1. Concepts and Applications Eighth Edition
Powerpoint Lecture Outline
Human Genetics
Concepts and Applications
Eighth Edition
Ricki Lewis
Prepared by
Dubear Kroening
University of Wisconsin-Fox Valley

2. Chapter 10 Gene Action: From DNA to Protein

3. Gene Expression Production of protein from the instructions on the DNA
Proteins have diverse functions in the body examples are listed in Table 10.1
Protein synthesis requires several steps including:
 Transcription - production of mRNA
 RNA processing
 Translation - production of protein using mRNA, tRNA, and rRNA

4. Central Dogma
Figure 10.1

5. Two Types of Nucleic Acids
Table 10.2

6. Major Types of RNA
Table 10.3

7. mRNA Carries information from DNA to ribosome Produced in the nucleus
Transported to the ribosome
A three nucleotide codon specifies a particular amino acid

8. rRNA With associated proteins make up ribosome
Two subunits that join during protein synthesis
Provides structural support and some are a catalyst (ribozymes)
Figure 10.4

9. tRNA
Cloverleaf shape
Anticodon of tRNA forms hydrogen bonds with the mRNA codon and has a specific amino acid at the other end
Figure 10.5

10. Figure 10.6

11. Protein Synthesis Transcription mRNA processing Translation
production of mRNA in the nucleus
mRNA processing
an mRNA exits the nucleus
Translation
Production of amino acid chain within ribosome

12. Transcription RNA is the bridge from DNA to protein
mRNA is synthesized from the template strand of DNA
The complementary strand is the coding strand of DNA
Requires enzyme RNA polymerase and transcription factors

13. Transcription Factors
In bacteria, operons control gene expression
In more complex organisms transcription factors control gene expression and link genome to environment
Over 2,000
Mutations in transcription factors may cause a wide range of effects

14. Figure 10.2

15. Base Pairing G G A T C G A T G C C T A G C T A C G G A U C G A U G
Template DNA strand
C C T A G C T A C
G G A U C G A U G
mRNA strand
G G A T C G A T G
Coding DNA strand

16. Steps in Transcription
Figure 10.7
Proteins and RNA polymerase bind to promoter region

17. Transcription Initiation
Figure 10.8
RNA polymerase reads the nucleotides on the template strand from 3’ to 5’ and creates an RNA molecule that looks like the coding strand

18. Transcription Occurs in three steps: Initiation  promoter
Elongation  RNA polymerase adds nucleotides to growing RNA
Termination  Sequences in the DNA prompt the RNA polymerase to fall off, ending the transcript

19. RNA Processing
mRNA transcripts are modified before use as a template for translation:
Addition of capping nucleotide at the 5’ end
Addition of polyA tail to 3’ end
Important for moving transcript out of nucleus and for regulating when translation occurs
Splicing occurs, removing internal sequences
Introns are sequences removed
Exons are sequences remaining

20. RNA Processing
Figure 10.10

21. Translation
The process of reading the RNA sequence of an mRNA and creating the amino acid sequence of a protein
Occurs within the ribosome
Figure 10.11

22. The Genetic Code
Codons are the triplet code groups of three RNA nucleotides used to encode one amino acid
The genetic code refers to which codons encode which amino acids, one start codon, and three stop codons
Non overlapping
Genetic code is universal  evidence of a common ancestor
The genetic code is degenerate  some codons encode the same amino acid

23. mRNA Nucleotides and the Amino Acids in a Protein
Proteins are formed from 20 amino acids in humans
Codons of three nucleotides:
AAA AGA ACA AUA AAG AGG ACG AUG
AAC AGC ACC AUC AAU AGU ACU AUU
GAA GGA GCA GUA GAG GGG GCG GUG
GAC GGC GCC GUC GAU GGU GCU GUU
CAA CGA CCA CUA CAG CGG CCG CUG
CAC CGC CCC CUC CAU CGU CCU CUU
UAA UGA UCA UUA UAG UGG UCG UUG
UAC UGC UCC UUC UAU UGU UCU UUU
Allows for 64 potential codons => sufficient!

24. The Genetic Code
Table 10.5

25. Translation Composed of three steps Initiation
Translation begins at start codon (AUG = methionine)
Elongation
The ribosome uses the tRNA anticodon to match codons to amino acids and adds those amino acids to the growing peptide chain
Termination
Translation ends at the stop codon
UAA, UAG or UGA

26. Translation Initiation
Figure 10.13

27. Translation Elongation
Figure 10.14a

28. Elongation
Figure 10.14b

29. Elongation
Figure 10.14c

30. Termination
Figure 10.15

31. Translation: Multiple Copies of a Protein Are Made Simultaneously
Figure 10.16

32. Protein Folding
After synthesis, proteins must be folded into three-dimensional shape
Enzymes and chaperone proteins assist
Misfolded proteins are tagged and dismantled
Proteins can fold in more than one way
Misfolded proteins can cause disease

33. Levels of Protein Structure
Figure 10.17

34. Misfolded Proteins Are Destroyed
Ubiquitin tags misfolded proteins
Transports it to a proteasome
Figure 10.19

35. Misfolding of Protein Impairs Function
Misfolded prion protein disrupts functions of other
normally folded prion proteins
Aberrant conformation can be passed on, propagating like
an “infectious” agent
Table 10.6

36. Study guide- DNA- Ch. 9; RNA & protein synthesis- Ch. 10.1-10.2
History of DNA knowledge:
Discoveries
Who is-
Miescher
Garrod
Frederick Griffith
Avery, Macleod, McCarty
Chargaff
Hershey & Chase
Levene
Wilkins & Franklin
Watson & Crick
Meselson & Stahl

37. Prions
Protein folding disorder  Infectious prions cause scrapie (sheep), bovine spongiform encephalopathy (cows), and a variant Creutzfeldt-Jakob disease (humans)
Figure 10.20

38. Experiments of transforming factor-
Griffith experiment
Hershey & Chase bacteriophage experiment
DNA structure-
Components of nucleotide
Directionality
5’, 3’
Arrangement of components
Bonding
DNA replication
Model- semiconservative
Process-
Enzymes- helicase, DNA polymerase- function
Complementary base pairing rules

39. Central Dogma of Biology RNA components
What are chromosomes?
Central Dogma of Biology
RNA components
3 Types of RNA
Complementary base rules
Protein Synthesis-
Transcription- process , where it occurs
Translation- process, where it occurs
Enzymes involved- RNA polymerase and transcription factors.
Triplet code, codon, anticodon, amino acid, proteins.
Folding of proteins
Mutations