1. Life of a cell: The Cell cycle
Cells, Cell Cycle, Mitosis, and Cancer
Chapter 8: page
January 23-26, 2017

2. A Organism at Different Stages of Life

3. What do we remember? We are looking at: Eukaryotic Cells
A plant cell
Has similar cell sizes
Rigid Membranes
Cell Wall
Dark dots
Nucleus

4. Evolutionary Difference
Prokaryotes
Reproduce asexually by binary fission
Asexual repoduction, a simpler reproductive process, single parent produces an identical offspring
Efficient, in some bacteria, can reproduce every 20 minutes
Advantegous due to where prokaryotes live, in less than ideal conditions limited by nutrients, H2O, predation
Cell Division (NEW)
About 25 million somatic cells (not gametes) are being made per second by your body
Creates identical cells of many different types of cells
It is the first and if possible the final step of cellular life, in the cell cycle
Binary Fission

5. Within A Cell Eukaryotes
Due to the presence of a nucleur membrane, different process of cellular division and reproduction (sex cells)
Prior to division, chromosomes are copied which contain instructions for gene expression and protein synthesis.
In cell reproduction, sex cell receive half of an organism’s genetic material when forming gametes
Chromosomes
Chromosomes are structures that consist of DNA and proteins
DNA remains in the nucleus of the cell
contains all of the directions that a cell needs to survive
for most of a cell’s life, chromosomes exist as chromatin
chromatin: long strands of DNA wrapped around proteins
Darken Dot is the Nucleus

6. Chromosomes

7. The Cell Cycle

8. The Cell Cycle Continued.
The sequence of growth and division of a cell
Interphase
G1 phase: cell grows
S phase: Chromosomes copy themselves and form sister chromatids (so that each new cell will have all the chromosomes the original cell had)
G2 phase: cell grows
At each phase, the cyclin checks if the cell is properly working
It will either repair the cell or
Lead to cell death, apoptosis
M phase: mitosis, or cell division, occurs

9. This Image has a Organism exhibiting a Different Stages of Life
Interphase
Interphase
Anaphase
Telophase
Metaphase
Interphase
Interphase
Prophase
Interphase

10. Mitosis Mitosis is used to create multicellular organisms
It is a process that creates new cells
It replaces damaged or old less efficient cells
Cell --> Tissue --> Organ --> Organ system --> Organism
Example:
muscle cell --> muscle tissue --> stomach --> digestive system --> animal

11. Mitosis
Cell division that produces 2 daughter cells that are identical to the original cell
Prophase
Nuclear membrane falls apart
chromasomes condense
centrioles move to opposite sides of the cell and start to form spindle fibers
Metaphase
sister chromatids line up along the spindle fibers in the middle of the cell
Anaphase
sister chromatids separate as the spindle fibers pull them apart to opposite ends of the cell
Telophase
chromosomes decondense
spindle fibers break down
new nuclear membrane forms around each set of chromosomes
Cytokinesis: cytoplasm divides, forming 2 new cells

12. Control of the Cell Cycle
Controlled by proteins called cyclins and enzymes that attach to the cyclins
Without Control, cells will continue to function past their time
Problem, nonfunctioning cells will continue to take resources and will over time starve and disrupt normal functioning cells
Cancer: malignant growth resulting from uncontrolled cell division
enzymes that attach to cyclins are not working properly due to a mutations in the genes for these enzymes
cell keeps dividing because the cell cycle is not working
forms a tumor: mass of cells that keep dividing
second leading cause of death in the US (second to heart disease)
genetics and environment can cause cancer
environmental causes: cigarette smoke, air and water pollution, UV radiation from sun
eating a low-fat, high-fiber diet can reduce your risk of cancer