1. Do Now
Why is it important to learn about DNA and how can DNA be used to help people?
NUA Notebook Check Today

2. Unit 4 Genetics
Ch. 12 DNA & RNA

3. Topic: The Components & Structure of DNA
Genes were known to do 3 specific things:
Carry info. from 1 generation to the next
Put that info. to work by determining heritable characteristics of organisms
Be easily copied, since all of a cell’s genetic info. is replicated every time a cell divides

4. The Components & Structure of DNA
DNA is a long molecule made up of units called nucleotides
Nucleotides - made up of 3 parts:
A sugar
A phosphate group
A nitrogenous base

5. The Components & Structure of DNA
Watson & Crick developed the model of DNA, a double helix, where 2 strands were wound around each other

6. The Components & Structure of DNA
The 2 strands of DNA are held together by hydrogen bonds
Those bonds only link adenine (A) & thymine (T), & guanine (G) & cytosine (C)
Base-pairing rule - A - T, G - C

7. Structure of DNA

8. BUILD A DNA MOLECULE
USING THE COLORED STICKS CREATE A DNA MOLECULE USING THE BASE PAIRING RULES. EACH STICK HAS A NUCLEOTIDE LETTER WRITTEN ON ONE SIDE OF THE STICK.
A = T
C = G
ATGC = ORIGINAL STRAND
CREATE NEW STRAND

9. COMPLETE WORKSHEET DNA AND RNA 12-1 WORKSHEET PAGE 287 TO 294
(textbook required)

10. Homework
Chapter 12
Vocabulary: Pages 287 and 295
Use online textbook or internet to complete

11. DO NOW WHAT ARE THE COMPLIMENTARY DNA BASES TO THE THIS GENETIC CODE?
HINT: USE NITROGEN BASE PAIRING RULES
A-T-T-G-G-C-A

12. DNA & Chromosomes
Most prokaryotes have a single circular DNA molecule in their cytoplasm

13. DNA & Chromosomes
Eukaryotic DNA is located in the nucleus, in the form of a # of chromosomes
The chromosome # varies from 1 species to another

14. DNA & Chromosomes
Eukaryotic chromosomes have both DNA & protein, packed tightly together to form chromatin
Chromatin - DNA that is tightly coiled around proteins (histones)

15. DNA & Chromosomes
From largest to smallest, genetic information is arranged the following way:
Chromosomes
Genes (found on chromosomes)
DNA (makes up genes)

16. DNA Replication
Each strand of DNA could be used to make the other strand, they compliment each other
Replication - when a cell’s DNA is copied

17. DNA Replication
During DNA replication, the DNA molecule separates into 2 strands, then produces 2 new complimentary strands following base pairing rules
Each strand of the double helix serves as a template, or model, for the new strand

18. DNA Replication
DNA polymerase - enzyme that joins individual nucleotides to produce a DNA molecule
It also proofreads each new DNA strand, to help prevent errors in copying the DNA

19. DNA Replication

20. AGENDA
COMPLETE DNA REPLICATION WORKSHEET. (QUIZ)
FINISH WORKSHEET FROM YESTERDAY
HOMEWORK
VOCABULARY ON PAGE 300

21. RNA & Protein Synthesis
Genes - coded DNA instruct. that control the production of proteins within the cell
The 1st step in decoding the genetic messages is to copy part of the nucleotide sequence from DNA into RNA

22. Do Now (Replication)
Using the genetic code given, separate the two original strands and create two molecules of DNA. Use the base pairing rules. (hint: what you did on your quiz)
A-T-C-C-G-T-A-C-G
T-A-G-G-C-A-T-G-C

23. The Structure of RNA There are 3 main differences between RNA & DNA:
The sugar is a ribose, instead of deoxyribose
RNA is single-stranded
RNA contains the nitrogenous base uracil (U) instead of thymine (T)

24. Types of RNA There are 3 main types of RNA: Messenger RNA
Ribosomal RNA
Transfer RNA

25. Types of RNA
Messenger RNA - (mRNA) - RNA molecules that carry copies of instructions for assembling amino acids into proteins
They serve as “messengers” from DNA to the rest of the cell

26. Types of RNA
Ribosomal RNA - (rRNA) - form of RNA that combines with proteins to make a ribosome

27. Types of RNA
Transfer RNA - (tRNA) - RNA molecule that transfers each amino acid to the ribosome as it is specified by coded messages in mRNA

28. Compare and contrast the three types of RNA (Venn Diagram)
Agenda
Complete worksheet on 12-2 (use textbook)
12-2 Assessment page 299 questions 1 through 5
Homework
Compare and contrast the three types of RNA (Venn Diagram)

29. Do Now
What do all forms of RNA have in common? mRNA rRNA tRNA PAGE 300 TEXTBOOK

30. Types of RNA
Transcription - process of producing RNA molecules by copying part of the nucleotide sequence of DNA into a complimentary sequence of RNA
RNA polymerase - enzyme that works similarly to DNA polymerase

31. Types of RNA
During transcription, RNA polymerase binds to DNA & separates the DNA strands
RNA polymerase then uses 1 strand of DNA as a template to assemble nucleotides into a strand of RNA

32. Transcription

33. The Genetic Code
Proteins are made by joining amino acids into long chains - polypeptides
Each polypeptide has a combination of any 20 different amino acids

34. The Genetic Code
Codon - 3 consecutive nucleotides that specify a single amino acid to be added to the polypeptide

35. The Genetic Code For ex.: UCGCACGGU Read 3 at a time:
Which represents amino acids:
Serine-Histidine-Glycine

36. The Genetic Code

37. Agenda Quick Lab page 303 How does a cell interpret DNA?
Complete worksheet on 12-3
Homework: Vocabulary 307
Chapter 12 Test on Thursday

38. Do Now
Using your textbook page 303 (genetic code) the mRNA codons from left to right, write the amino acid sequence of the polypeptide translated from the mRNA.
GATCCTTCCAACATC

39. Translation
Translation - (protein synthesis) -decoding an mRNA message into a polypeptide chain (protein)
It takes place on ribosomes
Before translation occurs, mRNA is transcribed (re-written) from DNA in the nucleus & released in the cytoplasm

40. Translation
Each tRNA molecule has an anticodon - 3 nitrogenous bases that are complimentary to 1 mRNA codon
The ribosome attaches 1 amino acid to another, forming the polypeptide chain, until it reaches the “stop” codon

41. Translation
After the amino acid is attached, the tRNA molecule that brought it into the ribosome, is released back into the cytoplasm
The result is a protein

42. Translation

43. Translation

44. Summary: Role of RNA & DNA
Start with a single strand of DNA
That DNA is transcribed into RNA
The RNA is separated into codons
The codons code for amino acids, which form a polypeptide chain

46. Mutations
Mutations - a mistake in the DNA base sequence, may occur during copying the DNA
Changes in the genetic material

47. Kinds of Mutations Gene mutations are changes in a single gene
Chromosomal mutations are changes in the whole chromosome

48. Gene Mutations
Point mutations - change in 1 or a few nucleotides, they occur at a single point in the DNA sequence
Frameshift mutations - adding or deleting a nucleotide, shifts the “reading frame” of the genetic message

49. Chromosomal Mutations
There are 4 types of chromosomal mutations: deletions, duplications, inversions, & translocations
Deletions involve the loss of all or part of a chromosome
Duplications produce extra copies of parts of a chromosome

50. Agenda
Worksheet (complete both sides) use textbook page 303 genetic code to write amino acid sequence.
12-3 Section Assessment 1 through 4
Vocabulary page 309

51. Chromosomal Mutations
Inversions reverse the direction of parts of chromosomes
Translocations occur when part of one chromosome breaks off & attaches to another

52. Significance of Mutations
Mutations cause changes in protein structure or gene activity
They are the cause of many genetic disorders
Some are associated with many types of cancer

53. Eukaryotic Gene Regulation
Genes that code for liver enzymes are not expressed in nerve cells
Cell specialization requires genetic specialization, but all cells in a multicellular organism carry the complete genetic code in their nucleus