Answer

Epistatic genes are those that can mask or modify the expression of genes at a different locus.

Question 16

-Using the illustration above and the assumption that half of a plant's sperm and eggs are a and half are A, one can predict that the chance of sperm a meeting egg A at fertilization is
A) 1/2 * 1/2.
B) 25 percent.
C) one out of four.
D) 1/2.
E) all of these EXCEPT 1/2.

Accepted Answer

The answer of 
-Using the illustration above and the assumption...

Question 17

In ____, a pair of nonidentical alleles affecting two phenotypes for a given trait are both expressed at the same time in heterozygotes.
A) pleiotropy
B) polygenic inheritance
C) complete dominance
D) codominance
E) a multiple allele system

Accepted Answer

In codominance, both alleles are expressed equally in heterozygotes, resulting in a phenotype that shows both traits. This is in contrast to complete dominance, where one allele is dominant and masks the expression of the other allele, and a multiple allele system, which refers to a trait in which there are more than two possible alleles that can code for it. Pleiotropy refers to a single gene affecting multiple traits, while polygenic inheritance refers to a trait controlled by multiple genes.

Question 18

According to Mendel, what kinds of genes "disappear" in F₁pea plants? A) sex-linked B) dominant C) recessive D) codominant E) lethal

Accepted Answer

According to Mendel's laws of inheritance, recessive genes are masked by dominant genes in heterozygous individuals but can reappear in the offspring of two heterozygotes. In the case of F₁pea plants, the letter "S" likely represents the dominant allele while "U1" and "B0" represent the recessive alleles. Therefore, in order for the recessive gene to disappear, it must not be present in the offspring, indicating that both parents must have at least one dominant allele.

Question 19

A gene locus is
A) a recessive gene.
B) an unmatched allele.
C) a sex chromosome.
D) the location of an allele on a chromosome.
E) a dominant gene.

Accepted Answer

A gene locus is the specific location of a gene or an allele on a chromosome. Therefore, the best choice is D – the location of an allele on a chromosome.

Question 20

Various forms of a single gene at a given locus is called
A) kinetochores.
B) alleles.
C) autosomes.
D) loci.
E) chromatids.

Accepted Answer

The definition given in the question matches the definition of alleles, which are different forms of the same gene at a specific location on a chromosome. The other options do not match the definition given.

Quiz 13: Observing Patterns in Inherited Traits

-The illustration above shows the F2 phenotypes from a monohybrid cross in snapdragons.What type of inheritance produces such an outcome?

The pea plant was an excellent choice for Mendel's experiments because

-Which offspring in the illustration above are homozygous recessive for both traits?

-A gene that produces multiple effects is called

For Mendel's explanation of inheritance to be correct,

An individual with a genetic makeup of aa BB is called

-The F2 phenotypic ratio of 9:3:4 is a result of a cross involving

The most accurate description of an organism with genotype AaBb is

Mendel's dihybrid crosses, but not his monohybrid crosses, show that

The ABO blood types are controlled by

The CFTR protein product is responsible for:

Multiple effects of a single gene is

Where would the CFTR gene not be heavily expressed?

Which of the following is NOT TRUE of cystic fibrosis?

-Genes at one locus that affect the expression of genes at a different locus are said to be

-Using the illustration above and the assumption that half of a plant's sperm and eggs are a and half are A, one can predict that the chance of sperm a meeting egg A at fertilization is

In ____, a pair of nonidentical alleles affecting two phenotypes for a given trait are both expressed at the same time in heterozygotes.

According to Mendel, what kinds of genes "disappear" in F1 pea plants?

A gene locus is

Various forms of a single gene at a given locus is called

-The illustration above shows the F₂phenotypes from a monohybrid cross in snapdragons.What type of inheritance produces such an outcome?

-The F₂ phenotypic ratio of 9:3:4 is a result of a cross involving

According to Mendel, what kinds of genes "disappear" in F₁pea plants?