Human Anatomy and Physiology I Chapter 3 - Part 1 The Cell Instructor: Mary Holman

Levels of Organization Subatomic particles Atom Molecule Macromolecule Organelle Cell Tissue Organ Organ system Organism Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig 1.3

Cells Basic units of all living things Differentiate into many different types All cell types have some basic characteristics in common Cytology The study of cellular structure

Fig. 3.2 (b) Epithelial cells protect underlying cells.(c) Muscle cells contract, pulling structures closer together. (a) A nerve cell transmits impulses from one body part to another. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig. 3.2

Fig. 3.3 Microtubules Flagellum Nuclear envelope Basal body Chromatin Ribosomes Cell membrane Mitochondrion Cilia Microtubules Microtubule Golgi apparatus Secretory vesicles Centrioles Microvilli Lysosomes Smooth Endoplasmic reticulum Rough Endoplasmic reticulum Nucleolus Nucleus Phospholipid bilayer Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pg 86 Fig. 3.3

Cell Membrane also called Plasma Membrane Outer surface of the cell Composed of phospholipid bi-layer Selectively permeable Protein molecules embedded in the membrane control entrance and exit of molecules

C H H H H C H H N O O Fatty acid O POCH O – Phosphate portion (the unshaded portion may vary) H CH C H H O Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig. 2.15b A Phospholipid Molecule

Fig. 2.15c Schematic representation of a phospholipid molecule Water-insoluble (hydrophobic) “tail” Water-soluble (hydrophilic) “head” Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Cell membrane “Heads” of phospholipid “Tails” of phospholipid Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Hydrophilic Middle of membrane Hydrophobic Fig. 3.6b cytoplasm

Fig. 3.7 Double layer of phospholipid molecules Fibrous protein Extracellular side of membrane Cytoplasmic side of membrane Carbohydrate Hydrophobic fatty acid “tail” Hydrophilic phosphate “head” Cholesterol molecules Globular protein Glycolipid Glycoprotein Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig. 3.7

Nucleus Surrounded by a nuclear membrane which has pores to the cytoplasm Contains a nucleolus consisting primarily of ribonucleic acid (RNA) The nucleoplasm contains darkly staining chromatin

Fig. 3.19a Nuclear pores Nucleus Nucleolus Chromatin Nuclear envelope Fig The Cell Nucleus

Fig. 3.19b Nucleolus Chromatin Nuclear envelope Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Stephen L. Wolfe 7,500x Fig. 3.19b

Cytoplasm Cellular material outside the nucleus but inside the cellular membrane Consists of a fluid portion called cytosol, acytoskeleton, organelles, and inclusions

Microfilaments Slender fibers of the protein actin Bundles of microfilaments along with microtubules provide the framework of the cytoskeleton Connect to cellular components providing a matrix to the cytoplasm and lending strength

Microtubules Long slender hollow tubes made up of the protein tubulin Two to three times larger in diameter than microfilaments Provide the framework for movement of organelles within the cell Basic component of centrioles, cilia, and flagella

Fig. 3.18a Mitochondrion Nucleus Rough endoplasmic reticulum Cell membrane MicrofilamentsRibosome Microtubules Vesicle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig. 3 18a

Microtubules Microfilaments Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © M. Schliwa/Visuals Unlimited Fig ,000x

Kirschner MW, Suter MM, Weingarten MD, Littman DR: The role of in the assembly of microtubules in vitro. Annals NY Acad Sci, 253:90-106, Weingarten MD, Suter MM, Littman DR, Kirschner MW: Properties of the depolymerization products of microtubules from mammalian brain. Biochemistry, 13: , 1974.

Organelles Small structures within cells with specialized functions The number and type of organelles within a specific cell are related to the specific structure and function of that cell

Ribosomes Site of protein synthesis Non-membranous Scattered throughout the cytoplasm and attached to endoplasmic reticulum (ER) Composed of two sub-units Subunits are manufactured separately in the nucleolus

ER membrane Ribosomes (a) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Don W. Fawcett/Photo Researchers, Inc. 28,500x Fig. 3.9a Ribosomes on the Endoplasmic Reticulum

Endoplasmic Reticulum (ER) Most extensive structure within the cytoplasm Composed of broad, flattened, interconnected sacs andtubules Interior spaces called cisternae Provides pathway for intracellular transport of molecules Called Rough ER (RER) when covered with ribosomes

ER Membranes Ribosomes Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Endoplasmic Reticulum Fig. 3.9

Smooth ER Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig. 3.9c

Golgi Apparatus Connected to Rough ER (RER) Composed of stacks of flattened membranous sacs called cisternae Modifies, packages, and distributes proteins and lipids made on rough and smooth ER Receives and transports molecules via vesicles

Fig. 3.10b Golgi apparatus Nucleus Cytosol Transport vesicle Secretion Cell membrane Nuclear envelope Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Rough Endoplasmic reticulum Fig. 3.10b Golgi Apparatus Nucleus

Fig. 3.10a Golgi apparatus Rough Endoplasmic reticulum Transport vesicle (a) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Gordon Leedale/Biophoto Associates 48,500x Golgi Apparatus Fig.3.10a

Vesicles Small membranous sacs that vary in size and contents Form by pinching off of small pieces of membrane that surround a tiny amount of liquid or solid Method of distributing molecules within a cell and/or into and out of cell

Fig Carbohydrates Cell membrane Mitochondrion Lysosome Nuclear pore Nuclear envelope mRNA Milk protein Lipids are Synthesized in the smooth Endoplasmic reticulum (ER ). Most proteins are synthesized On ribosomes associated with Membranes of the rough ER, Using amino acids in the cytosol. Sugars are synthesized in the smooth ER and Golgi apparatus and may be attached to proteins or secreted in vesicles. Proteins are secreted from vesicles that bud off of the Golgi apparatus. Fat droplets pick up a layer of lipid from the cell membrane as they exit the cell Milk protein genes are transcribed into mRNA. 1 mRNA exits through Nuclear pores. Milk Protein in Golgi vesicle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Fig 3.11 pg 93

Mitochondrion Rod-shaped bodies with double- layered walls Inner layer has many infoldings called cristae Major site of energy (ATP) production Have their own DNA and ribosomes which are inherited solely from the mother

Fig. 3.12a Cristae Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Bill Longcore/Photo Researchers, Inc. Mitochondrion 28,000x Fig.3.12

Lysosomes Membrane-enclosed vesicles of varying shape Contain a variety of enzymes Clean up the cell by destroying debris, unnecessary molecules, aging organelles and foreign particles Can play a role in facilitating cell death

Peroxisomes Similar to lysosomes in structure but usually smaller Contain enzymes for breaking down various often toxic substances peroxidases and catalase Most abundant in liver and kidney cells which are active in detoxification

Centrosome Located near the nucleus Consists of 2 non-membranous cylinders - centrioles, at right angles to each other Made up of microtubules Distribute chromosomes during cell division by forming spindle fibers

Fig. 3.14b Centriole (cross-section ) Centriole (longitudinal section) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Centrioles Pg 96

Fig. 3.14a (a) Centriole (cross-section ) Centriole (longitudinal section) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a: © Don W. Fawcett/Visuals Unlimited 120,000x Fig. 3.14a Centrioles

Cilia and Flagella Hair-like appendages on some cells Function in providing movement Both originate from centrioles and are made up of microtubules Cilia are usually <20 um long Flagella can be thousands of um in length The only human cell with a flagellum is the sperm cell

Fig. 3.15a Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Oliver Meckes/Photo Researchers, Inc. Epithelial cell lining the Respiratory Tract Cilia 5,400x Fig. 3.15a

Fig Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Colin Anderson/Brand X/CORBIS 1,400x Fig. 3.16

Fig. 3.3 Microtubules Flagellum Nuclear envelope Basal body Chromatin Ribosomes Cell membrane Mitochondrion Cilia Microtubules Microtubule Golgi apparatus Secretory vesicles Centrioles Microvilli Lysosomes Smooth Endoplasmic reticulum Rough Endoplasmic reticulum Nucleolus Nucleus Phospholipid bilayer Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Pg 78

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Microvilli Cell membrane Mitochondrion Golgi apparatus Nucleolus Nucleus (a) LumenMicrovilli (b) Rough endoplasmic reticulum Cytoplasm of epithelial cell b: © The McGraw-Hill Companies, Inc./Al Telser, photographer 16,000x Intestinal Epithelial Cell Chap 17 pg 678