#Question id: 10218
#6. System Physiology – Plant
An effect that appears to be a major factor in the stability of the photosynthetic apparatus is photoinhibition, which occurs when excess excitation arriving at the PSII reaction center leads to its inactivation and damage due to
#Question id: 12107
#10. Ecological Principles
#Question id: 7764
#5. Developmental Biology
Cellular senescence
may have evolved to protect organisms against cancer. Instead of dividing out
of control, the cells die. Cellular senescence appears to be regulated by
several tumor suppressor genes, especially p53.what is the most appropriate
reason behind this,
1) Transcription
factor p53 is thought to suppress tumorigenesis by causing cell arrest and
senescence in response to short telomeres, DNA damage, and viral or external
signals to divide
2) This factor can
stop the cell cycle, cause cellular senescence in rapidly dividing cells,
instruct genes to initiate cellular apoptosis, and activate DNA repair enzymes.
3) Induction of apoptosis or cellular senescence by p53 always beneficial.
#Question id: 11021
#7. System Physiology – Animal
A 75-year-old man goes to the hospital emergency department and faints. Five minutes later he is alert. An EKG shows 75 P waves per minute and 35 QRS waves per minute with a normal QRS width. Which of the following is the likely diagnosis?
#Question id: 10705
#10. Ecological Principles
Which of the following statements is TRUE for an ecotone?