1. Chapter 10
How proteins are made

2. 10-1 From Genes to protein Objectives
Compare the structure of DNA and RNA
Summarize the process of transcription
Outline the major steps of translation
SCS:B-4.4

3. Proteins are made by decoding the information in DNA
Traits are determined by proteins that are built according to the instructions found on DNA
Proteins are not built directly from DNA but from RNA (ribonucleic acid)
Copy of the DNA that is decoded

4. RNA – the facts Single stranded string of nucleotides Different bases
Has uracil instead of thymine
Different sugar – ribose

6. Gene expression – protein synthesis
A gene’s instructions for making a protein are coded in the sequence of nucleotides in the gene
Instructions are transferred from DNA to RNA in a process called transcription
The instructions are then decoded to make a protein in a process called translation

7. Transcription
Takes place in the nucleus of eukaryotic organisms and in the cytoplasm of prokaryotic organisms

8. Steps of transcription
RNA polymerase binds to the DNA molecule at the specific sequence that needs to be translated
RNA polymerase unwinds and separates strands
RNA polymerase adds nucleotides and links complimentary base until it reaches a “stop” signal.
RNA detaches then it leaves the nucleus to be translated.

10. Genetic code is written in 3 nucleotide “words”
3 types of RNA are made during transcription
Messenger RNA (mRNA) – copy of the DNA
Transfer RNA (tRNA) – carries nucleotides to the ribosome
Ribosomal RNA (rRNA) – part of the ribosome

12. Each codon codes for an amino acid or a start or stop signal
RNA instructions are written as a series of 3 nucleotide sequences of mRNA called codons
Each codon codes for an amino acid or a start or stop signal
the sequence can be decoded using the a genetic code
Specifies the amino acid, so it tells you what protein is being made
Nearly universal

13. Genetic Code

14. Translation Takes place in the cytoplasm
mRNA, tRNA, and rRNA are involved
Ribosomes are the site of protein synthesis
Translation can take place at multiple places on the mRNA

15. Steps of translation
mRNA leaves the nucleus; ribosome attaches at the start codon (AUG)
tRNA brings the complimentary anticodon with a amino acid attached
A peptide bond forms after another tRNA brings a second amino acid
The ribosome continues the above process until a stop message is reached in the mRNA.
The newly made protein detaches and the ribosome break apart.

17. 10-2 Gene regulation and Structure
Objectives
Summarize how protein synthesis is regulated
Describe the types of mutations that can occur during translation
SCS:B-4.4

18. Protein synthesis is controlled by “on” and “off” switches
This switch is called an operator
Controls the access of RNA polymerase to the sequence of DNA
A protein (repressor) binds to the DNA to keep RNA polymerase from binding to the promoter site (the group of genes that codes for a specific protein)

19. Regulation is more complex in eukaryotic organisms
Regulated in many ways

20. Most of your DNA does not code for anything useful
Introns – non coding region
Are “cut” out during translation
Exons – regions that actually code for proteins

21. Mutations result in nonfunctional proteins
Types of point mutations (occur in only a few nucleotides)
Substitution
Insertion
Deletion

22. Mutations can result in no protein being made, a nonfunctional protein, or have no affect at all
Many genetic disorders are a result of a single nucleotide mutation