1. Slide 0 Copyright © 2004. Mosby Inc. All Rights Reserved. Chapter 3 Cells

2. Slide 1 Copyright © 2004. Mosby Inc. All Rights Reserved. Size and Shape  Human cells vary considerably in size  All are microscopic  Cells differ notably in shape

3. Slide 2 Copyright © 2004. Mosby Inc. All Rights Reserved. Composition  Cytoplasm containing specialized organelles surrounded by a plasma membrane  Organization of cytoplasmic substances important for life

4. Slide 3 Copyright © 2004. Mosby Inc. All Rights Reserved.  Plasma membrane  Forms outer boundary of cell  Thin two-layered membrane of phospholipids containing proteins on the surface serving as identification tags.  Is selectively permeable Structural Parts

5. Slide 4 Copyright © 2004. Mosby Inc. All Rights Reserved. Structural Parts  Cytoplasm  Organelles o Ribosomes May attach to Endoplasmic Reticulum or lie free in cytoplasm Manufacture proteins Often called protein factories

6. Slide 5 Copyright © 2004. Mosby Inc. All Rights Reserved. Structural Parts  Endoplasmic reticulum (ER)  Network of connecting sacs and canals  Carry substances through cytoplasm  Types are rough and smooth  Rough ER collects and transports proteins by ribosomes  Smooth ER synthesizes chemicals; makes new membrane

7. Slide 6 Copyright © 2004. Mosby Inc. All Rights Reserved. Structural Parts  Golgi apparatus  Group of flattened sacs near nucleus  Collect chemicals that move from the smooth ER in vesicles  Called the chemical processing and packaging center

8. Slide 7 Copyright © 2004. Mosby Inc. All Rights Reserved.  Mitochondria  Composed of inner and outer membranes  Involved with energy-releasing chemical reactions  Often called power plants of the cell  Contain one DNA molecule Structural Parts

9. Slide 8 Copyright © 2004. Mosby Inc. All Rights Reserved. Structural Parts  Lysosomes  Membranous-walled organelles  Contain digestive enzymes  Have protective function (eat microbes)  Formerly thought to be responsible for apoptosis (programmed cell suicide)

10. Slide 9 Copyright © 2004. Mosby Inc. All Rights Reserved. Structural Parts  Centrioles  Paired organelles  Lie at right angles to each other near the nucleus  Function in cell reproduction/division

11. Slide 10 Copyright © 2004. Mosby Inc. All Rights Reserved. Structural Parts  Cilia  Fine hairlike extensions found on free or exposed surfaces of some cells  Capable of moving in unison in a wavelike fashion

12. Slide 11 Copyright © 2004. Mosby Inc. All Rights Reserved. Structural Parts  Flagella  Single projections extending from cell surfaces  Much larger than cilia  “Tails” of sperm cells are the only example of flagella in humans

13. Slide 12 Copyright © 2004. Mosby Inc. All Rights Reserved. Structural Parts  Nucleus  Controls cell because it contains the genetic code  Instructions for making proteins, which in turn determine cell structure and function  Component structures include nuclear envelope  Nucleoplasm, and chromatin granules  46 chromosomes contain DNA, which contains the genetic code

14. Slide 13 Copyright © 2004. Mosby Inc. All Rights Reserved. Relationship of Cell Structure and Function  Regulation of life processes  Survival of species through reproduction of the individual  Relationship of structure to function apparent in number and type of organelles seen in different cells  Heart muscle cells contain many mitochondria required to produced adequate energy needed for continued contractions  Flagellum of sperm cell gives motility, allowing movement of sperm through female reproductive tract, thus increasing chances for fertilization

15. Slide 14 Copyright © 2004. Mosby Inc. All Rights Reserved. Passive Transport Processes Passive transport processes do not require added energy and result in movement “down a concentration gradient”

16. Slide 15 Copyright © 2004. Mosby Inc. All Rights Reserved.  Diffusion  Substances scatter themselves evenly throughout an available space  It is unnecessary to add energy to the system  Movement is from high to low concentration  Osmosis and dialysis are specialized examples of diffusion across a selectively permeable membrane  Osmosis is diffusion of water (when some solutes cannot cross the membrane)  Dialysis is diffusion of solutes Passive Transport Processes

17. Slide 16 Copyright © 2004. Mosby Inc. All Rights Reserved. Passive Transport Processes  Filtration  Movement of water and solutes caused by hydrostatic pressure on one side of membrane  Responsible for urine formation

18. Slide 17 Copyright © 2004. Mosby Inc. All Rights Reserved. Movements of Substances Through Cell Membranes Active transport processes occurs only in living cells, movement of substances is “up the concentration gradient” Requires energy from ATP

19. Slide 18 Copyright © 2004. Mosby Inc. All Rights Reserved. Movements of Substances Through Cell Membranes  Ion pumps  An ion pump is protein complex in cell membrane  Ion pumps use energy from ATP to move substances across cell membranes against their concentration gradients  Examples: sodium-potassium pump, calcium pump  Some ion pumps work with other carriers so that glucose or amino acids are transported along with ions

20. Slide 19 Copyright © 2004. Mosby Inc. All Rights Reserved. Movements of Substances Through Cell Membranes  Phagocytes and pinocytosis  Both are active transport mechanisms because they require cell energy  Phagocytosis is a protective mechanism often used to destroy bacteria  Pinocytosis is used to incorporate fluids or dissolved substances into cells

21. Slide 20 Copyright © 2004. Mosby Inc. All Rights Reserved. Cell Reproduction DNA structure—large molecule shaped like a spiral staircase. Sugar (deoxyribose) and phosphate units comprise sides of the molecule Base pairs (adenine-thymine or guanine- cytosine) comprise “steps”; base pairs always the same but sequence of base pairs within a DNA molecule Genes dictate formation of enzymes and other proteins by ribosomes, thereby indirectly determining a cell’s structure and functions; in short, genes are hereditary determinants

22. Slide 21 Copyright © 2004. Mosby Inc. All Rights Reserved. Genetic Code  Genetic information—stored in base- pair sequences on genes—expressed through protein synthesis

23. Slide 22 Copyright © 2004. Mosby Inc. All Rights Reserved. Genetic Code  RNA molecules and protein synthesis  DNA—contained in cell nucleus  Protein synthesis—occurs in cytoplasm, thus genetic information must pass from the nucleus to the cytoplasm  Process of transferring genetic information from nucleus to cytoplasm where proteins are produced requires completion of transcription and translation

24. Slide 23 Copyright © 2004. Mosby Inc. All Rights Reserved. Genetic Code  Transcription  Double-stranded DNA separates to form messenger RNA and mRNA  Each strand of mRNA duplicates a particular gene (base-pair sequence) from a segment of DNA  mRNA molecules pass from the nucleus to the cytoplasm where they direct protein synthesis in ribosomes and ER

25. Slide 24 Copyright © 2004. Mosby Inc. All Rights Reserved. Genetic Code  Translation  Involves synthesis of proteins in cytoplasm by ribosome  Requires use of information contained in mRNA

26. Slide 25 Copyright © 2004. Mosby Inc. All Rights Reserved. Cell Division Reproduction of cell involving division of the nucleus (mitosis) and the cytoplasm Period when the cell is not actively dividing is called interphase

27. Slide 26 Copyright © 2004. Mosby Inc. All Rights Reserved. DNA Replication Process by which each half of a DNA molecule becomes a whole molecule identical to the original DNA molecule; precedes mitosis

28. Slide 27 Copyright © 2004. Mosby Inc. All Rights Reserved. Mitosis Process in cell division identical chromosomes (DNA molecules) to each new cell formed when the original cell divides; enables cells to reproduce their own kind; makes heredity possible

29. Slide 28 Copyright © 2004. Mosby Inc. All Rights Reserved. Stages of Mitosis Prophase—first stage  Chromatin granules become organized  Chromosomes (pairs of linked chromatids) appear  Centrioles move away from nucleus  Nuclear envelope disappears, freeing genetic material  Spindle fibers appear (Cont’d…)

30. Slide 29 Copyright © 2004. Mosby Inc. All Rights Reserved. Stages of Mitosis  Metaphase—second stage  Chromosomes align across center of cell  Spindle fibers attach themselves to each chromatid

31. Slide 30 Copyright © 2004. Mosby Inc. All Rights Reserved. Stages of Mitosis  Anaphase—third phase  Centromeres break apart  Separated chromatids now called chromosomes  Chromosomes are pulled to opposite ends of cell  Cleavage furrow develops at end of anaphase

32. Slide 31 Copyright © 2004. Mosby Inc. All Rights Reserved. Stages of Mitosis  Telophase—fourth stage  Cell division is completed  Nuclei appear in daughter cells  Nuclear envelope and nucleoli appear  Cytoplasm is divided (cytokinesis)  Daughter cells become fully functional

33. Slide 32 Copyright © 2004. Mosby Inc. All Rights Reserved. Tissues Epithelial tissue  Covers body and lines body cavities  Cells packed closely together with little surrounding material between them.  Classified by shape of cells  Squamous (flat)  Cuboidal (cube)  Columnar (higher than wide)  Transitional (varies)

34. Slide 33 Copyright © 2004. Mosby Inc. All Rights Reserved. Tissues  Also classified by arrangement of cells  Simple  Stratified  Simple squamous epithelium  Single thin layer of scale like cells  Substances can pass easily (Absorption)  Stratified squamous epithelium  Several layers of closely packed cells  Protection is primary function

35. Slide 34 Copyright © 2004. Mosby Inc. All Rights Reserved. Tissues  Simple columnar epithelium  Columnar cells arranged in a single layer  Line stomach and intestines  Contain mucus-producing goblet cells  Specialized for absorption  Stratified transitional epithelium  Found in body areas, such as urinary bladder, that stretch  Up to 10 layers of roughly cuboidal-shaped cells that distort to squamous (flat) shape when stretched

36. Slide 35 Copyright © 2004. Mosby Inc. All Rights Reserved. Tissues  Pseudostratified epithelium  Each cell touches basement membrane appearing to be two layers. (false)  Cilia lined cells of the trachea  Able to move mucus along the lining to protect from dust

37. Slide 36 Copyright © 2004. Mosby Inc. All Rights Reserved. Tissues  Simple cuboidal epithelium  Often specialized for secretory activity  Cuboidal cells may be grouped into glands  May secrete into ducts, directly into blood, and on body surface  Exocrine/Endocrine  Examples of secretions include saliva, digestive juices, and hormones  Cuboidal epithelium also forms the urine- producing tubules of the kidneys

38. Slide 37 Copyright © 2004. Mosby Inc. All Rights Reserved. Tissues  Connective tissue  Most abundant tissue in body  Most widely distributed tissue in body  Multiple types, appearances, and functions  Relatively few cells in intercellular matrix

39. Slide 38 Copyright © 2004. Mosby Inc. All Rights Reserved. Tissues  Types  Areolar — Glue that holds organs together  Most widely distributed  Adipose (fat) — Lipid storage is primary function  Fibrous — Strong, white collagen fibers  Provides strength and flexibility, but does not stretch.  Tendons – Connects muscle to bone

40. Slide 39 Copyright © 2004. Mosby Inc. All Rights Reserved. Tissues  Types  Bone – Hard and calcified  Storage for calcium  Support and protection  Cartilage — Chondrocyte is cell type  Blood — Fluid  Transportation and protection  Hemopoietic tissue forms blood cells

41. Slide 40 Copyright © 2004. Mosby Inc. All Rights Reserved. Tissues  Muscle Tissue Types  Skeletal—attaches to bones; also called striated or voluntary; control is voluntary; striations apparent when viewed under a microscope  Cardiac—also called striated involuntary; comprises heart wall; ordinarily cannot control contractions  Smooth—also called nonstriated (visceral) or involuntary; no cross striations found in blood vessels and other tube-shaped organs

42. Slide 41 Copyright © 2004. Mosby Inc. All Rights Reserved. Tissues Nervous tissue  Cell types  Neurons— Conducting cells  Glia (Neuroglia)— Supportive and connecting cells  Neurons  Cell components o Cell body o Axon (Carries impulse away) o Dendrites (Carries impulse towards)

43. Slide 42 Copyright © 2004. Mosby Inc. All Rights Reserved.  Function—rapid communication between body structures and control of body functions Tissues

44. Slide 43 Copyright © 2004. Mosby Inc. All Rights Reserved. The End