Cells are the basic unit of structure and function in living things. All cells share a few common structures - a nucleus that houses DNA, cytoplasm surrounded by a plasma membrane. Within the cytoplasm are various organelles that carry out specialized functions like mitochondria that generate energy. Cells can be specialized through variations in shape and internal structures to perform different roles in tissues and organs. Tissues are groups of similar cells that work together to perform a common function.

1. PowerPoint®
Lecture Slide Presentation
by Patty Bostwick-Taylor,
Florence-Darlington Technical College
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
PART A
3
Cells and
Tissues

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Cells and Tissues
 Carry out all chemical activities needed to sustain
life
 Cells are the building blocks of all living things
 Tissues are groups of cells that are similar in
structure and function

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Anatomy of the Cell
 Cells are not all the same
 All cells share general structures
 All cells have three main regions
 Nucleus
 Cytoplasm
 Plasma membrane
Figure 3.1a

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The Nucleus
 Control center of the cell
 Contains genetic material (DNA)
 Three regions
 Nuclear envelope (membrane)
 Nucleolus
 Chromatin

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The Nucleus
Figure 3.1b

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The Nucleus
 Nuclear envelope (membrane)
 Barrier of the nucleus
 Consists of a double membrane
 Contains nuclear pores that allow for
exchange of material with the rest of the cell

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The Nucleus
 Nucleoli
 Nucleus contains one or more nucleoli
 Sites of ribosome assembly
 Ribosomes migrate into the cytoplasm
through nuclear pores

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The Nucleus
 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

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Plasma Membrane
 Barrier for cell contents
 Double phospholipid layer
 Hydrophilic heads
 Hydrophobic tails
 Also contains proteins, cholesterol, and
glycoproteins

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Plasma Membrane
Figure 3.2
Membrane StructurePLAY

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Plasma Membrane Specializations
 Microvilli
 Finger-like projections that increase surface
area for absorption

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Cytoplasm
 Cytoplasm is the material outside the nucleus and
inside the plasma membrane

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Cytoplasm
 Contains three major elements
 Cytosol
 Fluid that suspends other elements
 Organelles
 Metabolic machinery of the cell
 “Little organs” that perform functions for
the cell
 Inclusions
 Chemical substances such as stored
nutrients or cell products

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Cytoplasmic Organelles
Figure 3.4

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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

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Cytoplasmic Organelles
 Ribosomes
 Made of protein and RNA
 Sites of protein synthesis
 Found at two locations
 Free in the cytoplasm
 As part of the rough endoplasmic
reticulum

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Cytoplasmic Organelles
 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

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Rough Endoplasmic Reticulum
Figure 3.5
Ribosome
Protein
Protein inside
transport vesicle
Transport
vesicle buds off
mRNA
Rough ER
As the protein is synthesized
on the ribosome, it migrates
into the rough ER cistern.
In the cistern, the protein folds
into its functional shape. Short
sugar chains may be attached
to the protein (forming a
glycoprotein).
The protein is packaged in a
tiny membranous sac called a
transport vesicle.
The transport vesicle buds from
the rough ER and travels to the
Golgi apparatus for further
processing or goes directly to
the plasma membrane where its
contents are secreted.

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Cytoplasmic Organelles
 Golgi apparatus
 Modifies and packages proteins
 Produces different types of packages
 Secretory vesicles
 Cell membrane components
 Lysosomes

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Figure 3.6
Extracellular fluid
Plasma membrane
Golgi vesicle containing
membrane components
fuses with the plasma
membrane
Golgi vesicle containing
digestive enzymes
becomes a lysosome
Proteins in cisterna
Lysosome fuses with
ingested substances
Membrane
Transport
vesicle
Pathway 3
Pathway 2
Secretory vesicles
Pathway 1
Golgi
apparatus
Golgi vesicle containing
proteins to be secreted
becomes a secretory
vesicle
Cisterna
Rough ER
Proteins
Secretion by
exocytosis

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Cytoplasmic Organelles
 Lysosomes
 Contain enzymes that digest worn-out or
nonusable materials within the cell

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Cytoplasmic Organelles
 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

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Cytoplasmic Organelles
 Cytoskeleton
 Network of protein structures that extend
throughout the cytoplasm
 Provides the cell with an internal framework
Figure 3.7a

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Figure 3.7b–d
Cytoplasmic Organelles
 Cytoskeleton
 Three different types of
elements
 Microfilaments
(largest)
 Intermediate
filaments
 Microtubules
(smallest)

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Cytoplasmic Organelles
 Centrioles
 Rod-shaped bodies made of microtubules
 Direct the formation of mitotic spindle during
cell division

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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

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Cell Diversity
Figure 3.8a

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Cell Diversity
Figure 3.8b

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Cell Diversity
Figure 3.8c

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Cell Diversity
Figure 3.8d

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Cell Diversity
Figure 3.8e

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Cell Diversity
Figure 3.8f

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Cell Diversity
Figure 3.8g