Cells and Tissues

PowerPoint® Lecture Slide Presentation by Patty Bostwick-Taylor, Florence-Darlington Technical College

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

PART A3

Cells and Tissues


Cells and Tissues

Cells are the building blocks of all living things.

Tissues are groups of cells that are similar in structure and function.

Together, they carry out all chemical activities needed to sustain life.


Anatomy of the Cell

Cells are not all the same

All cells share the same general structures

All cells have three main regions:

Region 1: Nucleus

Region 2: Plasma Membrane

Region 3: Cytoplasm

Figure 3.1a


Region 1: The Nucleus

Control center of the cell

Contains genetic material (DNA)

Three main areas:

Nuclear envelope (membrane)—Contains the nuclear material and separates it from cytoplasm

Nucleolus—Involved in protein synthesis

Chromatin—Unorganized DNA


Areas of the Nucleus

Control center of the cell Contains genetic

material (DNA) Nuclear envelope

(membrane) Barrier of the nucleus Consists of a double

layer membrane Contains nuclear pores

that allow for exchange of material with the rest of the cell



Nucleolus

Nucleus contains one or more nucleoli

Sites of ribosome assembly

Ribosomes migrate into the cytoplasm through nuclear pores



Chromatin

Composed of DNA and protein

Present when the cell is not dividing

Scattered throughout the nucleus

Condenses to form chromosomes when the cell divides



Barrier for cell contents

Consists of a double phospholipid layer

Hydrophilic heads (Hydro = water, philos = love), pointed outward

Hydrophobic tails (Hydro = water, phobe = fear). pointed inward

Also contains proteins, cholesterol, and glycoproteins



Figure 3.2

Video Clip: The Plasma Membrane


Plasma Membrane Specializations

Microvilli

Finger-like projections that increase surface area for absorption



Types of Membrane Junctions

Tight Junctions

Impermeable junctions

Bind cells together into leakproof sheets

Desmosomes

Anchoring junctions that prevent cells from being pulled apart

Gap Junctions

Allow communication between cells



TPS: Checkpoint #1

Video Clip: AP Intracellular Junctions


Region 3: Cytoplasm Cytoplasm is the material outside the nucleus and

inside the plasma membrane Contains three major elements:

Cytosol Fluid that suspends other elements

Organelles Metabolic machinery of the cell “Little organs” that perform specific

functions for the cell Inclusions

Chemical substances such as stored nutrients or cell products


Region 3: Cytoplasmic Organelles

Figure 3.4


Region 3: Cytoplasmic Organelles

Mitochondria

“Powerhouses” of the cell

Change shape continuously

Carry out reactions where oxygen is used to break down food

Provides ATP for cellular energy


Cytoplasmic Organelles

Ribosomes

Made of protein and RNA

Sites of protein synthesis

Found at two locations:

Free floating in the cytoplasm

As part of the rough endoplasmic reticulum



Endoplasmic reticulum (ER)

Fluid-filled tubules for carrying substances

Two types of ER

Rough endoplasmic reticulum

Studded with ribosomes

Synthesizes proteins

Smooth endoplasmic reticulum

Functions in lipid metabolism and detoxification of drugs and pesticides


Video Clip: Endoplasmic Reticulum


RER & Protein Synthesis

Figure 3.5, step 1

Ribosome

Protein

mRNA

Rough ER

As the protein is synthesizedon the ribosome, it migratesinto the rough ER cistern.



Figure 3.5, step 2

Ribosome

Protein

mRNA

Rough ER


In the cistern, the protein folds into its functional shape. Short sugarchains may be attachedto the protein (forming aglycoprotein).



Figure 3.5, step 3

Ribosome

Protein

Transportvesicle buds off

mRNA

Rough ER


In the cistern, the protein foldsinto its functional shape. Shortsugar chains may be attachedto the protein (forming aglycoprotein).

The protein is packaged in a tiny membranous sac called atransport vesicle.



Figure 3.5, step 4

Ribosome

Protein

Protein insidetransport vesicle

Transportvesicle buds off

mRNA

Rough ER

The transport vesicle buds fromthe rough ER and travels to theGolgi Apparatus for furtherprocessing OR goes directly tothe plasma membrane where itscontents are secreted.



Golgi Apparatus

Modifies and packages proteins

Produces different types of packages:

Secretory vesicles-help organize various cellular substances

Cell membrane components

Lysosomes—digestive system of the cell


Figure 3.6, step 5

Extracellular fluid

Plasma membrane

Proteins in cisterna

Membrane

Transportvesicle

Secretory vesicles

Pathway 1

Golgiapparatus

Golgi vesicle containingproteins to be secretedbecomes a secretoryvesicle

Cisterna

Rough ER

Proteins

Secretion byexocytosis


Figure 3.6, step 8

Extracellular fluid

Plasma membrane

Golgi vesicle containingmembrane componentsfuses with the plasmamembrane

Proteins in cisterna

Membrane

Transportvesicle

Pathway 2

Golgiapparatus

Cisterna

Rough ER


Figure 3.6, step 11

Extracellular fluid

Plasma membrane

Golgi vesicle containingdigestive enzymesbecomes a lysosome

Proteins in cisterna Lysosome fuses withingested substances

Membrane

Transportvesicle

Pathway 3

Golgiapparatus

Cisterna

Rough ER



Peroxisomes Membranous sacs of oxidase enzymes

Detoxify harmful substances such as alcohol and formaldehyde

Break down free radicals (highly reactive chemicals)

Replicate by pinching in half

Lysosomes

Contain enzymes that digest worn-out or nonusable materials within the cell

Checkpoint #2: Label the organelles & pathways in the cell diagrams in notes.


Video Clip: The Structure & Function of Lysosomes



Cytoskeleton

Network of protein structures that extend throughout the cytoplasm

Provides the cell with an internal framework

Figure 3.7a


Figure 3.7b–d


Cytoskeleton

Three different types of filaments

Microfilaments (largest)

Intermediate filaments

Microtubules (smallest)

Video Clip: The Cytoskeleton



Centrioles

Rod-shaped bodies made of microtubules

Direct the formation of mitotic spindle during cell division


Cellular Projections

Not found in all cells

Used for movement

Cilia move materials across the cell surface

Located in the respiratory system to move mucus

Flagella propel the cell

The only flagellated cell in the human body is sperm


Cell Diversity—Fibroblasts & Erythrocytes

Figure 3.8a


Cell Diversity—Epithelial Cells

Figure 3.8b


Cell Diversity—Skeletal & Smooth Muscle Cells

Figure 3.8c


Cell Diversity—Fat Cell

Figure 3.8d


Cell Diversity--Macrophage

Figure 3.8e


Cell Diversity—Nerve Cell

Figure 3.8f


Cell Diversity

Figure 3.8g

Cells and Tissues

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