Question 1

The "P" in P generation refers to

Accepted Answer

The "P" in P generation refers to the parental generation, which are the original individuals that are crossed to produce offspring in genetic studies.

Question 2

In humans,alleles for each gene are inherited from

Accepted Answer

Alleles for each gene are inherited from both parents, with one allele inherited from the mother and one allele inherited from the father. This is known as Mendelian inheritance and is represented by Punnett squares. Therefore, choice D (males and females - one allele from each parent) is the best choice.

Question 3

All gametes contain

Accepted Answer

Gametes are haploid cells and contain only one set of chromosomes. This means that they have half the number of chromosomes compared to the somatic cells of the body, which are diploid and have two sets of chromosomes. During fertilization, two gametes with one set of chromosomes each combine to form a zygote with a diploid set of chromosomes.

Question 4

If you,like Mendel,grow plants in the lab,and cross short (tt)pea plants with short pea plants,the offspring will be

Accepted Answer

Mendel's experiments with pea plants demonstrated that traits are inherited through discrete units known as genes. Shortness (tt) is a recessive trait, meaning that a plant must inherit two recessive alleles (one from each parent) to display the short phenotype. Crossing two short (tt) pea plants would only produce offspring with the tt genotype, resulting in all short offspring.

Question 5

Gametes may carry different combinations of alleles because of

Accepted Answer

Gametes can carry different combinations of alleles due to the process of crossing over, which occurs during meiosis. During crossing over, homologous chromosomes exchange genetic material, leading to new combinations of alleles on the chromosomes. Additionally, random alignment of chromosomes during meiosis can also result in different combinations of alleles in the resulting gametes.

Question 6

Of all the people who have studied inheritance,the person who made the earliest foundational study in the science of genetics is

Accepted Answer

Gregor Mendel is widely regarded as the “father of genetics” and made the earliest foundational study in the science of genetics in the mid-19th century through his work with pea plants, establishing the basic principles of inheritance.

Question 7

Mendel observed that some genetic traits seemed to mask others in the pea plants,and used the term ___ to describe these traits.

Accepted Answer

Mendel used the term "dominant" to describe traits that masked other traits in pea plants. The term "recessive" was used to describe traits that were masked by dominant traits when present in the heterozygous condition. The other answer choices are also relevant to genetics, but they do not accurately describe the specific concept that Mendel was trying to explain with his observations.

Question 8

Figuer:
Examine this image of chromosomes and identify the structural components. 
-A portion (location)of DNA that encodes a specific protein is a

Accepted Answer

A portion of DNA that encodes a specific protein is called a gene. Chromatids are identical copies of a chromosome that are joined at the centromere. A chromosome is a compact structure made up of DNA and protein that carries genetic information. The centromere is a region on a chromosome that serves as the attachment site for spindle fibers during cell division. The kinetochore is a protein structure that forms on the centromere during cell division, which helps to attach the spindle fibers to the chromosome.

Question 9

Mendel kept detailed records of the genetic traits of parent plants and their offspring plants.Among observations,he found that some traits would be expressed,whenever one particular allele was present,and called this allele

Accepted Answer

Mendel called the allele that is expressed whenever it is present the dominant allele.

Question 10

If the two alleles for a particular gene are identical the gene pair is

Accepted Answer

Homozygous refers to a gene pair that has identical alleles. Therefore, if the two alleles for a particular gene are identical it means the gene pair is homozygous.

Question 11

If an individual is heterozygous for a particular trait,

Accepted Answer

Heterozygous means that the individual has two different alleles for a particular trait, one inherited from each parent. Therefore, each parent contributed a different allele for that trait.

Question 12

Alternate forms (the DNA sequences indicated by alphabetic abbreviations)of the same gene are called

Accepted Answer

Alternate forms of a gene are called alleles. Centromeres are regions of a chromosome that attach sister chromatids. Chromosomes are structures that carry genetic information. Chromatids are identical copies of chromosomes that are held together by a centromere. Traits are observable characteristics of an organism that are determined by genes and the environment.

Question 13

Phenotype means

Accepted Answer

Phenotype refers to the observable physical or biochemical characteristics of an individual, which are determined by the expression of its genes. Therefore, the most appropriate option is D, which describes the observable expression of genes in an individual. A is incorrect because the number of chromosomes in an individual refers to his or her karyotype. Option B is incorrect because it refers to the DNA sequence an individual has, rather than its observable characteristics. Option C is partially correct, but it only refers to one aspect of phenotype, which is the combination of alleles, whereas phenotype comprises other factors such as environmental influences. Finally, option E is incorrect because the number of gametes is not related to phenotype.

Question 14

A physician reports to you the lab results in identifying your genetic condition relating to your skin health."DNA fingerprint" information indicates that you have two different versions of the allele for a particular skin protein,and this is called

Accepted Answer

The fact that the person has two different versions of the allele for a particular skin protein indicates that they are heterozygous for that allele. Heterozygous means that an individual has two different versions (or alleles) of a gene. In this case, the person has two different alleles for the gene that codes for the skin protein.

Question 15

In the study of genetics,the offspring of the parental generation is referred to as the

Accepted Answer

The F₁ generation refers to the first filial generation, which is the direct offspring of the parental (P) generation in genetic studies.

Question 16

The most common phenotype or allele for a gene in a population is referred to as the

Accepted Answer

The term "wild-type" refers to the most common form of a gene or phenotype in a population. Therefore, option E is the correct answer. Option A refers to a dominant trait or allele, but it does not necessarily reflect the most common in a population. Options B, C, and D refer to specific generations in genetics but do not provide an answer to the question.

Question 17

Genotype means

Accepted Answer

Genotype refers to the genetic makeup of an individual, including the combination of alleles (variations of genes) that the individual possesses. Thus, Choice E is the best answer. Choices A, B, C, and D are incorrect because they do not fully capture the meaning of genotype. Though the number of chromosomes an individual has is relevant to genetics, it alone does not determine genotype. Similarly, observable expression of genes (phenotype) and number of gametes do not capture the full genetic makeup of an individual. Choice C is the closest of the incorrect options but does not fully capture the idea that genotype refers to the combination of alleles an individual possesses rather than simply the genes themselves.

Question 18

This figure shows one reason among others why pea plants (Pisum sativum)are a good species for genetics studies.In reference to information given in the text,pea plants are good for genetics studies because

Accepted Answer

The text states that pea plants have many distinctly identifiable forms of genetic traits, growth is simple and easy, they can be self-fertilized for true-breeding genetic traits, and they produce large numbers of offspring (the peas). All of these reasons make pea plants a good species for genetics studies.

Question 19

A healthy young couple are both carriers of cystic fibrosis; the chance that each of their future children will inherit this serious illness is

Accepted Answer

Cystic fibrosis is an autosomal recessive disorder, meaning that a child must inherit two copies of the faulty gene (one from each parent) to develop the condition. When both parents are carriers, there is a 25% chance with each pregnancy that the child will inherit two copies of the faulty gene and thus have cystic fibrosis.

Question 20

When Mendel crossed tall (Tt)plants with tall plants of the same genotype,the offspring

Accepted Answer

When Mendel crossed tall (Tt) plants with tall plants of the same genotype (Tt), the offspring followed the Mendelian inheritance pattern of a monohybrid cross, resulting in a phenotypic ratio of 3 tall to 1 short. This is because the possible genotypes of the offspring could be TT, Tt, and tt, with tt being short.

Quiz 10: Patterns of Inheritance