1. Recall that cells use DNA to make protein
Recall that cells use DNA to make protein. This process is called protein synthesis.

2. Protein Synthesis
To make
The process by which cells make protein by polymerizing amino acids following the instructions in their DNA. C P P A A D

3. Protein synthesis is performed by ribosomes.G A G T C A G G

4. There are a couple of things that make protein synthesis difficult.

5. 1. DNA is stored in the nucleus, but is needed by ribosomes.
DNA can’t leave the nucleus – that would disrupt the cell cycle!
Make a copy of the DNA that can leave the nucleus!

6. 2. The DNA message is written in a code.
A C C G C G C T A T C A G C G A T T A C A!
Make some antibodies, dumba$$
Bro I got no idea what ur sayin’
Translate the message!

7. Protein synthesis happens in two parts: transcription and translation.
Ribosome

8. Transcription m
Ribosome
Making a copy of DNA, called mRNA, that can leave the nucleus. C M L N
messenger

9. Translation When a ribosome uses mRNA to make protein. Polymerize AA’s

10. Why is transcription necessary?

11. DNA never leaves the nucleus
DNA never leaves the nucleus. It is a master copy (similar to the “special collection” books that never leave a library.) D N

12. If you want to take the information from those books out of the library, you have to copy them.

13. mRNA must be chemically different from DNA so that it can leave the nucleus.
Different structure N
Different atoms

14. 1. mRNA is single-stranded rather than double stranded.

15. 2. mRNA contains the nucleotide uracil instead of thymine.

16. 3. The sugar in mRNA is ribose instead of deoxyribose (has an additional oxygen atom.)
DNA
RNA

17. Who makes the mRNA?

18. Like replication, transcription is performed by enzymes.

19. A C T G C T G C A T A G C T T A C T G C G C T C T G A C G A C G T A T
mRNA
DNA A C T G C T G C A T A G C T T A C T G C G C T C T G A C G A C G T A T C G A A T G A C G C G A G G C U G C A U A G C U U A C U

20. Polymerizes nucleotides
The name of the enzyme that makes mRNA is mRNA polymerase. M P
Polymerizes nucleotides
A, U, C, G
mRNA
DNA

21. Transcription DNA template mRNA polymerase Uracil mRNA
1. Name of process: 2.
DNA template 3.
mRNA polymerase 1.
Uracil 5. 4.
mRNA

22. Where does mRNA go once it’s made?

23. DNA
mRNA
Able to leave nucleus?
Number of strands
Nucleotides it contains
Sugar it contains
# of genes
Process that makes it
Enzyme that makes it No
Yes 2 1
A, T, C, G
A, U, C, G
Deoxyribose
Ribose
SKIP
Replication
Transcription
DNA polymerase
mRNA polymerase

24. A T A G C T T A C T A T C G A A T G A U A G C U U A C
Transcribe the bottom DNA strand into an mRNA strand. A T A G C T T A C
DNA T A T C G A A T G
mRNA A U A G C U U A C

25. The entire DNA molecule is not transcribed at once.

26. C G U A U C A C T G C T G C A T A G C T T A C T G C G C T C T G A C G
Instead, DNA is transcribed one gene at a time, making mRNA a much shorter molecule than DNA. G S C G U A U C
mRNA A C T G C T G C A T A G C T T A C T G C G C T C T G A C G A C G T A T C G A A T G A C G C G A G
DNA
Antibody Gene