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THE CELL
Structure
and
Function
THE CELL: Structure and Function
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Objectives
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Cellular basics
The cell membrane
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Alabama Course of Study
Alabama High School
Graduation Exam
Teacher/Text objectives
Structure and function
transport
Organelle structure and
function
Animal cells vs. Plant cells
Quiz
Objectives
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Alabama Course of Study
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17. Identify the basis of the cell theory
18. Analyze relationships among cell structure,
function, and organization in prokaryotes and
eukaryotes.
20. Relate cellular functions to specialized
structures within cells.
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Active and passive transport or materials (osmosis,
diffusion)
Waste disposal
Objectives continued…
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Alabama High School Graduation Exam
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Standard V: The student will understand concepts of cells
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Objective 1: Distinguish relationships among cell structures,
functions, and organization in living organisms.
Eligible content:
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Define and identify representations of diffusion and
osmotic systems.
Recognize differences between active and passive
transport of substances and the energy requirements
associated with each.
Objectives continued…
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AHSGE Eligible content continued:
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Identify and define similarities and differences between
plant and animal cells.
Classify organisms and prokaryotic or eukaryotic.
Describe cell locomotion by means of cilia and flagella.
Identify cell organelles and define functions of cell
organelles.
Distinguish and identify examples of cellular organization
at the cell, tissue, organ, system, and organism level.
Teacher / Text Objectives
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Differentiate between active and passive transport.
Describe the structure and functions of the cell
membrane.
Relate each organelle to a task essential to the life
of the cell.
Explain the structural differences between plant
and animal cells.
The Discovery of Cells
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Anton van Leeuwenhoek was  Matthias Schleiden concluded
the first person to record
that all plants are composed
looking at water under a
of cells.
microscope.
Cell Theory
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Discovered by Schleiden and Theodor Schwann in
1838
 All organisms are composed of one or more cells.
 The cell is the basic unit of organization of
organisms.
 All cells come from preexisting cells.
Schleiden
Schwann
Two Basic Cell Types
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Prokaryotes- cells that lack internal membranebound structures
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Eukaryotes- have cells that contain membrane
bound organelles.
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Lacks a true nucleus
Ex. Bacteria
Ex.-Nucleus
The membrane-bound structures within
eukaryotic cells
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organelles
Microscopes
*Electron microscopes use
electromagnets to focus and
magnify an image.
*A major difference between a
compound light microscope
and a transmission electron
microscope is that a light
microscope image can be
made from living unstained
materials.
*One advantage of electron
microscopes over light
microscopes is their higher
magnification.
Compound Microscope
The Plasma Membrane
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Objectives:
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Explain how a cell’s plasma membrane functions
Relate the function of the plasma membrane to the
fluid mosaic model.
Al COS: 4
AHSGE: Standard I-1, II-1, V-1
The Plasma Membrane - structure
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The plasma membrane is a selectively permeable
phospholipid bilayer surrounding the cell.
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A plasma membrane allows the movement of materials into
and out of a cell.
Does not allow a cell’s contents to be the same as its
surroundings.
Contents of the plasma
membrane(lipid bilayer)
Phospholipids
A polar
have a polar (water-loving) head region and a nonpolar
(water fearing) tail.
molecule has a partial negative charge on one side and a partial
positive charge on the other side. (Ex. Water)
Hydrogen
bonds are the bonds that hold water molecules together
A nonpolar
molecule has no negative and positive poles.(Ex. Oil)
Because
cells have a watery environment both inside and outside, the
polar ends of the phospholipids in the plasma membrane form double
layers.
The
fluid mosaic model describes a structure with polar layers on the
outside and nonpolar layer on the inside
Because
the phospholipid molecules and some proteins are free to move,
the plasma membrane is said to be fluid mosaic.
–Important because cell membranes can be structured to fit the
needs of different cell types
Cell membrane – function
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Through transportation, the cell membrane regulates the raw
materials (glucose, amino acids, and lipids) that enter the cell and
waste products that leave the cell.
This process of maintaining a cell’s internal environment is called
homeostasis.
The cell membrane also protects the cell from its external
environment.
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Folded membranes increase surface area for
efficiency.
Folded membranes are an advantage to a cell because
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Cell processes can be more efficient.
The membranes provide a large surface area.
The membranes form interconnected compartments.
Endoplasmic reticulum is made up of folded
membranes.
Ribosomes are sometimes attached to folded
membranes.
Cytoplasm and Cytoskeleton
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Cytoplasm is a clear
gelatinous fluid inside
the cell that surrounds
the organelles.
The cytoskeleton is a
framework of
microtubules(tiny
rods) and
microfilaments(tiny
filaments) that help
shape and support cells,
and to assist organelles
in moving from place to
place.
Mitochondria
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The mitochondria is the
site of energy production
through respiration.
It consists of two
membranes; The inner
membrane is folded into
structures called cristae.
Nicknamed “the
powerhouse”
Endoplasmic Reticulum
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The endoplasmic reticulum
(ER) resembles a folded
membrane that forms a
network of interconnected
compartments in the
cytoplasm
Smooth ER does not contain
ribosomes
Rough ER is covered with
ribosomes
Function: transportation of
materials between the
nucleus and the cytoplasm.
Ribosomes
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Ribosomes are the site
for protein synthesis in
the cell.
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Produced in the nucleolus
Found floating free in the
cytoplasm
Also exist on the rough
endoplasmic reticulum
Golgi Apparatus
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The Golgi apparatus
resembles closely
stacked flattened
membranous sacs
Function: processing,
packaging, and secreting
proteins, lipids, etc.
Vesicles are
membranous pouches
that may bud from the
ER or golgi apparatus
filled with protein.
Nucleus
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The nucleus is the control
center of the cell that
manages cellular functions.
Nucleolus – structure inside
the nucleus that produces
ribosomes.
Chromatin – tangles of long
strands of DNA
Nuclear pore – holes in the
nuclear envelope through
which ribosomes leave the
nucleus.
Lysosome
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Lysosomes are small,
spherical organelles
surrounded by a single
membrane and contain
digestive enzymes.
Function: to digest
excess or worn out cell
parts, food particles, and
invading viruses or
bacteria
Vacuole
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Stores food, water,
enzymes, and waste
products.
Vacuoles fill with water
through osmosis and
can fill up to 90% of the
cell. The pressure that
results inside the cell as
a result of this is called
turgor pressure.
Chloroplast
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Chloroplasts are the sites for
photosynthesis – capture light
energy and produce food.
Chloroplasts are a type of
plastid (organelle that contains
pigments)
They contain chlorophyll - a
green plant pigment that traps
energy from sunlight and gives
plants their green color.
In chloroplasts, the stacks of
membranes sacs are called
grana.
Cell wall
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The cell wall is found
outside the cell
membrane.
made of cellulose.
They are found in plants,
bacteria and fungi that
give cells their shape.
Centrioles
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CENTRIOLES
Centrioles are small,
rod-shaped structures
that appear during
mitosis.
Only found in animal
cells.
Organelles
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Cytoplasm
Cytoskeleton
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Mitochondria
Ribosomes
Endoplasmic Reticulum
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Microtubules
Microfilaments
Smooth
Rough
Golgi Apparatus
Lysosome
Nucleus
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Nucleolus
Chromatin
Special plant structures
 Vacuole
 Cell wall
 Chloroplasts
 Centrioles
 Vesicle
Plant vs. Animal Cells
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Only animal cells contain centrioles.
Only plant cells contain a cell wall, chloroplasts, and
large central vacuole.
Cellular basics review
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Cell – basic unit of living organisms
Prokaryote – cell without membrane-bound structures.
Example: bacteria
Eukaryote – cell with membrane-bound structures.
Examples: multicellular organisms such as plants and animals;
and some unicelllular organisms.
Cilia – short, numerous, hair-like structures that aid in
locomotion or feeding.
Flagella – long, whip-like structure used for locomotion.
Organelle – membrane-bound structures within a cell that carry
out a specific function.
How well do you know your cells?
match
game
a virtual cell
quiz
membrane
worksheet
Another
virtual cell
organelle
worksheet