Question

question 24
a chemical produced by a plant inhibits (prevents) cytokinesis from following mitosis.
what would be the result of exposure to this chemical?
cells would go through the cell cycle, but would double in nuclei following each mitosis
b cells would accelerate in growth and rate of divisions - increasing in number.
c cells would automatically experience apoptosis
d cells would become a tumor, leading to a malignant cancer.
question 25
stem cells become specialized in multicellular organism through _.
a differentiation
b binary fission
c spontaneous generation
d gap 1

Explanation:

Question 24

• Option a: Mitosis is the process of nuclear division. Cytokinesis is the process of cytoplasmic division. If cytokinesis is inhibited, after each mitosis (nuclear division), the cell will have double the number of nuclei (since the nucleus divides but the cell does not split into two daughter cells). The cell cycle (which includes interphase and mitosis) can still occur as mitosis is not inhibited, just the subsequent cytokinesis.
• Option b: Since cytokinesis is inhibited (cell - splitting is prevented), the number of cells will not increase. Growth in terms of cell - number increase requires cytokinesis.
• Option c: There is no indication that the chemical would cause apoptosis (programmed cell death). The chemical only affects cytokinesis.
• Option d: A tumor (and cancer) is usually associated with uncontrolled cell - cycle regulation (e.g., mutations in genes like \(p53\) that regulate the cell cycle). Here, the cell cycle is not described as being uncontrolled, just that cytokinesis is inhibited.

• Option a: Differentiation is the process by which stem cells (which are unspecialized) develop into specialized cell types (e.g., nerve cells, muscle cells). This involves changes in gene expression that lead to the development of specific cell - type characteristics.
• Option b: Binary fission is a form of asexual reproduction in prokaryotes (e.g., bacteria). It is not the process by which stem cells in multicellular organisms become specialized.
• Option c: Spontaneous generation is an outdated theory that living organisms can arise from non - living matter. It has no relation to stem - cell specialization.
• Option d: Gap 1 (\(G_1\)) is a phase in the cell cycle. It is a period of cell growth and preparation for DNA synthesis. It is not the process of stem - cell specialization.

Answer:

A. Cells would go through the cell cycle, but would double in nuclei following each mitosis

Question 25