1. DNA & GENES

2. What is DNA?  DNA (deoxyribonucleic acid) is a nucleic acid  It is composed of smaller units called nucleotides  These are:  A, T, C, and G  Shape—double helix

3. DNA

4. DNA Nucleotides

5. Complimentary Base Pairing

6.  AAA TCC GCT AAT CCG GGG  TTT AGG CGA TTA GGC CCC  Try another!  GCA TTA CCG AGA CCC TAA  CGT AAT GGC TCT GGG ATT

7. The Double Helix

8. Who discovered the Double Helix?  In 1953, James Watson and Francis Crick published an article on what DNA looked like.  Made of tow chains of nucleotides held together by nitrogen bases.  DOUBLE HELIX.

9. Hydrogen Bonds  How the nitrogen bases bond

10. What is DNA Replication?  The DNA in chromosomes is copied.  Enzymes break Hydrogen bonds  Add matching nucleotides  2 identical molecules made, each with 1 new, 1 old strand

11.  Chromosome

16. What is a GENE?  A sequence of DNA (nucleotides) that codes for a protein  Proteins = traits!

17. What is Protein Synthesis?  The process of making proteins from DNA instructions

18. What is mRNA?  mRNA is similar to DNA  Only one strand  Uses a “U” instead of a “T”  It brings the instructions from DNA in the nucleus to the cytoplasm.  Example:  DNA = AAT GGC CAT  mRNA=UUA CCG GUA

19. What is Transcription?  First part = TRANSCRIPTION  Enzymes separates DNA strand and “reads” the letters (nucleotides)  RNA copy of DNA is made  A molecule called mRNA is made

20. Transcription

21. What is Translation?  mRNA moves out of the nucleus and finds a ribosome  The information in the mRNA (nitrogen bases) is changed into a sequence of amino acids in protein.

22. Where and what happens during tranlation?  Ribosome uses instructions on mRNA to build one protein

23. Translation  Once at the ribosome, transfer RNA (tRNA) brings amino acids

24. Translation  tRNA drops off correct amino acid and adds it to the growing chain

25. What is tRNA?  Is the supplier RNA  It delivers amino acids to the ribosome to be assembled into a protein.

26. tRNA  Uses the same letters as mRNA; U’s instead of T’s.  U—uracil instead of thymine

27. How does mRNA and tRNA work in translation?  Each 3-letter chunk of mRNA is called a CODON (CUA)  Codons match the 3-letter chunk of tRNA called an ANTI- CODON (GAU)

28. How are codons and anti-codons coded?  Use a table to determine which amino acids are connected

29. Translation  There are about 20 different amino acids

30. What is rRNA?  Binds to the mRNA and uses the instructions to assemble the amino acids in the correct order.  Which are then transferred to the ribosomes by tRNA.

31. What are mutations?  Any change that occurs in the DNA sequence.  2 types –Point mutation –Frameshift mutation

32. What is a point mutation?  A change in a single base pair of DNA.  A has become a C (pt. mutation)

33. What is frameshift mutation?  Where a single base is added or deleted from DNA.

34. What causes mutations?  Caused by a mutagen.  Any agent that can cause a change in DNA. –Radiation –Cosmic rays –Ultraviolet light –Nuclear radiation –Alcohol

35. Mutagens

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