Cell Transport and the Cell Cycle

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How cells take in and release nutrients and the

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Cell Transport and the Cell Cycle:

Cell Transport and the Cell Cycle

Cellular Transport:

Cellular Transport Transportation of substances through the plasma membrane helps cells maintain homeostasis and keeps you healthy

Osmosis:

Osmosis The diffusion of water across a selectively permeable membrane Water moves from an area of high water concentration (low solute) to an area of low water concentration (high solute concentation)

Solution:

Solution When a solid is dissolved into a liquid Solute -the solid Solvent -the liquid

Concentration Gradient:

Concentration Gradient The difference in the concentration of solutes in one area compared to another area

Isotonic Solution:

Isotonic Solution A solution in which the concentration of dissolved substances in the solution is the some as the concentration of dissolved substances inside the cell Water neither enters or leaves the cell

Hypotonic Solution:

Hypotonic Solution When the concentration of dissolved substances is lower in the solution outside the cell than the concentration inside the cell Water enters the cell by osmosis and the cell swells

Hypertonic Solution:

Hypertonic Solution When the concentration of dissolved substances outside the cell is higher than the concentration inside the cell Water leaves the cell and the cell shrivels

Passive Transport:

Passive Transport The movement of particles across membranes by diffusion Does not require the use of energy

Facilitated Diffusion:

Facilitated Diffusion The passive transport of materials across the plasma membrane with the aid of transport proteins Is driven by a concentration gradient

Active Transport:

Active Transport Movement of materials through a membrane against a concentration gradient Requires energy use by the cell

Endocytosis:

Endocytosis The process by which a cell surrounds and takes in material from its environment The material is engulfed and enclosed by a portion of the cells membrane and forms a vacuole

Exocytosis:

Exocytosis The expulsion or secretion of materials from a cell Used to expel wastes, such as indigestible particles, from the interior to the exterior environment

Cell Growth and Reproduction:

Cell Growth and Reproduction

Cell Size:

Cell Size Most living cells are between 2 and 200 µm in diameter (µm is 1/1000 th of a mm) Blood cells can be a small as 8 µm The largest cell is the yolk of an ostrich egg measuring 8 cm The longest cells are nerve cell with lengths up to 1 m, but are very small in diameter

Limitations to Cell Size:

Limitations to Cell Size Cell size is limited because diffusion is slow and inefficient across large distances Cells must maintain an appropriate surface are to volume ratio Cell size is limited by DNA which instruct cells to divide before they become to large to function properly

Cell Reproduction:

Cell Reproduction Cell division is the process by which new cells are produced from one cell Results in two cells that are identical to the original parent cell New cells allow an organism to grow or replace old worn out cells

Chromosomes:

Chromosomes Condensed form of DNA and become darkly colored when stained Serve as the carriers of the genetic material that is copied and passed from generation to generation of cells

Chromatin:

Chromatin Long strands of DNA wrapped around proteins Resembles tangled spaghetti or string

The Cell Cycle:

The Cell Cycle The sequence of steps involved in the growth and division of a cell

Interphase:

Interphase The time between cell divisions when a cell grows in size and carries on metabolism Chromosomes are duplicated in preparation for the period of division The majority of a cells lifespan in spent in interphase

PowerPoint Presentation:

Centriole ► ◄ Spindle fibers ▼ Chromatids

Mitosis:

Mitosis Mitoses occurs after interphase is complete It consists of four stages that result in the formation of two daughter cells with identical copies of the DNA

Prophase:

Prophase The first and longest phase of mitosis Chromatin coils up into visible chromosomes which is made up of two halves of exact copies sister chromatids Sister chromatids are held together by a structure called a centromere

Prophase Cont’:

Prophase Cont’ As prophase continues the nucleus and nucleolus begin to disintegrate and disappear Centrioles (small, dark, cylindrical structures that are made of microtubules) begin to migrate to opposite ends of the cell The spindle (a football-shaped cage like structure made of microtubules) is formed

PowerPoint Presentation:

◄ Chromatids

Metaphase:

Metaphase The short second phase of mitosis The doubled chromosomes attach to the spindle fibers by their centromeres and begin to line up on the equator of the spindle

Anaphase:

Anaphase The third phase of mitosis during which the centromeres split apart and chromatid pairs from each chromosome separate from each other The chromatids are pulled apart by the shortening of the microtubules in the spindle fibers

Telophase:

Telophase The final phase of mitosis which begins as the chromatids reach the opposite poles of the cell The chromosomes unwind so they can begin to direct the metabolic activities of the new cells The spindle disappears and a two new nuclei form

Cytokinesis:

Cytokinesis After telophase when the cell’s cytoplasm divides The plasma membrane pinches in along the equator forming two new daughter cells In plants a new cell wall forms along a structure called a cell plate

Results of Mitosis:

Results of Mitosis The process guarantees genetic continuity Results in the production of two new cells with chromosome sets that are identical to those of the parent cell

Cellular Organization:

Cellular Organization Cells ► Tissues ► Organs ► Organism Systems ► Organisms

Control of the Cell Cycle:

Control of the Cell Cycle Accurate cell division and regulation is critical to the health of an organism

Enzymes:

Enzymes Proteins which control the rate of chemical reactions A series of enzymes monitors a cell’s progress from phase to phase during the cell cycle

Genes:

Genes A gene is a segment of DNA that controls the production of a protein

Cancer:

Cancer One result of uncontrolled cell division This loss of control may be caused by environmental factors or by changes in enzyme production

Cancer Cont’:

Cancer Cont’ The result of changes in one or more of the genes that produce enzymes that are involved in controlling the cell cycle

Metastasis:

Metastasis When cancer cells enter the circulatory system and spread throughout the body

Causes of Cancer:

Causes of Cancer Both genetic and environmental factors are involved People in different countries develop different types of cancers at different rates

Environmental Factors:

Environmental Factors Cigarette smoke Air and water pollution Exposure to ultraviolet radiation from the sun May also be carried by viral infections that damage genes

PowerPoint Presentation:

Pesticides

Air Pollution:

Air Pollution

Water Pollution:

Water Pollution

PowerPoint Presentation:

Sunburn

PowerPoint Presentation:

Skin Cancer

Cancer Treatment:

Cancer Treatment Chemotherapy-toxic chemicals which kill fast growing cancer cells Radiation therapy-bombards cancer cells with damaging radiation

Cancer Prevention:

Cancer Prevention A healthy lifestyle can prevent or reduce the incidence of cancer Eat a diet low in fat and high in fiber Vitamins and minerals may also help prevent cancer Limit exposure to sunlight

PowerPoint Presentation:

Radiation Treatment

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