Principles of Biology Exam 2 Shadwick Questions with Complete Answers Updated.

Nucleotides are composed of: - Answer sugar, phosphate, nitrogenous base What forms the backbone for a nucleic acid? - Answer sugar, phosphate What are the 4 nitrogenous bases? - Answer Thymine, Cytosine (Pyrimidines) and Adenine, and Guanine (Purines) Which nitrogenous bases pair? - Answer A-T, C-G (DNA) A-U, C-G (RNA) DNA replication depends on: - Answer specific base pairing What holds DNA strands together? - Answer hydrogen bonds What does DNA polymerase do? - Answer grabs onto a single strand What does DNA helices do? - Answer unzips the two parent strands by interfering with the hydrogen bonds 3 stages of transcription: - Answer initiation, elongation, termination Initiation (Transcription) - Answer starts with a promoter region that is recognized as the starting point of gene sequence Elongation (Transcription) - Answer base pairing occurs (T-A, G-C) Termination (Transcription) - Answer as RNA polymerase gets to the endpoint it lets go of the completed mRNA so it can be exported from the nucleus Translation (Transcription) - Answer a ribosome attaches to mRNA; tRNA translates the messages into a polypeptide What do codons do? - Answer they specify the amino acid sequence of a polypeptide