1. Cell cycle and Reproduction

2. BIO… LIFE…. THINK ABOUT THIS: What do we do in our lifetime? What are the major stages of our life?

3. What are the Major stages of physical development in our lives?  What would it look like if we put this into a pie chart?

4.  Cell cycle: repeating sequence of cellular growth and division during the life of an organism; check points trigger the next stage of the cycle

5. The life of a cell  Cells have a life cycle just like we do- born, grow, reproduce, and die.  They only spend part of their life cycle reproducing (M)- mitosis

6. Imagine you are a bacteria: What are the major stages in your life? TRY ME:  What is A? B? C?  What is D/E/F/G collectively called?  What is D?  What is E?  What is F?  What is G? https://www.youtube.com/watch?v=65SODTL _QsA

7. Figure 9-8 The eukaryotic cell cycle G 1 : cell growth and differentiation telophase and cytokinesis anaphase metaphase prophase S: synthesis of DNA; duplication of chromosomes G 2 : cell growth and preparation for cell division

8. Cell Cycle 1. Interphase (G1, S, G2) – cell grows, prepares to divide (G phases) and DNA replicates (S phase) 2. Mitosis: nucleus divides; each nuclei winds up with the same # and kind of chromosomes as the parent (P-M-A-T) 3. Cytokinesis: division of cytoplasm

9. WHY DO CELLS DIVIDE? WHY DO THEY DO MITOSIS???  UNICELLULAR vs. MULTICELLULAR?

10. Why do cells divide?  UNICELLULAR  To reproduce (asexual reproduction)- budding/binary fission  Ex. Bacteria  hydra  vs. MULTICELLULAR?  Grow  Repair/replace cells that have been lost or damaged

11. Let’s think a second: THINK: Why do we have cycles and cells split? Why doesn’t the cell just get bigger and bigger?

12. Which turtle has bigger cells? Neither!!! Their cells are the same size… this one just has MORE!

13. Why don’t cells continue to grow? There are two main reason why cells divide instead of continue to grow: 1.The larger the cell becomes, the more demands the cell places on its DNA 2.The cell has more trouble moving enough nutrients and wastes across the cell membrane.

14. DNA “Overload”  Information that controls a cell’s function is stored in a molecule knows as DNA  In eukaryotic cells, DNA is found in the nucleus

15. DNA “Overload”  When a cell is small, the information stored in the DNA is able to meet all of the cell’s needs  If a cell was too large an “information crisis” would occur and the cell would not function properly

16. Example: Small library in a large city

17. Exchanging Materials  Food, water and nutrients enter the cell through its cell membrane  Waste products leave in the same way

18. Exchanging Materials Example: Small streets in a big town

19. Exchanging Materials  The relationship between a cell’s volume and its surface area is the key to understanding why cells must divide as they grow!

20. Ratio of Surface Area to Volume

21.  The volume increases much faster than the surface area, causing the ratio of surface area to volume to decrease.  This decrease creates serious problems for the cell. Formula for calculating ratio: Ratio = Surface Area/Volume SPLIT GROUPS: FIND SA, Volume and ratios for 3x3, 5x5, 8x8, 10x10

22. Lab surface/volume ratio CAN WE FIND THIS EXPERIMENTALLY??? FIND SA, Volume and ratios for For: 3x3, 5x5, 8x8, 10x10 Problem: What happens to the surface/volume ratio when a cube gets really big? Hypothesis: Methods: Result table in excel: Conclusion:

23. So what happens when cells get TOO LARGE????  THEY SPLIT- MITOSIS.

24. DNA replicates in interphase? Which part of cell cycle??? What happens in each: PROPHASE METAPHASE ANAPHASE TELOPHASE http://highered.mcgraw-hill.com/sites/0072437316/student_view0/chapter11/animations.html#

26. no cell wallcell wall

27. Mitosis 46 chromosomes 92 chromosomes 46 chromosom es 46 chromosom es parent cell daughter cells

28. AMEOBA SISTERS: https://www.youtube.com/watch?v=gwcwSZIf KlM&list=PLwL0Myd7Dk1F1pp- DaLx3ygO_7xA-yyd4&index=3 https://www.youtube.com/watch?v=gwcwSZIf KlM&list=PLwL0Myd7Dk1F1pp- DaLx3ygO_7xA-yyd4&index=3 BUT WHY CELLS DON’T JUST SPLIT ALL THE TIME????

29. Or in other words…. What happens if things go wrong with checkpoints? THINK ABOUT THIS!!!!

30.  Loss of Control of the Cell Cycle  If checkpoints are not working properly, the cell cycle can cause the cell to grow uncontrollably  leads to cancer. THINKING QUESTION: What biomolecule controls checkpoints? AMEOBA SISTERS: https://www.youtube.com/watch?v=lpAa4TWjHQ4&list=PLwL0Myd7Dk1F1pp- DaLx3ygO_7xA-yyd4&index=2.

31. And what controls the making of proteins? DNA SO WHAT’S THE DIFFERENCE BETWEEN PROKARYOTIC AND EUKARYOTIC DNA

32. How Is the DNA in Eukaryotic Chromosomes Organized?  Eukaryotic chromosomes differ from prokaryotic chromosomes in important ways  Eukaryotic chromosomes are separated from the cytoplasm by a membrane-bound nucleus  Eukaryotic cells always have multiple chromosomes  Eukaryotic chromosomes are longer and have more DNA than prokaryotic chromosomes (human chromosomes are 10 to 80 times longer and have 10 to 50 times more DNA)  These differences account for the complexity of eukaryotic cell division

33. How Is the DNA in Eukaryotic Chromosomes Organized?  The eukaryotic chromosome consists of a linear DNA double helix bound to proteins  Each human chromosome contains a single DNA double helix, about 50 million to 250 million nucleotides long  Most of the time, the DNA in each chromosome is wound around proteins called histones  These DNA-histone spools are further folded into coils  Another layer of folding occurs as the coiled strand folds into loops, which are then attached to protein scaffolding, so that the chromosome is 1,000 times shorter than the extended DNA molecule  During cell division, more proteins fold up the DNA and histones, until it is 10 times shorter than during its resting state

34. Figure 9-4 Chromosome structure DNA double helix histone proteins DNA wound around histone proteins Loops attached to a protein scaffold; this stage of partial condensation typically occurs in a nondividing cell Coiled DNA/histone beads protein scaffold Folded chromosome, fully condensed in a dividing cell

35. WHAT DO THE FOLLOWING TERMS MEAN? HOW ARE THEY RELATED? DRAW THEM.  DNA-  GENES-  SISTER CHROMATIDS-  CENTROMERE  CHROMOSOMES-  HISTONES-  LOCI-  TELOMERE-

37. GENES, CHROMOSOMES, and DNA  The DNA in a chromosome consists of two long strands of nucleotides wound around each other, as a ladder would look if it was twisted into a corkscrew shape  This structure is called a double helix  The units of inheritance, called genes, are segments of DNA  The specific sequence of nucleotides in genes spells out the instructions for making the proteins of a cell  When a cell divides, it replicates its DNA to make two identical copies, and gives each daughter cell one of the two copies

38. 9.3 How Is the DNA in Eukaryotic Chromosomes Organized?  Genes are segments of the DNA of a chromosome  Genes are sequences of DNA from hundreds to thousands of nucleotides long  Each gene occupies a specific place, or locus (plural, loci) on the chromosome

39. 9.3 How Is the DNA in Eukaryotic Chromosomes Organized?  In addition to genes, every chromosome has specialized regions that are crucial to its structure and function  Two telomeres  One centromere  The two ends of a chromosome consist of repeated nucleotide sequences called telomeres, which are essential for chromosome stability

40. 9.3 How Is the DNA in Eukaryotic Chromosomes Organized?  Genes are segments of the DNA of a chromosome (continued)  The second specialized region of the chromosome is the centromere, which has two principal functions 1.It temporarily holds two daughter DNA double helices together after DNA replication 2.It is the attachment site for microtubules that move the chromosomes during cell division

41. Eukaryotes  Chromosomes carry the DNA…but you need two IDENTICAL COPIES of DNA to go to the 2 cells  chromosome # varies between species  humans- 46 chromosomes (23 pairs)

42. REMEMBER: The life of a cell  Before cells can divide, DNA needs to be replicated So the code can be passed on. Which phase does this happen in????

43.  DNA Replication  Process of copying a double stranded DNA to form 2 double stranded molecules  Basis of biological inheritance used by all living things  Occurs before a cell divides (mitosis)

44.  DNA Replication 1. Enzymes break the hydrogen bonds between the bases so the chains of DNA can separate or unwind

45. 2. Other enzymes add new nucleotides, which form new hydrogen bonds with their complimentary nucleotide. Red = original strand Blue = new strand  DNA Replication

46.  Results in 2 semi-conservative double stranded molecules

47. WHAT IS THE ROLE OF: Helicase- SSB- Replication fork- DNA Polymerase-

48. ANIMATIONS OF DNA REPLICATION http://www.bioteach.ubc.ca/TeachingResources/MolecularBiology/DNAReplication.swf http://www.mcb.harvard.edu/Losick/images/TromboneFINALd.swf http://highered.mcgraw- hill.com/sites/0072556781/student_view0/chapter11/animation_quiz_2.html http://www.sinauer.com/cooper/4e/animations0601.html AMEOBA SISTERS: https://www.youtube.com/watch?v=5qSrmeiWsuc&index=1&list=PLwL0Myd7Dk1F1pp- DaLx3ygO_7xA-yyd4