1. The Cell Cycle
Ch 3b

2. R. Hooke & cell theory
Cell division necessary for:
Growth
Healing
Cell replacement
Reproduction

3. Where does cell division occur?
# of chromosomes?
How does it reproduce?

4. The DNA Molecule

5. Rod shaped structure Chromosome Structure
Made of a single DNA molecule and proteins called histones
Histones maintain shape of chromosomes
Aids in tight packing of DNA
Seen during cell division
Coiled and compact

6. Chromosome consists of two identical halves
Chromosome Structure
Chromosome consists of two identical halves
Each half is a chromatid
Formed when DNA makes a copy of itself before cell division
Each new cell will receive one chromatid from each chromosome
Chromatids are held together by a centromere

8. A Pair of Homologous Chromosomes

9. Chromosomes Replicate

10. DNA Replication

11. DNA Replication

12. Replication Facts DNA has to be copied before a cell divides
Its copied during the S phase
New cells will need identical DNA strands

13. Synthesis Phase (S phase)
S phase during interphase of the cell cycle
Nucleus of eukaryotes

14. DNA Replication
Before new DNA strands can form, there must be RNA primers present to start the addition of new nucleotides
Primase is the enzyme that synthesizes the RNA Primer
DNA polymerase can then add the new nucleotides

15. DNA Damage & Repair
Chemicals & ultraviolet radiation damage the DNA in our body cells
Cells must continuously repair DAMAGED DNA
Excision repair occurs when any of over 50 repair enzymes remove damaged parts of DNA
DNA polymerase and DNA ligase replace and bond the new nucleotides together

16. Question: DNA 5’-CGTATG-3’
What would be the complementary DNA strand for the following DNA sequence?
DNA 5’-CGTATG-3’

17. Answer:
DNA 5’-CGTATG-3’
DNA 3’-GCATAC-5’

18. Human Chromosome

19. Human Chromosomes
autosomes
Sex chromosomes

20. Cell Cycle

21. Cell Cycle

22. Interphase- 75% of cell life cycle G1: rapid growth
Cell Cycle
Interphase- 75% of cell life cycle
G1: rapid growth
S: DNA replicates; centrioles replicate.
G2: cell prepares for cell division; microtubular structures form.

23. Mitosis: cell divides its nuclear components (chromosomes).
Cell Cycle
Cell Division
Mitosis: cell divides its nuclear components (chromosomes).
Cytokinesis: cell divides its cytoplasmic components.

24. Stages of Mitosis
Prophase
Metaphase
Anaphase
Telophase

25. Interphase

26. Prophase
Early
centrioles

27. Prophase
late

28. Centrioles During Prophase
nucleus

29. Metaphase

30. Metaphase
polar fibers
chromosomal fibers
sister chromatids

31. Chromosome at Metaphase

32. Anaphase

33. Telophase

34. Cytokinesis
cleavage furrow

35. Cytokinesis

36. Types of proteins in the Body Antibodies Enzymes Transport Structural
Protein Synthesis
Types of proteins in the Body
Antibodies
Enzymes
Transport
Structural
Receptors

37. Contrasting RNA with DNA

38. Contrasting RNA with DNA

39. Protein Synthesis
mRNA- copies DNA and directs protein synthesis
rRNA- joins with ribosomal proteins to make ribosomes
tRNA- transfers amino acids to ribosomes to make protein

40. Ribosome

41. tRNA

42. Protein Synthesis Transcription-occurs in nucleus
mRNA copies DNA nucleotide sequence
2. Translation
nucleotide sequence in mRNA is uncoded
mRNA binds to rRNA
tRNA brings appropriate amino acid to mRNA
Polypeptide is manufactured

43. Protein Synthesis

44. Transcription
DNA Sense Strand
mRNA Transcript

45. Transcription

46. Translation
mRNA exits nucleus

47. Translation
tRNA
anticodon
codon

48. Translation
START

49. Translation
ELONGATION T1 T2 T1 T2

50. Translation
ELONGATION T1 T2

51. Translation
ELONGATION

52. Translation
ELONGATION

53. Translation
STOP

54. INQUIRY
Which cells in the body are diploid and which are haploid?
During which stage does DNA replication occur?
Which stage of mitosis is seen in this picture?
At which stage is the cell binuclear?
In which phase do chromosomes line up in the center of the cell?
Where does the kinetochore attach?

55. Moment of Zen