Hormones are biochemical messengers utilized by multicellular organisms to coordinate development and behaviors. Hormones are secreted by the endocrine system and are key components in signal cascades that result in various essential activities. Plants, like animals, depend on hormonal signals for physiological adaptation and development.

There are several hormones that are primarily involved with seed germination and sprout formation. Abscisic acid, in high concentrations, prevents seed germination. Auxins are compounds that positively influence cell enlargement, the formation of buds, and the development of roots. Cytokinins influence cell division and shoot formation. Gibberellins promote seed germination as well as flowering and growth post-germination.

Study 1

Several scientists soaked Zea mays (corn) seeds in solutions rich in certain plant hormones. They observed and recorded seed germination and development over a three week period. At the end of the three week period, they measured coleoptile (the protective extension of sprout) and radicle (the primary root) growth of the seeds and plotted them in a graph (Figure 1).

Figure 1

Study 2

Scientists exposed Zea mays (corn) seeds to several hormonal treatments and measured coleoptile growth over a 14-day period and recorded their observations in a line graph (Figure 2). The groups consisted of a control exposed to saline solution, a treatment group exposed to a 0.15 millimolar solution of abscisic acid, and a treatment group exposed to a solution that included 0.15 millimoles of abscisic acid and 0.20 millimoles of gibberellins.

Figure 2

What biological system secretes hormones in multicellular organisms?

Hormones are biochemical messengers utilized by multicellular organisms to coordinate development and behaviors. Hormones are secreted by the endocrine system and are key components in signal cascades that result in various essential activities. Plants, like animals, depend on hormonal signals for physiological adaptation and development.

There are several hormones that are primarily involved with seed germination and sprout formation. Abscisic acid, in high concentrations, prevents seed germination. Auxins are compounds that positively influence cell enlargement, the formation of buds, and the development of roots. Cytokinins influence cell division and shoot formation. Gibberellins promote seed germination as well as flowering and growth post-germination.

Study 1

Several scientists soaked Zea mays (corn) seeds in solutions rich in certain plant hormones. They observed and recorded seed germination and development over a three week period. At the end of the three week period, they measured coleoptile (the protective extension of sprout) and radicle (the primary root) growth of the seeds and plotted them in a graph (Figure 1).

Figure 1

Study 2

Scientists exposed Zea mays (corn) seeds to several hormonal treatments and measured coleoptile growth over a 14-day period and recorded their observations in a line graph (Figure 2). The groups consisted of a control exposed to saline solution, a treatment group exposed to a 0.15 millimolar solution of abscisic acid, and a treatment group exposed to a solution that included 0.15 millimoles of abscisic acid and 0.20 millimoles of gibberellins.

Figure 2

The proper term for the shoot or sprout section of the germinating seed is which of the following?

Hormones are biochemical messengers utilized by multicellular organisms to coordinate development and behaviors. Hormones are secreted by the endocrine system and are key components in signal cascades that result in various essential activities. Plants, like animals, depend on hormonal signals for physiological adaptation and development.

There are several hormones that are primarily involved with seed germination and sprout formation. Abscisic acid, in high concentrations, prevents seed germination. Auxins are compounds that positively influence cell enlargement, the formation of buds, and the development of roots. Cytokinins influence cell division and shoot formation. Gibberellins promote seed germination as well as flowering and growth post-germination.

Study 1

Several scientists soaked Zea mays (corn) seeds in solutions rich in certain plant hormones. They observed and recorded seed germination and development over a three week period. At the end of the three week period, they measured coleoptile (the protective extension of sprout) and radicle (the primary root) growth of the seeds and plotted them in a graph (Figure 1).

Figure 1

Study 2

Scientists exposed Zea mays (corn) seeds to several hormonal treatments and measured coleoptile growth over a 14-day period and recorded their observations in a line graph (Figure 2). The groups consisted of a control exposed to saline solution, a treatment group exposed to a 0.15 millimolar solution of abscisic acid, and a treatment group exposed to a solution that included 0.15 millimoles of abscisic acid and 0.20 millimoles of gibberellins.

Figure 2

The proper term for the root section of the germinating seed is which of the following?

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).

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).

Table 2

At what temperature do fruit flies complete their lifespan in 12 days?

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).

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).

Table 2

How many pairs of chromosomes does the typical Drosophila melanogaster possess?

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).

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).

Table 2

Drosophila melanogaster is commonly known as which of the following?

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.

Ninety percent of the cell cycle is spent in which stage?

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.

What happens to the cell during the gap phases of interphase?

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 checkpoints are present in 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.

Cancer is defined as uncontrolled cellular division that results from the deregulation of the cell cycle. Which phases of the cell cycle are most likely to be subject to errors in regulation that could result in cancerous formations?