Question 1

Plants have special groups of self-renewing cells called

Accepted Answer

The self-renewing cells in plants are called meristems. They are found in areas of growth, such as the tips of roots and shoots, and are responsible for producing new cells and tissues. Chloroplasts are organelles found in plant cells that are responsible for photosynthesis. Cast cells are not a specialized cell type found in plants.

Question 2

In general,the blastomeres of the _____ form the endodermal tissues.

Accepted Answer

The vegetal pole contains the larger and more yolky blastomeres, which will eventually form the endodermal tissues of the developing embryo. The animal pole contains smaller, less yolk-filled blastomeres that eventually form the ectodermal tissues. The equator region contains blastomeres that will form intermediate tissues. The membrane is not a region of the embryo.

Question 3

In contrast to the cell cycle of adult somatic cells,the dividing cells of an early embryo lack which cell cycle stage(s)?

Accepted Answer

The dividing cells of an early embryo lack the G1 and G2 phases of the cell cycle, which are parts of interphase. This allows for rapid cell division.

Question 4

If cells from a wing are transplanted to the leg prior to their determination,into what will they likely develop?

Accepted Answer

Before determination, cells are not yet committed to becoming a specific type of cell. Therefore, if wing cells are transplanted to the leg area before they are determined, they will likely develop according to the new local environment and signals, which in this case would lead them to become leg cells.

Question 5

In Drosophila,the cells created by cleavage contain different developmental signals from the egg called cytoplasmic

Accepted Answer

The developmental signals contained within the egg cytoplasm are called determinants. These determinants are unequally distributed during cleavage, leading to the formation of different cell types that will give rise to various tissues and organs during development.

Question 6

Caenorhabditis elegans is an organism with exactly 959 somatic cells.This organism is a(n)

Accepted Answer

Caenorhabditis elegans is a nematode, also known as a roundworm. The fact that it has exactly 959 somatic cells is a unique characteristic of this species.

Question 7

During which initial period of division in a zygote is there no increase in the overall size of the embryo?

Accepted Answer

During the cleavage stage of zygote division, there is no increase in the overall size of the embryo. Instead, the zygote undergoes multiple rapid cell divisions, resulting in smaller and smaller cells without any significant increase in overall size.

Question 8

Very early in development,each cell is capable of expressing all its genes.This is referred to as

Accepted Answer

During the early stages of development, each cell retains the ability to differentiate into any cell type and form any tissue of the body. This is known as totipotency, which is the hallmark of early embryonic cells. As the cells divide and differentiate, they become increasingly more restricted in their developmental potential, eventually reaching a state of terminal differentiation where they can no longer divide or differentiate. Therefore, the correct answer is D) totipotency.

Question 9

In general,the blastomeres of the _____ form the ectodermal tissues.

Accepted Answer

The animal pole of the blastula contains smaller and more numerous blastomeres that will form the ectodermal tissue, which includes skin and nervous tissue. The vegetal pole forms the endodermal tissue, which includes gut and respiratory organs. The equator region of the blastula forms the mesodermal tissue, which includes muscle, bone, and connective tissue. The membrane is not a region of the blastula.

Question 10

A zygote initially divides into smaller cells,each called a(n)

Accepted Answer

After fertilization, a zygote undergoes a series of cell divisions called cleavage. The resulting smaller cells are called blastomeres.

Question 11

Check all of the features of C.elegans that make it a great model system to study developmental processes.

Accepted Answer

C.elegans is a great model system to study developmental processes because it is small and fast growing, has a complete lineage map, is transparent, and is useful in experimental genetics. Although C.elegans is not ubiquitous in the wild, this is not relevant to its value as a model organism for developmental studies.

Question 12

A muscle precursor cell expressing the MyoD1 gene would be considered to be

Accepted Answer

A muscle precursor cell expressing the MyoD1 gene is considered to be determined, as MyoD1 is a gene that plays a critical role in the determination of muscle cell fate. The cell has committed to the muscle cell lineage, but it is not yet fully differentiated into a functional muscle cell. Pluripotent cells have the potential to differentiate into multiple cell types, totipotent cells can differentiate into any cell type including extraembryonic tissues, and differentiated cells have already fully matured into their specialized cell type.

Question 13

A zygote is a fertilized egg formed by an egg and a sperm.The zygote undergoes many mitotic events as it develops into a solid ball of cells (ie,blastomeres)called a blastula.What changes occur in this early cleavage?

Accepted Answer

During the initial stages of cleavage, the zygote undergoes many mitotic events where the number of cells increases rapidly. However, the size of the blastomeres decreases as each new cell is smaller than the original zygote. This process is essential for generating the correct number of cells needed for proper embryonic development. Therefore, Choice C is the correct answer.

Question 14

A fertilized egg is called a(n)

Accepted Answer

A fertilized egg is known as a zygote, which is formed when sperm and egg cells combine during fertilization. Option B)ovule refers to the structure in plants that contains the female reproductive cells. C)oocyte is an immature egg cell, and D)blastocyst is a structure formed during early embryonic development.

Question 15

Plants do not utilize the process of cell migration in their development.Instead plants utilize

Accepted Answer

Plants utilize meristems present in their developing tissues to build themselves outwardly. Meristems are the actively dividing cells that lead to the formation of specialized tissues and organs in the plant. They are responsible for the growth and development of new cells, tissues, and organs throughout the life of the plant. By using meristems, plants are able to continuously grow and develop in response to their environment without the need for cell migration.

Question 16

What can be said about animal and vegetal poles?

Accepted Answer

When animal pole cells are cultured with vegetal pole cells, some of the animal pole cells become mesoderm.

Question 17

In a 32-cell stage tunicate embryo,vegetal marginal cells that lack functional genes for both macho-1 and the FGF receptor would develop as what cell type?

Accepted Answer

Macho-1 and FGF signaling are crucial for muscle and mesenchyme development. Without these, the cells default to a nerve cord fate.

Question 18

What can be said about Drosophila development?

Accepted Answer

Drosophila development is largely dependent on maternal genes, particularly during the early stages of embryogenesis. Maternal RNAs and proteins are deposited in the developing egg during oogenesis, and these play important roles in determining the initial course of development after fertilization. Paternal genes do not play a significant role in determining early development in Drosophila, and zygotic genes are not activated until several mitotic divisions have occurred. The syncytial blastoderm stage refers to a phase of development when the Drosophila embryo is a syncytium, or multinucleate cell, and gene expression is not yet regulated at the level of individual nuclei. While syncytial blastoderm genes may influence later stages of Drosophila development, they are not responsible for determining the initial course of development after fertilization.

Question 19

In a 32-cell stage tunicate embryo,if the vegetal marginal cells lack a functional FGF receptor,which structure(s)will fail to develop? (Select all that apply)

Accepted Answer

The answer of In a 32-cell stage tunicate embryo,if the...

Question 20

A complete cell lineage map exists for

Accepted Answer

A complete cell lineage map has been generated for the nematode C. elegans, which was the first multicellular organism for which every cell division and differentiation event has been described. While other organisms have also been extensively studied, none have a complete lineage map like C. elegans. Therefore, B) Drosophila, C) mouse, and D) human are not the best choices.

Quiz 19: Cellular Mechanisms of Development