Do Now

1. Where is the DNA located in the cell?

2. Where are the proteins made in the cell?

3. How do you think the information gets between these two places?

• Topic: DNA to proteins• Essential question: How is DNA the

instructions for making my body?

What are proteins made out of?

• Proteins are long chains of amino acids. Proteins can be made out of 100s to 100,000s of amino acids

• Many proteins are actually several proteins (chains of amino acids) put together

• There are 20 types of amino acids

Turn and talk

• Explain to your neighbor: What is the difference between a cell in your eye and a cell in your knee?

• Topic: Transcription and translation• Essential question: How is DNA

turned into proteins?

• DNA makes proteins in a two step process

• First, DNA is transcribed into RNA• Second, RNA is translated into amino

acids

• RNA is: (ribonucleuic acid)– A long chain of nucleotides• Phosphate• Sugar is ribose• Bases are G, C, A, and U (uracil)

– A single strand (DNA is a double strand)– Can leave the nucleus– Not self-replicating (DNA is self replicating)– A temporary copy of DNA

On your white boards

Make a Venn diagram for DNA and RNA

DNA RNA

Do Now

Go back to your “DNA to proteins” notes from yesterday (the first ones, not the second ones). Write a summary underneath your notes. I will stamp your summaries in three minutes.

Types of RNA

• mRNA – messenger RNA. Is a copy of the DNA.

• tRNA – transfer RNA. Brings the amino acid to the ribosome

• rRNA – ribosomal RNA. ribosomes are made out of RNA and protein.

Which is RNA? How do you know?

1. 2.

Transcription

• Transcription is making a RNA copy of the DNA• It happens in the nucleus• Steps1. Unzip the DNA2. mRNA nucleotides match to DNA nucleotides3. mRNA detaches from the DNA4. mRNA leaves the nucleus

Transcription

Transcription

Transcription (h)

• Transcription is making a RNA copy of the DNA• It happens in the nucleus• Steps1. The enzyme RNA polymerase binds to a region of DNA right before the gene called a promoter 2. RNA polymerase makes a RNA copy of the DNA using complementary base pairing. This copy molecule is called precursor mRNA

Transcription

• http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/transcription.swf

Why precursor mRNA?

• Genes consist of regions called introns and exons. Exons are part of genes that become the protein, and introns do not.

• Enzymes called splicesomes splice out the introns from the precursor mRNA

• The result is mRNA, which is ready to make a protein

• http://www.dnalc.org/resources/3d/rna-splicing.html

On your white board

• What is the mRNA that matches this strand of DNA (sequence for hemoglobin)?

A T G G T G C A C C T G A C T

Transcription

Just transcriptionhttp://www.youtube.com/watch?v=5MfSYnItYvg

Translation1. mRNA attaches to the ribosomes2. mRNA is read in three-letter words called

“codons”3. tRNA brings the amino acid that matches the

mRNA (remember, they are both RNAs, so can match nucleotides)

4. The chain of amino acids grows as the mRNA moves down the ribosome, three bases at a time

5. When the ribosome reaches the end of the mRNA, the chain of amino acids (protein) detaches from the ribosome and goes off to do its job in the cell.

• http://www.youtube.com/watch?v=8dsTvBaUMvw

• What is the amino acid sequence made from this RNA (for hemoglobin)?

U A C C A C G U G G A C U G A G G A C

Do Now1. What color is the DNA in this picture?2. What color is the RNA in this picture?3. What color is the RNA polymerase in this

picture?

• http://www.youtube.com/watch?v=8dsTvBaUMvw