1. C11- DNA and Genes
Chapter 11

2. Contents 11-1 DNA: The Molecule of Heredity 11-2 From DNA to Protein
Protein Synthesis video
11-3 Genetic Changes

3. 11-1 DNA: The Molecule of Heredity
Genetic info in DNA controls organism’s traits

4. 11-1 DNA: The Molecule of Heredity
Genetic info in DNA controls organism’s traits
Determines structure of proteins built

5. 11-1 DNA: The Molecule of Heredity
Genetic info in DNA controls organism’s traits
Determines structure of proteins built
Hershey & Chase (1952) used radioactively tagged viruses to infect bacteria and proved DNA is genetic material

6. 11-1 DNA: The Molecule of Heredity
Genetic info in DNA controls organism’s traits
Determines structure of proteins built
Hershey & Chase (1952) used radioactively tagged viruses to infect bacteria and proved DNA is genetic material

7. Nucleotide Structure
DNA polymer of repeating units called nucleotides.

8. Nucleotide Structure
DNA polymer of repeating units called nucleotides.
3 parts
Simple sugar
Phosphate
Phosphorus w/ 4 O
Nitrogenous base

9. Nucleotide Structure
DNA polymer of repeating units called nucleotides.
3 parts
Simple sugar
Phosphate
Phosphorus w/ 4 O
Nitrogenous base
C ring w/ 1 or more N & a base
Adenine (A)
Cytosine (C)
Guanine (G)
Thymine (T)

10. Nucleotides Join in long chains with phosphates connecting
to sugar of next unit
to form a backbone

11. Nucleotides Join in long chains with phosphates connecting
to sugar of next unit
to form a backbone
with the bases sticking out like the teeth of a zipper.
Adenine = Thymine
Guanine = Cytosine

12. Structure of DNA
James Watson & Francis Crick (1953) unraveled the structure of DNA.
Double Helix structure

13. Nucleotide Sequence
Forms unique genetic information of organism

14. Nucleotide Sequence Forms unique genetic information of organism
Can be used to determine evolutionary relationships between organisms

15. Nucleotide Sequence Forms unique genetic information of organism
Can be used to determine evolutionary relationships between organisms
Or familial relationships
DNA can identify victims or criminals

16. Replication of DNA
Copies DNA in chromosome during interphase

17. Replication of DNA Copies DNA in chromosome during interphase
Enzyme breaks the hydrogen bond between bases

18. Replication of DNA Copies DNA in chromosome during interphase
Enzyme breaks the hydrogen bond between bases
Complimentary base pairing allows duplication

19. Replication of DNA Copies DNA in chromosome during interphase
Enzyme breaks the hydrogen bond between bases
Complimentary base pairing allows duplication
Each strand is a template

20. 11-2 From DNA to Protein DNA controls the production of proteins.
Proteins are key cell structures & regulators of cell functions.

21. 11-2 From DNA to Protein DNA controls the production of proteins.
Proteins are key cell structures & regulators of cell functions.
RNA, another nucleic acid carries out DNA’s instructions

22. 11-2 From DNA to Protein DNA controls the production of proteins.
Proteins are key cell structures & regulators of cell functions.
RNA, another nucleic acid carries out DNA’s instructions
Structure differs 3 ways
Single-stranded
Sugar is ribose
Uracil replaces thymine

23. Three Types of RNA Protein assembly line: Messenger RNA (m-RNA)
Ribosomal RNA (r-RNA)
Transfer-RNA (t-RNA)

24. Three Types of RNA Protein assembly line: Messenger RNA (m-RNA)
Brings instructions from DNA to ribosome in the cytoplasm
Ribosomal RNA (r-RNA)
Transfer-RNA (t-RNA)

25. Three Types of RNA Protein assembly line: Messenger RNA (m-RNA)
Brings instructions from DNA to ribosome in the cytoplasm
Ribosomal RNA (r-RNA)
Reads instructions to assemble protein by binding to m-RNA
Transfer-RNA (t-RNA)

26. Three Types of RNA Protein assembly line: Messenger RNA (m-RNA)
Brings instructions from DNA to ribosome in the cytoplasm
Ribosomal RNA (r-RNA)
Reads instructions to assemble protein by binding to m-RNA
Transfer-RNA (t-RNA)
Delivers amino acids for assembly to ribosome

27. Transcription Occurs in the nucleus by enzymes copying part of the DNA
Enzyme unzips DNA
Assembles single-strand copy

28. Transcription Occurs in the nucleus by enzymes copying part of the DNA
Enzyme unzips DNA
Assembles single-strand copy
DNA rezips after m-RNA detaches

29. Transcription Occurs in the nucleus by enzymes copying part of the DNA
Enzyme unzips DNA
Assembles single-strand copy
DNA rezips after m-RNA detaches
m-RNA leaves nucleus by nuclear pore to enter cytoplasm

30. Transcription Occurs in the nucleus by enzymes copying part of the DNA
Enzyme unzips DNA
Assembles single-strand copy
DNA rezips after m-RNA detaches
m-RNA leaves nucleus by nuclear pore to enter cytoplasm
Carries instructions to ribosome

31. Translation Occurs in the ribosome
Process of converting series of bases into chain of amino acids forming a protein

32. Translation Occurs in the ribosome
Process of converting series of bases into chain of amino acids forming a protein
r-RNA reads sequence of 3 bases (codon)

33. Translation Occurs in the ribosome
Process of converting series of bases into chain of amino acids forming a protein
r-RNA reads sequence of 3 bases (codon)
t-RNA anticodon matches up with the codon from m-RNA and supplies the amino acid needed

34. Translation Occurs in the ribosome
Process of converting series of bases into chain of amino acids forming a protein
r-RNA reads sequence of 3 bases (codon)
t-RNA anticodon matches up with the codon from m-RNA and supplies the amino acid needed
Ribosome translates the next codon until finished assembling the protein

35. RNA & Protein Synthesis

36. RNA Processing Introns- noncoding nucleotide sequences
Exons- expressed sections of nucleotides
Enzymes cut out the introns & paste the exons together

37. Genetic Code Amino acids are the building blocks of proteins.
A sequence of 3 nucleotide bases code for each of the 20 amino acids.
64 different codons in m-RNA
AUG start codon
UAA stop codon
All organisms use the same genetic code.

38. Translating the m-RNA Code
T-RNA leaves amino acid in position to form peptide bond with previous amino acid

39. Translating the m-RNA Code
T-RNA leaves amino acid in position to form peptide bond with previous amino acid
The ribosome continues to assemble amino acids until stop codon is reached.

40. Translating the m-RNA Code
T-RNA leaves amino acid in position to form peptide bond with previous amino acid
The ribosome continues to assemble amino acids until stop codon is reached.
Translation is complete

41. Translating the m-RNA Code
T-RNA leaves amino acid in position to form peptide bond with previous amino acid
The ribosome continues to assemble amino acids until stop codon is reached.
Translation is complete
Amino acid chain is released & twists into complex folded shape of protein

42. Translating the m-RNA Code
T-RNA leaves amino acid in position to form peptide bond with previous amino acid
The ribosome continues to assemble amino acids until stop codon is reached.
Translation is complete
Amino acid chain is released & twists into complex folded shape of protein
Become enzymes & structures

43. 11-3 Genetic Changes Mutation- any change in DNA sequence
Caused by errors in
Replication
Translation
Cell division
Or by external agents such as UV or chemical exposure

44. Mutations in Reproductive Cells
Changes in the sequence of nucleotides can cause:
Altered gene in offspring
New traits
Nonfunctional protein with structural or functional problems in cells
Embryo may not survive
Positive effect

45. Mutations in Body Cells
Does not pass on to offspring
May cause problems for the individual
Impair function of the cell
Contributes to aging
Can cause cancer by making cells reproduce rapidly

46. Effects of Point Mutations
Point mutation - Change in a single base pair in DNA
Can change entire structure of the protein
Error may or may not affect protein function
Ex. Sickle cell anemia

47. Frameshift Mutations A single base is added to or deleted from DNA
Shifts the reading of the codons by one base
Nearly every amino acid after the insertion or deletion will be changed

48. Chromosomal Alterations
Chromosomal mutations
Deletions -Parts break & are lost during mitosis or meiosis
Insertions- Parts rejoin incorrectly
Inversions- Rejoin backwards
Translocations- Join other chromosomes
Common in plants

49. Causes of Mutations Mutagens- agents that cause change in DNA
Radiation
X-rays
Gamma rays
Ultraviolet light
Nuclear radiation
Chemicals
Dioxins
Asbestos
Benzene
Formaldehyde
High temperatures
6-legged frog
aflatoxin

50. Repairing DNA Repair mechanisms have evolved:
Enzymes proofread DNA & replace incorrect nucleotides.
The greater the exposure to the mutation, the less likely it can be corrected.
Limit exposure to mutagens.