2/9/12- Ch 12 DNA/RNA vocabulary 1. Nucleotide 2. Chromatin 3. Replication 4. Gene 5. Transcription 6. Codon 7. Translation 8. Anticodon 9. Mutation
DNA (deoxyribonucleic acid) is… • An organic compound • A type of nucleic acid • Double stranded • Made up of subunits called NUCLEOTIDES
Sugar molecule called DEOXYRIBOSE PHOSPHATE GROUP NITROGEN CONTAINING BASE Nucleotides have 3 parts
THE 4 NITROGEN CONTAINING BASES IN DNA: • ADENINE=A • GUANINE=G • CYTOSINE=C • THYMINE=T
ADENINE and GUANINE are PURINES Bases that have 2 rings of carbon and nitrogen atoms PURINES
CYTOSINE & THYMINE are PYRIMADINES Bases that have 1 ring of carbon and nitrogen atoms PYRIMADINES
WATSON & CRICK • WATSON & CRICK suggested that DNA is made of 2 nucleotide chains that wrap around each other to form a spiral shape called a double helix.
THE COMPLEMENTARY BASE PAIRING RULES • In a double helix, cytosine pairs with guanine & adenine pairs with thymine. • Therefore, A=T & C=G.
REPLICATION • The copying of DNA is called REPLICATION. • The 2 nucleotide chains separate by unwinding-each chain serving as a template for a new nucleotide chain. • If the original DNA strand sequence is: A-T-T-C-C-G, the new nucleotide chain would read: T-A-A-G-G-C. • When replication is finished, 2 new exact copies of the original DNA molecule are produced & the cell is ready to undergo cell division.
A change in a nucleotide sequence is called a MUTATION. • DNA may be damaged by a variety of things, such as chemicals and ultraviolet (UV) rays from the sun.
Quick Quiz • What are the three parts of a nucleotide? • What is stated by the complimentary base pairing rules? • What is replication?
2/10/12 Do Now: DNA is made of small subunits called _____. Nucleotides have three parts. They are ___, ___, & ___. The sugar found in DNA is ________. According to Chargaff’s Rules (complementary base pairing rules), adenine pairs with ____ & _____ pairs with guanine. Purines have ___ ring(s) of carbon & nitrogen, while pyrimadines have ___ ring(s) of carbon & nitrogen. The copying of DNA is ______. If the original strand of DNA reads ACTGGCTA, the new strand will read _______. Any change in DNA is referred to as a _____.
9/13/11-Pick up your book. Do-Now: Pick up and complete the DNA & Protein Synthesis Puzzle. Set out your vocab flashcards, DNA color sheet, & Scientist Graphic Organizer from yesterday.
RNA (ribonucleic acid) is… • An organic compound • Type of nucleic acid • Made up of nucleotides • Single strand • THYMINE is rarely part of RNA. URACIL (another pyrimadine) replaces thymine in RNA. This means that URACIL, not thymine, pairs with ADENINE in RNA. • U=A
Types of RNA (all 3 help to make proteins) 1.MESSENGER RNA (mRNA) is made of a single, uncoiled chain. mRNA carries genetic info from the DNA in the nucleus to the cytosol of a eukaryotic cell.
Types of RNA, cont. 2. TRANSFER RNA (tRNA) is a single chain of RNA nucleotides folded into a hairpin shape that binds to specific amino acids.
Types of RNA, cont. 3. RIBOSOMAL RNA (rRNA) is the most common RNA. rRNA is made of RNA nucleotides that are in globular form. rRNA makes up the ribosomes where proteins are made.
TRANSCRIPTION • The process by which genetic info is copied from DNA to RNA • All 3 types of RNA are made in this process • Continues until the TERMINATION SIGNAL is reached • Think of using a variety of colored paper in the copy machine…
Recall that… • The making of proteins is called PROTEIN SYNTHESIS • PROTEINS are made of AMINO ACIDS that are linked together by PEPTIDE BONDS. • The function of the protein is decided by the amino acids that make it up.
GENETIC CODE • The relationship between a nucleotide sequence and an amino acid sequence is called the GENETIC CODE. • It is used to translate mRNA transcripts into proteins. • The genetic info needed for making proteins is encoded in a series of 3 mRNA nucleotides called a CODON.
Genetic Code, cont. • Each codon codes for a specific amino acid. • Some codons signal for translation of an mRNA to start or stop. • The START CODON (AUG) makes a ribosome start translating an mRNA molecule. • STOP CODONS (UAA, UAG, UGA) cause the ribosome to stop translating the mRNA.
9/14/11-Pick up your book. Student Summaries for Sat. School? Do-Now: DNA is made of small subunits called _____. Nucleotides have three parts. They are ___, ___, & ___. The sugar found in DNA is ________. According to Chargaff’s Rules (complementary base pairing rules), adenine pairs with ____ & _____ pairs with guanine. Purines have ___ ring(s) of carbon & nitrogen, while pyrimadines have ___ ring(s) of carbon & nitrogen. The copying of DNA is ______. If the original strand of DNA reads ACTGGCTA, the new strand will read _______ (replication). Any change in DNA is referred to as a _____.
TRANSLATION • The process of assembling polypeptides from info encoded in the mRNA • Begins when mRNA leaves the nucleus through pores in the nuclear membrane • mRNA migrates to a ribosome where protein synthesis takes place
Translation, cont. • Amino acids floating in the cytosol are brought to the ribosomes by the tRNA molecules • On the opposite side of the tRNA molecule (from where the amino acid is attached), there is a loop that has a sequence of 3 nucleotides called an ANTICODON. • The tRNA anticodon is complementary to and pairs with its corresponding mRNA codon. • For example, a tRNA with an anticodon of AAA would bind to the mRNA codon sequence of UUU.
Protein Assembly • Starts with start codon (AUG) • As a ribosome moves down an mRNA transcript, each mRNA codon is paired with its tRNAanticodon. • This causes an amino acid to attach, forming a peptide bond. • As each amino acid is added to the chain, the ribosome moves 3 nucleotides (1 codon) ahead on the mRNA transcript, where the next amino acid will be translated. • It ends with a stop codon.
Practice! DNA replication is taking place. The original strand is ACTGCATCA. The new strand will read _____. Transcription is taking place. Transcribe your DNA (answer) from #1 to make mRNA. Translation is taking place. Translate your mRNA (answer) from #2 to determine the amino acid sequence. Use the genetic code from your book or your notebook.
9/15/11-Get your book. Do-Now: Copying DNA to make new DNA is called ___. Copying DNA to make RNA is called ____. Using the information on mRNA to assemble amino acids to make proteins is called ___. The monomers of DNA & RNA are ____. The 3 parts of a nucleotide are __, __, & __. List the 3 types of RNA & what they do.
More Practice! DNA replication is taking place. The original strand is TAGCATGGGCAT. The new strand will read _____. Transcription is taking place. Transcribe your DNA (answer) from #1 to make mRNA. Translation is taking place. Translate your mRNA (answer) from #2 to determine the amino acid sequence. Use the genetic code from your book or your notebook.
9/28/10-Pick up your book. Do-Now: Complete the crossword puzzle on the back of your DNA word search. If you turned this into me, I have put it on your desk for you.
Quick Quiz • What are two differences between RNA and DNA? • What is transcription? • What is translation? • What is the genetic code used for?