1. Happy Homecoming Friday!!!
1. Which of the following is required for osmosis to occur?
A. An enzyme
B. A fully permeable membrane
C. ATP
D. A solute concentration gradient
2. Which of the following processes take place during interphase?
I. Respiration
II. Active transport
III. Protein synthesis
IV.Replication of DNA
A. I only
B. I and II only
C. I, II and III only
I, II, III and IV

2. Pelican Book 1st Then IB book 3.3 THEN go over diffusion/osmosis lab
Test Corrections due when?!?!

3. IB Topics: DNA, Transcription, Translation
3.3, 3.4, 3.5

5. DNA Structure

7. Chemical formulas not required!  Simple shapes! Bases:
Outline DNA nucleotide structure in terms of sugar (deoxyribose), base and phosphate.
Chemical formulas not required! 
Simple shapes!
Bases: A T G C
Carbon #s
3.3.2 State the names of the four bases in DNA.

8. PYRIMIDINES

9. 3.3.3 Outline how DNA nucleotides are linked together by covalent bonds into a single strand.
Phosphodiester bond = cov
5’ P group + 3’ OH group
Condensation rxn—water
Released
Nucleotides added to 3’ end!
Sugar-phosphate backbone

11. 3.3.4 Explain how a DNA double helix is formed using complementary base pairing and hydrogen bonds.
A-T; G-C
A, G are purines—bigger
T, C are pyrimidines—smaller
Consistent width of dbl helix
Opposite directions (anti-parallel)

12. 3.3.5 Draw and label a simple diagram of the molecular structure of DNA
TOK:
story of elucidation of DNA structure
(collaboration; Watson and Crick’s discovery of 3D structure dependent on Franklin’s data…shared without her knowledge or consent!!!)

13. DNA Replication

16. Interphase, before cell division
Explain DNA replication in terms of unwinding the double helix and separation of the strands by helicase, followed by formation of the new complementary strands by DNA polymerase.
Interphase, before cell division
Chromatin
Helicase (100s of base pairs per sec!)
Moves base pair at a time, breaks H bonds
Each strand is now a template
DNA polymerases
Covalent bonds b/w new strand n’tides
Free nucleotides (nucleoside triphosphates)

19. Double stranded, complementary Each becomes a template
3.4.2 Explain the significance of complementary base pairing in the conservation of the base sequence of DNA.
Double stranded, complementary
Each becomes a template
Complementary  Identical daughter strands
Accuracy for passing on information
Gene expression
Fatal mistakes

21. 3.4.3 State that DNA replication is semi-conservative.
Neither is completely “new”
(Semi-conservative)
Meselson & Stahl expts
Heavy & light isotopes of N

22. 3.5 Transcription & Translation

25. 3. 5. 1. Compare the structure of RNA and DNA
3.5.1 Compare the structure of RNA and DNA. **similarities & differences!! 5 are listed (not 10!):
DNA
RNA
5-C sugar
Deoxyribose sugar
Ribose sugar
Each nucleotide has 1 of 4 nitrogenous bases
Bases are C, G, A, T
Bases are C, G, A, U
Double-stranded
Single-stranded

26. Why’s the nucleus called the “control center”?
Protein synthesis
Some are enzymes
Effects biochemistry of cell...carbs, lipids, etc.

33. Gene region on DNA is unzipped
3.5.2 Outline DNA transcription in terms of the formation of an RNA strand complementary to the DNA strand by RNA polymerase.
Gene region on DNA is unzipped
RNA polymerase moves along template DNA strand (1) & complementary RNA n’tides pair
U instead of T
Compl copy of ONE GENE of the chromosome

34. Codes for ONE amino acid “codon” Sequence for polypeptide
3.5.3 Describe the genetic code in terms of codons composed of triplets of bases.
3 mRNA bases
Codes for ONE amino acid
“codon”
Sequence for polypeptide

36. Happy THURSDAY!!! March 4th! Test Monday, Articles & Review Tomorrow!
1. During the process of translation which of the following statements describes the relationship between nucleic acids?
A. Anticodons on mRNA bind to complementary codons on DNA.
B. Anticodons on tRNA bind to complementary codons on mRNA.
C. Bases on DNA bind to complementary bases on mRNA.
D. A single strand of mRNA is produced from the DNA in the nucleus.
2. Define the term degenerate as it relates to the genetic code. (1 mark)
more than one codon / base triplet codes for an amino acid 1

37. Translation

38. 3.5.4 Explain the process of translation, leading to polypeptide formation.
Include the roles of messenger RNA (mRNA), transfer RNA (tRNA), codons, anticodons, ribosomes and amino acids.

39. RNA
mRNA:
complementary copy of a gene, codes for one polypeptide
rRNA:
ribosomal (ribosome = rRNA + ribosomal protein)
tRNA:
transfers ONE of the 20 AA to ribosome for polypeptide formation
anticodon complementary to codon, determines which AA attaches to tRNA

40. mRNA leaves through nuclear pore, goes to ribosome @ 1st 2 codons
3.5.4 Explain the process of translation, leading to polypeptide formation.
mRNA leaves through nuclear pore, goes to 1st 2 codons

41. tRNA anticodons match up, bring amino acids in sequence
3.5.4 Explain the process of translation, leading to polypeptide formation.
tRNA anticodons match up, bring amino acids in sequence

42. 3.5.4 Explain the process of translation, leading to polypeptide formation.
2nd tRNA brings next one, condensation rxn  cov bond creates peptide bond

43. tRNA breaks bond w/amino acid, floats away & reloads
3.5.4 Explain the process of translation, leading to polypeptide formation.
tRNA breaks bond w/amino acid, floats away & reloads
Ribosome moves down mRNA, ...until stop codon: all dissociate

55. 3.5.5 Discuss the relationship between one gene and one polypeptide.
Originally (1940s) 1 gene  1 enzyme
 all proteins
 many proteins are multiple polypeptides, each translated by a separate gene
would invariably code for one polypeptide, but many exceptions have been discovered.
ACTUALLY...one mRNA can be modified in different ways to produce different polypeptides...
TOK: The way in which theories are modified as related evidence accumulates could be discussed, and whether contrary evidence should cause a theory to be discarded immediately if there are exceptions to it. Where a theory is suddenly and totally abandoned, to be replaced by a different theory, this is known as a paradigm shift.