1. Transcription
Mrs. Harper
2/15/18
Biology

2. February 15, 2015 Begin working on Do Now
Have homework (DNA Replication WS) out

3. Do Now 12/2/15 Which nitrogen base pairs with which other?
What is the difference between purines and pyrimidines?
What type of bonds hold the nitrogen bases together?
What type of bonds hold the sugar and phosphates together?
What does helicase do?
What is the function of DNA ligase?
What are the segments in the lagging strand called?

4. Process following DNA Replication, Converts DNA into RNA
Transcription
Process following DNA Replication,
Converts DNA into RNA

5. The Central Dogma
DNA RNA  Proteins
Transcription
Translation

6. Transcription
Transcription is the synthesis of an RNA strand from a DNA template.
DNA transcribed to messenger RNA (mRNA).
mRNA carries the code from DNA to the ribosomes where translation occurs

7. DNA vs RNA Double stranded Deoxyribose sugar Contains thymine
Single stranded
Ribose sugar
Contains uracil (NOT thymine)
COMMON TRAITS (place these in the middle)
-Both have bases A, G, C
-Both are nucleic acids

8. 3 Types of RNA:
Messenger RNA: (mRNA) carries nucleotide sequence from nucleus to ribosome
Transfer RNA: (tRNA) picks up amino acid in cytoplasm and carries them to ribosome
Ribosomal RNA: (rRNA)found in ribosome, joins mRNA and tRNA; forms protein

9. Synthesis of an RNA Transcript
The three stages of transcription are:
Initiation
Elongation
Termination

10. Initiation
RNA polymerase binds to DNA at a specific sequence of nucleotides called the promoter.
The promoter contains an initiation site where transcription of the gene begins.
RNA polymerase then unwinds DNA at the beginning of the gene.

11. Elongation
RNA polymerase synthesizes a single strand of RNA complementary to the DNA template strand adding to the 3’ end of the RNA chain
As RNA polymerase moves along the DNA it continues to untwist the double helix.
Elongation
RNA
polymerase
Non-template
strand of DNA
RNA nucleotides
3 end C A E G U T 3 5
Newly made
Direction of transcription
(“downstream”)
Template

12. Termination
RNA polymerase continues to elongate until it reaches the terminator, a specific sequence of nucleotides that signals the end of transcription.
Transcription stops and RNA polymerase and the new mRNA transcript are released from DNA.
The DNA double helix reforms.

13. Transcription Overview

14. Practice Transcribing
Create the complementary mRNA strand for each DNA strand
(remember use U instead of T when pairing A)
DNA strand 5’ ACTAGCTA 3’
mRNA strand
DNA strand 5’ TTCCAGCA 3’

15. Assignment
Complete the Transcription Homework independently on Code Red
Unfinished classwork will become homework