PowerPoint ® Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings PART A 3 Cells and Tissues

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Cells and Tissues  Carry out all chemical activities needed to sustain life  Cells are the building blocks of all living things  Tissues are groups of cells that are similar in structure and function

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Overview  Made of 5 Main Elements  Carbon  Hydrogen  Oxygen  Nitrogen  And Phosphorus  Living cells are about 60% Water  Cells are constantly bathed in a saltwater-like solution called INTERSTITIAL FLUID.  All exchanges between CELLS and BLOOD are made through this fluid

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Cells Vary in Anatomy  STRUCTURE defines FUNCTION  What organelles are present?  How big/small is the cell?  What is the SHAPE of the cell?  Where in the body is the cell located?

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Cells Vary in Physiology  Ability to move throughout the blood/body?  What products are made by the cell?  Do these products impact other cells?  Is it able to communicate with other cells?

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Anatomy of the Cell  Cells are not all the same  All cells share general structures  All cells have three main regions  Nucleus  Cytoplasm  Plasma membrane Figure 3.1a

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Nucleus  Control center of the cell  Contains genetic material (DNA)  Three regions  Nuclear envelope (membrane)  Nucleolus  Chromatin

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Nucleus Figure 3.1b

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Nucleus  Nuclear envelope (membrane)  FUNCTION: Control what enters/exits the nucleus.  CHARACTERISTICS:  Consists of a double phospholipid membrane  Contains nuclear pores that allow for exchange of material with the rest of the cell

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Nucleus  Nucleoli  FUNCTION: Sites of ribosome assembly  CHARACTERISTICS: Nucleus contains one or more nucleoli  Dark-staining round body(s)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings The Nucleus  Chromatin  FUNCTION: DNA carries instructions for cell structure and function through the production of proteins.  CHARACTERISTICS:  When cell is not dividing DNA is present as chromatin (spaghetti on a plate)  When the cell is dividing (mitosis) DNA condenses to form chromosomes (“X”)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Plasma Membrane  Barrier for cell contents  Double phospholipid layer  Contains  Hydrophilic heads  Hydrophobic tails  Also contains  Proteins that act as channels  Cholesterol that makes cell membrane more rigid  Glycoproteins provides cell surface identity

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Plasma Membrane Figure 3.2 Membrane Structure PLAY

Plasma Membrane Specializations  Microvilli  Finger-like projections that increase surface area for absorption  Membrane junctions  Tight junctions  Impermeable junctions  Bind cells together into leak-proof sheets  Desmosomes  Anchoring junctions that prevent cells from being pulled apart  Gap junctions  Allow communication between cells

Plasma Membrane Specializations Desmosomes (Anchoring Junctions) PLAY Tight Junctions PLAY

Cytoplasm  Cytoplasm is the material outside the nucleus and inside the plasma membrane  Contains three major elements  Cytosol  Jelly-like fluid that suspends other elements  Organelles  Metabolic machinery of the cell  “Little organs” that perform functions for the cell  Inclusions  Chemical substances such as stored nutrients or cell products

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Cytoplasmic Organelles Figure 3.4

ORGANELLE GENERAL FUNCTION Mitochondria Contains own circular piece of DNA Produce ATP (energy) from glucose Ribosomes Free in cytoplasm and attached on ER Assemble proteins Endoplasmic reticulum 2 forms, smooth and rough Smooth - transport Rough – transports proteins Golgi ApparatusPackages mainly lipids for transport Lysosomes Double membrane structure for protection Contains digestive enzymes Peroxisomes Specialized lysosomes Contains catalase to breakdown hydrogen peroxide CytoskeletonCell support, structure, and framework CentriolesCreates spindle fibers during mitosis for separation of chromosomes. Specialized StructuresCilia – moves substances over surface of cell (respiratory cells) Flagella – moves the cell itself (sperm)

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Cell Diversity

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Cell Diversity Tour of the Cell PLAY

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Membrane Transport  movement of substances into and out of the cell. The Plasma membrane is SELECTIVELY PERMEABLE; it allows some substances to pass through while excluding others.  Intracellular fluid: WITHIN THE CELL; nucleoplasm and cytosol. Small amounts of gases (O 2 and CO 2 ), nutrients and salts dissolved in water.  Interstitial fluid: OUTSIDE OF CELL; rich and nutritious. Contains nutrients, hormones, neurotransmitters, salts, and waste products. Cells must EXTRACT needed substances from this fluid in order to maintain HOMEOSTASIS.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings What happens to membrane permeability in UNHEALTHY cells? Explain below. SELECTIVE PERMEABILITY is a property of healthy, functioning cells. When cells are damaged or dying, they lose the ability to control the movement of substances across the cell membrane therefore losing HOMEOSTASIS.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Passive Transport Processes  Diffusion: Particles tend to distribute themselves EVENLY within a solution.  Movement is from HIGH concentration to LOW concentration.  Molecules will diffuse through the plasma membrane if: 1.They are small enough to pass through pores (membrane proteins). 2.They can dissolve in the fatty portion of the membrane. 3.They are assisted by a membrane carrier.

Types of diffusion Simple diffusion: unassisted movement through the membrane. Solutes are lipid-soluble materials or small enough to pass through membrane pores What materials will pass through the membrane by SIMPLE DIFFUSION?  Lipid-soluble (fats, gases, some vitamins) or small enough to pass (ions) through pores.  Osmosis: simple diffusion of WATER.  Facilitated diffusion  Transports lipid-INSOLUBLE and large substances.  Substances require a MEMBRANE carrier for passive transport.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Types of Diffusion: Filtration Filtration: Water and solutes are forced through a membrane by fluid, or HYDROSTATIC pressure.  Hydrostatic pressure is usually exerted by the BLOOD.  Filtration is necessary for the KIDNEYS to do their job properly.  Solute-containing fluid is pushed from a HIGHER- pressure area to a LOWER- pressure area.

Active Transport Processes ATP is used for transport  Needed when:  Substances are transported that are unable to pass by diffusion.  Substances may be too LARGE.  Substances may not be able to dissolve in the FAT CORE (lipid) of the membrane.  Substances may have to move AGAINST a concentration gradient

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Solute Pumping  Amino acids, some sugars, and most ions are transported by Solute Pumps.  Sodium-Potassium Pump: what purpose does this Solute Pump serve? Carries sodium ions out of an potassium ions into the cell. This is needed for normal transmission of impulses by nerve cells. These ions move against their concentration gradients, from LOW to HIGH so they must be PUMPED (forced) into the desired locations across the cell membrane; this requires ENERGY in the form of ATP.

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Vesicular transport  Exocytosis: Moves materials OUT OF the cell  Material is carried in a membranous VESICLE or SAC.  Vesicle migrates to plasma membrane  Vesicle combines with plasma membrane  Material is emptied to the outside

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Endocytosis Extracellular substances are engulfed by being enclosed in a membranous vesicle.  Phagocytosis: “cell eating”  Needed by white blood cells to consume and digest foreign particles. The vesicle fuses with a lysosome to digest contents and detoxify.  What types of cells perform phagocytosis?  SOME white blood cells  Pinocytosis: “cell drinking”  Receptor-mediated endocytosis: SELECTIVE uptake of products needed by the cell.  What products are taken into cells by this process?  Enzymes, hormones, cholesterol, and iron. SOME viruses. 

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Receptor-mediated endocytosis SELECTIVE uptake of products needed by the cell.  What products are taken into cells by this process?  Enzymes, hormones, cholesterol, and iron. SOME viruses.