Download Cells Under the Microscope The Cell Theory Cell Size All Cells

11/8/2012
Cell Size
Smalls cells
More efficient
Higher surface area-to-volume ratio
Chapter 3
Cells Under the Microscope
All Cells Have
Plasma Membrane: Selective
outer boundary
Cytoplasm: Water-like interior
DNA: Genetic material
Ribosomes: Synthesize
Proteins
Anton van Leeuwenhoek (16321723) - First to see “animalcules” in
pond water
The Cell Theory
1. All living things are made of one or
more cells.
2. Cells are the basic unit of structure &
function of all living things.
3. All cells arise from existing cells.
Two Basic Cell Types
Prokaryote
Eukaryote
Size
Small (1/10 of
Euk)
Large (10X prok)
DNA
In “nucleoid”
region
Within
membrane-bound
nucleus
Organelles
No membranebound organelles
Membrane-bound
organelles
Body Type
Unicellular
Unicellular or
Multi-cellular
1
11/8/2012
Prokaryote
Nucleus
Bacteria
Smallest simplest
cells
Contain DNA
(chromatin &
chromosomes)
Cell Wall: Surrounds
cell membrane &
provides structural
support
Nuclear Envelope:
Membrane
surrounding nucleus
Flagellum: Long
threadlike structures
that enable movement
Nucleolus: Where
ribosomes are made
Eukaryotic
•
•
•
•
Protista
Fungi
Plantae
Animalia
They Both Have
Unicellular or
multicellular
Some have cell
walls some don’t
Can be autotrophic
or heterotropic
CYTOPLASM – the jelly-like fluid
that fills the cell
CYTOSKELETON – protein fibers that
provide framework for cell, like a
skeleton does for your body
2
11/8/2012
Organelle
Mitochondria
Membrane-bound structure that carries
out specific activities for the cell.
Endoplasmic Reticulum (ER)
Makes ATP from
breaking down food
Cells that need lots of
energy have lots of
mitochondria. (muscle
cells)
Surrounded by
membranes, contain
DNA & ribosomes, and
are thought to be
descendents of
prokaryotic cells
(endosymbiotic theory)
Vesicles-small membranebound sacs
Membrane bound
Rough ER:
Ribosomes
attached
Transports
Proteins to Golgi
Smooth ER:
Makes Lipids
Detoxifies
chemicals
Golgi Apparatus
The cell’s packaging
and distribution
center. Modifies
macromolecules for
the cell or for
secretion outside
cell
Vesicles bud from
the apparatus
LYSOSOMES- vesicles
that bud from Golgi
apparatus and contain
digestive enzymes;
“clean up crew” usually
found only in animal
cells
PEROXISOMES – vesicles
that bud from ER; break
down hydrogen peroxide in
cells; found in both plant
and animal cells
Cells Can Have
Cilia: Hair-like
structures used for
“sweeping” or cell
movement (cells of
bronchi,
paramecium)
Flagella: long,
threadlike structures
for movement
(sperm, some
bacteria)
3
11/8/2012
Plant Cells
Central Vacuole
Chloroplasts
Uses light energy to
make carbohydrates
from water and carbon
dioxide.
Provide energy for
cell.
Surrounded by double
membrane, contains
DNA, thought to be
descendents of
prokaryotic cells.
(endosymbiosis)
Large membrane bound sac that stores
water & other substances
When full makes cell rigid
Cell Analogy
Cell Wall
Surrounds & supports Cell
Maintains cell shape
Protects
Connects to other cells
4