This document provides an overview of cell biology concepts including: - The basic unit of structure and function in the human body is the cell, with trillions of cells varying in size and shape. - A typical cell contains organelles like the nucleus, mitochondria, Golgi apparatus, and endoplasmic reticulum that allow for specialized functions. - Substances move into and out of cells through passive diffusion or active transport processes that either require or do not require energy. - Cell division through mitosis and cytokinesis allows cells to replicate, while cell cycle regulation and apoptosis control cell numbers.

1. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 3 Lecture PowerPoint

2. 2401 Anatomy and Physiology I Chapter 3 Susan Gossett [email_address] Department of Biology Paris Junior College

3. Hole’s Human Anatomy and Physiology Twelfth Edition Shier  Butler  Lewis Chapter 3 Cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

4. 3.1: Introduction The basic organizational structure of the human body is the cell. There are 50-100 trillion cells in the human body. Differentiation is when cells specialize. As a result of differentiation, cells vary in size and shape due to their unique function.

5. 3.2: A Composite Cell Also called a ‘typical’ cell Major parts include: Nucleus Cytoplasm Cell membrane Microtubules Flagellum Nuclear envelope Basal body Chromatin Ribosomes Cell membrane Mitochondrion Cilia Microtubules Microtubule Centrioles Microvilli L ysosomes Nucleolus Nucleus Phospholipid bilayer Smooth Endoplasmic reticulum Rough Endoplasmic reticulum Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Golgi apparatus Secretory vesicles

6. Cell Membrane (aka Plasma Membrane) Outer limit of the cell Controls what moves in and out of the cell Selectively permeable Phospholipid bilayer Water-soluble “heads” form surfaces (hydrophilic) Water-insoluble “tails” form interior (hydrophobic) Permeable to lipid-soluble substances Cholesterol stabilizes the membrane Proteins: Receptors Pores, channels and carriers Enzymes CAMS Self-markers

7. Cell Membrane (a) “ Heads” of phospholipid “ Tails” of phospholipid Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a: © Biophoto Associates/Photo Researchers, Inc. Fibrous protein Carbohydrate Glycolipid Glycoprotein Extracellular side of membrane Cytoplasmic side of membrane Cholesterol molecules Globular protein Double layer of Phospholipid molecules Hydrophobic fatty acid “ tail” Hydrophilic Phosphate “ head” Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cell membrane Cell membrane (b)

8. 3.1 Clinical Application Faulty Ion Channels Cause Disease

9. Cell Adhesion Molecules (CAMs) Guide cells on the move Selectin – allows white blood cells to “anchor” Integrin – guides white blood cells through capillary walls Important for growth of embryonic tissue Important for growth of nerve cells Adhesion White blood cell Integrin Selectin Exit Splinter Attachment (rolling) Blood vessel lining cell Carbohydrates on capillary wall Adhesion receptor proteins Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

10. Cytoplasm Cytosol = water Organelles = solids Cytoplasm is really like a Jello fruit salad where the Jello is the cytosol and the fruits (oranges, grapes, bananas, maybe walnuts, etc.) are the organelles.

11. Organelles Endoplasmic Reticulum (ER) Connected, membrane-bound sacs, canals, and vesicles Transport system Rough ER Studded with ribosomes Smooth ER Lipid synthesis Added to proteins arriving from rough ER Break down of drugs Ribosomes Free floating or connected to ER Provide structural support and enzyme activity to amino acids to form protein Membranes Ribosomes Membranes (b) (c) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

12. Organelles Golgi apparatus Stack of flattened, membranous sacs Modifies, packages and delivers proteins Vesicles Membranous sacs Store substances Inner membrane Outer membrane Cristae (a) (b) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a: © Bill Longcore/Photo Researchers, Inc. Mitochondria Membranous sacs with inner partitions Generate energy

13. Organelles Lysosomes Enzyme-containing sacs Digest worn out cell parts or unwanted substances Peroxisomes Enzyme-containing sacs Break down organic molecules Centrosome Two rod-like centrioles Used to produce cilia and flagella Distributes chromosomes during cell division (a) (b) Centriole (cross-section) Centriole (longitudinal section) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a: © Don W. Fawcett/Visuals Unlimited

14. Organelles Cilia Short hair-like projections Propel substances on cell surface Flagellum Long tail-like projection Provides motility to sperm Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. a: © Oliver Meckes/Photo Researchers, Inc. © Colin Anderson/Brand X/CORBIS

15. Organelles Microfilaments and microtubules Thin rods and tubules Support cytoplasm Allows for movement of organelles Inclusions Temporary nutrients and pigments Microtubules Microfilaments Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © M. Schliwa/Visuals Unlimited

16. 3.2 Clinical Application Disease at the Organelle Level

17. Cell Nucleus Control center of the cell Nuclear envelope Porous double membrane Separates nucleoplasm from cytoplasm Nucleolus Dense collection of RNA and proteins Site of ribosome production Chromatin Fibers of DNA and proteins Stores information for synthesis of proteins Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Nucleus Nucleolus Chromatin (a) Nuclear pores Nuclear envelope

18. 3.3: Movements Into and Out of the Cell Passive (Physical) Processes Require no cellular energy and include: Simple diffusion Facilitated diffusion Osmosis Filtration Active (Physiological) Processes Require cellular energy and include: Active transport Endocytosis Exocytosis Transcytosis

19. Simple Diffusion Movement of substances from regions of higher concentration to regions of lower concentration Oxygen, carbon dioxide and lipid-soluble substances T ime Solute molecule W ater molecule A B A B (2) (3) Permeable membrane A B (1) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

20. Facilitated Diffusion Diffusion across a membrane with the help of a channel or carrier molecule Glucose and amino acids Region of higher concentration Transported substance Region of lower concentration Protein carrier molecule Cell membrane Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

21. Osmosis Movement of water through a selectively permeable membrane from regions of higher concentration to regions of lower concentration Water moves toward a higher concentration of solutes T ime Protein molecule W ater molecule A B A B (1) (2) Selectively permeable membrane Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

22. Osmosis and Osmotic Pressure Osmotic Pressure – ability of osmosis to generate enough pressure to move a volume of water Osmotic pressure increases as the concentration of nonpermeable solutes increases Isotonic – same osmotic pressure Hypertonic – higher osmotic pressure (water loss) Hypotonic – lower osmotic pressure (water gain) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © David M. Phillips/Visuals Unlimited (b) (a) (c)

23. Filtration Smaller molecules are forced through porous membranes Hydrostatic pressure important in the body Molecules leaving blood capillaries Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Capillary wall Larger molecules Smaller molecules Blood pressure Blood flow Tissue fluid

24. Active Transport Carrier molecules transport substances across a membrane from regions of lower concentration to regions of higher concentration Sugars, amino acids, sodium ions, potassium ions, etc. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Carrier protein Binding site (a) (b) Cell membrane Carrier protein with altered shape Phospholipid molecules Transported particle Cellular energy Region of higher concentration Region of lower concentration

25. Active Transport: Sodium-Potassium Pump Active transport mechanism Creates balance by “pumping” three (3) sodium (Na+) OUT and two (2) potassium (K+) INTO the cell 3:2 ratio

26. Endocytosis Cell engulfs a substance by forming a vesicle around the substance Three types: Pinocytosis – substance is mostly water Phagocytosis – substance is a solid Receptor-mediated endocytosis – requires the substance to bind to a membrane-bound receptor Nucleus Nucleolus V esicle Cell membrane Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

27. Endocytosis Cytoplasm V esicle (a) (b) (c) (d) Receptor protein Cell membrane Molecules outside cell Cell membrane indenting Receptor-ligand combination Nucleus Nucleolus Particle Vesicle Phagocytized particle Cell membrane Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

28. Exocytosis Reverse of endocytosis Substances in a vesicle fuse with cell membrane Contents released outside the cell Release of neurotransmitters from nerve cells Nucleus Endoplasmic reticulum Golgi apparatus Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

29. Transcytosis Endocytosis followed by exocytosis Transports a substance rapidly through a cell HIV crossing a cell layer V iruses bud HIV Exocytosis Receptor-mediated endocytosis HIV-infected white blood cells Anal or vaginal canal Lining of anus or vagina (epithelial cells) Virus infects white blood cells on other side of lining Receptor-mediated endocytosis Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Cell membrane

30. 3.4: The Cell Cycle Series of changes a cell undergoes from the time it forms until the time it divide Stages: Interphase Mitosis Cytokinesis Apoptosis G 2 phase Prophase Metaphase Anaphase Telophase Cytokinesis Restriction checkpoint Remain specialized Proceed to division S phase: genetic material replicates G 1 phase cell growth Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Mitosis Interphase

31. Interphase Very active period Cell grows Cell maintains routine functions Cell replicates genetic material to prepare for nuclear division Cell synthesizes new organelles to prepare for cytoplasmic division Phases: G phases – cell grows and synthesizes structures other than DNA S phase – cell replicates DNA

32. Mitosis Produces two daughter cells from an original somatic cell Nucleus divides – karyokinesis Cytoplasm divides – cytokinesis Phases of nuclear division: Prophase – chromosomes form; nuclear envelope disappears Metaphase – chromosomes align midway between centrioles Anaphase – chromosomes separate and move to centrioles Telophase – chromatin forms; nuclear envelope forms

33. Mitosis Telophase and Cytokinesis Nuclear envelopes begin to reassemble around two daughter nuclei. Chromosomes decondense. Spindle disappears. Division of the cytoplasm into two cells. Anaphase Sister chromatids separate to opposite poles of cell. Events begin which lead to cytokinesis. Metaphase Chromosomes align along equator, or metaphase plate of cell. Prophase Chromosomes condense and become visible. Nuclear envelope and nucleolus disperse. Spindle apparatus forms. Late Interphase Cell has passed the restriction checkpoint and completed DNA replication, as well as replication of centrioles and mitochondria, and synthesis of extra membrane. Early Interphase of daughter cells— a time of normal cell growth and function. Cleavage furrow Nuclear envelopes Nuclear envelope Chromatin fibers Chromosomes Spindle fiber Centromere Aster Centrioles Late prophase Sister chromatids Microtubules Mitosis Cytokinesis S phase G 1 phase Interphase Restriction checkpoint (a) (b) (c) (d) (e) Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Ed Reschke G 2 phase

34. Cytoplasmic Division Also known as cytokinesis Begins during anaphase Continues through telophase Contractile ring pinches cytoplasm in half

35. 3.5: Control of Cell Division Cell division capacities vary greatly among cell types Skin and blood cells divide often and continually Neuron cells divide a specific number of times then cease Chromosome tips ( telomeres ) that shorten with each mitosis provide a mitotic clock Cells divide to provide a more favorable surface area to volume relationship Growth factors and hormones stimulate cell division Hormones stimulate mitosis of smooth muscle cells in uterus Epidermal growth factor stimulates growth of new skin Tumors are the consequence of a loss of cell cycle control Contact (density dependent) inhibition

36. Tumors Two types of tumors: Benign – usually remains localized Malignant – invasive and can metastasize; cancerous Two major types of genes cause cancer: Oncogenes – activate other genes that increase cell division Tumor suppressor genes – normally regulate mitosis; if inactivated they are unable to regulate mitosis Cells are now known as “immortal” Normal cells (with hairlike cilia) Cancer cells Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. © Tony Brain/Photo Researchers, Inc.;

37. 3.6: Stem and Progenitor Cells Stem cell : Can divide to form two new stem cells Self-renewal Can divide to form a stem cell and a progenitor cell Totipotent – can give rise to every cell type Pluripotent – can give rise to a restricted number of cell types Progenitor cell : Committed cell Can divide to become any of a restricted number of cells Pluripotent

38. Stem and Progenitor Cells one or more steps Sperm Egg Fertilized egg Stem cell Stem cell Progenitor cell Progenitor cell Progenitor cell Blood cells and platelets Fibroblasts (a connective tissue cells) Bone cells Progenitor cell Astrocyte Neuron Skin cell Sebaceous gland cell produces another stem cell (self-renewal) Progenitor cell Progenitor cell Progenitor cell Progenitor cell Progenitor cell Progenitor cell Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

39. 3.1 From Science to Technology Therapeutic Stem Cells

40. 3.7: Cell Death Apoptosis: Programmed cell death Acts as a protective mechanism Is a continuous process

41. Important Points in Chapter 3: Outcomes to be Assessed 3.1: Introduction Define cell. State the range of cell numbers and cells sizes in a human body. State the term for cell specialization. 3.2: A Composite Cell List the three major parts of a composite cell. State the general function of organelles. Explain how the structure of a cell membrane makes possible its function. Describe each type of organelle, and explain its function. Describe the parts of a cell nucleus and their functions.

42. Important Points in Chapter 3: Outcomes to be Assessed 3.3: Movement Into and Out of the Cell Explain the various ways that substances move through the cell membrane. Discuss how the mechanisms of crossing cell membranes differ. 3.4: The Cell Cycle Describe the parts of the cell cycle and identify the major activities during each part. Explain why regulation of the cell cycle is important to health. Distinguish between mitosis and cytokinesis. List the stages of mitosis and describe the events of each stage.

43. Important Points in Chapter 3: Outcomes to be Assessed 3.5: Control of Cell Division Explain how different types of cells differ in their rate of cells division. State the range of cell divisions a cell typically undergoes. Discuss factors that influence whether or not a cell divides. Explain how cancer arises from too-frequent cell division. Distinguish the two types of genetic control of cancer. 3.6: Stem and Progenitor Cells Define differentiation. Distinguish between a stem cell and a progenitor cell. Explain how two differentiated cell types can have the same genetic information, but different appearances and functions.

44. Important Points in Chapter 3: Outcomes to be Assessed 3.7: Cell Death Define apoptosis. Distinguish apoptosis from necrosis. List the steps of apoptosis. Describe the relationship between apoptosis and mitosis.

45. Quiz 3 Complete Quiz 3 now! Read Chapter 4.