for the QUIZ :  Name the 4 MAJOR, most abundant elements in the body. O H C N  What are ionic and covalent bonds  What is metabolism?  What is CATABOLISM? What is ANABOLISM?  What is HYDROLYSIS? What is DEHYDRATION SYNTHESIS?  Name the vital roles played by WATER in the body.  What is the ‘NORMAL’ pH of the blood?

Name the 4 Categories of Key ORGANIC COMPOUNDS in the body. Name the distinguishing characteristics between DNA and RNA Name the organelles of the cell

Prep for Quiz, cont.  Describe the structure of the cell membrane  Name the cellular structure which is the command /control center, the site of genetic material for the cell.  What cell. organelle is the Powerhouse of the cell?  Name the 4 phases of MITOSIS and how they look

Chapter 3: Anatomy of Cells

Slid e 5 The BASIC,STRUCTURAL and FUNCTIONAL building blocks of the BODY are the CELLS - Each individual cell is capable of carrying out ALL the basic functions of LIFE, yet cells are SPECIALIZED, and DIFFERENTIATED

Slid e 6  BASIC CELL STRUCTURES: PLASMA (cell) MEMBRANE, CYTOPLASM;  Nucleus, N ucleolus  Mitochondria,  Endoplasmic reticulum, (smooth and rough)  Golgi Apparatus,  RIBOSOMES,  Lysosomes Proteosomes, Peroxisomes  Centrosomes, Centrioles  (newly discovered: VAULTS )  CYTOSKELETON : microfilaments, microtubules, cellular extensions: CILIA, MICROVILLI, FLAGELLA 

Slide 7 This is a ‘cartoon’ version of a typical or composite cell, to demonstrate the various components

‘actual’ cells are of varying shapes and sizes

Cell structures  PLASMA MEMBRANE : separates the cell from its surrounding environment  Primary structure of a cell membrane is a double layer of PHOSPHOLIPID MOLECULES  Heads are hydrophilic (“water loving”)  Tails are hydrophobic (“water fearing”)  Arrange themselves in BILAYERS in water

Cell membranes, cont  CHOLESTEROL MOLECULES are scattered among the phospholipids to stabilize the membrane.  Most of the bilayer is hydrophobic; therefore water and water-soluble molecules DO NOT pass through easily.  Therefore, there are proteins which form CHANNELS, and carrier proteins

The plasma (cell) membrane From these choices, identify the structures: A.Membrane channel protein E. Glycoprotein B.Hydrophobic tail F Phospholipid molecule C.Cholesterol molecule G. Hydrophilic head D. Microtubule H. Lipoprotein

Membrane proteins  A cell controls what moves through the membrane by membrane proteins embedded in the phospholipid bilayer. ( carriers, channels)  Some membrane proteins have carbohydrates attached to them and, as a result, form GLYCOPROTEINS that act as identification markers  Some membrane proteins are RECEPTORS that react to specific chemicals, such as hormones

CYTOPLASM AND ORGANELLES  Cytoplasm: gel-like internal substance of cells that includes:  many organelles and  cytoskeletal structures, and  molecules of various types  suspended in a watery intracellular fluid also called CYTOSOL  The cytoplasm allows for movement of molecules, etc inside the cell

NUCLEUS  spherical body in center of cell; enclosed by an envelope with many pores  CONTAINS THE GENETIC MATERIAL –  DNA MOLECULE within the CHROMOSOME - ALSO SEEN AS CHROMATIN, when the cell is not dividing  (Interphase) Also inside the nucleus: NUCLEOLUS - made up of RNA, it produces ribosomal subunits

NUCLEUS (cont.)  Structure (cont.)  Contains DNA (heredity molecules), which appear as:  Chromatin threads or granules in nondividing cells  Chromosomes in early stages of cell division  Functions of the nucleus are functions of DNA molecules; DNA determines the structure and function of cells, as well as heredity.

Nuclear pore complexes are elaborate gateways in and out of the nucleus >>>

 Mitochondria (Figure 3-11)  wall composed of inner and outer membranes separated by fluid; enzyme molecules are attached to both membranes  The “power plants” of cells; mitochondrial enzymes catalyze series of oxidation reactions that provide most of a cell’s energy supply (CELLULAR RESPIRATION)  Each mitochondrion has a DNA molecule, which allows it to produce its own enzymes and replicate copies of itself MITOCHONDRIA, the power houses of the cell

CYTOPLASM AND ORGANELLES (cont.)  Endoplasmic reticulum (Figure 3-5)  Made of membranous, walled canals and flat, curving sacs arranged in parallel rows throughout the cytoplasm; extend from the plasma membrane to the nucleus  Proteins move through the canals, and are packaged

Endoplasmic reticulum

ENDOPLASMIC RETICULUM  Two types of endoplasmic reticulum  Rough endoplasmic reticulum  RIBOSOMES dot the outer surface of the membranous walls  Ribosomes synthesize proteins, which are moved toward the Golgi apparatus and then eventually leave the cell Function in protein synthesis and intracellular transportation  Smooth endoplasmic reticulum  No ribosomes border the membranous wall  Functions in packaging and storage - steroids and various ions :  Synthesizes certain lipids and carbohydrates and creates membranes for use throughout the cell  Removes and stores calcium ions from the cell’s interior

RIBOSOMES: make protein!  Many are attached to the rough endoplasmic reticulum  and many lie FREE, scattered throughout the cytoplasm  Each ribosome is a nonmembranous structure made of two pieces, a large subunit and a small subunit;  each subunit is composed of rRNA and protein

Ribosomes make protein  Ribosomes in the E.R. make proteins for “export,” or for the plasma membrane;  FREE ribosomes make proteins for the cell’s ‘domestic’, internal use

Ribosomes, two subunits

GOLGI APPARATUS  Membranous organelle consisting of cisternae stacked on one another and located near the endoplasmic reticulums (Figure 3-7)  Processes protein molecules from the endoplasmic reticulum (Figure 3-8)  Processed proteins leave the final cisterna in a vesicle ; contents may then be secreted to outside the cell

(Janitors of the cells): Lysosomes, peroxisomes, and Proteosomes  LYSOMOMES ; solid waste compactors and incinerators, for cellular debris and foreign invaders Abnormalities may lead to cellular injury and death  PEROXISOMES: chemical detoxifiers; TOXINS, such as ethanol  PROTEOSOMES : Recycle PROTEINS

LYSOSOMES  Lysosomes (Figure 3-9)  Made of microscopic membranous sacs that have “pinched off” from Golgi apparatus  THE CELL’S OWN DIGESTIVE SYSTEM ; enzymes in lysosomes digest the protein structures of defective cell parts, including plasma membrane proteins, and particles that have become trapped in the cell

PEROXISOMES act as detoxifiers  Peroxisomes  Small membranous sacs containing enzymes that detoxify harmful substances that enter the cells  Often seen in kidney and liver cells

PROTEASOMES - BREAKDOWN DEFECTIVE PROTEINS  Proteasomes (Figure 3-10)  Hollow protein cylinders found throughout the cytoplasm  Break down abnormal or misfolded proteins and normal proteins no longer needed by the cell (and that may cause disease)  Break down protein molecules one at a time by tagging each molecule, unfolding the protein as it enters the proteasome, and then breaking apart peptide bonds, RELEASING THE AMINO ACIDS,  WHICH ARE THEN AVAILABLE FOR RECYCLING !!!!!!

CYTOSKELETON  The cell’s internal supporting framework;  made of rigid, rodlike pieces that provide support and allow movement and  mechanisms that can move the cell or its parts (Figure 3-14)

CYTOSKELETON (cont.)  Centrosome (Figure 3-16)  near the nucleus  coordinates the building and breaking apart of microtubules in the cell  Nonmembranous structure also called the microtubule organizing center  Plays an important role during cell division  General location of the centrosome is identified by the centrioles

CYTOSKELETON (cont.)  Cell extensions  Cytoskeleton forms projections that extend the plasma membrane outward to form tiny, fingerlike processes  Three types of these processes; each has specific functions (Figure 3-18)

CYTOSKELETON (cont.)  Microvilli: found in epithelial cells that line the intestines and other areas where absorption is important; help increase the surface area manyfold

Cytoskelton, cell extensions  Cilia and flagella: cell processes that have cylinders made of microtubules and molecular motors at their core  Cilia are shorter and more numerous than flagella; cilia have coordinated oarlike movements that brush material past the cell’s surface  FLAGELLA are found only on human sperm cells; flagella move with a tail-like movement that propels the sperm cell forward

Ciliated respiratory epithelium

Flagellated spermatazoa

CELL CONNECTIONS  Cells are held together by fibrous nets that surround groups of cells  (e.g., muscle cells), or  cells have direct connections to each other  Three types of direct cell connections (Figure 3-20)

CELL CONNECTIONS: DIRECT  DESMOSOME  Fibers on the outer surface of each desmosome interlock with each other; anchored internally by intermediate filaments of the cytoskeleton  Spot desmosomes are like “spot welds” at various points connecting adjacent membranes  Belt desmosomes encircle the entire cell  Gap junctions : membrane channels of adjacent plasma membranes adhere to each other; have two effects  Form gaps or “tunnels” that join the cytoplasm of two cells  Fuse two plasma membranes into a single structure  TIGHT JUNCTIONS  Occur in cells that are joined by “collars” of tightly fused material  Molecules cannot permeate the cracks of tight junctions  Occur in the lining of the intestines and other parts of the body where controlling what gets through a sheet of cells is important