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.

How many daughter cells are produced during the cell cycle?

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).

Figure 1

Figure 2

What cellular component moves chromosomes to the center of cells during metaphase?

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).

Figure 1

Figure 2

Chromosomes can be defined as which of the following?

Five experiments are done to test the relative infectiousness of different serotypes of the Influenza A virus when exposed to tissue from different organisms and competition from one another.

When the virus is more infectious, it will result in more detectable antigens.

Antigens are detected via Enzyme-linked immunosorbent assay (ELISA), which elicits a detectable hue of purple whenever antigens are detected. The hue darkens in response to increased detection of antigens according to this qualitative scale:

Very Dark Purple, Dark Purple, Purple, Light Purple, and Very Light Purple

Experiment 1

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were separately centrifuged onto single layers on human cells and viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Dark purple     H5N1: purple

Experiment 2

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were separately centrifuged onto single layers on chicken cells and viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Dark purple     H5N1: Very dark purple

Experiment 3

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were separately centrifuged onto single layers on swine cells and viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Very dark purple     H5N1: Purple

Experiment 4

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were centrifuged together onto single layers of duck cells while viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Very dark purple     H5N1: Very dark Purple

Experiment 5

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were centrifuged together onto equal layers of human, chicken, swine, and duck cells while viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Purple     H5N1: Light Purple

In experiment 5, what is the most likely purpose of sampling all of the serotypes together on the 4 cell types?

Five experiments are done to test the relative infectiousness of different serotypes of the Influenza A virus when exposed to tissue from different organisms and competition from one another.

When the virus is more infectious, it will result in more detectable antigens.

Antigens are detected via Enzyme-linked immunosorbent assay (ELISA), which elicits a detectable hue of purple whenever antigens are detected. The hue darkens in response to increased detection of antigens according to this qualitative scale:

Very Dark Purple, Dark Purple, Purple, Light Purple, and Very Light Purple

Experiment 1

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were separately centrifuged onto single layers on human cells and viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Dark purple     H5N1: purple

Experiment 2

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were separately centrifuged onto single layers on chicken cells and viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Dark purple     H5N1: Very dark purple

Experiment 3

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were separately centrifuged onto single layers on swine cells and viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Very dark purple     H5N1: Purple

Experiment 4

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were centrifuged together onto single layers of duck cells while viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Very dark purple     H5N1: Very dark Purple

Experiment 5

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were centrifuged together onto equal layers of human, chicken, swine, and duck cells while viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Purple     H5N1: Light Purple

What is a likely explanation for experiment 2 and experiment 4 having similar outcomes?

Five experiments are done to test the relative infectiousness of different serotypes of the Influenza A virus when exposed to tissue from different organisms and competition from one another.

When the virus is more infectious, it will result in more detectable antigens.

Antigens are detected via Enzyme-linked immunosorbent assay (ELISA), which elicits a detectable hue of purple whenever antigens are detected. The hue darkens in response to increased detection of antigens according to this qualitative scale:

Very Dark Purple, Dark Purple, Purple, Light Purple, and Very Light Purple

Experiment 1

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were separately centrifuged onto single layers on human cells and viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Dark purple     H5N1: purple

Experiment 2

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were separately centrifuged onto single layers on chicken cells and viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Dark purple     H5N1: Very dark purple

Experiment 3

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were separately centrifuged onto single layers on swine cells and viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Very dark purple     H5N1: Purple

Experiment 4

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were centrifuged together onto single layers of duck cells while viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Very dark purple     H5N1: Very dark Purple

Experiment 5

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were centrifuged together onto equal layers of human, chicken, swine, and duck cells while viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Purple     H5N1: Light Purple

Based on the experiments, can it be determined which is (relatively) the most infectious serotype?

Five experiments are done to test the relative infectiousness of different serotypes of the Influenza A virus when exposed to tissue from different organisms and competition from one another.

When the virus is more infectious, it will result in more detectable antigens.

Antigens are detected via Enzyme-linked immunosorbent assay (ELISA), which elicits a detectable hue of purple whenever antigens are detected. The hue darkens in response to increased detection of antigens according to this qualitative scale:

Very Dark Purple, Dark Purple, Purple, Light Purple, and Very Light Purple

Experiment 1

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were separately centrifuged onto single layers on human cells and viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Dark purple     H5N1: purple

Experiment 2

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were separately centrifuged onto single layers on chicken cells and viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Dark purple     H5N1: Very dark purple

Experiment 3

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were separately centrifuged onto single layers on swine cells and viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Very dark purple     H5N1: Purple

Experiment 4

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were centrifuged together onto single layers of duck cells while viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Very dark purple     H5N1: Very dark Purple

Experiment 5

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were centrifuged together onto equal layers of human, chicken, swine, and duck cells while viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Purple     H5N1: Light Purple

According to the experiments, H5N1 is most infectious in __________.

Five experiments are done to test the relative infectiousness of different serotypes of the Influenza A virus when exposed to tissue from different organisms and competition from one another.

When the virus is more infectious, it will result in more detectable antigens.

Antigens are detected via Enzyme-linked immunosorbent assay (ELISA), which elicits a detectable hue of purple whenever antigens are detected. The hue darkens in response to increased detection of antigens according to this qualitative scale:

Very Dark Purple, Dark Purple, Purple, Light Purple, and Very Light Purple

Experiment 1

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were separately centrifuged onto single layers on human cells and viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Dark purple     H5N1: purple

Experiment 2

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were separately centrifuged onto single layers on chicken cells and viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Dark purple     H5N1: Very dark purple

Experiment 3

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were separately centrifuged onto single layers on swine cells and viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Very dark purple     H5N1: Purple

Experiment 4

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were centrifuged together onto single layers of duck cells while viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Very dark purple     H5N1: Very dark Purple

Experiment 5

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were centrifuged together onto equal layers of human, chicken, swine, and duck cells while viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Purple     H5N1: Light Purple

One of the issues with ELISA as a detection method is that due to its qualitative nature, the "resolution" of results is low. In other words, measurements of "Very dark purple" are indistinguishable.

Assume another method is tested and reveals that infectiousness for H2N2 in duck and swine is much higher than H1N1, what is a possible implication?

Five experiments are done to test the relative infectiousness of different serotypes of the Influenza A virus when exposed to tissue from different organisms and competition from one another.

When the virus is more infectious, it will result in more detectable antigens.

Antigens are detected via Enzyme-linked immunosorbent assay (ELISA), which elicits a detectable hue of purple whenever antigens are detected. The hue darkens in response to increased detection of antigens according to this qualitative scale:

Very Dark Purple, Dark Purple, Purple, Light Purple, and Very Light Purple

Experiment 1

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were separately centrifuged onto single layers on human cells and viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Dark purple     H5N1: purple

Experiment 2

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were separately centrifuged onto single layers on chicken cells and viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Dark purple     H5N1: Very dark purple

Experiment 3

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were separately centrifuged onto single layers on swine cells and viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Very dark purple     H5N1: Purple

Experiment 4

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were centrifuged together onto single layers of duck cells while viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Very dark purple     H5N1: Very dark Purple

Experiment 5

Three separate serotypes of Influenza A are used: H1N1, H2N2, and H5N1. Viral samples were centrifuged together onto equal layers of human, chicken, swine, and duck cells while viral activity was identified using ELISA. The results are as follows:

H1N1: Very dark purple    H2N2: Purple     H5N1: Light Purple

According to the experiments, can it be determined which is the least infectious serotype?

A medical researcher is testing the effectiveness of a particular supplementation regimen in controlling the accumulation of LDL cholesterol. Her experimental animals are three different groups of mice. Strains X and Y are laboratory mice whose tendencies toward accumulation of LDL cholesterol are well known. The last group consists of mice caught in the wild.

Experiment 1

Population A, consisting of all three groups, was bred for several generations and given a diet moderate in saturated and trans fats. No supplementation was given. Accumulation of LDL cholesterol occurred at the following rates:

Strain XA: 109 milligrams per deciliter (mg/dL)

Strain YA: 163 milligrams per deciliter (mg/dL)

Wild mice A: 104 milligrams per deciliter (mg/dL)

Experiment 2

Population B, consisting of all three groups, was bred for several generations and given a diet very high in saturated and trans fats. No supplementation was given. Accumulation of LDL cholesterol occurred at the following rates:

Strain XB: 155 milligrams per deciliter (mg/dL)

Strain YB: 189 milligrams per deciliter (mg/dL)

Wild mice B: 115 milligrams per deciliter (mg/dL)

Experiment 3

Population C, consisting of all three groups, was bred for several generations and given a diet very high in saturated and trans fats. Supplementation of iodine, copper, and selenium (ICS) was administered regularly. Accumulation of LDL cholesterol occurred at the following rates:

Strain XC: 150 milligrams per deciliter (mg/dL)

Strain YC: 171 milligrams per deciliter (mg/dL)

Wild mice C: 112 milligrams per deciliter (mg/dL)

Experiment 4

Population D, consisting of all three groups, was bred for several generations and given a diet moderate in saturated and trans fats. Supplementation of iodine, copper, and selenium (ICS) was administered regularly. Accumulation of LDL cholesterol occurred at the following rates:

Strain XD: 100 milligrams per deciliter (mg/dL)

Strain YD: 153 milligrams per deciliter (mg/dL)

Wild mice D: 98 milligrams per deciliter (mg/dL)

It would be accurate to conclude from the four experiments that __________