1. Warm-Up (10/27) Translate this mRNA sequence:
On the piece of white paper from the back, answer the following question.
Name
Date
Period
Translate this mRNA sequence:
5' AUGAACAAUAGAUAACCGUAG 3'

2. The Central Dogma, Revisited
Nucleus
DNA
“transcription”
cytoplasm
RNA
In prokaryotes, transcription is coupled to translation.
“translation”
Ribosome
protein

3. The Central Dogma, Revisited
Nucleus
DNA
“transcription”
In eukaryotes, RNA is post-transcriptionally processed
3’ poly-A tail added
5’ cap added
Introns are excised (cut out)
cytoplasm
RNA
“translation”
Ribosome
protein

4. Intron Excision
Happens in the nucleus

5. Independent Practice An mRNA has the sequence:
5’ AUGGCAGGGGAUAAGAAUCGCGCAAUUU
GCGGCGAAAAGCUAGGUCACACGAGUAA 3’
The red sequences are introns. Cut out the introns, then translate the processed mRNA into a protein.

6. Case Study: Lactose Intolerance
phenotype: the effect on an organism of a protein’s function.
H2O +
lactase gene
Lactose
Glucose
Galactose
lactase mRNA
High lactase activity = lactose tolerant
Low lactase activity = lactose intolerant
Lactase protein
(an enzyme)
Lactose

7. Case Study: Lactose Intolerance
Northern European peoples began domesticating cows for milk ~7,000 years ago. Other peoples have historically relied much less on milk.
Lactose

8. Independent Practice
page 350 numbers 2, 3, 5, 6, 7

9. Closure (10/27)
On the piece of white paper from the back, answer the following question:
Name
Date
Period
What would happen to a person if the third codon of lactase was mutated from UAU to UAG?
Scale 1 – 10