An adult hemopoietic stem cell found in the bone marrow ______________________
(a) will occasionally produce epidermal cells when necessary.
(b) can produce only red blood cells.
(c) can undergo self-renewing divisions for the lifetime of a healthy animal.
(d) will express all the same transcription factors as those found in an unfertilized egg.
Choice (c) is correct. Adult stem cells are specialized, and thus an adult hemopoietic stem cell does not produce epidermal cells [choice (a)] and also stably expresses the transcriptional regulators that ensure that its progeny will become blood cells [choice (d)]. An adult hemopoietic stem cell has the ability to produce all the many types of cell in the blood [choice (b)].
You might also like to view...
What structure protects the heart and lungs?
a. vertebral column b. pelvic girdle c. pectoral girdle d. ribs and sternum e. all of these
Which of the following statements is false?
a. Individuals are injected with antibodies in passive immunity. b. A genetically engineered virus is not as potentially dangerous as a weakened but intact pathogen. c. Allergies occur when the body makes a secondary immune response to a normally harmless substance. d. Allergies are a nuisance but are never dangerous or life-threatening. e. Allergies cause the secretion of mucus, prostaglandins, and histamines.
In a polyribosome, which end of the mRNA would have the shortest polypeptides?
What will be an ideal response?
In 1964, Nirenberg and Leder used the triplet binding assay to determine specific codon assignments. A complex of which of the following components was trapped in the nitrocellulose filter?
A) ribosomes and DNA B) sense and antisense strands of DNA C) free tRNAs D) charged tRNA, RNA triplet, and ribosome E) uncharged tRNAs and ribosomes