#Question id: 3875
#Unit 3. Fundamental Processes
Splicing of introns in nuclear mRNA primary transcripts requires:
#Question id: 15137
#Unit 2. Cellular Organization
#Question id: 5028
#Unit 11. Evolution and Behavior
What is the probable sequence in which the following clades of animals originated, from earliest to most recent?
1. tetrapods
2. vertebrates
3. deuterostomes
4. amniotes
5. bilaterians
#Question id: 23833
#Unit 2. Cellular Organization
#Question id: 2533
#Unit 2. Cellular Organization
Cellulose microfibrils have an ordered structure and are synthesized at the plasma membrane, given characteristics of microfibrils;
a) Each microfibril is composed of an estimated 18 parallel chains of (1,4)-linked β-D-glucose chains tightly bonded to each other to form a crystalline microfibril
b) Microfibrils have hydrophilic surfaces, populated by polar –OH groups extending from theplane of the sugar rings
c) Microfibrils have hydrophobic surfaces, populated by nonpolar C–H groups populating thesides of stacked glucose chains
d) microfibril important for enzymatic attack by microbial cellulases, which dock onto the hydrophobic surface and remove one glucan chain at a time
Which of the following from given characterstics of microfibrils is incorrect?