1. Mitosis

2. The Cell Theory All living things are made up of one or more cells
Cells are the basic unit of structure and function in living things
All cells come from preexisting cells

3. Section Summary The genetic material is deoxyribonucleic acid (DNA).
DNA is packaged into chromatin, which condenses to form chromosomes.

4. Section Summary
During interphase of the cell cycle, the cell lives, grows, and replicates its DNA.
In mitotic phase (M phase), the chromosomes distribute to daughter cells.
A duplicated chromosome consists of two sister chromatids.

6. Human Karyotype

7. Chromosome numbers

9. Genes Every cell’s DNA is organized into genes.
Genes are units of inherited information that carry a code for specific traits or functions.

10. Genes Many genes code for proteins.
The information contained in genes is responsible for inheritance — the passing down of traits from parent organisms to their offspring.

11. DNA The nucleus contains the cell’s DNA.
For much of a cell’s life, its DNA exists as a mass of very long fibres called chromatin, a combination of DNA and protein.
Chromatin is very thin and not usually visible with a light microscope.

12. Chromosomes
As a cell is preparing to divide, its chromatin fibres condense, becoming visible compact structures called chromosomes.

13. Chromosomes
A chromosome consists of one long, condensed DNA molecule containing hundreds or thousands of genes.

14. Chromosome
Chromatin

15. The Components of DNA
DNA consists of a long chain of subunits called nucleotides. A nucleotide has three parts: 1. A ring-shaped sugar called deoxyribose 2. A phosphate group 3. A nitrogenous base (or base, for short): a single or double ring of carbon and nitrogen atoms

16. DNA limits cell size Nucleus contains blueprints for cell proteins
Proteins used by almost all organelles to function

17. DNA limits cell size
There is a limit of how quickly proteins can be copied and made in nucleus
Cell cannot survive unless DNA can support protein needs of cell

18. Cell Cycle
Cell Cycle: Sequence of growth and division of the cell.

19. Phases of Cell Cycle INTERPHASE: The longest phase Cell grows in size
Cell carries on
metabolism
Chromosomes are
duplicated to prepare
for division

20. Phases of the Cell Cycle
After Interphase, cell enters period of division, called Mitosis.
Mitosis:
Forms two identical daughter cells each with a complete set of chromosomes
Mitosis

21. Phases of Mitosis
Four phases:
Prophase
Metaphase
Anaphase
Telophase

22. Prophase chromosomes condense
nucleolus and nuclear envelope disintegrates
centrioles migrate to opposite ends
spindles form between centrioles

23. Prophase Long stringy chromatin coils up into visible chromosomes

24. Prophase
Each duplicated chromosome is made of two halves called sister chromatids.
Sister chromatids are held together by a centromere
Centromere
Sister chromatids

25. Prophase Spindle fibers Disappearing nuclear envelope
Double stranded chromosome
Disappearing nuclear envelope
Spindle fibers

26. Metaphase
Double stranded chromosomes attach to spindle fibers by centromeres
Double stranded chromosomes pulled by spindle fibers and line up on equator

27. Metaphase
This arrangement of the chromatids ensures that each new cell receives identical and complete set of chromosomes

28. Anaphase Centromeres split Sister chromatids separate
Shortening of spindle fibers pull apart chromatids to opposite poles

29. Telophase Begins once chromatids reach opposite poles
Chromosomes begin to unwind
Spindle breaks down

30. Telophase
Nucleolus and nuclear envelope reappears around new set of chromosomes
Two identical daughter cells formed

31. Cytokinesis After Telophase, the cell’s cytoplasm divides.
Animal Cells: the plasma membrane pinches together, forming two separate cells.
Plant Cells: Cell plate laid across cell’s equator—there is no pinching off. Cell membrane forms around each cell and new cell walls form on each side of cell plate

32. Cytokinesis

33. What are the results of Mitosis?
Two identical daughter cells
Single celled organism remains a single cell but has replicated itself
Multicellular organisms have grown or created another cell that will work together as tissue to perform a certain function

34. Mitosis Animation
CellsAlive

35. Cell Growth and Reproduction
Section Quiz:
The stringy structures in the cell nucleus that contain DNA are __________.
Centromeres
Chromatin
Genes
Chlorophylls

36. Cell Growth and Reproduction
Section Quiz:
2. What phases are the following cells in?

37. Cell Growth and Reproduction
TELOPHASE

38. Cell Growth and Reproduction
PROPHASE

39. Cell Growth and Reproduction
METAPHASE

40. Cell Growth and Reproduction
ANAPHASE

41. Cell Growth and Reproduction
CYTOKINESIS

42. Cell Growth and Reproduction
INTERPHASE

43. Control of the Cell Cycle
What happens when MITOSIS goes WILD?
CANCER

44. Control of the Cell Cycle
Cancer:
Malignant growth due to uncontrolled cell division
Caused by environmental factors
Changes in enzyme production
                                                                                                                               
Figure 1 Lung cancer cells (530x). These cells are from a tumor located in the alveolus (air sac) of a lung.

46. Cancer Cancerous cells form masses of tissues called MALIGNANT tumors.
Tumors starve normal cells from nutrients
Wait! But can’t I have a BENIGN tumor?
YES! Benign tumors are masses of tissues that are harmless. (BENIGN = HARMLESS)
Created by slower growing cells that clump together to form lump

48. Control of the Cell Cycle
Can I prevent Cancer?
Diets high in fiber and low in fat
Take vitamins
Daily exercise
Refrain from smoking and use of other tobacco products
Avoid exposure to UV light (in sunlight)
Avoid exposure to X-rays