Principles of Biology Exam 2 Shadwick |Q’s and A’s
Nucleotides are composed of: - -sugar, phosphate, nitrogenous base
-What forms the backbone for a nucleic acid? - -sugar, phosphate
-What are the 4 nitrogenous bases? - -Thymine, Cytosine (Pyrimidines) and Adenine, and
Guanine (Purines)
-Which nitrogenous bases pair? - -A-T, C-G (DNA) A-U, C-G (RNA)
-DNA replication depends on: - -specific base pairing
-What holds DNA strands together? - -hydrogen bonds
-What does DNA polymerase do? - -grabs onto a single strand
-What does DNA helices do? - -unzips the two parent strands by interfering with the
hydrogen bonds
-3 stages of transcription: - -initiation, elongation, termination
-Initiation (Transcription) - -starts with a promoter region that is recognized as the
starting point of gene sequence
-Elongation (Transcription) - -base pairing occurs (T-A, G-C)
-Termination (Transcription) - -as RNA polymerase gets to the endpoint it lets go of the
completed mRNA so it can be exported from the nucleus
-Translation (Transcription) - -a ribosome attaches to mRNA; tRNA translates the
messages into a polypeptide
-What do codons do? - -they specify the amino acid sequence of a polypeptide
-How do mutations occur? - -changes in the DNA sequence caused by some error in DNA
or mutagens
-What is a phage? - -a virus that reproduces itself in bacteria
-Lytic cycle (Viruses) - -1. Phage DNA enters a bacterium, then it is replicated, transcribed,
and translated
2. Viral DNA assembles into new phages, which burst from the host cell
Nucleotides are composed of: - -sugar, phosphate, nitrogenous base
-What forms the backbone for a nucleic acid? - -sugar, phosphate
-What are the 4 nitrogenous bases? - -Thymine, Cytosine (Pyrimidines) and Adenine, and
Guanine (Purines)
-Which nitrogenous bases pair? - -A-T, C-G (DNA) A-U, C-G (RNA)
-DNA replication depends on: - -specific base pairing
-What holds DNA strands together? - -hydrogen bonds
-What does DNA polymerase do? - -grabs onto a single strand
-What does DNA helices do? - -unzips the two parent strands by interfering with the
hydrogen bonds
-3 stages of transcription: - -initiation, elongation, termination
-Initiation (Transcription) - -starts with a promoter region that is recognized as the
starting point of gene sequence
-Elongation (Transcription) - -base pairing occurs (T-A, G-C)
-Termination (Transcription) - -as RNA polymerase gets to the endpoint it lets go of the
completed mRNA so it can be exported from the nucleus
-Translation (Transcription) - -a ribosome attaches to mRNA; tRNA translates the
messages into a polypeptide
-What do codons do? - -they specify the amino acid sequence of a polypeptide
-How do mutations occur? - -changes in the DNA sequence caused by some error in DNA
or mutagens
-What is a phage? - -a virus that reproduces itself in bacteria
-Lytic cycle (Viruses) - -1. Phage DNA enters a bacterium, then it is replicated, transcribed,
and translated
2. Viral DNA assembles into new phages, which burst from the host cell
