How do organisms grow?

1. How do organisms grow?

2. How do organisms grow? Paramecium 400x Onion skin cells 400x

3. How do organisms grow?

4. How do organisms grow? • Living things grow by producing more cells. • Cells will divide rather than growing larger. • The larger a cell becomes, the more demands the cell places on its DNA and the more trouble the cell has moving enough nutrients and waste across cell membrane.

5. The cell

6. BASIC GENETICS • Each cell in the human body containstwo sets of 23 chromosomes • Mitosis identically replicates this information • Each cell therefore has the same genetic material • Reproductive cells only have one set of chromosomes. These combine to make a new person with different genetic material to both parents

7. A packaged chromosome Chromatid Identical chromatid Replication Anaphase Chromosomes, Chromatids and Centromeres Chromosome arm Two identical chromosomes Centromere Chromosome arm

8. Chromosomes

10. Sister Chromatids centromerre Spindle fibers

11. The Cell Cycle • The series of events that cells go through as they grow and divide

12. http://www.cellsalive.com/cell_cycle.htm Cell Cycle

13. Cell Cycle

14. Interphase

15. The Cell Cycle Interphase: • G1: The cell grows and does its job (produce proteins). • S: The cell will replicate (copy) the chromosomes. • G2 : The cell makes copies of all the other organelles.

16. Mitosis: PMAT

17. Mitosis • All daughter cells contain the same genetic information from the original parent cell from which it was copied. • Every different type cell in your body contains the same genes, but only some act to make the cells specialise – e.g. into nerve or muscle tissue.

18. The Spindle A spindle is a web type structure made up of microtubule fibers. It is essential for mitosis because it arranges the chromosomes into their correct positions in preparation for cell division. Mitotic center A cell atmetaphase a spindle Microtubule

19. mitosis

20. Mitosis (M Phase): How the Cells Divide: • Used for asexual reproduction as well as for growth and repair • There are four stages: • PMAT ( Prophase, Metaphase, Anaphase and Telophase)

21. Prophase • Chromatin condenses into chromosomes. •  The centrioles migrate to opposite ends of the cell. • Spindle fibers and the aster forms.  

22. Late Prophase • The spindle fibers have attached themselves to the chromosomes.  

23. Metaphase • The chromosomes migrate to the equator (middle) of the cell.

24. Anaphase • Begins with the separation of the sister chromatids, • by pulling chromosomes to opposite ends of the cell.  

25. Telophase • the chromosomes reach the ends of their respective sides, the nuclear envelope reforms. • There are now two smaller cells each with exactly the same genetic information.  

26. Cytokinesis • Division of cytoplasm

27. Summarize each phase in your own words

28. Asexual Reproduction • the cell just divides into two identical cells.

29. Advantages: • Widely dispersed populations can still reproduce. • Cells are identical to parents and should survive well if conditions don't change.

30. Disadvantages: • Cells are identical to parents and so are vulnerable to the same environmental stresses. • The characteristics of the cells change very slowly

31. Regeneration • Echinoderms exhibit this type of reproduction

32. Regeneration • A piece of a parent is detached, it can grow and develop into a completely new individual Planarians exhibit this type of reproduction.

33. binary fission • involves an equal division of both the organism cytoplasm and nucleus to form two identical organisms. Paramecium

34. Budding • one parent dividing its nucleus (genetic material) equally, but cytoplasm unequally • Hydras, yeasts exhibit this type of reproduction.

35. Parthenogenesis • ("virgin birth"), the females produce eggs, but these develop into young without ever being fertilized. • occurs in some fishes, several kinds of insects, and a few species of lizards.

36. sporulation (spore formation) • reproduction involving specialized single cells coming from one parent

37. Vegetative Propagation • the ability of plants to reproduce without sexual reproduction, by producing new plants from existing vegetative structures. • Vegetative propagation is an example of asexual reproduction.

38. Natural vegetative propagation

39. Vegetative Propagation

40. Vegetative Propagationrunner

41. Artificial Vegetative Propagation Cutting

42. Artificial Vegetative propagationgrafting

43. Telomeres • Telomeres are specialized chromosome tips. • Telomeres are lost during cell division. This causes the chromosomes to SHORTEN each time they divide.

44. How is the cell cycle regulated? • Biochemical checkpoints--a clock provided by shortening chromosome tips, and chemical signals from outside and inside the cell--regulate the cell cycle. • Stem cells maintain the growth and specialization of a tissue.

46. Stem cells • Stem cells are capable of producing specialized cells throughout the body. When a stem cell divides to form two new daughter cells, one specializes (to form a skin cell for example) while the other remains a stem cell--ready to divide again. As a result, skin cells can be replaced without having to divide themselves.

47. Cell division All complex organisms originated from a single fertilized egg. Every cell in your body started here, through cell division the numbers are increased Cell then specialize and change into their various roles

48. Cancer--When the Cell Cycle Goes Awry • cancer cells repeatedly go through the cell  cycle and, essentially, never die…they continue to grow uncontrollably. • Cancer is caused by a series of genetic mutations leading to the development of a tumor (an abnormal mass of cells).

49. Big IDEA: Sexual Reproduction • This process involves two parents.   • Both parents contribute one gamete or sex cell to the process.   • The genetic information given to the offspring will be obtained equally from each parent.