#Question id: 2585
#Unit 1. Molecules and their Interaction Relevant to Biology
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: 8787
#Unit 9. Diversity of Life Forms
Which of the following statements is accurate, at least according to our present knowledge?
#Question id: 12872
#General Aptitude
#Question id: 7258
#Unit 5. Developmental Biology
A four-cell embryo normally develops into a blastocyst
consisting of trophectoderm (TE) cells on the outside and inner cell mass (ICM)
cells inside. The transplantation experiments were done with mouse embryos.
A. If a labeled cell is placed on the outside of a very early
embryo, it is likely to form extraembryonic tissues.
B. If a labeled cell is placed on the inside of a very early embryo, it is likely to form embryonic tissues.
According to above observations which of the following statement is true?
#Question id: 10734
#Unit 10. Ecological Principles
This term is a measure of the ability of a system to resist change in the face of outside influences.