Bio 103 - Chapter 14 (2) - Pharmacgy | Attempts: 77

2.

Tag-Sachs disease is an inherited disorder in humans:

True
False

Correct Answer

A. True

Explanation

Tag-Sachs disease is indeed an inherited disorder in humans. It is a rare genetic disorder caused by a deficiency of an enzyme called hexosaminidase A (Hex A). This enzyme is responsible for breaking down a fatty substance called GM2 ganglioside in the brain and spinal cord. Without enough Hex A, GM2 ganglioside accumulates, leading to the destruction of nerve cells in the brain. This results in various symptoms such as progressive loss of motor skills, developmental regression, seizures, and eventually, premature death. Since it is inherited, individuals with Tay-Sachs disease have a faulty gene that is passed down from their parents.

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3.

What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants?

There is a considerable genetic variation in garden peas
Traits are inherited in discrete units, and are not the results of “blending”
Recessive genes occur more frequently in the F1 generation
Genes are composed of DNA

Correct Answer

A. Traits are inherited in discrete units, and are not the results of “blending”

Explanation

Gregor Mendel drew the conclusion that traits are inherited in discrete units, and are not the result of "blending" from his experiments with pea plants. This means that traits are passed down from parents to offspring in a predictable and independent manner, rather than being a mixture or combination of the parents' traits. Mendel's experiments showed that certain traits would be expressed in the offspring, while others would not, indicating that there is a clear separation and segregation of traits. This concept of discrete inheritance units laid the foundation for our understanding of genetics.

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4.

Albinism is a recessive trait. A man and woman both show normal pigmentation, but both have one parent who has albinism (without melanin pigmentation). What is the probability that their first child will have albinism?

0
1/2
1/4
1

Correct Answer

A. 1/4

Explanation

The probability that their first child will have albinism is 1/4. Since albinism is a recessive trait, both parents must carry the recessive gene in order for their child to have albinism. In this case, both parents have one parent who has albinism, which means they each carry one copy of the recessive gene. When they have a child, there is a 1/4 chance that both parents will pass on their recessive genes, resulting in the child having albinism.

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5.

When red flower mates white flower, the F1 individuals are pink, what is the type of dominance here?

Incomplete dominance
Multiple alleles
Pleiotropy
Epistasis

Correct Answer

A. Incomplete dominance

Explanation

Incomplete dominance is the type of dominance observed when the F1 offspring of a cross between two different homozygous parents display an intermediate phenotype. In this case, when a red flower mates with a white flower, the resulting F1 individuals have a pink color, which is a blend of the parental colors. This indicates that neither the red nor the white allele is dominant over the other, resulting in incomplete dominance.

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6.

Which of the following is considered as quantitative character?

Skin pigmentation
ABO system
Sickle-cell anemia
Tay-sachs

Correct Answer

A. Skin pigmentation

Explanation

Skin pigmentation is considered as a quantitative character because it can be measured and expressed numerically. Quantitative characters are traits that can be measured on a continuous scale, such as height, weight, or skin color. In the case of skin pigmentation, it can be measured using various methods, such as spectrophotometry or visual assessment, and the results can be quantified using numerical values. Therefore, skin pigmentation fits the definition of a quantitative character.

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7.

A genotype is the genetic makeup of a trait

True
False

Correct Answer

A. True

Explanation

A genotype refers to the specific combination of genes present in an organism, which determines its genetic makeup and potential traits. It is a fundamental concept in genetics and is responsible for the inheritance of traits from parents to offspring. Therefore, the statement "A genotype is the genetic makeup of a trait" is correct because it accurately describes the relationship between genotype and traits.

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8.

Inheritance patterns are often more complex than predicted by simple Mendelian genetics

True
False

Correct Answer

A. True

Explanation

Inheritance patterns can be more complex than predicted by simple Mendelian genetics because there are many factors that can influence the expression of genes. Mendelian genetics only considers the inheritance of single genes, but in reality, many traits are influenced by multiple genes and environmental factors. Additionally, there are different types of inheritance patterns, such as incomplete dominance, codominance, and polygenic inheritance, that do not follow the simple dominant/recessive pattern described by Mendel. Therefore, it is true that inheritance patterns can be more complex than predicted by simple Mendelian genetics.

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9.

To determine the genotype of an organism with a dominance phenotype, we could perform:

Monhybrid cross
Test cross
Dihybrid cross
We can’t determine

Correct Answer

A. Test cross

Explanation

A test cross is performed to determine the genotype of an organism with a dominance phenotype. In a test cross, the organism with the dominant phenotype is crossed with a homozygous recessive individual. If all the offspring have the dominant phenotype, it suggests that the organism is homozygous dominant. However, if some of the offspring have the recessive phenotype, it indicates that the organism is heterozygous. Therefore, a test cross is a useful method to determine the genotype of an organism with a dominance phenotype.

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10.

Alternative versions of genes are called phenotype

True
False

Correct Answer

A. False

Explanation

Phenotype refers to the observable characteristics of an organism, which are determined by the interaction between its genes (genotype) and the environment. Alternative versions of genes are actually called alleles, not phenotype. Alleles are different forms of the same gene that can produce variations in the phenotype. Therefore, the given answer "False" is correct.

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11.

Suppose two individuals with the genotype AaBbCc are mated. Assuming that the genes are not linked, what fraction of the offspring are expected to be homozygous recessive for the three traits?

1/4
1/8
1/16
1/64

Correct Answer

A. 1/64

Explanation

When two individuals with the genotype AaBbCc are mated, each trait is inherited independently. The probability of an offspring being homozygous recessive for each trait is 1/4 (since it requires both recessive alleles). Since there are three traits, the probability of an offspring being homozygous recessive for all three traits is (1/4) * (1/4) * (1/4) = 1/64. Therefore, the fraction of the offspring expected to be homozygous recessive for the three traits is 1/64.

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12.

In Tay-Sachs disease, what is the type of dominance at organismal level?

Incomplete dominance
Multiple alleles
Complete dominance
Epistasis

Correct Answer

A. Complete dominance

Explanation

Complete dominance refers to a situation where one allele completely masks the expression of the other allele in a heterozygous individual. In Tay-Sachs disease, a recessive genetic disorder, the presence of a normal allele is sufficient to prevent the disease from occurring. Therefore, the normal allele exhibits complete dominance over the disease-causing allele, as individuals with one normal allele and one disease-causing allele are phenotypically normal.

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13.

How many genotypes and phenotypes does the ABO system has?

4-6
6-4
4-4
6-6

Correct Answer

A. 6-4

Explanation

The ABO system has 6 genotypes and 4 phenotypes. This is because there are three alleles that determine blood type (A, B, and O), and each individual has two of these alleles. The possible genotypes are AA, AO, BB, BO, AB, and OO. However, the phenotypes are only A, B, AB, and O, as the presence or absence of the A and B antigens on red blood cells determines the blood type.

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14.

Which of the following is an example of testcross?

Hh x hh
Hh x Hh
Hh x hh
Hh x hh

Correct Answer

A. Hh x hh

Explanation

A testcross is a breeding experiment used to determine the genotype of an individual with a dominant phenotype. In this case, the cross between Hh and hh is an example of a testcross because hh is a homozygous recessive individual, while Hh is a heterozygous individual. By crossing Hh with hh, if any of the offspring display the recessive phenotype, it can be concluded that Hh is the genotype of the parent with the dominant phenotype.

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15.

The MN phenotype is intermediate between M and N phenotypes:

True
False

Correct Answer

A. False

Explanation

The MN phenotype is not intermediate between M and N phenotypes. Instead, it is a distinct phenotype that can be inherited from both M and N alleles. The M and N alleles are codominant, meaning that both alleles are expressed equally and independently of each other. Therefore, individuals with the MN phenotype can have both M and N antigens on their red blood cells, rather than a blend of the M and N antigens.

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Bio 103 - Chapter 14 (2) - Pharmacgy

Mendel used the scientific approach to identify two laws of inheritance:

Quiz Preview

Tag-Sachs disease is an inherited disorder in humans:

What was the most significant conclusion that Gregor Mendel drew from his experiments with pea plants?

Albinism is a recessive trait. A man and woman both show normal pigmentation, but both have one parent who has albinism (without melanin pigmentation). What is the probability that their first child will have albinism?

When red flower mates white flower, the F1 individuals are pink, what is the type of dominance here?

Which of the following is considered as quantitative character?

A genotype is the genetic makeup of a trait

Inheritance patterns are often more complex than predicted by simple Mendelian genetics

To determine the genotype of an organism with a dominance phenotype, we could perform:

Alternative versions of genes are called phenotype

Suppose two individuals with the genotype AaBbCc are mated. Assuming that the genes are not linked, what fraction of the offspring are expected to be homozygous recessive for the three traits?

In Tay-Sachs disease, what is the type of dominance at organismal level?

How many genotypes and phenotypes does the ABO system has?

Which of the following is an example of testcross?

The MN phenotype is intermediate between M and N phenotypes: