Chapter 11 Genetics Practice Quiz

The given question is asking for the counterpart of "Female = XX" in terms of the genetic makeup of males. In humans, females have two X chromosomes (XX), while males have one X and one Y chromosome (XY). Therefore, the correct answers are "XY" and "YX" as they represent the genetic makeup of males.

Sex chromosomes consist of X and Y. In humans, females have two X chromosomes (XX) and males have one X and one Y chromosome (XY). The presence of the Y chromosome determines the development of male characteristics, while the absence of the Y chromosome leads to the development of female characteristics. Therefore, the correct answer is X and Y.

The statement is true because in genetics, the dominant allele is expressed and masks the effects of the recessive allele. This means that even if an individual has both a dominant and recessive allele for a particular trait, only the dominant allele will be visible in their phenotype. The recessive allele will only be expressed if an individual has two copies of it, meaning they are homozygous recessive.

The genotype for Type O blood is ii, which means that it lacks both A and B antigens on the red blood cells. This is the correct answer because individuals with Type O blood have two copies of the "i" allele, which does not produce any antigens.

Pedigrees are diagrams that show the inheritance of a specific trait or condition within a family. They are commonly used in genetics to track the occurrence of genetic disorders or traits within a family tree. By analyzing a pedigree, one can determine patterns of inheritance and identify individuals who are carriers or affected by the trait. Therefore, the statement that pedigrees show a family history tracing for one specific trait is true.

A Hemophiliac is not a normal trait. Hemophilia is a genetic disorder that affects the blood's ability to clot, resulting in excessive bleeding. It is caused by a mutation in one of the genes responsible for blood clotting. People with hemophilia have a deficiency or absence of certain clotting factors, which can lead to spontaneous bleeding or excessive bleeding following injuries or surgeries. This condition is inherited and cannot be considered a normal trait.

The correct answer is Ff and FF. This is because heterozygous traits have two different alleles, represented by different letters (Ff), while homozygous traits have two identical alleles, represented by the same letter (FF). In this case, Ff represents the heterozygous trait, while FF represents the homozygous trait.

Men have one X chromosome and one Y chromosome, while women have two X chromosomes. This means that if a man inherits a recessive trait on his X chromosome, he will express that trait because he does not have another X chromosome to mask it. In contrast, women have two X chromosomes, so even if they inherit a recessive trait on one X chromosome, they may have a dominant allele on the other X chromosome that masks the recessive trait. Therefore, recessive traits on the X chromosome are more likely to appear in men.

X inactivation is a natural process that occurs in female mammals, including humans, where one of the X chromosomes in each cell is randomly inactivated. This is to ensure equal gene expression between males and females, as males only have one X chromosome. The inactivated X chromosome becomes a condensed structure called a Barr body. This process occurs early in embryonic development and is maintained throughout the individual's life. Therefore, the statement that X inactivation is when females turn off one X chromosome is true.

Autosomes are chromosomes that are not involved in determining the sex of an individual. In humans, there are a total of 23 pairs of chromosomes, with one pair being the sex chromosomes (X and Y) and the remaining 22 pairs being autosomes. Therefore, the correct answer is 22.

Multiple alleles refer to a situation where more than two alleles exist for a particular gene in a population. These different alleles can control the phenotype, or observable characteristics, of an organism. In the case of blood tissue, there are three alleles - A, B, and O - that determine the blood type. Each individual can have two of these alleles, resulting in different blood types. This phenomenon does not create co-dominance, where both alleles are expressed equally, but rather follows a specific pattern of dominance and recessiveness.

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Polygenic traits are traits that are controlled by multiple genes, not just two genes. These traits are influenced by the interaction of many different genes, each contributing a small effect to the overall phenotype. Therefore, the statement that polygenic traits are controlled by only 2 genes is incorrect.

The question is asking if there are 3 alleles in blood types, which doesn't necessarily align with the concept of multiple alleles. The answer is true because blood types indeed have three alleles (A, B, and O). Additionally, the question asks if A and B are codominant, which is also true as both alleles can be expressed simultaneously in individuals with AB blood type.

During meiosis, the process of cell division that produces gametes (sperm and eggs), nondisjunction can occur in both meiosis 1 and meiosis 2. Nondisjunction is the failure of homologous chromosomes or sister chromatids to separate properly, resulting in an abnormal distribution of chromosomes in the resulting gametes. This can lead to genetic disorders such as Down syndrome. Therefore, the statement that nondisjunction can happen in both meiosis 1 and meiosis 2 is true.

Females have two X chromosomes, but in order to prevent an overdose of X chromosome genes, one of the X chromosomes is inactivated. This process is known as X chromosome inactivation or Lyonization. It occurs randomly in early embryonic development and results in the formation of a Barr body, which is a condensed, inactive X chromosome. This inactivation ensures that both males and females have an equal dosage of X chromosome genes. Therefore, the statement "Females inactive one of their X chromosomes" is true.

This example demonstrates incomplete dominance in the phenotype. In incomplete dominance, neither allele is completely dominant over the other, resulting in a blending or intermediate phenotype. In this case, the FF genotype produces a red phenotype, ff genotype produces a white phenotype, and Ff genotype produces a pink phenotype.

The given answer is correct because individuals with Type B blood have the genotype (I^B)(I^B), which means they have two copies of the B allele. This genotype allows them to donate blood to individuals with Type AB blood because the AB blood type has both A and B antigens, and the B antigen is compatible with the B allele. Additionally, individuals with Type B blood can receive blood from individuals with Type O blood because Type O blood does not have A or B antigens, making it compatible with any blood type.

Red/green colorblindness is an example of a sex-linked trait because it is caused by a gene located on the sex chromosomes, specifically the X chromosome. This means that the trait is more commonly seen in males, as they only have one X chromosome and are more likely to inherit the gene. Females, on the other hand, have two X chromosomes and would need to inherit the gene from both parents to exhibit the trait. Red/green colorblindness is characterized by difficulty in distinguishing between red and green colors.

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Can occur in autosomals

During meiosis 1, homologous chromosomes separate, resulting in two daughter cells with an unequal distribution of chromosomes. This is known as non-disjunction. Non-disjunction can lead to genetic disorders and abnormalities in the offspring, as the resulting cells may have an abnormal number of chromosomes. In contrast, during meiosis 2, sister chromatids separate, resulting in four daughter cells with an equal distribution of chromosomes. Therefore, the correct answer is "Unequal Separation of chromosomes during meiosis 1."

The given correct answer states that Type A blood has a genotype of (I^A)(i), which means it carries both the A and the O alleles. This genotype allows Type A blood to donate to Type AB because Type AB individuals have both A and B antigens on their red blood cells. Type A blood can also receive blood from Type A or Type O individuals because Type A blood can recognize and accept both A and O antigens.

Sex Linked traits are found on the X chromosome

The given answer correctly explains that when both alleles are present and show up unmasked, it is an example of codominance. In codominance, both alleles are expressed fully and neither is dominant or recessive over the other. The answer also mentions that a heterozygous allele will be present, which means that the individual carries two different alleles for the same trait. The example given of "Silver Stars and Polka Dots" further illustrates that both alleles are expressed and visible in the phenotype.