Transcript The Cell - Bremen High School District 228

The Cell
Cells are the basic unit
of life!
Robert Hooke
Viewed cork samples
and observed
hollow boxes which he
called cells.
Anton von Leeuwenhoek
•First to describe
microorganisms as seen
through a simple
microscope
Matthais Schleiden - Botanist
All plants are made of cells.
Theodor Schwann - Physiologist
All animals are made of cells.
The studies of Schleiden and Schwann, along with
others, led to the development of the cell theory.
•All organisms are composed of one
or more cells.
•The cell is the
basic unit of
organization
for organisms.
•All cells come from pre-existing
cells.
(Cell reproduction
makes exact copies
of existing cells.)
Basic Cell Types
Prokaryote vs. Eukaryote
Pro = Before
Eu = True
Kary = Nucleus; Kernel
Prokaryote
• Lacks internal
structures surrounded
by membranes
• Lacks a true nucleus
• DNA is contained in
the nucleoid
• Most are single celled
organisms.
Eukaryote
• Has membrane
bound structures
• Has a true nucleus
• Allows cell parts
to specialize in
particular
function
Eukaryote
• Can be unicellular or
multi-cellular
• The membrane bound
structures are called
organelles
• Allows different
chemical reactions to
take place within the
cell
Eukaryotic plant cell
Bacteria & Viruses
Bacteria
A. Prokaryotic organisms
B. Divided into 2 kingdoms
1. Eubacteria
a. Very diverse; live almost anywhere
b. Surrounded by a cell wall
2. Archaebacteria
a. Live in harsh conditions
b. Possible ancestor to eukaryotes
C. Identified by specific characteristics
1. Shape
a. Rod: bacilli
b. Round/spherical: cocci
c. Spiral: spirrilla
2. Cell Wall (thick or thin)
3. Movement
a.
b.
c.
d.
Sessile
Flagella
Snake or spiral forward
Glide along a slime-like material
D. Metabolic Processes
1. Mostly heterotrophs
2. Some autotroughs
3. All need energy
E. Growth and reproduction
1. Binary Fission
2. Conjugation
3. Spore formation
F. Purpose: Vital to the maintenance of the
living world
1. Environment
a. Decomposers
b. Nitrogen fixers
2. Human uses
a. Food production
b. Industrial Uses
c. Genetic Engineering
d. Produce vitamins within our bodies
Viruses
A. Characteristics
1. Considered abiotic; does not have all the
characteristics of life
2. Composed of a core of DNA or a RNA
surrounded by a protein coat (capsid)
3. The capsid enable the virus to enter the
host cell
4. Highly specific to the type of cell they
infect
B. Need host cell to reproduce; parasitic
C. May have evolved from the genetic
material from living cells; viruses
continue to evolve and adapt to their
changing environment
Cellular Structure
and Function
Boundary Organelles
Plasma Membrane
• Location: Surrounds the cell
• Function: boundary between
cell and environment
Controls what goes into and
out of the cell.
* Also called: cell membrane
or phospholipid bilayer
Cell Wall
• Location: surrounds the
plasma membrane in
plant cells
• Function: support
• Inflexible barrier
Nuclear Envelope
(membrane)
• Location: surround the nucleus
• Function: controls what goes into and out of the nucleus
* The nuclear membrane is 4 layers thick
Control Organelles
Nucleus
(largest organelle)
• Location: center of the cell
• Function: manage cell functions
Chromatin/Chromosomes
• Location: in the nucleus
• Function: form chromosomes during cell reproduction
* Formed from DNA
DNA
• Location: in the nucleus, on
the chromosomes
• Function: carries the codes for
protein synthesis; carries
genetic information
Assembly, Transport and
Storage Organelles
Cytoplasm/Cytosol
• Location: from the nuclear envelope to the cell membrane,
surrounding the organelles
• Function: a clear, jelly-like fluid that holds the organelles in
place
Nucleolus
• Location: in the nucleus
• Function: produce ribosomes
Ribosomes
• Location: nucleolus, endoplasmic reticulum, cytoplasm
• Function: assembles enzymes and proteins for protein
synthesis
* Not surrounded by membranes *
Endoplasmic Reticulum
(smooth/rough)
• Location: within the
cytoplasm
• Function: site of lipid
& protein synthesis
• Cell’s delivery system;
network of canals
•Rough ER - studded with ribosomes
•Attached to nuclear membrane
•site of protein synthesis and processing
•Smooth ER - lacks ribosomes
•site of synthesis of phospholipids and
the packaging of proteins into vesicles
Golgi Apparatus
• Location: within the cytoplasm
• Function: Receives and
distributes the new proteins
and lipids from the ER and
distributes substances from
the vesicles
Vacuole
• Location: within the cytoplasm
• Function: temporary storage of
material (food, water, waste,
enzymes)
• One large vacuole in plants
• Many small vacuoles in animals
Lysosomes
• Location: within the
cytoplasm (animals only)
• Function: digests worn out
or extra cell parts, food,
virus/bacteria
Energy Transformers
Mitochondria
“power house”
• Location: within cytoplasm
• Function: breaks down food to release energy;
cellular respiration
Chloroplasts
• Location: Within the cytoplasm
• Function: Change light energy into usable chemical energy
• Chloroplasts are larger and more complex than mitochondria
• Contain green pigment called chlorophyll that absorbs sunlight
in the first step of photosynthesis
• Found ONLY in PLANTS
• Chloroplast structure includes
• Thylakoids, membranous sacs,
• stacked to form a granum
• Stroma, the internal fluid
Chlorophyll: green pigment that
gives plants their color and traps
light energy
Belongs to a group of plant
organelles called plastids which
are used for storage. They store
starches (carbohydrates), lipids
and pigments
Support and Locomotion
Organelles
Cytoskeleton
• Location: Within the cytoplasm
• Function: provides support for organelles
Composed of microtubules and
microfilaments
Microtubules: thin, hollow
cylinders made of proteins
Microfilaments: solid protein
fibers
Intermediate filaments: have a
diameter between microtubules
and microfilaments
Centrioles
• Location: Within the cytoplasm
• Function: Aids in cellular reproduction
• Found only in animal cells
• Small clusters of microtubules; found in pairs
Cilia
• Location: outside of the cell
• Function: move the cell
* tiny, hair-like projections
Flagella
• Location: outside the cell
• Function: move the cell
*Tail-like structure