1.
What are the two major groups types of cells in your body called?
Correct Answer
A. Somatic Cells and Germ Cells
Explanation
On page 168
2.
What is a testcross?
Correct Answer
B. Cross between organism with unknown genotype and a recessive genotype
Explanation
On page 185
3.
What is a karyotype?
Correct Answer
D. Picture of all of the chromosomes in the cell
Explanation
A karyotype refers to a picture of all of the chromosomes in a cell. It provides a visual representation of an individual's chromosomes, arranged in pairs according to size and structure. This allows for the identification of any abnormalities or mutations in the chromosomes, such as deletions or rearrangements. By analyzing a karyotype, geneticists can diagnose genetic disorders and determine the sex of an individual.
4.
Researchers crossed two types of mice together, type A and type B. In the resulting offspring. half of the DNA comes from type A and half comes from type B. Why?
Correct Answer
C. Each parent contributes one set of chromosomes to each offspring
Explanation
Each parent contributes one set of chromosomes to each offspring. This is because during sexual reproduction, each parent donates one set of chromosomes to the offspring. In mice, like in most organisms, the offspring receive half of their DNA from the mother (via the egg) and half from the father (via the sperm). Therefore, in the resulting offspring, half of the DNA comes from type A and half comes from type B.
5.
In peas, the gene for green pod color (G) is dominant to the gene for yellow pod color (g). If a heterozygous plant (Gg) is crossed with another heterozygous plant (Gg), what phenotype and genotype will likely be the most common among the offspring?
Correct Answer
B. Green (Gg)
Explanation
When a heterozygous plant (Gg) is crossed with another heterozygous plant (Gg), there is a 25% chance of obtaining offspring with the genotype GG (green), a 50% chance of obtaining offspring with the genotype Gg (green), and a 25% chance of obtaining offspring with the genotype gg (yellow). Therefore, the most common phenotype and genotype among the offspring will likely be green (Gg).
6.
A scientist studying two traits in mice knows that each trait is determined by one gene and that both genes are on the same chromosome. If the two traits are not always inherited together by the offspring of the mice, what must be true?
Correct Answer
C. The genes are far enough apart to allow crossing over
Explanation
The correct answer is that the genes are far enough apart to allow crossing over. Crossing over is a process that occurs during meiosis, where genetic material is exchanged between homologous chromosomes. If the two traits are not always inherited together, it suggests that crossing over has occurred between the genes on the chromosome, leading to a recombination of the traits. This implies that the genes must be far enough apart to allow for this exchange of genetic material to happen.
7.
The different colors seen on calico cats are examples of...
Correct Answer
D. X-Chromosome Inactivation
Explanation
Calico cats have different colors due to X-chromosome inactivation. In female mammals, one of the X chromosomes is randomly inactivated in each cell during early development. This results in patches of cells with either the orange or black color gene expressed, leading to the distinct color patterns seen in calico cats. This process is known as X-chromosome inactivation and is responsible for the variation in coat colors in these cats.
8.
A blue eyed parent, named Bob, marries a green eyed parent, named Bobelina, and all of the offspring were blue eyed. Two of the blue eyed children married each other and had one child with green eyes and three children with blue eyes. What was the genotype of Bob?
Correct Answer
B. BB
Explanation
The correct answer is BB. This is because all of the offspring from Bob and Bobelina were blue eyed. Since blue eye color is a recessive trait, both Bob and Bobelina must have had the genotype BB, as they could only pass on the blue eye allele. If either of them had the genotype Bb or bb, there would have been a chance of producing green eyed offspring. Therefore, the genotype of Bob is BB.
9.
How many inner squares does the dihybrid punnet square have?
Correct Answer
D. 16
Explanation
A dihybrid Punnett square is used to determine the possible combinations of alleles for two different traits in offspring. Each trait has two possible alleles, and when crossing two individuals heterozygous for both traits, the Punnett square will have 4 rows and 4 columns. This results in a total of 16 inner squares in the Punnett square, representing all the possible genotypes of the offspring for both traits.
10.
Which of the following scientists worked with fruit flies?
Correct Answer
A. Thomas Hunt Morgan
Explanation
Thomas Hunt Morgan is the correct answer because he is well-known for his work with fruit flies, specifically the study of their inheritance patterns. Morgan's experiments with fruit flies provided important insights into genetics and helped establish the chromosome theory of inheritance. His research on fruit flies laid the foundation for modern genetics and earned him the Nobel Prize in Physiology or Medicine in 1933.
11.
Males have a higher chance of inheriting sex linked disorders.
Correct Answer
A. True
Explanation
Sex-linked disorders are genetic conditions that are linked to the sex chromosomes, specifically the X chromosome. Males have one X and one Y chromosome, while females have two X chromosomes. Since the genes responsible for sex-linked disorders are located on the X chromosome, males have a higher chance of inheriting these disorders. This is because if a male inherits a defective X chromosome, he does not have a second X chromosome to compensate for the defect. In contrast, females have two X chromosomes, so even if one is defective, the other X chromosome can often compensate for the defect. Therefore, it is true that males have a higher chance of inheriting sex-linked disorders.
12.
Males can be carriers of sex linked disorders.
Correct Answer
B. False
Explanation
This statement is incorrect. Males cannot be carriers of sex-linked disorders because they only have one copy of the X chromosome. In sex-linked disorders, the gene responsible for the disorder is located on the X chromosome. Females have two X chromosomes, so they can be carriers of sex-linked disorders even if they do not show any symptoms. However, males who inherit the faulty gene on their single X chromosome will typically exhibit the symptoms of the disorder.
13.
If an allele is recessive to one allele, it can be dominant to another allele.
Correct Answer
A. True
Explanation
This statement is true because dominance and recessiveness are relative terms. An allele can be dominant to one allele if it is able to express its traits in the presence of that allele. However, the same allele can be recessive to another allele if it is unable to express its traits in the presence of that allele. Therefore, an allele can exhibit both dominant and recessive characteristics depending on the specific alleles it is being compared to.
14.
Traits produced by two or more genes are called Epistasis.
Correct Answer
B. False
Explanation
Epistasis refers to the interaction between different genes where the expression of one gene is dependent on the presence or absence of another gene. It is not the term used to describe traits produced by multiple genes. Therefore, the statement that traits produced by two or more genes are called Epistasis is false.
15.
It is called incomplete dominance when both traits are fully and separately expressed.
Correct Answer
B. False
Explanation
Incomplete dominance occurs when neither trait is fully expressed, but instead a blend of the two traits is observed. This means that the correct answer is False, as the statement implies that both traits are fully and separately expressed, which is not the case in incomplete dominance.
16.
A ________ does not show the symptoms, but can pass on the disease-causing allele to the offspring.
Correct Answer
carrier
Explanation
A carrier is an individual who does not exhibit any symptoms of a disease or condition, but carries a disease-causing allele and can pass it on to their offspring. This means that carriers possess the genetic mutation responsible for the disease, but do not experience any negative effects themselves. However, they can still transmit the allele to their children, who may then develop the disease. Carriers are important in understanding the inheritance patterns of genetic diseases and can play a significant role in the spread of certain conditions within a population.
17.
A ________ is a cross between an organism with an unknown genotype and an organism with the recessive phenotype.
Correct Answer
testcross
Explanation
A testcross is a breeding experiment performed to determine the genotype of an organism with a dominant phenotype. It involves crossing the organism with an individual that is homozygous recessive for the trait of interest. By observing the phenotypes of the offspring, the genotype of the unknown organism can be inferred. In this case, the correct answer, "testcross," accurately describes the process of crossing an organism with an unknown genotype with another organism displaying the recessive phenotype.
18.
A __________ is a type of chart that can help trace the phenotypes and genotypes in a family to determine whether people carry recessive alleles.
Correct Answer
pedigree
Explanation
A pedigree is a type of chart that displays the genetic information of a family, allowing for the tracing of phenotypes and genotypes. It is used to determine whether individuals carry recessive alleles, which are responsible for certain traits or conditions. By analyzing the relationships and patterns within a pedigree, geneticists can identify carriers of recessive alleles and assess the likelihood of passing on these traits to future generations.
19.
Which of the following is part of the "Law of Segregation"? (There may be more than one).
Correct Answer(s)
A. Organisms inherit two copies of a gene, one from each parent
D. Organisms donate only one gene in their gametes
Explanation
The Law of Segregation states that organisms inherit two copies of a gene, one from each parent. This means that individuals receive two alleles for each gene, and these alleles separate during the formation of gametes. Additionally, the Law of Segregation also states that organisms donate only one gene in their gametes, meaning that only one allele for each gene is passed on to the offspring.