Transcription - Liberty Union High School District

Warm Up Questions

1. Where is DNA located? 2. Name the 3 parts of a nucleotide.

3. Enzymes can catalyze many different reactions (T or F)

4. How many variables should you have in an experiment?

5. A red flower and a white flower create all pink offspring. This is an example of what kind of inheritance?

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Unit: DNA

Transcription

Targets

11. I can list the 3 steps of the central dogma

12. I can explain what genes are

13. I can explain how all cells have DNA but look different and have different functions

14. I can explain the role of DNA and mRNA in transcription

15. I can identify where transcription happens in the cell

16. I can explain what happens in transcription

17. I can write the mRNA strand for the DNA sequence 5' ACGTTACAG 3'

Central Dogma

Information flows in one direction:

1. Replication copies DNA

2. Transcription converts DNA into RNA

3. Translation interprets RNA message into string of amino acids or proteins

What is a gene?

A section of DNA that contains instructions on how to make a specific protein.

Each gene has a locus (location) on DNA Alleles are different forms of a gene DNA located in the nucleus only

What is transcription?

Process of copying a sequence of DNA (gene) to produce strand of RNA

RNA is a copy of a gene, not the entire strand of DNA. Strand of RNA is complementary to DNA strand Small segment can exit nucleus into cytoplasm

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Steps of Transcription

1. RNA Polymerase recognizes the start of the gene, attaches to the DNA strand and begins to unwind and unzip using helicase.

2. RNA Polymerase adds RNA nucleotides to section of DNA being used as template.

3. Transcription complex moves along DNA, adding nucleotides, until complete gene is copied.

4. Complete mRNA strand breaks off and moves out of nucleus.

What does transcription produce?

mRNA ? message that is ultimately translated into a protein

Practice transcribing...... Don't forget to swap U for T

DNA: A C G T T A C A G RNA: U G C A A U G U C



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Reflection #2

Define Replication: Create the complementary strand for the DNA

sequence:

(original) A G C C T C A G T T C A G

(new)

Define Transcription: Translate the complementary strand from above into

mRNA:

(new)

(mRNA)

Warm up:

1. The cell membrane allows certain things to pass through. We call this ________?

2. Which organelle builds proteins? 3. Which organelle packages and ships products made by the cell? 4. What is a gene? 5. Cell wall is found in what type of cell?

Unit 5: DNA

Translation

Targets:

18. I can explain how translation works and where it happens in a cell. 19. I can write the amino acid sequence for the DNA strand 5' ACGTTACAG 3'

Central Dogma

Information flows in one direction:

1. Replication copies DNA

2. Transcription converts DNA into mRNA

3. Translation interprets RNA message into string of amino acids or proteins

Review

Replication duplicates an entire strand of DNA DNA to DNA

DNA base pair rules A = T C = G T=A G=C

Original: A T C C G T A A C T G New: T A G G C A T T G A C

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Transcription creates a copy of DNA segment (gene) called mRNA DNA to RNA

RNA base pair rules A = U C = G T=A G=C

DNA: G T A T C C G T T A C G A mRNA:C A U A G G C A A U G C U

Translation: the mRNA strand moves out of the nucleus and into the cytoplasm where ribosomes translate the message into a string of amino acids called proteins

Steps in Translation:

1. mRNA leaves nucleus, attaches to ribosome in cytoplasm

2. A codon enters the ribosome codon = 3 bases on mRNA strand, also called a `triplet'

3. Anticodon (tRNA) brings the correct amino acid for that codon anticodon = complementary bases for mRNA codon

Has bases on one end And the amino acid on the other end

4. Amino acids are joined together by peptide bonds

Peptide bonds = 2 atoms share electrons

5. Process continues until STOP codon is reached. Protein strands break off and head to Golgi Bodies where they are folded into its proper shape.

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Ribosome reads mRNA codes 3 at a time. Chart is used to convert mRNA triplet into amino acids.

mRNA: U G G U A C A U G

AAcids: Trp ? Tyr - Met

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20 different amino acids = thousands of different proteins

How many letters in the alphabet? 26 How many words can those 26 letters make? Thousands

20 different amino acids strung together in different combinations and lengths can create thousands of different proteins.

Reflection #3 1. Replicate the following strand of DNA

code:

Original: A T T C G A A G C C C T A A G

New: 2. Transcribe the new strand into mRNA: New: (copy from above) mRNA: 3. Translate the mRNA code into amino

acids (remember to mark your triplets) mRNA: (copy from above) Amino Acids:

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