Biology B Final Exam 2023 with 100% correct answers

Explain the purpose of DNA replication. The purpose is to produce two identical copies of a DNA molecule. The steps of DNA replication. 1. An enzyme breaks the hydrogen bonds between bases that hold the two strands together, which unzips the DNA 2. The DNA continues to unzip, nucleotides that are floating free into their base pair by hydrogen bonding. Another enzyme bonds these nucleotides into a bond. 3. This continues until the entire molecule has been unzipped and replicated. Where in the cell does DNA replication occur? This happens on the DNA strand. Describe the functions of the 3 types of RNA. mRNA: This transcribes the genetic code from DNA into a form that can be read and used to make protein then carries the genetic information from the nucleus to the cytoplasm of a cell. rRNA: This directs the translation of mRNA into proteins. tRNA: This transfers amino acids to the ribosome that correspond to each three-nucleotide codon of rRNA. Where in the cell is RNA located and where are they synthesized? It is found in cytoplasm and is synthesized in the nucleus. Compare and Contrast DNA and RNA RNA is found in the cytoplasm, while DNA is found in the nucleus. DNA has four nucleotides: adenine, thymine, guanine, cytosine. RNA has four nucleotides, but one is different: adenine, thymine, guanine, uracil. Which nitrogen bases are found in DNA? In RNA? DNA: adenine, thymine, guanine, and cytosine. RNA: adenine, uracil, guanine, and cytosine. Which nitrogen bases form complementary pairs in DNA? In RNA? DNA: A=T G=C RNA: A=U G=C What is the purpose of transcription? Describe the steps involved and where in the cell it takes place. Its use is to make RNA copies of individual genes that the cell can use in the biochemistry. 1. The DNA molecule unwinds and separates to form a small open complex. RNA polymerase binds. 2. RNA polymerase moves along the template strand, synthesizing a mRNA molecule. 3. Transcription is then terminated. 4. After transcription the RNA molecule is processed.