1. Do Now: Label as much as you can:

3. Focus Question: How does DNA express phenotype?
IB Topic 3.5 Transcription and Translation
Overview Animation

4. Transcription/Translation
Transcription- the making of RNA from DNA
Translation- reading the RNA code to make proteins

5. DNA vs. RNA DNA Deoxyribonucleic Acid 2 strands- double helix Sugar
Deoxyribose
Bases
A, C, T, G
RNA
Ribonucleic Acid
Single strand
Sugar
Ribose
Bases
A, C, U, G

6. RNA strand contains a new base
U = uracil
Takes the place of T in DNA.
An “A” in DNA will generate a complimentary “U” in RNA.

7. Types of RNA: rRNA: ribosomal RNA- tRNA: transfer RNA
Major component of ribosomes
tRNA: transfer RNA
Carries amino acids to mRNA
An interpreter in translation
mRNA: messenger RNA
Encodes genetic info from DNA and convey it to the ribosomes, where the info is translated into amino acid sequences

8. IB Topic 3.5- Transcription and Translation
The process by which RNA is made from a DNA template
Purpose: to read the DNA, one gene at a time. RNA polymerase starts transcription.
Complimentary RNA strand is formed
RNA is assembled in the 5’ 3’ direction
Bubbles open- instead of unzipping/unwinding
2.6.2

9. DNA “words”… DNA gives instructions.
The instructions are written in a language where words are ALWAYS three base pairs long.
Ex: AAT,CCG,GCA,TTC, etc.
Each is called a triplet.

10. Triplets on DNA make Codons on mRNA
Codon- genetic code made of one triplet of bases.
Codons are found on mRNA (messenger RNA)

11. Formation of mRNA
Creates a “mirror image” of the triplets found on DNA (except TU)
mRNA then travels out of the nucleus and toward a ribosome.
This is called transcription

12. New Enzyme- RNA Polymerase
Links together the growing chain of RNA nucleotides during transcription
Uses DNA as template
Similar to DNA polymerase but only facilitates a reaction on one side of the strand
Animation

13. Once at the ribosome
Translation starts

14. Steps of Translation mRNA codons get “read” by the ribosome.
tRNA brings matching anticodon to codon.
Amino acid associated with that tRNA drops onto polypeptide chain
AUG is the start codon

15. CodonAmino Acid
Use a codon chart to determine which AA’s are being made
Example:

16. Polypeptide Polypeptide- a string of amino acids.
Ex: leu-cys-ser-tryp-leu
Intro to translation

17. Why make proteins?
Proteins make up most tissue in your body – skin, all organs, muscles, etc. Proteins make you who you are.

18. Protein synthesis = Translation
Ribosomes- synthesize protein (polypeptide chains) in a process called Translation.

19. The Code is Degenerate
Degenerate- each amino acid can by synthesized by more than one codon.
Ex: both UUU and UUC make phenylalanine

20. The code is universal
The same codons are found in all living organisms.

21. What section of DNA makes one polypeptide?
One gene  one polypeptide
A “gene” is defined as such because it contains the code for making ONE polypeptide.
Each polypeptide can draw its origins back to ONE gene.
One gene one polypeptide hypothesis

23. Animation!!