ACT Science : ACT Science

Study concepts, example questions & explanations for ACT Science

varsity tutors app store varsity tutors android store varsity tutors ibooks store

Example Questions

Example Question #411 : Act Science

Drosophila melanogaster, the common fruit fly, is frequently utilized for genetic studies due to its simple food requirements, hardy nature, and because it completes its life cycle within 12 days at room temperature. This particular fly species has four pairs of chromosomes with traits that have been studied and observed to be inherited in a Mendelian fashion.

The predictive capacity of Mendelian genetics depends on traits whose physiological characteristics, know as phenotypes, are determined by genetic combinations of alleles, known as genotypes. The exhibition of observable traits is determined by the combination of two alleles for a specific characteristic. For example, the dominant allele for the wild type red eye color is E and the recessive sepia-brown color is e. Likewise, the dominant allele for long wings is W and the recessive allele for short wings is w. When a dominant allele is present with a recessive one, the organism physically exhibits the trait of the dominant allele and the organism is known as heterozygous for that trait. If an organism has two dominant or two recessive alleles for a particular trait, it is known as homozygous for that trait. Only when two recessive alleles are present does the organism physically exhibit the trait of the recessive allele. Heterozygous individuals are often known as carriers because the dominant allele phenotype masks the recessive allele phenotype and the organism can carry the recessive allele without exhibiting any of its physical traits.

Study 1

A researcher wants to study the inheritance of eye color in fruit flies. The scientist mates a homozygous recessive (ee) group with a homozygous dominant (EE) group in order to obtain the F1 Generation. Two members of the F1 Generation were then mated in order to obtain the F2 Generation (Table 1).

Eye

Table 1

Study 2

A researcher decided to perform a dihybrid cross of fruit flies possessing red eyes and long wings with fruit flies possessing sepia-brown eyes and short wings. The scientist bred homozygous dominant flies with homozygous recessive flies in the F1 Generation. The members of the F1 Generation were then mated in order to obtain the F2 Generation (Table 2).

Dihybrid

Table 2

In Study 2, how many physical outcomes are possible for the fruit flies in the F2 Generation?

Possible Answers:

8

2

16

4

Correct answer:

4

Explanation:

There are four possible phenotypic or physical outcomes for the offspring in the F2 Generation. Offspring may have red eyes and long wings, red eyes and short wings, sepia-brown eyes and long wings, or sepia brown eyes and short wings. This is despite there being nine genotypic combinations (EEWW, EEWw, EEww, EeWW, EeWw, Eeww, eeWW, eeWw, eeww).

Example Question #131 : How To Find Synthesis Of Data In Biology

Drosophila melanogaster, the common fruit fly, is frequently utilized for genetic studies due to its simple food requirements, hardy nature, and because it completes its life cycle within 12 days at room temperature. This particular fly species has four pairs of chromosomes with traits that have been studied and observed to be inherited in a Mendelian fashion.

The predictive capacity of Mendelian genetics depends on traits whose physiological characteristics, know as phenotypes, are determined by genetic combinations of alleles, known as genotypes. The exhibition of observable traits is determined by the combination of two alleles for a specific characteristic. For example, the dominant allele for the wild type red eye color is E and the recessive sepia-brown color is e. Likewise, the dominant allele for long wings is W and the recessive allele for short wings is w. When a dominant allele is present with a recessive one, the organism physically exhibits the trait of the dominant allele and the organism is known as heterozygous for that trait. If an organism has two dominant or two recessive alleles for a particular trait, it is known as homozygous for that trait. Only when two recessive alleles are present does the organism physically exhibit the trait of the recessive allele. Heterozygous individuals are often known as carriers because the dominant allele phenotype masks the recessive allele phenotype and the organism can carry the recessive allele without exhibiting any of its physical traits.

Study 1

A researcher wants to study the inheritance of eye color in fruit flies. The scientist mates a homozygous recessive (ee) group with a homozygous dominant (EE) group in order to obtain the F1 Generation. Two members of the F1 Generation were then mated in order to obtain the F2 Generation (Table 1).

Eye

Table 1

Study 2

A researcher decided to perform a dihybrid cross of fruit flies possessing red eyes and long wings with fruit flies possessing sepia-brown eyes and short wings. The scientist bred homozygous dominant flies with homozygous recessive flies in the F1 Generation. The members of the F1 Generation were then mated in order to obtain the F2 Generation (Table 2).

Dihybrid

Table 2

A researcher mates two groups of fruit flies: one homozygous recessive for short wings and one homozygous dominant for long wings. Two of the heterozygous offspring of the F1 Generation are mated. What genotypic possibilities will there be in the F2 generation?

Possible Answers:

Ww and ww

WW, Ww, and ww

WW and Ww

WW and ww

Correct answer:

WW, Ww, and ww

Explanation:

In order to answer this question, one can base their reasoning on Table 1. The same exact scenario took place in that study. If one homozygous dominiant and homozygous recessive mate, then all of the offspring in the F1 Generation will be heterozygous. In this case, they would possess the Ww genotype. If two of the flies in the F1 Generation are mated, their offspring would follow the same pattern as seen in the F2 Generation of Table 1 and the genotypic possibilities would be WW, Ww, and ww.

Example Question #412 : Act Science

Drosophila melanogaster, the common fruit fly, is frequently utilized for genetic studies due to its simple food requirements, hardy nature, and because it completes its life cycle within 12 days at room temperature. This particular fly species has four pairs of chromosomes with traits that have been studied and observed to be inherited in a Mendelian fashion.

The predictive capacity of Mendelian genetics depends on traits whose physiological characteristics, know as phenotypes, are determined by genetic combinations of alleles, known as genotypes. The exhibition of observable traits is determined by the combination of two alleles for a specific characteristic. For example, the dominant allele for the wild type red eye color is E and the recessive sepia-brown color is e. Likewise, the dominant allele for long wings is W and the recessive allele for short wings is w. When a dominant allele is present with a recessive one, the organism physically exhibits the trait of the dominant allele and the organism is known as heterozygous for that trait. If an organism has two dominant or two recessive alleles for a particular trait, it is known as homozygous for that trait. Only when two recessive alleles are present does the organism physically exhibit the trait of the recessive allele. Heterozygous individuals are often known as carriers because the dominant allele phenotype masks the recessive allele phenotype and the organism can carry the recessive allele without exhibiting any of its physical traits.

Study 1

A researcher wants to study the inheritance of eye color in fruit flies. The scientist mates a homozygous recessive (ee) group with a homozygous dominant (EE) group in order to obtain the F1 Generation. Two members of the F1 Generation were then mated in order to obtain the F2 Generation (Table 1).

Eye

Table 1

Study 2

A researcher decided to perform a dihybrid cross of fruit flies possessing red eyes and long wings with fruit flies possessing sepia-brown eyes and short wings. The scientist bred homozygous dominant flies with homozygous recessive flies in the F1 Generation. The members of the F1 Generation were then mated in order to obtain the F2 Generation (Table 2).

Dihybrid

Table 2

In Study 1, what proportion of the fruit flies in the F2 Generation will express the sepia-brown eye color phenotype?

Possible Answers:

Correct answer:

Explanation:

According to the passage, sepia-brown eye color is a recessive trait; therefore, in order to display this phenotype, an individual must possess two recessive alleles. In this case, the individual would have to possess the ee genotype. In the F2 Generation, only one out of the four groups possess this genotype.

Example Question #133 : How To Find Synthesis Of Data In Biology

Drosophila melanogaster, the common fruit fly, is frequently utilized for genetic studies due to its simple food requirements, hardy nature, and because it completes its life cycle within 12 days at room temperature. This particular fly species has four pairs of chromosomes with traits that have been studied and observed to be inherited in a Mendelian fashion.

The predictive capacity of Mendelian genetics depends on traits whose physiological characteristics, know as phenotypes, are determined by genetic combinations of alleles, known as genotypes. The exhibition of observable traits is determined by the combination of two alleles for a specific characteristic. For example, the dominant allele for the wild type red eye color is E and the recessive sepia-brown color is e. Likewise, the dominant allele for long wings is W and the recessive allele for short wings is w. When a dominant allele is present with a recessive one, the organism physically exhibits the trait of the dominant allele and the organism is known as heterozygous for that trait. If an organism has two dominant or two recessive alleles for a particular trait, it is known as homozygous for that trait. Only when two recessive alleles are present does the organism physically exhibit the trait of the recessive allele. Heterozygous individuals are often known as carriers because the dominant allele phenotype masks the recessive allele phenotype and the organism can carry the recessive allele without exhibiting any of its physical traits.

Study 1

A researcher wants to study the inheritance of eye color in fruit flies. The scientist mates a homozygous recessive (ee) group with a homozygous dominant (EE) group in order to obtain the F1 Generation. Two members of the F1 Generation were then mated in order to obtain the F2 Generation (Table 1).

Eye

Table 1

Study 2

A researcher decided to perform a dihybrid cross of fruit flies possessing red eyes and long wings with fruit flies possessing sepia-brown eyes and short wings. The scientist bred homozygous dominant flies with homozygous recessive flies in the F1 Generation. The members of the F1 Generation were then mated in order to obtain the F2 Generation (Table 2).

Dihybrid

Table 2

In Study 1, what proportion of the fruit flies in the F2 Generation possess a heterozygous allele combination for eye color?

Possible Answers:

Correct answer:

Explanation:

Individuals that are heterozygous for eye color in this scenario will possess the Ee genotype. Two of the four groups in the Punnett square exhibit this characteristic; therefore; half of the F2 Generation's population will be heterozygous for the trait.

Example Question #134 : How To Find Synthesis Of Data In Biology

Drosophila melanogaster, the common fruit fly, is frequently utilized for genetic studies due to its simple food requirements, hardy nature, and because it completes its life cycle within 12 days at room temperature. This particular fly species has four pairs of chromosomes with traits that have been studied and observed to be inherited in a Mendelian fashion.

The predictive capacity of Mendelian genetics depends on traits whose physiological characteristics, know as phenotypes, are determined by genetic combinations of alleles, known as genotypes. The exhibition of observable traits is determined by the combination of two alleles for a specific characteristic. For example, the dominant allele for the wild type red eye color is E and the recessive sepia-brown color is e. Likewise, the dominant allele for long wings is W and the recessive allele for short wings is w. When a dominant allele is present with a recessive one, the organism physically exhibits the trait of the dominant allele and the organism is known as heterozygous for that trait. If an organism has two dominant or two recessive alleles for a particular trait, it is known as homozygous for that trait. Only when two recessive alleles are present does the organism physically exhibit the trait of the recessive allele. Heterozygous individuals are often known as carriers because the dominant allele phenotype masks the recessive allele phenotype and the organism can carry the recessive allele without exhibiting any of its physical traits.

Study 1

A researcher wants to study the inheritance of eye color in fruit flies. The scientist mates a homozygous recessive (ee) group with a homozygous dominant (EE) group in order to obtain the F1 Generation. Two members of the F1 Generation were then mated in order to obtain the F2 Generation (Table 1).

Eye

Table 1

Study 2

A researcher decided to perform a dihybrid cross of fruit flies possessing red eyes and long wings with fruit flies possessing sepia-brown eyes and short wings. The scientist bred homozygous dominant flies with homozygous recessive flies in the F1 Generation. The members of the F1 Generation were then mated in order to obtain the F2 Generation (Table 2).

Dihybrid

Table 2

In Study 1, what proportion of the fruit flies in the F1 Generation exhibited wild type red eyes?

Possible Answers:

Correct answer:

Explanation:

All of the fruit flies in the F1 generation possessed a dominant E allele; therefore, they will all exhibit the trait of red eyes because the dominant allele will mask the recessive one.

Example Question #416 : Biology

The process by which cells divide and multiply is known as the cell cycle. This cycle consist of two main phases: interphase and mitosis. Each phase consists of a series of clearly defined and observable steps. At the conclusion of the cycle, each parent cell produces two genetically identical daughter cells that may undergo a cycle of replication.

Roughly 90 percent of the cell cycle is spent in interphase. Interphase is comprised of three main steps: the first gap phase, the synthesis phase, and the second gap phase. The initial gap phase is a period of cellular preparation in which the cell increases in size and readies itself for DNA synthesis. In the synthesis phase, DNA replication occurs. In the second gap phase the cell grows in size and prepares for cellular division in the mitotic phase. At the end of each gap phase the cell has to pass regulatory checkpoints to ensure proper cell growth and environmental conditions.

Mitosis is a form of nuclear division and is broken down into five distinct phases. During prophase, the genetic material contained in chromatin condenses into distinct chromosomes. Prometaphase is marked by the breakdown of the nuclear envelope and the formation of centrosomes at the poles of the cell. During metaphase, kinetochores attached to the microtubules migrate the chromosomes to the center of the cell. A checkpoint ensures that the chromosomes are aligned on the center and halts the cycle if an error occurs. Anaphase occurs when chromosomes break apart at their center or centromere and sister chromatids move to opposite ends of the cell. Last, telophase and cytokinesis occurs as nuclear membranes form in each new daughter cell and when chromosomes unwind into loose chromatin. Cytokinesis is defined as the division of the each cell’s cytoplasm and organelles. The conclusion of the cell cycle results in the production of two genetically identical daughter cells.

Study 1

Scientists study the role of the cell cycle in the cells of a growing onion. They investigate the number of cells in each phase of the cycle in two parts of the onion: the fast growing root and the slow growing bulb. They record their observations and calculate the percentage of cells undergoing each phase (See Figure 1 andFigure 2).

 

Root

Figure 1

Bulb

Figure 2

If investigators counted a total of 1,400 bulb cells then how many were in interphase according to Figure 2?

Possible Answers:

1,624

1,246

1,426

890

Correct answer:

1,246

Explanation:

1,246

If 1,400 root cells were counted then 89 percent would be in interphase according to Figure 2. In order to solve this problem, one must calculate 89 percent of 1,400, which is 1,246 cells.

Example Question #414 : Biology

The process by which cells divide and multiply is known as the cell cycle. This cycle consist of two main phases: interphase and mitosis. Each phase consists of a series of clearly defined and observable steps. At the conclusion of the cycle, each parent cell produces two genetically identical daughter cells that may undergo a cycle of replication.

Roughly 90 percent of the cell cycle is spent in interphase. Interphase is comprised of three main steps: the first gap phase, the synthesis phase, and the second gap phase. The initial gap phase is a period of cellular preparation in which the cell increases in size and readies itself for DNA synthesis. In the synthesis phase, DNA replication occurs. In the second gap phase the cell grows in size and prepares for cellular division in the mitotic phase. At the end of each gap phase the cell has to pass regulatory checkpoints to ensure proper cell growth and environmental conditions.

Mitosis is a form of nuclear division and is broken down into five distinct phases. During prophase, the genetic material contained in chromatin condenses into distinct chromosomes. Prometaphase is marked by the breakdown of the nuclear envelope and the formation of centrosomes at the poles of the cell. During metaphase, kinetochores attached to the microtubules migrate the chromosomes to the center of the cell. A checkpoint ensures that the chromosomes are aligned on the center and halts the cycle if an error occurs. Anaphase occurs when chromosomes break apart at their center or centromere and sister chromatids move to opposite ends of the cell. Last, telophase and cytokinesis occurs as nuclear membranes form in each new daughter cell and when chromosomes unwind into loose chromatin. Cytokinesis is defined as the division of the each cell’s cytoplasm and organelles. The conclusion of the cell cycle results in the production of two genetically identical daughter cells.

Study 1

Scientists study the role of the cell cycle in the cells of a growing onion. They investigate the number of cells in each phase of the cycle in two parts of the onion: the fast growing root and the slow growing bulb. They record their observations and calculate the percentage of cells undergoing each phase (See Figure 1 and Figure 2).

 

Root

Figure 1

Bulb

Figure 2

If the investigators counted a total of 1,000 root cells then how many were interphase according to Figure 1?

Possible Answers:

90

630

10

900

Correct answer:

630

Explanation:

630

If 1,000 root cells were counted then 63 percent would be in interphase. In order to solve this problem, one must calculate 63 percent of 1,000, which is 630 cells.

 

Example Question #411 : Biology

The process by which cells divide and multiply is known as the cell cycle. This cycle consist of two main phases: interphase and mitosis. Each phase consists of a series of clearly defined and observable steps. At the conclusion of the cycle, each parent cell produces two genetically identical daughter cells that may undergo a cycle of replication.

Roughly 90 percent of the cell cycle is spent in interphase. Interphase is comprised of three main steps: the first gap phase, the synthesis phase, and the second gap phase. The initial gap phase is a period of cellular preparation in which the cell increases in size and readies itself for DNA synthesis. In the synthesis phase, DNA replication occurs. In the second gap phase the cell grows in size and prepares for cellular division in the mitotic phase. At the end of each gap phase the cell has to pass regulatory checkpoints to ensure proper cell growth and environmental conditions.

Mitosis is a form of nuclear division and is broken down into five distinct phases. During prophase, the genetic material contained in chromatin condenses into distinct chromosomes. Prometaphase is marked by the breakdown of the nuclear envelope and the formation of centrosomes at the poles of the cell. During metaphase, kinetochores attached to the microtubules migrate the chromosomes to the center of the cell. A checkpoint ensures that the chromosomes are aligned on the center and halts the cycle if an error occurs. Anaphase occurs when chromosomes break apart at their center or centromere and sister chromatids move to opposite ends of the cell. Last, telophase and cytokinesis occurs as nuclear membranes form in each new daughter cell and when chromosomes unwind into loose chromatin. Cytokinesis is defined as the division of the each cell’s cytoplasm and organelles. The conclusion of the cell cycle results in the production of two genetically identical daughter cells.

Study 1

Scientists study the role of the cell cycle in the cells of a growing onion. They investigate the number of cells in each phase of the cycle in two parts of the onion: the fast growing root and the slow growing bulb. They record their observations and calculate the percentage of cells undergoing each phase (See Figure 1 andFigure 2).

 

Root

Figure 1

Bulb

Figure 2

What percentage of the cells in Figure 1 were in mitosis? 

Possible Answers:

8 percent

36 percent

63 percent

37 percent

Correct answer:

37 percent

Explanation:

37 percent

In Figure 1, the following cell groups were in mitosis: prophase, prometaphase, metaphase, anaphase, telophase/cytokinesis. These groups represented 37 percent of the cells in the pie chart; therefore, 37 percent of the cells were in mitosis.

Example Question #135 : How To Find Synthesis Of Data In Biology

The process by which cells divide and multiply is known as the cell cycle. This cycle consist of two main phases: interphase and mitosis. Each phase consists of a series of clearly defined and observable steps. At the conclusion of the cycle, each parent cell produces two genetically identical daughter cells that may undergo a cycle of replication.

Roughly 90 percent of the cell cycle is spent in interphase. Interphase is comprised of three main steps: the first gap phase, the synthesis phase, and the second gap phase. The initial gap phase is a period of cellular preparation in which the cell increases in size and readies itself for DNA synthesis. In the synthesis phase, DNA replication occurs. In the second gap phase the cell grows in size and prepares for cellular division in the mitotic phase. At the end of each gap phase the cell has to pass regulatory checkpoints to ensure proper cell growth and environmental conditions.

Mitosis is a form of nuclear division and is broken down into five distinct phases. During prophase, the genetic material contained in chromatin condenses into distinct chromosomes. Prometaphase is marked by the breakdown of the nuclear envelope and the formation of centrosomes at the poles of the cell. During metaphase, kinetochores attached to the microtubules migrate the chromosomes to the center of the cell. A checkpoint ensures that the chromosomes are aligned on the center and halts the cycle if an error occurs. Anaphase occurs when chromosomes break apart at their center or centromere and sister chromatids move to opposite ends of the cell. Last, telophase and cytokinesis occurs as nuclear membranes form in each new daughter cell and when chromosomes unwind into loose chromatin. Cytokinesis is defined as the division of the each cell’s cytoplasm and organelles. The conclusion of the cell cycle results in the production of two genetically identical daughter cells.

Study 1

Scientists study the role of the cell cycle in the cells of a growing onion. They investigate the number of cells in each phase of the cycle in two parts of the onion: the fast growing root and the slow growing bulb. They record their observations and calculate the percentage of cells undergoing each phase (See Figure 1 andFigure 2).

 

Root

Figure 1

Bulb

Figure 2

If investigators counted 1,400 bulb cells then how many were undergoing mitosis in Figure 2?

Possible Answers:

90

154

11

514

Correct answer:

154

Explanation:

154

The cells undergoing mitosis consisted of the following groups: prophase, prometaphase, metaphase, anapahse, telophase/cytokinesis. These cell groups represented 11 percent of the counted cells in Figure 2. In order to solve this problem, one simply had to calculate 11 percent of the total 1,400 cells counted, which is 154 cells in mitosis.

Example Question #420 : Biology

The process by which cells divide and multiply is known as the cell cycle. This cycle consist of two main phases: interphase and mitosis. Each phase consists of a series of clearly defined and observable steps. At the conclusion of the cycle, each parent cell produces two genetically identical daughter cells that may undergo a cycle of replication.

Roughly 90 percent of the cell cycle is spent in interphase. Interphase is comprised of three main steps: the first gap phase, the synthesis phase, and the second gap phase. The initial gap phase is a period of cellular preparation in which the cell increases in size and readies itself for DNA synthesis. In the synthesis phase, DNA replication occurs. In the second gap phase the cell grows in size and prepares for cellular division in the mitotic phase. At the end of each gap phase the cell has to pass regulatory checkpoints to ensure proper cell growth and environmental conditions.

Mitosis is a form of nuclear division and is broken down into five distinct phases. During prophase, the genetic material contained in chromatin condenses into distinct chromosomes. Prometaphase is marked by the breakdown of the nuclear envelope and the formation of centrosomes at the poles of the cell. During metaphase, kinetochores attached to the microtubules migrate the chromosomes to the center of the cell. A checkpoint ensures that the chromosomes are aligned on the center and halts the cycle if an error occurs. Anaphase occurs when chromosomes break apart at their center or centromere and sister chromatids move to opposite ends of the cell. Last, telophase and cytokinesis occurs as nuclear membranes form in each new daughter cell and when chromosomes unwind into loose chromatin. Cytokinesis is defined as the division of the each cell’s cytoplasm and organelles. The conclusion of the cell cycle results in the production of two genetically identical daughter cells.

Study 1

Scientists study the role of the cell cycle in the cells of a growing onion. They investigate the number of cells in each phase of the cycle in two parts of the onion: the fast growing root and the slow growing bulb. They record their observations and calculate the percentage of cells undergoing each phase (See Figure 1 andFigure 2).

 

Root

Figure 1

Bulb

Figure 2

Why would scientists classify the root cells as "fast growing" when compared to the bulb cells in Figure 1 and 2?

Possible Answers:

The root cells are faster growing compared to the bulb cells because less of them are in interphase.

The root cells are faster growing than the bulb cells because fewer of them are in mitosis.

The root cells are faster growing than the bulb cellls because they are bigger in size.

None of the choices indicate why the root cells are faster growing than the bulb cells.

Correct answer:

The root cells are faster growing compared to the bulb cells because less of them are in interphase.

Explanation:

The root cells are faster growing compared to the bulb cells because less of them are in interphase.

The root cells are considered faster growing because more are undergoing mitotic and cytoplasmic division. Many cells remain in interphase until conditions are correct in order to grow and divide. The root cells are faster growing because more are in mitosis and can divide rapidly into daughter cells.

Learning Tools by Varsity Tutors