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Chapter 1
2 Lecture
HUMAN ANATOMY
Fifth Edition
Chapter 2
The Cell
Frederic Martini
Michael Timmons
Robert Tallitsch
Copyright © 2005 Pearson Education, Inc., publishing as Benjamin Cummings
Introduction
• Cell theory:
– Cells are the smallest structural units that
perform all vital functions.
The Study of Cells
• The study of cells is cytology:
– Light microscopy
– Transmission electron microscopy
– Scanning electron microscopy
Figure 2.1a,b,c Different Technique, Different Perspective
Cellular Anatomy
Cells have four
types of
component:
1) Membranes
2) Organelles
3) Cytoplasm
4) inclusions
Figure 2.3 Anatomy of a Typical Cell
Cellular Anatomy
Figure 2.4 A Flow Chart for the Study of Cell Structure
Cell Structure
This movie reviews cell structure.
PLAY
Cell Structure
The Cell Membrane
Figure 2.5 The Cell Membrane
The Cell Membrane
• Major functions of the cell membrane can
be described:
– Regulation of exchange with the
environment
– Receptors and ID
Membrane Permeability: Passive Processes
• Diffusion
• Osmosis
• Facilitated
Diffusion
Figure 2.6 Diffusion across the Cell Membrane
Membrane Permeability: Active Processes
• Active transport uses enzymes and carrier
proteins:
– Ions pumps are carrier proteins for charged
particles.
– Ions moved regularly by active transport
include Na+, Ca2+, Mg2+, K+
– Ion pumps are specific.
– An ion pump that moves two ions
simultaneously in opposite directions is
called an exchange pump.
Membrane Permeability: Active Processes
Figure 2.7a Pinocytosis
Membrane Permeability: Active Processes
Figure 2.7b Phagocytosis
Membrane Permeability: Active Processes
Figure 2.8 Receptor-Mediated Endocytosis
Cytoplasm
• The cytoplasm is the general term for the
material inside the cell.
– It is a fluid very high in protein.
– The cytosol is the intracellular fluid:
• It is high in potassium ions.
• It contains an overall negative charge.
– Transmembrane potential
• It 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
– Microtubules
• Microvilli
QuickTime™ and a
decompressor
are needed to see this picture.
Nonmembranous Organelles
Figure 2.9 The Cytoskeleton
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:
• Are attached to the endoplasmic reticulum
Figure 2.11 Ribosomes
Membranous Organelles
• Mitochondria are double membraned
organelles.
– Cristae are the folds of the inner membrane
– Inner fluid is the matrix.
Figure 2.12 Mitochondria
Membranous Organelles
• The nucleus is the control center of the cell.
– Nucleoplasm
– Nuclear envelope
– Perinuclear space
– Nuclear pores
– Nuclear matrix
Membranous Organelles
Figure 2.13a The Nucleus
Membranous Organelles: Nucleus
• Chromosomes:
– DNA wrapped
around proteins
called histones.
– Nucleosomes
– Chromatin
Figure 2.14 Chromosome Structure
Membranous Organelles
• The ER has four major functions:
– Synthesis of all classes of macromolecules
– Storage of the manufactured molecules
– Transport of substances from on area of the
cell to another
– Enzymes in the lumen of the ER provide
detoxification
Membranous Organelles
Figure 2.15 The Endoplasmic Reticulum
Membranous Organelles
• The three main
functions of the
Golgi apparatus:
– Synthesis and
packaging of
secretions.
– Packaging of
enzymes for use
in the cytosol.
– Renewal and
modification of
the cell membrane.
Figure 2.16b The Golgi Apparatus
Membranous Organelles
•
Lysosome function
in three manners:
1. Fuse with
phagosomes to
digest solid
materials.
2. Fuse with and
recycle damaged
organelles.
3. Sometimes rupture
a process resulting
in autolysis.
Figure 2.18 Lysosomal Functions
Intercellular Attachment
Figure 2.19 Cell Attachments
The Cell Life Cycle
Figure 2.20 The Cell Life Cycle
DNA Replication
Figure 2.21 DNA Replication
Interphase
Figure 2.22a
Prophase
Figure 2.22b,c
Metaphase and Anaphase
Figure 2.22d,e
Telophase and Cytokinesis
Figure 2.22f,g