Answer the following statements true (T) or false (F)
1. The type of cellular response that is caused by a given signaling molecule depends on the type of cell responding to the signal.
2. Apoptosis can occur via both intrinsic and extrinsic pathways.
3. Apoptosis is necessary in humans in order to eliminate cells infected by viruses, cells that are worn out, and those that have the potential to cause cancer.
4. Ligands that promote cell death are typically produced on the surface of cells of the immune system that recognize abnormal cells and target them for destruction.
1. TRUE
2. TRUE
3. TRUE
4. TRUE
You might also like to view...
The value for ? in root tissue was found to be -0.15 MPa. If you take the root tissue and place it in a 0.1 M solution of sucrose (? = -0.23 MPa), the net water flow would _____
A) be from the tissue into the sucrose solution B) be from the sucrose solution into the tissue C) be in both directions and the concentration of water would remain equal D) occur only as ATP was hydrolyzed in the tissue E) be impossible to determine from the values given here
Which of the following characteristics indicates that Tiktaalik was an intermediate form between fish and amphibian?
a. The fossil reveals the presence of true lungs, with no gills present. b. Evidence suggests that the eyes were forward facing, similar to a terrestrial predator. c. The attachment of the fin bones to the shoulder suggest that they might be weight bearing. d. The DNA evidence shows that Tiktaalikâs enzymes were adapted for terrestrial habitats.
Most viruses?
A. infect only a few closely related species. B. infect only animal cells. C. cannot infect living cells. D. infect only plant cells. E. infect a wide variety of organisms.
Which of the following statements about thymine dimers is false?
A) Patients with xeroderma pigmentosum have faulty DNA repair mechanisms. B) They are repaired by excision repair. C) They can be produced by exposure to UV light. D) They are repaired by one enzyme that can clip out, lay down new nucleotides, and seal the gap. E) If resulting mutations accumulate, it can result in cancers.