Transcription and Translation

Transcription occurs in the nucleus.

In Translation, proteins are made from RNA.

What you will learn today

In Transcription, DNA is copied to make a strand of RNA.

Translation occurs in the ribosome.

Codons are 3 nucleotides that code for an amino acid, which then make proteins.

The Gene Scene: http://www.youtube.com/watch?v=xc2wbIDfO7E

DNA Structure video: http://www.youtube.com/watch?v=qy8dk5iS1f0&feature=player_embedded

Full Name Sugar StructureNitrogen Bases

Deoxyribonucleic Acid

Ribonucleic Acid

Deoxyribose Ribose

Double Stranded Single Stranded

A, T, C, GA, U (Uracil), C, G

Location

Picture

Nucleus

Outside of the nucleus (ribosome)

DNARNAProtein

• DNA has the instructions for the order of amino acids which determines the proteins that make up the traits (including physical characteristics such as height, eye color, hair color, etc.) of any organism.

Function: A single strand of RNA is made from DNA.

DNA RNALocation: Nucleus

The DNA is kept safe in the nucleus while the RNA is sent out into the cell to direct the building of proteins

http://www.concord.org/~btinker/workbench_web/models/eukTranscription.swf

1. RNA polymerase (an enzyme) attaches to DNA at a special sequence that serves as a “start signal”.

2. The DNA strands are separated and one strand serves as a template.

3. The RNA bases attach to the complementary DNA template, and mRNA is made!

4. The RNA polymerase recognizes a ‘stop’ part on the DNA molecule and releases the new mRNA molecule.• (mRNA leaves the nucleus

and travels to the ribosome in the cytoplasm.)

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

Transcribe this strand of DNA into RNA (Transcription!):

DNA: AATCTAGATCATTARNA:________________

*Remember: There are no ‘T’s in RNA!

Function: Pieces of RNA make amino acids, which then make proteins.

RNA ProteinsLocation: Ribosome

http://www.concord.org/~btinker/workbench_web/models/eukTranscription.swf

There are different types of RNA:

mRNA: messenger RNACarries a message (genetic code) from the nucleus to the ribosome (how to make proteins)

tRNA: transfer RNATransports amino acids to the ribosome

1. mRNA leaves the nucleus and binds to a ribosome.

2. The ribosome looks for codons.

Codon: group of 3 nucleotides on the messenger RNA that specifies one amino acid.

3. tRNA (transfer RNA) carries Amino Acids to the mRNA.

4. This tRNA has an anticodon that matches the codon on the mRNA strand.

Anticodon: group of 3 unpaired nucleotides on a tRNA strand.

5. Each amino acid is dropped off and a chain forms. When the chain is completed, it disconnects and makes a protein!

Interactive animations : •http://www-class.unl.edu/biochem/gp2/m_biology/animation/gene/gene_a3.html•http://www.stolaf.edu/people/giannini/flashanimat/molgenetics/translation.swf

The mRNA sequence reads the following codons. What amino acids do they stand for?

AUGGGAGAGCAA What amino acid does the anticodon CGU stand for?

Find the amino acid sequence for the following mRNA sequence (translation):

AUGCGACGAAUUUAA

First-- Transcribe this strand of DNA into mRNA:

DNA: AATCTAGATCATTAC

RNA:________________*Remember: There are no ‘T’s in RNA!

Second—Translate that strand of mRNA into amino acids.

DNA: AATCTAGATCATTACRNA: UUAGAUCUAGUAAUGAA: ___ ___ ___ ___ ___

Second—Translate that strand of mRNA into amino acids.

DNA: AATCTAGATCATTACRNA: UUAGAUCUAGUAAUGAA: Leu Asp Leu Val Met

Transcription

Translation

mRNA

Ribosome

Proteins

Nucleus

RibosomeAmino Acids