2.How are proteins made in a cell? Do Now- Review! 1.What controls cell activity? 3. Where do you receive your genetic information? 4. What is a nucleic acid?

What is DNA? It is the genetic information that is passed from generation to generation. Where is it found? It is found in the nucleus of every living cell. No DNA = Death! Does every single cell in our body have the same DNA? Yes!!! But WHY????

THE BUILDING BLOCKS OF DNA: Nucleotides Nitrogenous Bases (A T G C) Sugar: Deoxyribose Phosphate Group PHOSPHATE GROUPS SUGARS NITROGEN BASES

Nitrogenous Bases 1.Adenine 2.Thymine These pairs 3.Guanine 4.Cytosine Represented as interlocking shapes and are joined to the sugar of the nucleic acid A T

ATCGATCG A Adenine T Thymine C Cytosine G Guanine SUGAR- PHOSPHATE BACKBONE NUCLEOTIDE HYDROGEN BONDS A T C G

Who discovered the shape of DNA? Watson and Crick -- Won The Nobel Prize What do they call this model? A Double Helix Made of: 2 Strands of alternating Sugar & Phosphate molecules ( sides of ladder ) Held together by 4 nitrogen bases. (A-T G-C) ( rungs of ladder ) SUGAR- PHOSPHATE BACKBONE NUCLEOTIDE HYDROGEN BONDS

A always pairs with T G always pairs with C on your paper, try to figure out the 2 nd, complimentary DNA strand for this: AGGGCTTACACATTT TCCCGAATGTGTAAA

THE FUNCTION OF DNA What is replication: Making an exact copy. When would DNA need to do this? How does it happen?

The replication of DNA The process of DNA replication occurs with three important enzymes! Helicase Polymeras e Ligase Replication Replication Clip 1 ClipClip 2

A G A T G C T C T A C G T T A A C C A A T T G G 5’ 3’ Parent DNA Molecule DNA Helicase Enzyme 3’ 5’

A G A T G C T C T A C G T T A A C C A A T T G G 3’5’ 3’ DNA Helicase Enzyme

A C G T T DNA Polymerase Enzymes A G A T G C T C T A A C C A A T T G 3’ 5’ 3’ 5’ G

T T New Strands of DNA A G A T G C T C T A C G A A C C A T A T G 3’ 5’ 3’ 5’ G C C A A Free Nucleotides C A A C G T

T T New Strands of DNA A G A T G C T C T A C G A A C C A T A T G 3’ 5’ 3’ 5’ G C C A A C A A C G T A A T T T

On the “Leading Strand” DNA Polymerase continuously adds new nucleotides, as it follows DNA Helicase On the “Lagging Strand” DNA Polymerase runs in the opposite direction of the Helicase, and therefore must make a series of discontinuous pieces (or fragments). 3’ 5’ A G A T G C T A C G T T A A C C A T T A G G 3’ 5’ T C T A C G T T A A C C A T T 3’ 5’ A G G

3’ 5’ A G A T G C T A C G T T A A C C A T T A G G 3’ 5’ T C T A C G T T A A C C A T T 3’ 5’ A G G

3’ 5’ A G A T G C T A C G T T A A C C A T T A G G 3’ 5’ T C T A C G T T A A C C A T T 3’ 5’ A G G

3’ 5’ A G A T G C T A C G T T A A C C A T T A G G 3’ 5’ T C T A C G T T A A C C A T T 3’ 5’ A G G

3’ 5’ A G A T G C T A C G T T A A C C A T T A G G 3’ 5’ T C T A C G T T A A C C A T T 3’ 5’ A G G

3’ 5’ A G A T G C T A C G T T A A C C A T T A G G 3’ 5’ T C T A C G T T A A C C A T T 3’ 5’ A G G

T 3’ 5’ A G A T G C T A C G T T A A C C A T T A G G 3’ 5’ T C T A C G T T A A C C A T T 3’ 5’ A G G C T A G A

T 3’ 5’ A G A T G C T A C G T T A A C C A T T A G G 3’ 5’ T C T A C G T T A A C C A T T 3’ 5’ A G G C T A G A 3’ G C

T 5’ A G A T G C T A C G T T A A C C A T T A G G 3’ 5’ T C T A C G T T A A C C A T T 3’ 5’ A G G C T A G A 3’ G C

T 5’ A G A T G C T A C G T T A A C C A T T A G G 3’ 5’ T C T A C G T T A A C C A T T 3’ 5’ A G G C T A G A 3’ G C On the “Lagging Strand” DNA Polymerase Leaves a gap in the backbone of the newly Forming strand because It is unable to form the Last covalent bond In the backbone. 3’

DNA Ligase enzyme can connect the two fragments by forming a covalent bond between them. T 3’ 5’ A G A T G C T A C G T T A A C C A T T A G G 3’ 5’ T C T A C G T T A A C C A T T 3’ 5’ A G G C T A G A 3’ G C

T 5’ A G A T G C T A C G T T A A C C A T T A G G 3’ T C T A C G T T A A C C A T T 5’ A G G C T A G A 3’ G C We now have two identical daughter molecules of DNA, and the cell is ready for a Mitosis or a Meiosis division.

DNA Replication DNA copies itself to allow mitosis and meiosis to occur; it passes genetic info on to the new cells Steps in replication: DNA Molecule DNA “Unzips” Free nucleotides join the unzipped strands A TATATAT T ATATATA C GCGCGCG

Functions of Nucleic Acids 1.DNA- Contains the hereditary material inside nucleus 2.RNA- directs the synthesis of proteins made of Nucleic Nucleotides Nitrogenous AcidsBases (A,T,C,G)

How is RNA different from DNA? -“U” base, ribose, single stranded What are the subunits of RNA? Nucleotides – similar to DNA Sugar -- Ribose Nitrogenous Base Phosphate

RNA – RiboNucleic Acid Made of nucleotides too, but some differences: A = Adenine C= Cytosine U = Uracil G = Guanine Sugar = Ribose Phosphate Group

Transcription: The making of mRNA from DNA biomovies\DNAtran scription.mov Transcription Clip

Steps in Transcription DNA DNA Codon mRNA Template A TAU GC every 3 nit base is a GC Codon CG template for Codon CG CGCG TA Unzips TA Codon AT (Template used to make mRNA) AU Codons will go to the ribosome to be “read” It is the nitrogenous bases that determine the codon! Template strand “Transcription” Unzips at weak H bond

Transcription Animation Shared Server

3 Types of RNA 1. mRNA Messenger RNA Transcribed from the DNA template, to make single stranded RNA Is made in the nucleus Travels through the Cytoplasm and then to the ribosome/ Found all over the cell

2. tRNA Transfer RNA Translates the 3 letter codon of the mRNA to the tRNA molecule Anticodon- Codon (tRNA) (mRNA) Found in the Cytoplasm and at the ribosome

3. rRNA Ribosomal RNA Hold the “m” and “t” together Found at the Ribosome

biomovies\DNAtra nslation.mov Translation Clip TRANSLATION

Review of Proteins: What do we already know?? 1.DNA is a code. The code is found in a sequence of 2. These are instructions for making a 3. Polypeptide is another name for a 4.Proteins are long chains of 5.Proteins make up 6. Proteins are made in the nucleotides protein Amino acids Muscles, hair/ fur, nutrient storage. Enzymes ribosome

Translation- Protein Synthesis Steps in making a protein! 1.DNA lives in the nucleus and carries the code to make the proteins! 2.The double helix was split and “read” to make mRNA. 3.This copy is unlike DNA because it is single stranded and contains uracil! 4.mRNA now takes the code to free ribosome in the cytoplasm

5. The ribosome can only read 3 letters at a time- called CODONS. 6. Each time the ribosome reads 3 letters, it calls for tRNA – the anti codon. 7. The tRNA is carrying an amino acid! There are hundreds of tRNAs. So if the codon for the mRNA is GGG- ribosome tells tRNA to bring the opposite code of CCC 8. Now amino acids are linking together forming peptide bonds!

DNA mRNA Protein Transcription Translation

Amino Acids t-RNA’s m-RNA 3’ 5’ Ribosome START CODON

Amino Acids t-RNA’s m-RNA 3’ 5’ START CODON Peptide bond forms Ribosome

Amino Acids t-RNA’s m-RNA 3’ 5’ Ribosome

Amino Acids t-RNA’s m-RNA 3’ 5’ Ribosome

Amino Acids t-RNA’s m-RNA New Protein 3’ 5’ Ribosome

Amino Acids t-RNA’s m-RNA New Protein 3’ 5’ Ribosome

Amino Acids t-RNA’s m-RNA New Protein 3’ 5’ Ribosome

Amino Acids t-RNA’s m-RNA New Protein 3’ 5’ Ribosome

Amino Acids t-RNA’s New Protein 3’ 5’ Ribosome

Amino Acids t-RNA’s 3’ 5’ New Protein STOP CODON Ribosome

Amino Acids t-RNA’s m-RNA New Protein 3’ 5’

Amino Acids t-RNA’s m-RNA New Protein 3’ 5’ NH 2 COOH

3’ 5’ GAC CUG GAC AMINO ACID = ASPARTATE AMINO ACID = LEUCINE

Gene Expression 20,000 to 25,000 different genes on 46 chromosomes (23 paired) Every cell arises from 1 st cell (zygote) How do we get different types of cells? Only certain genes are used in certain cells. The use of info from a gene = gene expression. Proteins are made only from genes that are exposed or “turned on.” All other genes are silent, or “turned off.” Homeotic genes do the turning on/off Creating different/specialized cells through gene expression is called cell differentiation (without this, you would be made of only one type of cell).

The effect of the environment on gene expression: The environment CAN affect how a gene is expressed! 1.The more intense the light, the more chlorophyll is produced in a plant. (If parts of a plant are blocked from the light, chlorophyll decreases and the plant turns brown). 2.Himalayan rabbits- if some of their white fur is shaved and an ice pack is placed on it, the hair grows back black! The gene for black fur is “turned on” at low temperatures. 3. Identical twins- if separated at birth and raised in different environments, there will be differences in appearance (skin shades, weight, and height).

Ok, so what kinds of things can go wrong????

Gene Mutations! Any change in the order of bases on the DNA is a gene mutation. What are some kinds of mutations? Substitution- 1 letter or gene changed Deletion- 1 or more letters deleted Addition- 1 or more letters added Inversion- wrong order