1.
Probability is
Correct Answer
B. The chance that an event will occur
Explanation
The correct answer is "the chance that an event will occur." Probability is a measure of the likelihood or chance that a specific event will happen. It is often expressed as a ratio or a fraction, such as 3:1, to indicate the relative likelihood of the event occurring compared to not occurring.
2.
What are the possible genotypes of the children in this Punnett square (Bb X bb)?
Correct Answer
C. Bb, bb
Explanation
The possible genotypes of the children in this Punnett square are Bb and bb. , it means that at least one of the parents must have the genotype bb. The other possible genotype for the children is Bb, which means that the other parent has the genotype Bb. None of the children can have BB.
3.
If you cross 2 heterozygous parents (using the letter 'A') what is the percentage the children will end up having a dominant trait?
Correct Answer
B. 75%
Explanation
When crossing two heterozygous parents (Aa x Aa), there is a 25% chance that the child will inherit two recessive alleles (aa) and display a recessive trait. However, there is a 75% chance that the child will inherit at least one dominant allele (A) and display a dominant trait. Therefore, the percentage of children that will end up having a dominant trait is 75%.
4.
An organism's physical appearance is known as its
Correct Answer
B. Phenotype
Explanation
An organism's physical appearance is known as its phenotype. This includes observable traits such as hair color, eye color, and height. Phenotype is determined by a combination of genetic factors (genotype) and environmental influences. Heredity refers to the passing of traits from parents to offspring, while genotype refers to the genetic makeup of an organism.
5.
In a pedigree chart what do the half-filled squares represent?
Correct Answer
C. A male that carries the trait.
Explanation
Half-filled squares in a pedigree chart represent males who are carriers of the trait. Carriers are individuals who possess a copy of the gene for a certain trait but do not express it themselves. In this case, the trait is likely a recessive trait that requires two copies of the gene to be expressed. Males only have one copy of the gene on their X chromosome, so if they possess the gene, they are considered carriers.
6.
In this pedigree chart with four shaded circles, how many females have the trait?
Correct Answer
A. 4
Explanation
The correct answer is 4 because in the given pedigree chart, there are four females who have the trait.
7.
Which of Mendel's Laws states that each trait is inherited independently of the other?
Correct Answer
B. Law of Independent Assortment
Explanation
The Law of Independent Assortment states that each trait is inherited independently of each other. This means that the inheritance of one trait does not affect the inheritance of another trait. In other words, the genes for different traits segregate independently during the formation of gametes, leading to a random assortment of traits in offspring. This law was proposed by Gregor Mendel based on his experiments with pea plants, where he observed the inheritance patterns of different traits.
8.
An organism that has 2 different alleles for a trait is described as,
Correct Answer
A. Heterozygous
Explanation
An organism that has 2 different alleles for a trait is described as heterozygous. Heterozygous means that the organism has two different versions of a gene, or alleles, for a particular trait. In this case, the organism has one dominant allele and one recessive allele for the trait. This can result in a combination of traits or characteristics that are different from either of the individual alleles.
9.
A carrier is a person who has
Correct Answer
B. 1 recessive and 1 dominant allele for a trait.
Explanation
A carrier is a person who carries a recessive allele for a trait but does not express it because they also have a dominant allele for the same trait. This means that carriers can pass on the recessive allele to their offspring, even though they themselves do not show any symptoms or characteristics associated with that allele.
10.
What is an example of a homozygous recessive genotype?
Correct Answer
C. Bb
Explanation
The correct answer is "bb" because a homozygous recessive genotype means that both alleles for a specific trait are the same and recessive. In this case, the lowercase "b" represents the recessive allele, so having two lowercase "b" alleles (bb) indicates a homozygous recessive genotype.
11.
If you cross a white flower (pp) with a purple flower (PP) what are the possible genotypes of the offspring?
Correct Answer
C. All Pp
Explanation
When you cross a white flower (pp) with a purple flower (PP), the possible genotypes of the offspring are all Pp. This is because the purple flower (PP) is dominant over the white flower (pp), so all the offspring will inherit one dominant purple allele (P) from the purple flower parent and one recessive white allele (p) from the white flower parent. Therefore, all the offspring will have the genotype Pp, which means they will have the purple flower phenotype.
12.
If you cross 2 rabbits that have the genotype Bb, how many possible genotypes can be found in the offspring?
Correct Answer
C. 3
Explanation
When you cross two rabbits with the genotype Bb, each rabbit can pass on either the B or the b allele to their offspring. Therefore, there are three possible genotypes that can be found in the offspring: BB, Bb, and bb.
13.
In a pedigree, a blank square or circle indicates that the person
Correct Answer
C. Does not have a certain trait
Explanation
A blank square or circle in a pedigree indicates that the person does not have a certain trait. This means that the person is not affected by the trait being studied or i a carrier of the trait.
14.
Alleles can be dominant or ____________.
Correct Answer
A. Recessive
Explanation
Alleles can be dominant or recessive. Dominant alleles are expressed when present, while recessive alleles are only expressed if there are no dominant alleles present. This means that the phenotype, or physical trait, associated with a recessive allele will only be observed if an individual has two copies of that recessive allele. In contrast, individuals with one or two copies of a dominant allele will exhibit the phenotype associated with that allele. Heredity refers to the passing of traits from parents to offspring and is not directly related to the dominance or recessiveness of alleles.
15.
Humans have a total of _____ chromosomes in their body cells.
Correct Answer
46
Explanation
Humans have a total of 46 chromosomes in their body cells. Chromosomes are thread-like structures that contain DNA, the genetic material that carries the instructions for the development and functioning of the human body. Each chromosome is made up of DNA tightly coiled around proteins. Humans typically have 23 pairs of chromosomes, with one set inherited from each parent. These chromosomes carry the genes that determine various traits and characteristics of an individual, such as hair color, eye color, and height. The total number of chromosomes in human body cells is 46, with 23 coming from the mother and 23 from the father.
16.
Humans have a total of ____ chromosomes in their reproductive cells.
Correct Answer
23
Explanation
Humans have a total of 23 chromosomes in their reproductive cells. This is because reproductive cells, also known as gametes, are haploid cells that contain half the number of chromosomes compared to other cells in the body. Humans have 46 chromosomes in their somatic cells, but during the process of meiosis, the number is reduced to 23 in the gametes. This is important for sexual reproduction, as when the gametes combine during fertilization, the resulting zygote will have the correct number of chromosomes for normal development.
17.
In a pedigree chart, a square is represented by a female.
Correct Answer
B. False
Explanation
In a pedigree chart, a square is typically used to represent a male, not a female. This is a common convention in genetics and family tree diagrams. Female individuals are usually represented by circles in a pedigree chart.
18.
In a pedigree chart, a half-shaded circle would be a carrier who is female.
Correct Answer
A. True
Explanation
A half-shaded circle in a pedigree chart represents a female carrier. A carrier is an individual who carries a genetic mutation or trait but does not exhibit any symptoms or characteristics of it. In the context of the pedigree chart, a half-shaded circle indicates that the female individual carries a specific genetic mutation or trait, which can be passed on to her offspring. This is an accurate representation of how pedigree charts are typically used to track genetic traits and inheritance patterns in families.
19.
Explain how two brown eyed parents could have a blue eyed child.
(*This answer must be in sentence form and a complete paragraph to earn full credit.)
20.
Explain what Mendel's did in his experiments, and also explain his Law of Dominance.
(*This answer must be in sentence form and a complete paragraph, with several examples listed.)
21.
What is an example of a heterozygous genotype?
Correct Answer
C. Aa
Explanation
A heterozygous genotype refers to an individual having two different alleles for a specific gene. In the given options, only "Aa" fits this definition as it represents a genotype where one allele is dominant (A) and the other is recessive (a). This combination of alleles results in a heterozygous genotype, making "Aa" the correct answer.
22.
Humans produce reproductive cells through a process called?
Correct Answer
B. Meiosis
Explanation
Humans produce reproductive cells through a process called meiosis. Meiosis is a type of cell division that results in the formation of gametes, such as sperm and eggs. Unlike mitosis, which produces genetically identical cells, meiosis involves two rounds of division and leads to the production of cells with half the number of chromosomes. This reduction in chromosome number is necessary for sexual reproduction and ensures that offspring receive a unique combination of genes from their parents. Transformation is not the correct answer as it refers to the uptake and incorporation of foreign DNA into a cell.