DNA(Deoxyribonucleic Acid)
Genetic material of cells…• GENES – units of genetic material that  CODES FOR A SPECIFIC TRAIT• Called NUCLEIC ACIDS• DNA ...
DNA NucleotidePhosphate  Group  O              5O=P-O        CH2  O                          O                            ...
A HISTORY OF DNA                        SEE p. 292-293• Discovery of the DNA double helix  A. Frederick Griffith – Discove...
Watson & Crick proposed…•DNA had specific pairing between the    nitrogen bases:         ADENINE – THYMINE        CYTOSINE...
DNA Double Helix                   “Rungs of ladder”                   Nitrogenous                   Base (A,T,G or C)    ...
DNA Double Helix    5       O                           3        3                               OP                       ...
Nitrogenous Bases• PURINES  1. Adenine (A) 2. Guanine (G)                           A or G• PYRIMIDINES  3. Thymine (T) 4....
Chargaff’s Rule• Adenine must pair with Thymine• Guanine must pair with Cytosine• Their amounts in a given DNA molecule wi...
BASE-PAIRINGS      H-bonds  G         C  T             A
Genetic Diversity…• Different  arrangements of  NUCLEOTIDES in a  nucleic acid (DNA)  provides the key to  DIVERSITY among...
The Code of Life…• The “code” of the chromosome is the  SPECIFIC ORDER that bases occur.       A T C G T A T G C G G…
See p. 297  DNA is wrapped tightly aroundhistones and coiled tightly to form         chromosomes
DNA Replication          • DNA must be copied          • The DNA molecule produces 2            IDENTICAL new complementar...
DNA Replication• Semiconservative  Model:    1. Watson and Crick    showed: the two strands    of the parental molecule   ...
Replication Quiz1. Why is replication necessary?   A---?                                   G---?2. When does replication o...
Replication Quiz                                         A---T1. Why is replication necessary?         G---CSo both new ce...
(1961)   Watson & Crick proposed…• …DNA controlled cell function by  serving as a template for PROTEIN  structure.• 3 Nucl...
DNA Transcription• DNA can “unzip”  itself and RNA  nucleotides match  up to the DNA  strand. See p.301• Both DNA & RNA  a...
DNA Translation • The cell uses   information from   “messenger” RNA   to produce proteins    See p.304-305    We willdisc...
Transcription/Translation Quiz1.   Why is transcription necessary?2.   Describe transcription.3.   Why is translation nece...
1. Why is transcription necessary?   Transcription makes messenger RNA (MRNA)   to carry the code for proteins out of the ...
4. Describe translation.   The cell uses information from MRNA to   produce proteins.5. What are the main differences betw...
AMAZING DNA FACTS…• DNA from a single human  cell extends in a single  thread for almost 2 meters  long!!!• It contains in...
LET’S REVIEW DNA…                 LM p.441. List the conclusions Griffith & Avery,   Hershey & Chase drew from their   exp...
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Dna notes

  1. 1. DNA(Deoxyribonucleic Acid)
  2. 2. Genetic material of cells…• GENES – units of genetic material that CODES FOR A SPECIFIC TRAIT• Called NUCLEIC ACIDS• DNA is made up of repeating molecules called NUCLEOTIDES
  3. 3. DNA NucleotidePhosphate Group O 5O=P-O CH2 O O N Nitrogenous base C4 C1 (A, G, C, or T) Sugar (deoxyribose) C3 C2
  4. 4. A HISTORY OF DNA SEE p. 292-293• Discovery of the DNA double helix A. Frederick Griffith – Discovers that a factor in diseased bacteria can transform harmless bacteria into deadly bacteria (1928) B. Rosalind Franklin - X-ray photo of DNA. (1952) C. Watson and Crick - described the DNA molecule from Franklin’s X-ray. (1953)
  5. 5. Watson & Crick proposed…•DNA had specific pairing between the nitrogen bases: ADENINE – THYMINE CYTOSINE - GUANINE•DNA was made of 2 long stands of nucleotides arranged in a specificway called the “Complementary Rule”
  6. 6. DNA Double Helix “Rungs of ladder” Nitrogenous Base (A,T,G or C) “Legs of ladder” Phosphate & Sugar Backbone
  7. 7. DNA Double Helix 5 O 3 3 OP 5 P 5 O 1 G C 3 2 4 4 2 1 3 5 OP P 5 T A 3 O O 5P 3 P
  8. 8. Nitrogenous Bases• PURINES 1. Adenine (A) 2. Guanine (G) A or G• PYRIMIDINES 3. Thymine (T) 4. Cytosine (C) T or C
  9. 9. Chargaff’s Rule• Adenine must pair with Thymine• Guanine must pair with Cytosine• Their amounts in a given DNA molecule will be about the same. T A G C
  10. 10. BASE-PAIRINGS H-bonds G C T A
  11. 11. Genetic Diversity…• Different arrangements of NUCLEOTIDES in a nucleic acid (DNA) provides the key to DIVERSITY among living organisms.
  12. 12. The Code of Life…• The “code” of the chromosome is the SPECIFIC ORDER that bases occur. A T C G T A T G C G G…
  13. 13. See p. 297 DNA is wrapped tightly aroundhistones and coiled tightly to form chromosomes
  14. 14. DNA Replication • DNA must be copied • The DNA molecule produces 2 IDENTICAL new complementary strands following the rules of base pairing: A-T, G-C•Each strand of theoriginal DNA serves asa template for the newstrand See p. 298
  15. 15. DNA Replication• Semiconservative Model: 1. Watson and Crick showed: the two strands of the parental molecule separate, and each functions as a template for synthesis of a new complementary strand. DNA Template Parental DNA. New DNA
  16. 16. Replication Quiz1. Why is replication necessary? A---? G---?2. When does replication occur? C---? T---?3. Describe how replication works. A---? G---?4. Use the complementary rule to A---? create the complementary G---? strand: C---? A---? G---? T---?
  17. 17. Replication Quiz A---T1. Why is replication necessary? G---CSo both new cells will have the correct C---GDNA T---A2. When does replication occur? A---TDuring interphase (S phase). G---C3. Describe how replication works. A---TEnzymes unzip DNA and complementary nucleotides join each original strand. G---C4. Use the complementary rule to C---G create the complementary strand: A---T G---C T---A
  18. 18. (1961) Watson & Crick proposed…• …DNA controlled cell function by serving as a template for PROTEIN structure.• 3 Nucleotides = a triplet or CODON (which code for a specific AMINO ACID) See p.303• AMINO ACIDS are the building blocks of proteins.
  19. 19. DNA Transcription• DNA can “unzip” itself and RNA nucleotides match up to the DNA strand. See p.301• Both DNA & RNA are formed from NUCLEOTIDES and are called NUCLEIC acids.
  20. 20. DNA Translation • The cell uses information from “messenger” RNA to produce proteins See p.304-305 We willdiscuss details of this on a later date
  21. 21. Transcription/Translation Quiz1. Why is transcription necessary?2. Describe transcription.3. Why is translation necessary?4. Describe translation.5. What are the main differences between DNA and RNA.6. Using the chart on page 303, identify the amino acids coded for by these codons: UGGCAGUGC
  22. 22. 1. Why is transcription necessary? Transcription makes messenger RNA (MRNA) to carry the code for proteins out of the nucleus to the ribosomes in the cytoplasm.2. Describe transcription. RNA polymerase binds to DNA, separates the strands, then uses one strand as a template to assemble MRNA.3. Why is translation necessary? Translation assures that the right amino acids are joined together by peptides to form the correct protein.
  23. 23. 4. Describe translation. The cell uses information from MRNA to produce proteins.5. What are the main differences between DNA and RNA. DNA has deoxyribose, RNA has ribose; DNA has 2 strands, RNA has one strand; DNA has thymine, RNA has uracil.6. Using the chart on page 303, identify the amino acids coded for by these codons: UGGCAGUGC tryptophan-glutamine-cysteine
  24. 24. AMAZING DNA FACTS…• DNA from a single human cell extends in a single thread for almost 2 meters long!!!• It contains information equal to some 600,000 printed pages of 500 words each!!! (a library of about 1,000 books)
  25. 25. LET’S REVIEW DNA… LM p.441. List the conclusions Griffith & Avery, Hershey & Chase drew from their experiments.2. Summarize the relationship between genes & DNA.3. Describe the overall structure of the DNA molecule.4. What are the 4 kinds of bases?

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