#Question id: 2585
#Unit 2. Cellular Organization
Which of the following is the correct sequence that describes the excitation and contraction of a skeletal muscle fiber?
A. Tropomyosin shifts and unblocks the cross-bridge binding sites.
B. Calcium is released and binds to the troponin complex.
C. Transverse tubules depolarize the sarcoplasmic reticulum.
D. The thin filaments are ratcheted across the thick filaments by the heads of the myosin molecules using energy from ATP.
E. An action potential in a motor neuron causes the axon to release acetylcholine, which depolarizes the muscle cell membrane.
#Question id: 31279
#Unit 2. Cellular Organization
#Question id: 579
#Unit 1. Molecules and their Interaction Relevant to Biology
Oxidases, peroxidases, oxygenases or reductases are all
#Question id: 7081
#Unit 5. Developmental Biology
In xenopus, If either Nodal or Vg1 signaling is blocked, there is:
#Question id: 7286
#Unit 5. Developmental Biology
Which of the floral whorls is affected in apetala 3/pistillata (ap3/pi) mutants?