Happy Tuesday! – 2/9 In this model, weak hydrogen bonds connect which of the following? A G to C B x to y C y to G D G to T

DNA, Protein Synthesis, and Gene Expression Video clip - http://www.youtube.com/watch?v=41_Ne5mS2ls This PowerPoint has many animated slide progressions. You may only want to print the following slides: 1-11; 33-47; 62; 64-65

Two Types of Nucleic Acids 1. DNA 2. RNA a. mRNA (messenger) b. tRNA (transfer)

Where are proteins made? Ribosomes

Compare DNA & RNA DNA: deoxyribonucleic acid DNA is double stranded. Contains sugar deoxyribose. DNA contains bases adenine, thymine, guanine, cytosine. DNA never leaves the nucleus. RNA: ribonucleic acid RNA is single stranded. Contains sugar ribose. RNA contains bases adenine, URACIL, guanine, cytosine. RNA can leave the nucleus. This is a review of DNA and RNA. The slide is animated; each statement comes up automatically

Overall process of Protein Synthesis transcription translation During gene expression, the information in DNA is first transcribed in the nucleus as a molecule of mRNA and then translated in the cytoplasm and used to build a protein. DNA mRNA Protein

DNA’s tragedy DNA DNA contains volumes of information about making protein. Unfortunately, DNA is too huge to leave the nucleus. Remind students that DNA holds the instructions for making the protein but it cannot leave the nucleus. However, the proteins are made in the ribosomes. ribosomes nucleus

How does the cell solve this problem….transcription That’s where mRNA comes in. mRNA helps get DNA’s message out to the ribosomes... DNA mRNA A mRNA copy of DNA is transcribed (made) because mRNA can leave the nucleus and take the message to the ribosomes.

First, DNA unzips itself... ATGACGATT TACTGCTAA DNA unzips itself, exposing free nitrogen bases. The slide is animated; the DNA unzips automatically

First, DNA unzips itself... ATGACGATT TACTGCTAA DNA unzips itself, exposing free nitrogen bases. The slide is animated; the DNA unzips automatically

First, DNA unzips itself... ATGACGATT TACTGCTAA DNA unzips itself, exposing free nitrogen bases. The slide is animated; the DNA unzips automatically

First, DNA unzips itself... ATGACGATT TACTGCTAA DNA unzips itself, exposing free nitrogen bases. The slide is animated; the DNA unzips automatically

First, DNA unzips itself... ATGACGATT TACTGCTAA DNA unzips itself, exposing free nitrogen bases. The slide is animated; the DNA unzips automatically

Transcription The process of going DNA to mRNA Occurs in the nucleus

Transcription c. Steps of Transcription: 1. First DNA unzips itself along the segment of code (gene) needed for a certain protein. 2. mRNA is made by forming complementary bases on the unzipped portion of DNA.

Transcription 3. DNA’s code is copied into groups of 3 bases at a time called a codon. 4. Each codon codes for 1 amino acid. 5. Once the mRNA strand is transcribed, it leaves the nucleus to find a ribosome.

Next, mRNA is made... ATGACGATT mRNA is made from the DNA template mRNA matches with free DNA nitrogen bases in a complimentary fashion Have students notice that the mRNA is made from ONE side of the DNA molecule The slide is animated; the DNA unzips automatically

Next, mRNA is made... U ATGACGATT mRNA is made from the DNA template mRNA matches with free DNA nitrogen bases in a complimentary fashion The slide is animated; the RNA bases automatically pair up with DNA

Next, mRNA is made... U ATGACGATT mRNA is made from the DNA template mRNA matches with free DNA nitrogen bases in a complimentary fashion The slide is animated; the RNA bases automatically pair up with DNA

Next, mRNA is made... UA ATGACGATT mRNA is made from the DNA template mRNA matches with free DNA nitrogen bases in a complimentary fashion UA The slide is animated; the RNA bases automatically pair up with DNA

Next, mRNA is made... UA ATGACGATT mRNA is made from the DNA template mRNA matches with free DNA nitrogen bases in a complimentary fashion UA The slide is animated; the RNA bases automatically pair up with DNA

Next, mRNA is made... UAC ATGACGATT mRNA is made from the DNA template mRNA matches with free DNA nitrogen bases in a complimentary fashion UAC The slide is animated; the RNA bases automatically pair up with DNA

Next, mRNA is made... UAC ATGACGATT mRNA is made from the DNA template mRNA matches with free DNA nitrogen bases in a complimentary fashion UAC The slide is animated; the RNA bases automatically pair up with DNA

Next, mRNA is made... UACU ATGACGATT mRNA is made from the DNA template mRNA matches with free DNA nitrogen bases in a complimentary fashion UACU The slide is animated; the RNA bases automatically pair up with DNA

Next, mRNA is made... UACU ATGACGATT mRNA is made from the DNA template mRNA matches with free DNA nitrogen bases in a complimentary fashion UACU The slide is animated; the RNA bases automatically pair up with DNA

Next, mRNA is made... UACUG ATGACGATT mRNA is made from the DNA template mRNA matches with free DNA nitrogen bases in a complimentary fashion UACUG The slide is animated; the RNA bases automatically pair up with DNA

Next, mRNA is made... UACUG ATGACGATT mRNA is made from the DNA template mRNA matches with free DNA nitrogen bases in a complimentary fashion UACUG The slide is animated; the RNA bases automatically pair up with DNA

Next, mRNA is made... UACUGC ATGACGATT mRNA is made from the DNA template mRNA matches with free DNA nitrogen bases in a complimentary fashion UACUGC The slide is animated; the RNA bases automatically pair up with DNA

Next, mRNA is made... UACUGC ATGACGATT mRNA is made from the DNA template mRNA matches with free DNA nitrogen bases in a complimentary fashion UACUGC The slide is animated; the RNA bases automatically pair up with DNA

Next, mRNA is made... UACUGCU ATGACGATT mRNA is made from the DNA template mRNA matches with free DNA nitrogen bases in a complimentary fashion UACUGCU The slide is animated; the RNA bases automatically pair up with DNA

Next, mRNA is made... UACUGCU ATGACGATT mRNA is made from the DNA template mRNA matches with free DNA nitrogen bases in a complimentary fashion UACUGCU The slide is animated; the RNA bases automatically pair up with DNA

Next, mRNA is made... UACUGCUA ATGACGATT mRNA is made from the DNA template mRNA matches with free DNA nitrogen bases in a complimentary fashion UACUGCUA The slide is animated; the RNA bases automatically pair up with DNA

Next, mRNA is made... UACUGCUA ATGACGATT mRNA is made from the DNA template mRNA matches with free DNA nitrogen bases in a complimentary fashion UACUGCUA The slide is animated; the RNA bases automatically pair up with DNA

Next, mRNA is made... ATGACGATT UACUGCUAA mRNA is made from the DNA template mRNA matches with free DNA nitrogen bases in a complementary fashion Remind students that the RNA strand has Uracil instead of Thymine and that the Uracil pairs up with Adenine.

Translation The process of going mRNA to proteins Occurs in the cytoplasm Involves tRNA Every tRNA has one anti-codon and one amino acid.

Translation e. Steps of Translation: 1. Ribosome reads mRNA and brings in matching tRNA. 2. The codon of mRNA bases pairs to anti-codon of tRNA. 3. tRNA drops off amino acid to ribosome and then float away. 4. Ribosome pieces together amino acids to build proteins.

Regulation of Transcription and Translation Think about your house, do you keep all the lights on ALL the time in every room?? Gene expression is a regulated process where genes can be turned on and off as needed due to environmental factors.

In summary… DNA contains the information needed to make proteins. However, DNA is too large to leave the nucleus. RNA carries instructions to ribosomes so they can make proteins. Gene expression is a regulated process.