Cellular Reproduction

How Do Cells Receive Nutrients? Cell Membrane The membrane allows in: Food Water Oxygen

The Cell Membrane Selectively permeable – allows only certain materials to pass through. Diffusion – the movement of molecules from areas of higher concentration to areas of lower concentration Osmosis – the movement of molecules from areas of higher to areas of lower concentration through the cell membrane.

The Cell Membrane Three types of solution Hypotonic Note: = Water = Concentration

The Cell Membrane Three types of solution Isotonic Note: = Water = Concentration

The Cell Membrane Three types of solution Hypertonic Note: = Water = Concentration

The Cell Membrane Three types of solutions Hypotonic Isotonic Hypertonic The concentration of water outside of the cell is: Higher Same Lower

The Cell Membrane Three types of solutions Hypotonic Isotonic Hypertonic The concentration of dissolved substance outside of the cell is: Lower Same Higher

The Cell Membrane Three types of solutions Hypotonic Isotonic Hypertonic The cell contents will: Swell Stay the same Shrink

The Cell Membrane The concentration (amount) of dissolved substance affects the movement of water into and out of the cell.

The Cell Membrane Homeostasis – the ability of an organism to maintain a constant internal balance even when the conditions around it change. Examples: Turgor Pressure – the force of the cell contents pushing against the cell wall

The Cell Membrane Passive Transport – the movement of substances through the cell membrane without using energy. Active transport – the movement of molecules from areas of lower to higher concentration with the use of energy.

The Cell Membrane Protein Molecules Lipid Molecules

Surface Area to Volume Ratio Cell Diameter increases 10 times Surface Area increases 100 times Volume increases 1000 times

Surface Area to Volume Ratio Double the cell size (2 times) 8 times more nutrients required 8 times more waste to excrete Surface area increase only 4 times Cell starve to death or be poisoned

Why is it important to have many small cells rather than one Larger cell? Larger cell has: Difficulty in receiving enough nutrients and oxygen Difficulty in removing wastes One copy of DNA

Cell divides into two daughter cells Cell Division Cell divides into two daughter cells

Mitosis Process by which the nucleus of the cell is divided into two nuclei, each with the same number and kinds of chromosomes as the parent cell.

Interphase G1 phase S phase G2 phase Cellular Growth Development DNA Replication Protein synthesis G2 phase Synthesis of organelles Materials for cell division

Interphase

Chromosomes Contain the genetic information (DNA) that is passed from one generation of cells to the next.

Chromosomes DNA Proteins (histones)

Chromosome Structure Sister Chromatid Centromere DNA

Number of Chromosomes Organism Chromosome Number Amoeba 50 Carrot 18 Cat 32 Chimpanzee 48 Dog 78 Earthworm 36 Goldfish 94 HUMAN 46 Lettuce

Prophase Appearance of chromosomes Nucleolus disappears Longest (50 - 60%) Appearance of chromosomes Nucleolus disappears Nuclear membrane breaks down Centrioles separate and migrate to opposite poles of cell Spindle fibers from the centrioles attach to the centromeres Chromatin coils up (shortens) into chromosomes

Prophase

Metaphase Chromosomes line up across center (equator) of cell Shortest Chromosomes line up across center (equator) of cell Spindle fibers from centromere to centrioles

Metaphase Chromosome Centriole Spindle Fiber

Anaphase Sister Chromatids split at Centromere Individual Chromosomes move toward poles Chromatid pairs from each chromosome separate from each other Chromatids are pulled apart by the shortening of the microtubules in the spindle fibers

Anaphase

Telophase Spindle fibers breakdown Chromosomes uncoil into Chromatin Final Phase Spindle fibers breakdown Chromosomes uncoil into Chromatin Nuclear envelope (membrane) reforms Nucleolus becomes visible Chromosome reach the ends of the cell The centrioles double The cytoplasm is divided

Telophase

Mitosis in Whitefish and Onion

Cytokinesis The process by which the cytoplasm divides, forming two new cells.

Cytokinesis Animals Cell membrane pinches inward Plants Cell plate

Result of Mitosis Two cells that are identical to each other.

Cell Theory Developed by Robert Hooke Came up with the name cells Encouraged other scientists to look for cells in their research Cell theory is made up of three main ideas:

Cell Theory All organisms are composed of one or more cells. Most organisms are multicellular Cells are the basic units of structure and function in organisms All cell arise from existing cells Cell theory states that a cell divides to form two identical cells

Cancer

“When Cell Division Goes Bad” Cancer “When Cell Division Goes Bad”

Cancer Uncontrolled cell growth creating a malignant tumor

Tumor A growth from a single mutated cell that has repeatedly undergone cell division

Malignant A tumor that invades surrounding tissue and spreads to other parts of the body

Benign A tumor that does not invade surrounding tissues and does not spread

Metastasize The spread of cancer from the place of origin throughout the body The cancer migrates and invades tissues

Causes of Cancer Heredity -- Breast Cancer, Retinoblastoma Changes in enzymes production Carcinogens -- environmental agent Tobacco (smoke and smokeless), saccharin, pesticides, herbicides, asbestos, benzene, water polution Radiation -- UV light, X-rays, nuclear bombs Viruses -- papillomavirus

Types of Cancer Breast Lung Prostate Colon/Rectum Bladder Lymphoma

Types of Cancer Uterus Skin (melanoma) Oral Cancer Leukemia Pancreas Ovary Testicular

Treatments for Cancer Surgery -- the actual removal of the tumor and other infected areas Chemotherapy -- the use of a drug to selectively kill off cancer cells Radiation -- mutating the dividing cells to stop them from dividing

Prevention Low fat diet High fiber diet Vitamins and minerals Daily Exercise Not using tobacco