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
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.
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.
The Study of Cells The study of cells is cytology. Most common methods of study: Light microscopy Transmission electron microscopy Scanning electron microscopy
The Study of Cells Figure 2.1 Different Techniques, Different Perspectives
The Study of Cells Figure 2.2 The Diversity of Cells in the Body
Figure 2.3 Anatomy of a Typical Cell
Figure 2.4 A Flow Chart for the Study of Cell Structure
The Plasmalemma Four major functions of the cell membrane can be described: Physical isolation Regulation of exchange with the environment Sensitivity Structural support
The Plasmalemma Membrane permeability: passive processes Diffusion Osmosis Facilitated diffusion
Figure 2.6 Diffusion across Plasmalemmae
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.
Figure 2.7 Pinocytosis and Phagocytosis
Figure 2.8 Receptor-Mediated Endocytosis
Figure 2.9 The Cytoskeleton
Figure 2.9a The Cytoskeleton
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.
Nonmembranous Organelles The Cytoskeleton: Microfilaments Intermediate filaments Thick filaments Microtubules
Nonmembranous Organelles: Centrioles Cilia Flagella
Figure 2.10 Centrioles and Cilia
Nonmembranous Organelles Ribosomes: 60% RNA and 40% protein Free ribosomes: Float in the cytoplasm Fixed ribosomes: Attached to the endoplasmic reticulum
Figure 2.11 Ribosomes
Membranous Organelles Mitochondria are double-membraned organelles: Cristae are the folds of the inner membrane. The inner fluid is the matrix. They produce ATP.
Figure 2.12 Mitochondria
Membranous Organelles The Nucleus is the control center of the cell. Nucleoplasm Nuclear envelope Perinuclear space Nuclear pores Nuclear matrix
Figure 2.13 The Nucleus
Membranous Organelles The Nucleus Chromosomes: DNA wrapped around proteins called histones. Nucleosomes Chromatin
Figure 2.14 Chromosome Structure
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
Figure 2.15 The Endoplasmic Reticulum
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
Figure 2.16 The Golgi Apparatus
Figure 2.17 The Function of the Golgi Apparatus
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.
Figure 2.18 Lysosomal Functions
Membranous Organelles Peroxisomes function as intracellular digestive vesicles: Are abundant in liver cells Digest fats and toxins Convert hydrogen peroxide to water
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.
Intercellular Attachment There are three major types of cell junctions: Tight junctions Communicating junctions Anchoring junctions
Intercellular Attachment Figure 2.19 Cell Attachments
The Cell Life Cycle
The Cell Life Cycle Figure 2.21 DNA Replication
The Cell Life Cycle Mitosis the distribution process of genetic information Mitosis consists of four stages: Prophase Metaphase Anaphase Telophase
The Cell Life Cycle Figure 2.22 Interphase and Mitosis
The Cell Life Cycle
The Cell Life Cycle
The Cell Life Cycle