Presentation is loading. Please wait.

Presentation is loading. Please wait.

Largest Cell Longest Cell Diffusion limits cell sizeDiffusion limits cell size –Slow and inefficient over large areas –Will stop growing and dividing.

Similar presentations


Presentation on theme: "Largest Cell Longest Cell Diffusion limits cell sizeDiffusion limits cell size –Slow and inefficient over large areas –Will stop growing and dividing."— Presentation transcript:

1

2 Largest Cell Longest Cell

3 Diffusion limits cell sizeDiffusion limits cell size –Slow and inefficient over large areas –Will stop growing and dividing when crowded DNA limits cell sizeDNA limits cell size –Limit to how quickly DNA can be read –Limit to # of proteins built/period of time Surface area to volume ratio limits cell sizeSurface area to volume ratio limits cell size –Volume increases faster than surface area –Requires more nutrients, produces more waste, but with relatively smaller surface area

4 Which one of these has the best ratio of surface area to cell volume?Which one of these has the best ratio of surface area to cell volume?

5 All cells in the world today came from preexisting cells (Cell Theory)All cells in the world today came from preexisting cells (Cell Theory) How does this happen?How does this happen? The cell cycleThe cell cycle

6 The cell life cycle is the series of changes a cell goes through from the time it forms until it divides.The cell life cycle is the series of changes a cell goes through from the time it forms until it divides. Two major periods:Two major periods: –Interphase – cell grows and carries on metabolic activities –Cell Division – cell reproduces itself

7 InterphaseInterphase –G1: Cell growth –S: DNA replication –G2: Prepare to divide MitosisMitosis –Process which forms two daughter cells.

8 Longest phase in cell cycle (90+% of time)Longest phase in cell cycle (90+% of time) Cell is very activeCell is very active Plant CellAnimal Cell

9 Chromosomes form

10 DNA when it is tightly packed. Chromosomes appear just before a cell reproduces.DNA when it is tightly packed. Chromosomes appear just before a cell reproduces. – Formed from condensed chromatin

11 Two halves called sister chromatidsTwo halves called sister chromatids Center region called centromereCenter region called centromere Nucleus disappearsNucleus disappears Centrioles migrate to opposite polesCentrioles migrate to opposite poles Spindle fibers made of microtubules form between centriolesSpindle fibers made of microtubules form between centrioles

12 Chromosomes line up

13 Chromosomes attached to spindle fibers at centromeresChromosomes attached to spindle fibers at centromeres Pulled to middle (equator) by spindle fibersPulled to middle (equator) by spindle fibers Each sister chromatid has own fiberEach sister chromatid has own fiber

14 Chromosomes begin to pull apart

15 Sister chromatids separate into individual chromosomesSister chromatids separate into individual chromosomes Chromosomes are moved apartChromosomes are moved apart

16 Chromosomes at opposite ends

17 Nucleus reformsNucleus reforms Chromosomes unwind into ChromatinChromosomes unwind into Chromatin Spindle breaks downSpindle breaks down Nucleolus reappearsNucleolus reappears

18 Cell splits into two cells.

19 Division of the cytoplasm itself into two new cells.Division of the cytoplasm itself into two new cells. In animal cells, they are pinched apartIn animal cells, they are pinched apart In plant cells, a cell plate is formed which develops into new cell wall.In plant cells, a cell plate is formed which develops into new cell wall.

20 During normal mitotic division, a cell will divide into daughter cells with the same number of chromosomes as they had.During normal mitotic division, a cell will divide into daughter cells with the same number of chromosomes as they had. For example, a mother cell with four chromosomes will divide into two daughter cells. They will both have four chromosomes as well.For example, a mother cell with four chromosomes will divide into two daughter cells. They will both have four chromosomes as well.

21 Mitosis in Real Time - Video

22 G1G1 S G2G2 PROPHASEPROPHASE METAPHASEMETAPHASE ANAPHASEANAPHASE TELOPHASETELOPHASE CYTOKENISISCYTOKENISIS INTERPHASE MITOSIS

23 Allows for multicellular organismsAllows for multicellular organisms Cells  tissues  organs  organ systems  organismsCells  tissues  organs  organ systems  organisms

24

25 Cell division can be regulated by factors outside the cell.Cell division can be regulated by factors outside the cell. Proteins called Cyclins interact with enzymes to become activatedProteins called Cyclins interact with enzymes to become activated These proteins control the cell cycleThese proteins control the cell cycle

26 Cancer – malignant growth resulting from uncontrolled cell division.Cancer – malignant growth resulting from uncontrolled cell division. Change in one or more genes that produce CyclinChange in one or more genes that produce Cyclin Gene p53 is the most common defective gene in cancerous cells.Gene p53 is the most common defective gene in cancerous cells. p53 normally halts the cell cycle until all chromosomes have been replicated.p53 normally halts the cell cycle until all chromosomes have been replicated. A defective p53 gene may inflict chromosomal damage to a cellA defective p53 gene may inflict chromosomal damage to a cell

27 Cancerous cells form masses called tumorsCancerous cells form masses called tumors 2 nd leading cause of death in US2 nd leading cause of death in US Affects any tissue in bodyAffects any tissue in body

28 –Environmental Conditions (carcinogens) Affect Genes: segment of DNA responsible for production of a proteinAffect Genes: segment of DNA responsible for production of a protein Failure to produce enzymesFailure to produce enzymes Overproduction of enzymesOverproduction of enzymes –Viral Infection Bob MarleyBob Marley

29 Cancer cells do not respond to signals that regulate the growth of most cells.Cancer cells do not respond to signals that regulate the growth of most cells. Chemotherapy acts by killing cells that divide rapidly – by stopping the cell cycle (Mitosis)Chemotherapy acts by killing cells that divide rapidly – by stopping the cell cycle (Mitosis)

30

31 1.Lung Cancer 2.Head and Neck Cancer 3.Mouth Cancer 4.Esophageal Cancer and Throat Cancer 5.Pancreatic Cancer 6.Colorectal Cancer 7.Stomach Cancer 8.Bladder Cancer 9.Cervical Cancer 10.Breast Cancer 11.Colorectal Cancer 12.Kidney Cancer 13.Myeloid Leukemia 14.Liver cancer Encyclopedia of Cancer by R.N. Tamara L. Brown http://www.ash.org.uk/html/factsheets/html/fact04.html

32

33

34 Diets low in fat and high in fiber contentDiets low in fat and high in fiber content Vitamins and minerals may also prevent cancerVitamins and minerals may also prevent cancer Daily exercise and controlling environmental conditions help as well.Daily exercise and controlling environmental conditions help as well. DON’T SMOKE!DON’T SMOKE!


Download ppt "Largest Cell Longest Cell Diffusion limits cell sizeDiffusion limits cell size –Slow and inefficient over large areas –Will stop growing and dividing."

Similar presentations


Ads by Google