Chapter 10 - Protein Synthesis

Chapter 10 Vocabulary List

1. Anticodon

2. Codon

3. Gene expression

4. Genetic code

5. Messenger RNA

6. Point mutation

7. Intron

8. Exon

9. promoter

10. Ribonucleic acid (RNA)

11. Ribosomal RNA

12. Transcription

13. Transfer RNA

14. Translation

15. Polypeptide

16. Frameshift mutation

17. Mutagen

Don’t lose your DNA!!

Proteins are Made by Decoding the Information Stored in DNA

A. Transcription1. Copying DNA into RNA

B. Translation1. Converting message from nucleic acid to amino acid

C. Transcription + Translation = Gene Expression

RNA – Ribonucleic Acid

A. Single-Stranded

1. DNA is double-stranded

B. 5-Carbon sugar – ribose

1. DNA uses Deoxyribose

C. Thymine is replaced by Uracil

D. 3 types of RNA:

1. messenger RNA (mRNA)

2. transfer RNA (tRNA)

3. ribosomal RNA (rRNA)http://www.biologycorner.com/resources/mRNA-colored.gif

http://en.wikipedia.org/wiki/Adenosine_triphosphate

ATP

Transcription (TX)

A. The transfer of the protein blueprint from DNA into RNA1. DNA is too large

and valuable to let out of the nucleusi. It is the primary

computer code for the cell

2. RNA is a portable copyi. It is like the

copy of a song for your I-Pod

B. Tx is transcribing or copying the message carried on the DNA

C. Tx occurs in the nucleus

Translation (TL)A. Using the instructions in RNA to put together amino

acids to make protein

B.TL occurs in the cytoplasm on Ribosomes

C. TL is also called Protein Synthesis

Review Questions

1. What is Transcription?

2. What is Translation?

3. What is Gene Expression?

4. How many different types of RNA are there?

5. What are they?

6. How does RNA differ from DNA?

Transcription Transfers Information from DNA to RNA

A. RNA Polymerase – an enzyme1. Unwinds DNA and adds

nucleotides to make RNA2. Promoters- RNA polymerase

only binds to regions of DNA with specific sequences.

B. RNA is made following same base-pairing rules as for DNA replication1. Thymine is replaced by Uracil2. A – U and G – C

http://www.idigitalmotion.com/portfolio.htm

A = adenineT = thymineG = guanineC = cytosineU = uracil

Introns and ExonsA. Genes are made up of coding and noncoding sequenceB. Introns – noncoding

1. DNA that does not code for protein sequence

C. Exons – coding1. DNA that

encodes protein

D. After Tx, Introns are removed and Exons are joined together

The Genetic Code is Written in 3-Nucleotide “Words” on mRNA

A. mRNA

1. Carries instructions from the nucleus to the cytoplasm

http://www.iir.suite.dk/IIR/15genes/images/15DNAToProt2.gif

2. A portable copy of the DNA

B. Codons

1. 3-Nucleotide sequences that codes for a single amino acid

The Genetic Code

A. 64 mRNA codons are possible

1. Four nucleotides in 3-letter combinations

2. 43 (4 cubed)

B. There are only 20 amino acids

1. In some cases, several codons code for the same amino acid

C. Some codons are “start” and “stop” codons

http://www.emc.maricopa.edu/faculty/farabee/BIOBK/code.gif

Third letter

The Genetic Code

Review Questions

7. What enzyme makes RNA?

8. What type of RNA does it make?

9. After Tx, are Introns or Exons removed from the mRNA?

10. What do you call the 3-Nucleotide sequences that code for an amino acid?

11. How many codons are there?

Translation – Transfer RNA

A. tRNA

1. Carries amino acids to the ribosome during translation

B. Anticodons on tRNA

1. Complementary to the codons on the mRNA

Translation – Ribosomal RNAA. rRNA – the third

type of RNA

B. rRNA makes up much of the structure of the Ribosomes

C. Ribosomes are the assembly line in the factory where protein “robots” are made

ttp://www.frontiers-in-genetics.org/page.php?id=protein-synthesis_en

TranslationA. Step I: the ribosome

reads codons on mRNA

B. Step II: the 1st tRNA brings the 1st amino acid

C. Step III: a tRNA brings the next amino acid

D. Step IV: the two amino acids are connected and the empty tRNA leaves

E. Step V: steps III & IV are repeated until a stop codon is reached

http://www.google.com/imgres?imgurl=http://frank.itlab.us/spider_2002/translation.jpg&imgrefurl=http://frank.itlab.us/spider_2002/dna.html&usg=__jrmqoW6vkV0iIxaug6iXugrDnR4=&h=388&w=469&sz=28&hl=en&start=24&zoom=1&tbnid=ahLACycLUfHd4M:&tbnh=147&tbnw=178&ei=ioW1TdavBui40QGI6oD-CA&prev=/search%3Fq%3DProtein%2Btranslation%26hl%3Den%26safe%3Dactive%26client%3Dfirefox-a%26sa%3DG%26rls%3Dorg.mozilla:en-US:official%26biw%3D1280%26bih%3D810%26site%3Dsearch%26tbm%3Disch0%2C570&um=1&itbs=1&iact=hc&vpx=692&vpy=394&dur=749&hovh=204&hovw=247&tx=118&ty=91&page=2&ndsp=24&ved=1t:429,r:9,s:24&biw=1280&bih=810

II

III

IV

V

Translation

F. When a stop codon is reached, the new protein is released from the Ribosome

G. The order of amino acids in a protein is called the protein or amino acid sequence

http://fc06.deviantart.net/fs17/i/2008/237/6/f/Protein_Synthesis_by_TheElephantMan.jpg

Gene Expression

Translation

Let’s Watch a Movie:

http://207.207.4.198/pub/flash/26/transmenu_s.swf

Transcription & Translation Movie:

Review Questions

12. What types of RNA are associated with ribosomes?

13. What do you call the 3-Nucleotide sequences on tRNAs that recognize codons?

14. What cellular machine reads the message on an mRNA and makes protein?

15. What are the steps of Translation?

Mutations

A. Alterations in the DNA sequence that change amino acid sequence are called Mutations

B. Mutations that change 1 or a few nucleotides are called Point Mutations

http://www.brooklyn.cuny.edu/bc/ahp/BioInfo/graphics/Mutation.04.GIF

C. There are several types of Point Mutations1. Substitutions2. Insertions3. Deletions

Frameshift Mutation: a shift in the reading frame of the genetic code.

Which of these 3 mutations is a frameshift mutation?

Point Mutations – SubstitutionA. One nucleotide is replaced (substituted for) by another

B. Sickle-cell Anemia is caused by a substitution mutation in the gene for Hemoglobin

1. A is substituted for T

2. Valine is substituted for Glutamic Acid

http://www.bbc.co.uk/scotland/education/bitesize/higher/biology/genetics_adaptation/mutations1_rev.shtml

Point Mutations – InsertionA. A new nucleotide is added

B. This changes the sequence of all the amino acids following the insertion

http://ghr.nlm.nih.gov/dynamicImages/understandGenetics/mutations_and_disorders/Insertion.jpg

C. The altered protein may be shorter or longer, and may not function

Point Mutations – DeletionA. One nucleotide is lost

B. This changes the sequence of all the amino acids following the insertion

http://biotech-adventure.okstate.edu/low/basics/protein/10-mutation/point_deletion/point_deletion.gif

C. The altered protein may be shorter or longer, and may not function

Sometimes Substitutions have little or no Effect

A. UCU to UGC or UCA – all code for Serine

1. No amino acid change

2. Conservative substitutions

B. UCU to ACU or GCU – code for different amino acids

1. The amino acid will change

2. These are substitution mutations

Do not Confuse Point Mutations with Chromosomal Mutations!

http://www.stanford.edu/group/hopes/causes/mutation/f_q02mutation.jpg

A. Chromosomal mutations are Large pieces of DNAB. Point mutation- a change in a single Nucleotide of DNA

Genetic Disease Reviewprotein genetics mutation

Sickle Cell Anemia

Hemoglobin recessive substitution

PhenylketonuriaPhenylalanine Hydroxylase

recessivemultiple

types

Tay-Sachs Disease

Hexosaminidase recessivemultiple

types

Cystic Fibrosis CFTR recessive deletion

Huntington’s Disease

Huntingtin dominant insertion

Hemophilia Clotting Factor recessive (sex-linked)

multiple types

Review Questions

16. What is a Point Mutation?

17. What is a:a. Substitution mutation?b. Insertion mutation?c. Deletion mutation?

18. Will a mutation always produce a mutant protein?

19. What are some mutagenic agents?