Peroxisome Biogenesis Occurs by Division of Preexisting Peroxisomes

Question 1

peroxisomes increase in number as?
what is this proliferation of organelles called?
what are the peroxisomal proteins required for this process?

Answer 1

• peroxisomal cells grow and divide
• this proliferation of organelles is called biogenesis
• the peroxisomal proteins required for this process are called peroxins

Question 2

recent evidence suggests that peroxisomes can be fored by either of these two methods…

Answer 2

1. fusion of vesicles budding from the golgi complex
2. division of preexisting peroxisomes
   or perhaps a combination of the two…

Question 3

• what is incorporated into the peroxisome? (step 1)
• what happens next? (step 2)
• some peroxisomes may obtain…. or?

Answer 3

• membrane components, matrix enzymes, and cofactors from the cytosol are incorporated into the peroxisome
• then, new peroxisomes are formed by division of a preexisting one
• some peroxisomes may obtain materials or form de novo(from beginning) from vesicles derived from the ER

Question 4

signals that target some proteins to peroxisomes (2) where are they located?

Answer 4

• the signals that targets the protein to the peroxisome is SKL (ser-lys-leu) called PTS-I (peroxisomal targetting signal- I) on the c terminus
• a second signal, PTS-2 is found on the N-terminus of some proteins