What serves as the cardiac pacemaker?
a. sinoatrial node
b. atrioventricular node
c. gap junction
d. the left ventricle
e. conducting fiber
a
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What process enables a single gene to encode two or more polypeptides that are different in their amino acid sequence?
A. Reverse transcription B. Self-splicing C. Capping D. Alternative splicing E. Regulatory splicing
Flowering in Arabidopsis appears to require ____
a. production in leaves of CO protein and FT protein b. movement of CO protein from leaves to the shoot apex c. expression of CO protein in the shoot apex d. movement of FT mRNA from leaves to the shoot apex e. movement of FT protein from leaves to the shoot apex
Viral spikes
A. allow bacteria to evade host defenses. B. are always present on enveloped viruses. C. attach the viral capsid and envelope. D. are for recognition among the various types of viruses. E. are derived from host proteins.
Transcription factors _____
A) regulate the synthesis of DNA in response to a signal B) transcribe ATP into cAMP C) control gene expression D) regulate the synthesis of lipids in the cytoplasm