The Cell - Napa Valley College 218/02...material inside the cell. Cytoplasm is a fluid that is very...

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 pre-

existing cells.

Cells are the smallest structural units that

perform all vital functions.

Copyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

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


Cellular Anatomy

Figure 2.3 Anatomy of a Typical CellCopyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Cellular Anatomy

Figure 2.4 A Flow Chart for the Study of Cell Structure


Cellular Anatomy


Cellular Anatomy


The Plasmalemma

Four major functions of the cell membrane

can be described:

Physical isolation

Regulation of exchange with the environment

Sensitivity

Structural support

Cellular Anatomy


Cellular Anatomy


The Plasmalemma

Membrane permeability: passive processes

Diffusion

Osmosis

Facilitated diffusion

Cellular Anatomy

Figure 2.6 Diffusion across Plasmalemmae


Cellular Anatomy


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+

Ca2+

Mg2+

K+

An ion pump that moves two ions simultaneously in

opposite directions is called an exchange pump.

Cellular Anatomy

Figure 2.7 Pinocytosis and PhagocytosisCopyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Cellular Anatomy

Figure 2.8 Receptor-Mediated EndocytosisCopyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Cellular Anatomy


Cellular Anatomy


Figure 2.9 The Cytoskeleton

Cellular Anatomy


Figure 2.9a The Cytoskeleton

Cellular Anatomy


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.

Cellular Anatomy


Nonmembranous Organelles

The Cytoskeleton:

Microfilaments

Intermediate filaments

Thick filaments

Microtubules

Cellular Anatomy


Nonmembranous Organelles:

Centrioles

Cilia

Flagella

Cellular Anatomy

Figure 2.10 Centrioles and Cilia


Cellular Anatomy


Cellular Anatomy


Nonmembranous Organelles

Ribosomes:

60% RNA and 40% protein

Free ribosomes:

Float in the cytoplasm

Fixed ribosomes:

Attached to the endoplasmic reticulum

Cellular Anatomy

Figure 2.11 Ribosomes


Cellular Anatomy


Membranous Organelles

Mitochondria are double-membraned

organelles:

Cristae are the folds of the inner membrane.

The inner fluid is the matrix.

They produce ATP.

Cellular Anatomy

Figure 2.12 Mitochondria


Cellular Anatomy



The Nucleus is the control center of the cell.

Nucleoplasm

Nuclear envelope

Perinuclear space

Nuclear pores

Nuclear matrix

Cellular Anatomy

Figure 2.13 The Nucleus


Cellular Anatomy


Membranous Organelles—The Nucleus

Chromosomes:

DNA wrapped around proteins called histones.

Nucleosomes

Chromatin

Cellular Anatomy

Figure 2.14 Chromosome Structure


Cellular Anatomy



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

Cellular Anatomy

Figure 2.15 The Endoplasmic Reticulum


Cellular Anatomy



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

Cellular Anatomy

Figure 2.16 The Golgi Apparatus


Cellular Anatomy

Figure 2.17 The Function of the Golgi Apparatus


Cellular Anatomy



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.

Cellular Anatomy

Figure 2.18 Lysosomal Functions


Cellular Anatomy



Peroxisomes function as intracellular

digestive vesicles:

Are abundant in liver cells

Digest fats and toxins

Convert hydrogen peroxide to water

Cellular Anatomy


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 AttachmentsCopyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cell Life Cycle


The Cell Life Cycle

Figure 2.21 DNA ReplicationCopyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

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 MitosisCopyright © 2009 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

The Cell Life Cycle


The Cell - Napa Valley College 218/02...material inside the cell. Cytoplasm is a fluid that is very...

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