The Cell. C h a p t e r. PowerPoint Lecture Slides prepared by Jason LaPres North Harris College Houston, Texas

Transcription

1 C h a p t e r 2 The Cell PowerPoint Lecture Slides prepared by Jason LaPres North Harris College Houston, Texas Copyright 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

2 Introduction Cells are the structural building blocks of all plants and animals. Cells are produced by the division of preexisting cells. Cells are the smallest structural units that perform all vital functions.

3 Introduction Cells fall into two categories: Sex cells (germ cells or reproductive cells), which are the sperm in males and oocyte in females. Somatic cells are all of the other cells in the body that are not sex cells.

4 The Study of Cells The study of cells is cytology. Most common methods of study: Light microscopy Transmission electron microscopy Scanning electron microscopy

5 The Study of Cells Figure 2.1 Different Techniques, Different Perspectives

6 The Study of Cells Figure 2.2 The Diversity of Cells in the Body

7 Figure 2.3 Anatomy of a Typical Cell

8 Figure 2.4 A Flow Chart for the Study of Cell Structure

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11 The Plasmalemma Four major functions of the cell membrane can be described: Physical isolation Regulation of exchange with the environment Sensitivity Structural support

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13 The Plasmalemma Membrane permeability: passive processes Diffusion Osmosis Facilitated diffusion

14 Figure 2.6 Diffusion across Plasmalemmae

15 The Plasmalemma Membrane permeability: active processes: Active transport uses enzymes and carrier proteins. Ion pumps are carrier proteins for charged particles. Ions moved regularly by active transport include: Na + Ca 2+ Mg 2+ K + An ion pump that moves two ions simultaneously in opposite directions is called an exchange pump.

16 Figure 2.7 Pinocytosis and Phagocytosis

17 Figure 2.8 Receptor-Mediated Endocytosis

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19 Figure 2.9 The Cytoskeleton

20 Figure 2.9a The Cytoskeleton

21 The cytoplasm is the general term for the material inside the cell. Cytoplasm is a fluid that is very high in protein. The cytosol is the intracellular fluid. The cytosol is high in potassium ions. Cytosol contains an overall negative charge. Transmembrane potential The cytosol contains high concentrations of proteins. Organelles are structures within the cytoplasm that have a particular function and very distinct structure.

22 Nonmembranous Organelles The Cytoskeleton: Microfilaments Intermediate filaments Thick filaments Microtubules

23 Nonmembranous Organelles: Centrioles Cilia Flagella

24 Figure 2.10 Centrioles and Cilia

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26 Nonmembranous Organelles Ribosomes: 60% RNA and 40% protein Free ribosomes: Float in the cytoplasm Fixed ribosomes: Attached to the endoplasmic reticulum

27 Figure 2.11 Ribosomes

28 Membranous Organelles Mitochondria are double-membraned organelles: Cristae are the folds of the inner membrane. The inner fluid is the matrix. They produce ATP.

29 Figure 2.12 Mitochondria

30 Membranous Organelles The Nucleus is the control center of the cell. Nucleoplasm Nuclear envelope Perinuclear space Nuclear pores Nuclear matrix

31 Figure 2.13 The Nucleus

32 Membranous Organelles The Nucleus Chromosomes: DNA wrapped around proteins called histones. Nucleosomes Chromatin

33 Figure 2.14 Chromosome Structure

34 Membranous Organelles The endoplasmic reticulum (ER) has four major functions: Synthesis of all classes of macromolecules Storage of the manufactured molecules Transport of substances from one area of the cell to another Enzymes in the lumen of the ER provide detoxification. Smooth and rough ER

35 Figure 2.15 The Endoplasmic Reticulum

36 Membranous Organelles The Golgi apparatus has three main functions: Synthesis and packaging of secretions Packaging of enzymes for use in the cytosol Renewal and modification of the cell plasmalemma

37 Figure 2.16 The Golgi Apparatus

38 Figure 2.17 The Function of the Golgi Apparatus

39 Membranous Organelles Lysosomes function in three manners: Lysosomes fuse with phagosomes to digest solid materials. Lysosomes fuse with and recycle damaged organelles. Lysosomes sometimes rupture a process resulting in autolysis.

40 Figure 2.18 Lysosomal Functions

41 Membranous Organelles Peroxisomes function as intracellular digestive vesicles: Are abundant in liver cells Digest fats and toxins Convert hydrogen peroxide to water

42 Membrane flow is the continual movement and recycling of the plasmalemma. The ER, Golgi apparatus, and vesicles constantly recycle the lipids, protein channels, and enzymes of the plasmalemma.

43 Intercellular Attachment There are three major types of cell junctions: Tight junctions Communicating junctions Anchoring junctions

44 Intercellular Attachment Figure 2.19 Cell Attachments

45 The Cell Life Cycle

46 The Cell Life Cycle Figure 2.21 DNA Replication

47 The Cell Life Cycle Mitosis the distribution process of genetic information Mitosis consists of four stages: Prophase Metaphase Anaphase Telophase

48 The Cell Life Cycle Figure 2.22 Interphase and Mitosis

49 The Cell Life Cycle

50 The Cell Life Cycle

51 The Cell Life Cycle