Transcript Cell Structure - 4J Blog Server

Cell Structure
Organelles
Recall the Characteristics of Life
All Living things share the following:
Cells
Organization
Energy use
Homeostasis
Growth/Development
Reproduction
The Cell Theory

Cells are the only characteristic that cannot be found in
non-living things. Because of their importance, much
cell research has taken place and been compiled into
the cell theory:
1. All living things are composed of one or more
cells.
2. Cells are the basic units of structure and
function in an organism.
3. Cells come only from the reproduction of
existing cells.
2 Levels of Organization
 Molecular and Cellular
 Macromolecules are organized into structures
called organelles. Organelles working together
make up a cell.
 One cell has all it needs to carry out all life
processes.
The organelles carry out all of the
functions of life.
How is a single, tiny little cell able to do so
much?
 Each organelle in the cell performs a specific
function.
 Remember, all cells have
A cell membrane
DNA (genetic information)
cytoplasm
 Only eukaryotic cells have a nucleus and
other membrane-bound organelles.
Macromolecules
Four macromolecules make up all the
organelles:
Proteins
Lipids (fats)
Nucleic Acids
Carbohydrates
CELL MEMBRANE
STRUCTURE: Organized in
a bilayer. Outer portion is
hydrophilic and inner is
hydrophobic. Mostly made
of lipids (phospholipids)
and proteins.
Analogy: security guard
or border control
Found in: ALL cells
(prokaryotic and
eukaryotic)
FUNCTION: the cell
membrane surrounds the
cytoplasm of a cell and
physically separates the
inside of the cell from the
outside environment.
Allows needed materials to
pass through.
Cheek Cell
Cell Membrane
Nuclear membrane
Nucleus
CELL WALL
 Function: Gives cells
Rigidity and Strength, and
offers protection and overall
provides skeletal support.
 Structure: Composed of
cellulose, a type of carbohydrate.
The structure is rigid, yet flexible,
and it will bend rather than hold a
shape, like when a plant wilts.
Found in: Prokaryotic and
Plant cells
Analogy: Brick walls of a
builiding
Cell Wall
The cytoplasm contains the organelles of a
cell
 Structure: The cytoplasm is the region of the
cell between the membrane and the nucleus.
It consists of a gelatin-like fluid which
“bathes” the organelles.
It is a solution with dissolved salts, minerals,
etc.
 Function: Region where most of the cell’s
activities are carried out.
Analogy: Jell-O with fruit pieces in it
Found in: ALL Cells
Cytoplasm
Cytoplasm
Mitochondria
Structure: Mitochondria has
two membranes. The outer
membrane is smooth. The
inner membrane is folded to
allow more room for chemical
reactions to occur.
Function: Mitochondria break
down compounds from food
to release usable energy for
the cell
Analogy: Power
Plant- converts
energy to a
usable form.
Found in: Plant
and Animal Cells
Cytoplasm
Mitochondria
Cell Membrane
Ribosomes
 Function-Ribosomes are responsible for
translating code from mRNA and making
proteins.
 Structure- Ribosomes are made up of
proteins and RNA and consist of two parts,
a large subunit and a small subunit. Some
are attached to the endoplasmic reticulum;
others float freely in the cytoplasm.
Found in: ALL cells
Analogy: Construction
workers
Ribosome
Ribosomes
Structure: Membranous network of
sac-like structures that are
connected by cytoskeleton (Rough ER
has ribosomes on it)
•Function: Transports materials within
cells (an intracellular highway)
-Rough ER has a role in protein
synthesis
-Smooth ER synthesizes (makes) lipids,
breaks down toxic substances
Analogy: factory;
conveyor belts,
machines, etc.
Found in: Plant
and Animal
Cells
Golgi Body
•Structure: It is a network of
flattened and stacked
membrane-bound sacs found
within cells
•Function: The golgi body stores,
packages, and distributes the
proteins and lipids made in the
endoplasmic reticulum
Analogy: shipping
department, Post
Office
Found in: Plant and Animal Cells
Rough
ER
Ribosome
Golgi Body
Smooth
ER
Structure- lysosomes are
spherical organelles
contained by a single-layer
membrane containing
digestive enzymes inside
Function- Lysosomes
contain the enzymes
for breakdown of worn
out cell parts.
 Analogy: garbage/waste
disposal.
 Found in: Plant and
Animal Cells
Lysosomes
Cytoskeleton
Functions- It maintains the cell’s

shape and helps in the
movement of the organelles.
Structures- Flexible scaffold-like
structure made up of
microfilaments,
microtubules, and proteins.
Analogy: frame of a car/house.
Found in: ALL cells
Cytoskeleton
Nucleus
Structure: It has a double-layered
membrane. It has large pores through
which materials pass back and forth.
•Function: The nucleus directs all activity in the
cell, controls the growth and reproduction of the cell,
and contains the blueprints of the cell in the DNA.
•Analogy: county office that stores the original
building blueprints. “Brain”, stores info and sends
out messages.
•Found in: Plant and Animal Cells
Nuclear membrane
Nucleus
Cilia
 FUNCTION:
 The cilia generate water
currents
 STRUCTURE:
 In eukaryotic cells, cilia and
Analogy: cilia are like
flagella contain proteins and
fans
microtubules, which are
composed of linear polymers
of globular proteins called
Cilia found in: Animal Cells
tubulin.
Cilia
Flagella
 FUNCTION:
 Flagella are used primarily for
movement of single cells.
 STRUCTURE:
 In eukaryotic cells, cilia and
Analogy: flagella are
flagella contain proteins and
like boat rudders
microtubules, which are
composed of linear polymers
of globular proteins called
Flagella found in: Animal and
tubulin.
Prokaryotic Cells
Flagella
Animal Sperm Cell
Prokaryotic Bacterial
Cell
Animal and Plant Cells Share Many
Structures in Common
Animal Cell
Plant Cell
Plant cells and Animal cells have some
key differences:
A cell wall
Vacuole
Plastids (Chloroplasts)
Vacuole
Structure: Large sac
surrounded by a membrane
Function: Stores salts,
minerals, nutrients, water, etc.
and plays an important
structural role for plants
Analogy: Warehouse
Found in: Plant cells and
animal cells (very tiny)
Plastids (Chloroplasts)
Structure: Surrounded by doublemembrane, contains chlorophyll
Function: contain pigments, capture
energy from the sun to make organic
compounds (food), may store food
(starch)
Analogy: solar panels
Found in: Plant cells
Cell Wall
Chloroplast
Cell Wall
Nucleus