#Question id: 5236
#Unit 5. Developmental Biology
Following statements regarding to signaling pathways that control the properties of germline stem cells in drosophila.
A. The signaling molecules—the TGF-β-family proteins Dpp and Gbb as well as Hedgehog (Hh)—are maintain the self -renewal property of germline stem cells by the repression of differentiation factor.
B. Both E-cadherin and Arm are important in maintaining the germline stem-cell niche and regulate the proliferation of stem cells.
C. The signaling molecules—the TGF-β-family proteins Dpp and Gbb as well as Hedgehog (Hh)—are maintain germline stem cell
niche as well as self-renewal property.
D. Both E-cadherin and Arm are important in maintaining the self -renewal property of germline stem cells by the repression of differentiation factor.
Which of the following is correct?
#Question id: 5237
#Unit 5. Developmental Biology
Match the following stem cell type (Column I) with their niche location (Column II).
|
Column I |
Column II |
|
A. Intestine |
i. Bone marrow |
|
B. Hematopoietic stem cells |
ii. Bulge |
|
C. Hair follicle |
iii. Testes |
|
D. Sperm |
iv. Base of small intestinal crypts |
Which of the following is correct?
#Question id: 5238
#Unit 5. Developmental Biology
all tissue types possess a unique stem cell niche, and despite many differences among the niche architecture of different tissues, several common principles of stem cell regulation can be applied to all environments. These principles involve extracellular mechanisms leading to intracellular changes that regulate stem cell behavior.
|
Column A |
Column B |
|
I. Extracellular regulatory mechanisms |
i. Regulation by endocrine, paracrine, or juxtacrine mechanisms |
|
II. Intracellular regulatory mechanisms |
ii. Regulation by a network of transcription factors |
|
iii. Epigenetic regulation |
|
|
iv. Regulation by cell-to-cell and cell-to-matrix adhesions |
|
|
v. Regulation by cytoplasmic determinants |
Match the following regulatory mechanism (column A) with the factors that regulate stem cell behavior (column B).
#Question id: 5239
#Unit 8. Inheritance Biology
Which of the following statements is not true for Hfr strains of E. coli ?
#Question id: 5240
#Unit 8. Inheritance Biology
If bacteria grow in the presence of a large amount of DNase, which of the following recombination process completely inhibited?
#Question id: 5241
#Unit 8. Inheritance Biology
Genes a, b, and c are widely spaced in the bacterial genome. Transducing phage from an a+ b+ c+ bacterium were used to infect a culture of a- b- c- cells, and b+ transductants were selected. Which of the following best describes the predicted genotypes of these transductants?