CHAPTER 12 STUDY GUIDE MATER LAKES ACADEMY MR. R. VAZQUEZ BIOLOGY

DNA Avery and other scientists discovered that DNA is the nucleic acid that stores and transmits the genetic information from one generation of an organism to the next. Watson and Crick’s model of DNA was a double helix, in which two strands were wounded around each other. Nucleotide – nucleic acid made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base There are four nitrogenous bases: Thymine (T), Adenine (A), Guanine (G), Cytosine (C) Base pairing – principle that bonds in DNA can form only between A and T and between G and C.

CHROMOSOMES AND DNA REPLICATION During DNA replication, the DNA molecule separates into two strands, then produces two new complementary strands following the rules of base pairing. Each strand of the double helix serves as a template, or model, for the new strand. Chromatin – granular material visible within the nucleus, consists of DNA tightly coiled around proteins Replication – copying process by which cells duplicate its DNA DNA polymerase – enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule

RNA AND PROTEIN SYNTHESIS There are three main types of RNA: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA). During transcription, RNA polymerase binds to DNA and separates the DNA strands. RNA polymerase the uses one strand of DNA as a template from which nucleotides are assembled into a strand of RNA. When assembling the RNA strand, Thymine is replaced by Uracil (U). During translation, the cell uses information from mRNA to produce proteins. Gene – sequence of DNA that codes for a protein and thus determines a trait. mRNA – RNA molecule that carries copies of instructions for the assembly of amino acids into proteins from DNA to the rest of the cell rRNA – type of RNA that makes up the major part of ribosomes tRNA – type of RNA molecule that transfers amino acids to ribosomes during protein synthesis Codon – three-nucleotide sequence of mRNA that codes for a single amino acid. Anticodon – group of three bases on a tRNA molecule that are complementary to an mRNA codon. Promoter – region of DNA that indicates to an enzyme where to bind to make RNA

MUTATIONS Mutations are changes in genetic material. Gene mutations result from changes in a single gene. Chromosomal mutations involve changes in whole chromosomes. Frameshift mutation – mutation that shifts the “reading” frame of the genetic message by inserting or deleting a nucleotide. Point mutation – gene mutations involving changes in one or a few nucleotides  Insertion – a base is inserted into the DNA sequence  Deletion – a base is deleted from the DNA sequence  Substitution – a base is changed for another in a DNA sequence

CHAPTER 12 ASSESSMENT QUESTIONS Pages 315 – 316 This review will be 25% of your test grade! Answer the following questions only! 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 21, 23, 28, 29, 31 For multiple choice questions, write the question and your answer choice! Answer all other questions in COMPLETE SENTENCES!