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Homework for break Read Chapter 12 in textbook 2 Webquests Short Essay for second webquest typed.

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Presentation on theme: "Homework for break Read Chapter 12 in textbook 2 Webquests Short Essay for second webquest typed."— Presentation transcript:

1 Homework for break Read Chapter 12 in textbook 2 Webquests Short Essay for second webquest typed.

2 Homework Read beginning of chapter 12; complete workbook section 12.1! Do Now: 1.How is meiosis different than mitosis? 2.What is the macromolecule involved in storing information (be careful!)? 3.What are the monomers of this polymer?

3 DNA and RNA Genetics

4 Frederick Griffith 1928 Transformation Transformation - process in which one strain of bacteria is changed by a gene or genes from another strain of bacteria

5 Do Now Homework: workbook 12.2 w/ associated reading; have workbook 12.1 out to check 1. What did Griffith’s and Avery’s experiments prove? Give a brief paragraph explaining the importance of their findings.

6 Oswald Avery 1944 World knows a molecule carries the genetic information. Doesn’t know if the molecule is a: protein, lipid, carbohydrate, RNA, or DNA Avery performs Griffith’s experiment again with a twist. 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.

7 Hershey-Chase Experiment 1952 Good scientists are naturally skeptical. Hershey-Chase are testing to see if DNA is the molecule that carries genetic information. BacteriophageBacteriophage - virus that infects bacteria

8 Quiz Explain the importance of Griffith’s and Avery’s experiments in determining the molecule responsible for determining genetic inheritance… Homework: Section Assessment 1 and 2 of chapter 12 (LL)

9 Hershey-Chase Experiment

10 DNA Structure Nucleotide - monomer of nucleic acids made up of a 5- carbon sugar, a phosphate group, and a nitrogenous base

11 Sugar-Phosphate Backbone and Chargaff’s Rule Simply states: If I have a certain number of Cytosines I will have about the ______ number of Guanines. Same with A’s and T’s.

12 Rosalind Franklin 1950 X-Ray Diffraction Clues from the X-Ray –Coiled (forming Helix) –Double- stranded –Nitrogeneous bases are in the center

13 Watson & Crick Francis Crick – British physicist James Watson – American Biologist –Building a 3D model of DNA –Franklin’s X-Ray opened their eyes to the Double Helix Watson and Crick’s model of DNA was a double helix, in which two strands were wound around each other.

14 Double Helix

15 Homework Study Guide 12-1 and 12-2 1.List the conclusions and how each of these scientist got there: –Griffith –Avery –Hershey and Chase 2.How did Watson and Crick’s model explain why there are equal amounts of thymine and adenine in DNA? 3.Why did Hershey and Chase grow viruses in cultures that contained both radioactive phosphorus and radioactive sulfur? What might have happened if they only used one?

16 Prokaryote DNA Prokaryotes –No Nucleus one circular chromosome –Most have one circular chromosome located in the cytoplasm with some plasmids as well –E.Coli (1.6μm diameter) –4,639,221 base pairs 1.6mm long –Like packing 300m of rope in your backpack

17 Eukaryotes and DNA 1000 time more base pairs than bacterial DNA Smallest human chromosome has 30million base pairs of DNA How do eukaryotes fit all that DNA in its nucleus?

18 DNA to Chromosomes Vocab –Chromatin - granular material (uncondensed) within the nucleus; consists of DNA tightly coiled around proteins –Chromosomes – condensed chromatin –Histone - globular protein molecule around which DNA is tightly coiled in chromatin


20 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 of DNA serves as a template, or model, for the new strand.

21 Read 12-3 Crossword Puzzle

22 1.Enzymes unwind DNA 2.Enzymes split “unzip” double helix DNA polymerase, 3.The enzyme, DNA polymerase, finds and attaches the corresponding N- base 4.Each “old” stand serves as a template and is matched up with a new stand of DNA 5.New helixes wind back up.

23 DNA Replication A – C – T – T – G – G – A – C T – G – A – A – C – C – T - G

24 Homework 12-3 Study Guide Quiz (5 min. – LL)

25 RNA and Protein Synthesis Codon - three-nucleotide sequence on messenger RNA that codes for a single amino acid Anticodon - group of three bases on a tRNA molecule that are complementary to an mRNA codon

26 Protein Synthesis Two Main Parts Transcription –Formation of a single strand of messenger RNA from DNA in the nucleus Translation –Occurs on ribosomes –Cell uses the information on mRNA to assemble amino acids in the proper order to form specific proteins

27 Transcription 1.Occurs in nucleus 2.Enzymes unwind DNA 3.Enzymes split “unzip” double helix 4.RNA Polymerase binds to promoter sequence on DNA 5.RNA Polymerase transcribes a single strand of mRNA

28 mRNA Editing before going to transcription Intron - intervening sequence of DNA; does not code for a protein (not used) Exon - expressed sequence of DNA; codes for a protein (used)

29 Translation


31 Genes and Proteins Most genes only have instructions for assembling proteins. If that’s the case what do proteins have to do with eye color, hair color or height?


33 Homework Complete workbook section 12.3 and 12.4; study for quiz (E Day) Do Now: 1.Discuss DNA Replication. How is it related to RNA replication? List all the details you can in sequential order! 2.What happens when there are errors in “copying”? What are some of the ways we can fix this? What happens if we don’t?

34 Mutations Mutation - change in a DNA sequence that affects genetic information Two Main Types: –Gene Mutation Mutation that causes a change in a single gene –Chromosomal Mutation Mutation that causes a change in an entire chromosome

35 Gene Mutations Point Mutation (substitution) –mutation that affects a single nucleotide, usually by substituting one nucleotide for another Frameshift Mutation (insertion or deletion) –mutation that shifts the “reading” frame of the genetic message by inserting or deleting a nucleotide

36 Chromosomal Mutations Chromosomal mutations involve changes in whole chromosomes.

37 Homework: Check site!

38 Gene Regulation

39 Prokaryote Gene Regulation –Will often have one OPERATOR (regulatory site) controlling the expression of more than one gene. OPERON Eukaryote Gene Regulation –Most eukaryotic genes are controlled individually and have regulatory sequences that are much more complex than those of the lac operon

40 Gene Regulation Vocab Promoter - region of DNA that indicates to RNA polymerase where to bind to make RNA Operon - group of genes operating together Operator - region of chromosome within an operon to which the repressor binds when the operon is “turned off”

41 Lac Operon (E. coli) Operator bound – RNA polymerase can’t transcribe genetic information (not expressed) Operator free – gene(s) expressed

42 Eukaryote Gene Regulation DNA region about 30bp long TATATAAA: help to align RNA Polymerase Genes are regulated in a variety of ways by enhancer sequences

43 Gene Reg. and Development hox genes - series of genes that controls the organs and tissues that develop in various parts of an embryo Mutations affecting the hox genes in the fruit fly, Drosophila, for example, can replace the fly’s antennae with a pair of legs growing right out of its head!

44 1.What is meant by term base pairing? How is base pairing involved in DNA replication? 2.When a DNA molecule is replicated, how do the new molecules relate to the original molecule? 3.What is the difference between introns and exons? 4.What is a codon? Anticodon? How do they relate? 5.Explain why controlling proteins in an organism controls the organism’s traits. 6.Name two major types of mutations. What do they have in common? How are they different? Give an example of each. 7.The word transcribe means “to write out”, and the word translate means “to express in another language.” Review the meanings of transcription and translation in genetics. How do the technical meanings of these words relate to meanings of the words in ordinary language?

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