Bellwork: Write the 2 questions and answer them in your notes Bellwork: Write the 2 questions and answer them in your notes. Then, draw and label the parts of the nucleotide below. 1. What are the 3 components of this DNA nucleotide? 2. What is the function of DNA in the cell?

Genetics DNA and Genes DNA: The Molecule of Heredity Unit Overview – pages 250-251

Contributors to DNA Discovery 1943 Oswald Avery: DNA carries genetic information 1952 Franklin took the first picture of DNA using X-RAY

Contributors to DNA Discovery 1953 - Watson & Crick proposed the structure of DNA 1962 - Nobel Prize to Watson and Crick “FATHERS OF DNA”

Contributors to DNA Discovery What event occurred allowing Watson and Crick to discover the DNA structure?

Section 11.1 Summary – pages 281 - 287 What is DNA? Deoxyribonucleic Acid determines an organism’s traits ultimately determines the structure of proteins. body is made up of proteins body’s functions depend on proteins called enzymes. Section 11.1 Summary – pages 281 - 287

Section 11.1 Summary – pages 281 - 287 The Structure of DNA DNA is a polymer made of nucleotides. Nucleotides have three parts: simple sugar phosphate group nitrogenous base. Section 11.1 Summary – pages 281 - 287

Section 11.1 Summary – pages 281 - 287 Nucleotide Structure: composed of one atom of phosphorus surrounded by four oxygen atoms. carbon ring structure that contains one or more atoms of nitrogen. Phosphate group Sugar (deoxyribose) Nitrogenous base Deoxyribose is the simple sugar in DNA Section 11.1 Summary – pages 281 - 287

Section 11.1 Summary – pages 281 - 287 The structure of nucleotides In DNA, there are four possible nitrogenous bases: adenine (A), guanine (G), cytosine (C), and thymine (T). *always pair * always pair Cytosine (C) Adenine (A) Thymine (T) Guanine (G) Section 11.1 Summary – pages 281 - 287

The structure of nucleotides Thus, in DNA there are four possible nucleotides, each containing one of these four bases. Nucleotides join together to form long chains. Formed by covalent bonds These chains are known as the Double Helix

Section 11.1 Summary – pages 281 - 287

Section 11.1 Summary – pages 281 - 287 The importance of nucleotide sequences The sequence of nucleotides in each gene contains information for assembling the string of amino acids Chromosome Section 11.1 Summary – pages 281 - 287

Genes and Proteins DNA ultimately determines structure of proteins Proteins make up the structure of an organism AND control all of the organism’s chemical reactions to keep it alive

Question 1 Which of the following is NOT a component of DNA? A. simple sugars B. phosphate groups C. nitrogenous bases D. proteins The answer is D. Section 1 Check

Question 2 Which of the following correctly comprises a complimentary base pair? A. adenine – thymine B. thymine – guanine C. guanine – adenine D. cytosine – thymine The answer is A. Section 1 Check

DNA and Cell Division

DNA to Proteins Remember…DNA ultimately determines structure of proteins. These proteins are what makes “us” and enables “us” to function….. So how do we get these specific proteins?

Section 11.1 Summary – pages 281 - 287 Replication of DNA Before a cell can divide by mitosis or meiosis, it must first make a copy of its chromosomes.( Interphase) The DNA in the chromosomes is copied in a process called DNA replication. Without DNA replication, new cells would have only half the DNA of their parents. Section 11.1 Summary – pages 281 - 287

Section 11.2 Summary – pages 288 - 295 Cells Start Here: Transcription Transcription results in the formation of one single-stranded RNA molecule. takes place in the nucleus mRNA, which is seen in here, takes the instructions from the nucleus to the cytoplasm. Section 11.2 Summary – pages 288 - 295

Section 11.2 Summary – pages 288 - 295 What is RNA? RNA is single stranded The sugar is ribose Rather than thymine, RNA contains a similar base called uracil (U). Uracil Hydrogen bonds Adenine Section 11.2 Summary – pages 288 - 295

Why RNA? DNA provides workers with the instructions for making the proteins, and workers build the proteins. The workers for protein synthesis are RNA molecules.

Back to Copying DNA…. Once mRNA is in the cytoplasm… Ribosomal RNA (rRNA) binds to the mRNA and uses the instructions to assemble the amino acids in the correct order. This starts Translation

Section 11.2 Summary – pages 288 - 295 Translation: From mRNA to Protein Translation is the process of converting the information in a sequence of nitrogenous bases in mRNA into a sequence of amino acids in protein. Translation takes place at the ribosomes in the cytoplasm. Section 11.2 Summary – pages 288 - 295

Section 11.2 Summary – pages 288 - 295 The role of transfer RNA Amino acid Each tRNA molecule attaches to only one type of amino acid. An anticodon is a sequence of three bases found on tRNA. Chain of RNA nucleotides Transfer RNA molecule Anticondon Section 11.2 Summary – pages 288 - 295

Section 11.2 Summary – pages 288 - 295 The role of transfer RNA Ribosome mRNA codon Section 11.2 Summary – pages 288 - 295

Section 11.2 Summary – pages 288 - 295 The role of transfer RNA The first codon on mRNA is AUG, which codes for the amino acid methionine. AUG signals the start of protein synthesis. Then the ribosome slides along the mRNA to the next codon. Section 11.2 Summary – pages 288 - 295

Section 11.2 Summary – pages 288 - 295 The role of transfer RNA Methionine tRNA anticodon Section 11.2 Summary – pages 288 - 295

Section 11.2 Summary – pages 288 - 295 The role of transfer RNA A new tRNA molecule carrying an amino acid pairs with the second mRNA codon. Alanine Section 11.2 Summary – pages 288 - 295

Section 11.2 Summary – pages 288- 295 The role of transfer RNA The amino acids are joined when a peptide bond is formed between them. Methionine Alanine Peptide bond Section 11.2 Summary – pages 288- 295

Section 11.2 Summary – pages 288 - 295 The role of transfer RNA A chain of amino acids is formed until the stop codon is reached on the mRNA strand. Stop codon Section 11.2 Summary – pages 288 - 295

Section 11.2 Summary – pages 288 - 295 The Genetic Code The Messenger RNA Genetic Code First Letter Third Letter Second Letter U C A G U Phenylalanine (UUU) Serine (UCU) Tyrosine (UAU) Cysteine (UGU) U Phenylalanine (UUC) Serine (UCC) Tyrosine (UAC) Cysteine (UGC) C Leucine (UUA) Serine (UCA) Stop (UAA) Stop (UGA) A Leucine (UUG) Serine (UCG) Stop (UAG) Tryptophan (UGG) G C Leucine (CUU) Proline (CCU) Histadine (CAU) Arginine (CGU) U Leucine (CUC) Proline (CCC) Histadine (CAC) Arginine (CGC) C Leucine (CUA) Proline (CCA) Glutamine (CAA) Arginine (CGA) A Leucine (CUG) Proline (CCG) Glutamine (CAG) Arginine (CGG) G A Isoleucine (AUU) Threonine (ACU) Asparagine (AAU) Serine (AGU) U Isoleucine (AUC) Threonine (ACC) Asparagine (AAC) Serine (AGC) C Isoleucine (AUA) Threonine (ACA) Lysine (AAA) Arginine (AGA) A Methionine;Start (AUG) Threonine (ACG) Lysine (AAG) Arginine (AGG) G G Valine (GUU) Alanine (GCU) Aspartate (GAU) Glycine (GGU) U Valine (GUC) Alanine (GCC) Aspartate (GAC) Glycine (GGC) Glycine (GGC) C Valine (GUA) Alanine (GCA) Glutamate (GAA) Glycine (GGA) A Valine (GUG) Alanine (GCG) Glutamate (GAG) Glycine (GGG) G Section 11.2 Summary – pages 288 - 295

DNAi Triplet code Translation http://www.pbs.org/wgbh/nova/body/rnai.html

Question 1 What are the three chemical differences between RNA and DNA? Answer RNA consists of a single strand of nucleotides whereas DNA is a double strand. RNA contains ribose as its sugar and DNA contains deoxyribose as its sugar. Uracil in RNA replaces thymine in DNA as the nitrogenous base. Section 2 Check

Question 2 Answer What is the role of rRNA in protein synthesis? Ribosomal RNA binds to messenger RNA and assembles the amino acids in the order needed for the protein to be synthesized. Section 2 Check

Question 3 Which regions of the mRNA travel to the ribosome; introns, exons, or both? Answer Only exons, which contain coding information, travel to the ribosome. Introns, noncoding nucleotide sequences, do not travel to the ribosome. Section 2 Check

Question 4 Answer What is an anticodon, and what does it represent? An anticodon is a sequence of three nucleotides on the tRNA molecule that binds to a codon of the mRNA strand. Section 2 Check

Question 4 What is the product of replication; of transcription; of translation? Answer Two DNA molecules; one mRNA molecule; a protein Section 2 Check

11.3 Section Objectives – page 296 1. Why is this exact base sequence important? 2. What may be the result of “wrong” base sequencing? 11.3 Section Objectives – page 296

11.3 Section Summary 6.3 – pages 296 - 301 Mutations Organisms have evolved many ways to protect their DNA from changes. In spite of these mechanisms, however, changes in the DNA occasionally do occur. A mutation is any change in a DNA sequence. Mutations can be caused by errors in replication, transcription, cell division, or by external agents. 11.3 Section Summary 6.3 – pages 296 - 301

11.3 Section Summary 6.3 – pages 296 - 301 Mutations in reproductive cells Mutations can occur in the reproductive cells. This then becomes part of the genetic makeup of the offspring. If the change makes a protein nonfunctional, the embryo may not survive. 11.3 Section Summary 6.3 – pages 296 - 301

11.3 Section Summary 6.3 – pages 296 - 301 Mutations in body cells What happens if powerful radiation, such as gamma radiation, hits the DNA of a nonreproductive cell, a cell of the body such as in skin, muscle, or bone? If the body cell’s DNA is changed, this mutation would not be passed on to offspring. The mutation may cause problems for the individual. 11.3 Section Summary 6.3 – pages 296 - 301

11.3 Section Summary 6.3 – pages 296 - 301 The effects of point mutations A point mutation is a change in a single base pair in DNA. A change in a single nitrogenous base can change the entire structure of a protein because a change in a single amino acid can affect the shape of the protein. 11.3 Section Summary 6.3 – pages 296 - 301

11.3 Section Summary 6.3 – pages 296 - 301 The effects of point mutations mRNA Normal Protein Stop Replace G with A Point mutation mRNA Protein Stop 11.3 Section Summary 6.3 – pages 296 - 301

11.3 Section Summary 6.3 – pages 296 - 301 Frameshift mutations A frameshift mutation is a mutation in which a single base is added or deleted from DNA. A frameshift mutation shifts the reading of codons by one base. This mutation would cause nearly every amino acid in the protein after the deletion to be changed. 11.3 Section Summary 6.3 – pages 296 - 301

11.3 Section Summary 6.3 – pages 296 - 301 Frameshift mutations Deletion of U Frameshift mutation mRNA Protein 11.3 Section Summary 6.3 – pages 296 - 301

11.3 Section Summary 6.3 – pages 296 - 301 Chromosomal Alterations Chromosomal mutations are structural changes in chromosomes. When a part of a chromosome is left out, a deletion occurs A B C D E F G H A B C E F G H Deletion 11.3 Section Summary 6.3 – pages 296 - 301

11.3 Section Summary 6.3 – pages 296 - 301 Chromosomal Alterations When part of a chromatid breaks off and attaches to its sister chromatid, an insertion occurs. The result is a duplication of genes on the same chromosome. A B C D E F G H A B C B C D E F G H Insertion 11.3 Section Summary 6.3 – pages 296 - 301

11.3 Section Summary 6.3 – pages 296 - 301 Chromosomal Alterations When part of a chromosome breaks off and reattaches backwards, an inversion occurs. A B C D E F G H A D C B E F G H Inversion 11.3 Section Summary 6.3 – pages 296 - 301

11.3 Section Summary 6.3 – pages 296 - 301 Chromosomal Alterations When part of one chromosome breaks off and is added to a different chromosome, a translocation occurs. A B C D E F G H W X A B C D E F G H W X Y Z Y Z Translocation 11.3 Section Summary 6.3 – pages 296 - 301

11.3 Section Summary 6.3 – pages 296 - 301 Causes of Mutations A mutagen is any agent that can cause a change in DNA. Mutagens include radiation, chemicals, and even high temperatures. Forms of radiation, such as X rays, cosmic rays, ultraviolet light, and nuclear radiation, are dangerous mutagens because the energy they contain can damage or break apart DNA. 11.3 Section Summary 6.3 – pages 296 - 301

11.3 Section Summary 6.3 – pages 296 - 301 Causes of Mutations The breaking and reforming of a double-stranded DNA molecule can result in deletions. Chemical mutagens include dioxins, asbestos, benzene, and formaldehyde, substances that are commonly found in buildings and in the environment. Chemical mutagens usually cause substitution mutations. 11.3 Section Summary 6.3 – pages 296 - 301

11.3 Section Summary 6.3 – pages 296 - 301 Repairing DNA Repair mechanisms that fix mutations in cells have evolved. Enzymes proofread the DNA and replace incorrect nucleotides with correct nucleotides. These repair mechanisms work extremely well, but they are not perfect. The greater the exposure to a mutagen such as UV light, the more likely is the chance that a mistake will not be corrected. 11.3 Section Summary 6.3 – pages 296 - 301

Question 1 Any change in DNA sequences is called a _______. A. replication B. mutation C. transcription D. translation The answer is B. Section 3 Check

Question 2 Which is more serious, a point mutation or a frameshift mutation? Why? Answer A frameshift mutation is more serious than a point mutation because it disrupts more codons than a point mutation. Section 3 Check

Question 3 Why are chromosomal mutations rarely passed on to the next generation? Answer Few chromosomal changes are passed on to the next generation because the zygote usually dies. If the zygote survives, it is often sterile and incapable of producing offspring. Section 3 Check

Question 4 How does DNA control the structures and functions of a cell? Answer DNA determines the structure of proteins. Some proteins become important cell structures. Other proteins, such as enzymes, control chemical reactions that perform key life functions. Chapter Assessment

Question 5 The process through which the order of bases in messenger RNA codes for the order of amino acids in a protein is: A. transcription B. translation C. replication D. point mutation The answer is B. Chapter Assessment

Question 6 Why would scientists use nucleotide sequences to identify bodies of crime victims? Answer In comparing nucleotide sequences in the DNA of a crime victim with nucleotide sequences from a possible close relative of the crime victim, scientists can determine if the two are related. Chapter Assessment

Question 7 What happens when a stop codon is reached during translation? Answer When a stop codon is reached, translation ends and the amino acid strand is released from the ribosome. Chapter Assessment

Question 8 A ________ bond forms between adjacent amino acids during translation. A. nucleotide B. phosphate C. hydrogen D. peptide The answer is D. Chapter Assessment

Question 9 Answer Why is DNA replication important to cell division? Without DNA replication, new cells would have only half the DNA of their parents. Species could not survive and individuals could not grow or reproduce successfully. Chapter Assessment

Question 10 Answer What is the role of mRNA in protein synthesis? The messenger RNA acts as a genetic message, providing the complete information, in sequences of codons, for the building of a protein. Chapter Assessment

Question 11 The DNA sequences of a parrot _________. A. are more similar to those of a clam than a robin B. are more similar to a fern than a dog C. are exactly the same as those of a human D. contain exactly the same nucleotides as those of a beetle The answer is D. Chapter Assessment

Mutate your name! Name: R A C H E L R O ‘ C O N N O R Insertion: Copy the chart below in your notes Write your name in the first box so that there are 3 bases per codon Draw a box around each codon Do each of the mutations by filling in the rest of the chart Put a box around each codon after the mutation Name: R A C H E L R O ‘ C O N N O R Insertion: (Add a base to the sequence) Deletion: (Delete a base) Substitution: (Take out a base a replace it with another)

Name: Insertion: Deletion: Substitution: (Add a base to the sequence) R A C H E L R B O ‘ C O N N O R Deletion: (Delete a base) Substitution: (Take out a base a replace it with another)

A DNA sequence reads: THE CAT ATE THE BIG RAT What type of mutation would change the sequence to: THE CAT ATA ETH EBI GRA T

Original DNA sequence: THE BIG RAT ATE THE CAT Mutated sequence: THE BIG FAT ATE THE CAT

Original DNA sequence: THE FAT BAT ATE THE RAT Mutated sequence: THE FAT BAT AT THE RAT