1. Chapter 13- RNA and Protein Synthesis
BIG IDEA: How does info. flow from DNA to RNA to direct the synthesis of proteins.

2. 13.1 RNA How is RNA different from DNA?
-Ribonucleic acid, RNA is a nucleic acid consisting of a large chain of nucleotides
3 Important diff. between DNA and RNA:
sugar is ribose, NOT deoxyribose
RNA is generally single-stranded instead of double-stranded
RNA contains uracil in place of thymine

3. Functions of RNA:
Messenger RNA (mRNA)- carry info. from DNA to other parts of cell
Ribosomal RNA (rRNA)- subunits that make up proteins
Transfer RNA (tRNA)- transfers each amino acid to the ribosome as specified by the messages in mRNA

4. How does the cell make RNA?
In transcription, segments of DNA serve as templates to produce complementary RNA molecules.
RNA complements base sequences of DNA
RNA polymerase binds DNA to complementary strand

5. Introns- pieces of RNA that are cut out and discarded
Promoter- a specific base sequence that tells RNA polymerase where to start and stop RNA synthesis
RNA Editing
Introns- pieces of RNA that are cut out and discarded
Exons- The remaining pieces of RNA that are spliced (put) back together to form the final RNA
introns and exons may play a major role in evolution. , small changes in DNA and RNA can create big changes on how genes affect cellular functions

6. 13.2 Ribosomes and Protein Synthesis
What is the genetic code and how is it read?
Bases (in the case of RNA)- A,U, C, and G form the genetic code.
Code is read 3 a time. Each “word” is 3 bases long, and corresponds to an amino acid
Each 3 letter “word”= codon

7. 4 different bases in RNA= 64 different possible 3-base codons
Most amino acids can be specified by more than 1 codon.
Can be read using genetic code table

9. GAC AAG TCC ACA ATC
From left to right, write the sequence of mRNA transcribed.
Use codon table to translate into amino acids
Repeat step 1 using complementary strand as new base

10. What role does the ribosome play in assembling proteins?
Ribosomes use the sequence of codons in mRNA to assemble amino acids into polypeptide chains
Translation is the decoding of mRNA→ protein

11. Steps in Translation
start codon (AUG). Ribosome attaches to mRNA
“EPA” assembly line
Continues until ribosome reaches “stop” codon.

12. Central Dogma of Molecular Biolgy
Information is transferred from DNA → RNA → protein
Gene expression= the in which DNA, RNA, and proteins put genetic info. into action in living cells.

13. 13.3 Mutations
Mutations are heritable changes in the genetic information

14. Point mutations
-Changes in 1 or a few nucleotides that a single point
*Substitution- 1 base (A/U/C/G) is changed into a different base. Usually affect 1 amino acid and may have no affect
*Insertion/Deletion (frameshift mutation)- 1 base is inserted or deleted from DNA sequence. Can change every amino acid following the mutation.

15. Chromosomal mutations: 1) deletion: loss of part or all of chromosome
2) duplication: extra copy of all or parts of chromosome
3) inversion: reversing the direction of parts
4) translocation: part of chromosome breaks off and reattaches to diff. chromosome
mutaTIONS ARE PRODUCED BY ERRORS in the genetic process. genetic material can be altered naturally or by artificial means. small changes may have little to no effect, but over time the changes gradually accumulate

16. What type of mutation? milk → mile fast → fats beast → best lot → lost
substitution, deletion, insertion, inversion

17. Some mutations are caused by physical agents in the environment, called mutagens
The effects of mutations can have little/no effect, or can negatively disrupt gene function

18. Harmful mutations vs. Helpful mutations
Change protein structure or gene activity
Some cancers
Diseases
New or altered functions in proteins that can be useful to organisms in changing environments.
Genetic diversity
Disease resistance

19. 13.4 Gene Regulation and Expression
To conserve energy prokaryotes transcribe certain a time.
-Regulated by DNA-binding proteins
Operon= group of genes that are regulated together

20. lac (lactose) operon is on when lactose is present , bacteria knows when it needs nutrients
Promoter=where RNA-polymerase binds to start transcription
Operator= region that controls rate of transcription

21. Eukaryotic gene regulation: transcription factors control the expression of genes
Some open up chromatin to start transcription, some attract RNA polymerase, etc.
Cell specialization (nerve cells, epithelial,cardiac, etc.)
RNA interface (RNAi) turns genes on and off, plays a role in growth/development

22. Cell differentiation = cells become specialization in structure and function
Master control genes (homeotic genes) regulate where specific organs grow in the body
Homeotic genes are like switches that trigger certain patterns of development and differentiation in cells and tissues.