Download Inside the cell ppt

Ch 4
CELL STRUCTURE AND
FUNCTION
The Cell
• The cell is the smallest unit of life
that can carry out life processes.
Chapter 4
Section 2 Introduction to Cells
Cellular Organization
Discoveries Leading to
The Cell Theory
• Robert Hooke – 1665 -observed cork
through a light microscope.
• Anton Van Leewenhoek – 1675 -observed
LIVING cells.
• Matthias Schleiden – 1883 –plants are
made of cells.
• Theodor Schwann – 1839 –animals are
made of cells
The Cell Theory
• The cell theory states that all living
organisms are made of one or more
cells, cells are the basic units of
structure and function, and cells
come only from pre-existing cells.
Two Basic Types of Cells
Prokaryotic Cell
• Prokaryoticcells that do not
have a nucleus
and internal
membrane-bound
structures
– Most unicellular
organisms are
prokaryotes.
– Bacteria
Eukaryotic Cell
• Eukaryotic-Cells
that do have a
nucleus and
internal
membrane-bound
structures.
– Most multicellular
organisms are
eukaryotes.
– Yeast and algae
(unicellular,
eukaryotes)
– Plant and animal
Features Common to Cells:
• Cytoplasm – Gel
like material that
protects,
supports and
suspends
organelles.
All cells have either DNA
or RNA or both.
Features Common to Cells:
• Cell membrane – Semi-permeable allows
some materials in and keeps others out.
This helps to maintain cellular homeostasis.
Structure of the Plasma
Membrane
• Phospholipid Bilayer -2
layers ofphospholipids.
• Phospholipid- phosphate
head attached to two lipids
(fattyacid tails).
• Polar phosphate group allows
membrane to interact with
its environment.
• Fatty acid tails create a
water-insoluble layer in the
middle which is non-polar.
• Fluid mosaic modelmembrane is flexible
• Cholesterol-keeps fatty
acid tails from sticking
together
• Transport proteins-allow
needed substances to move
through the membrane
Chapter 4
Parts of the Cell
Nucleus
• “Command center”
• Surrounded by a
nuclear envelope
• Contains genetic
material:
– chromatin
– chromosomes
• Nucleolus-makes
ribosomes
– Ribosomes-site where
proteins are made
• Can be found floating
in the cytoplasm or
attached to
endoplasmic reticulum
Endoplasmic Reticulum (ER)
• Series of folded
membranes allow a
large amount of work
to be done in a small
amount of space
• Transportation unit
for the cell
• Rough Endoplasmic
Reticulum (RER)
– Ribosomes attached
– Protein synthesis
• Smooth
Endoplasmic
Reticulum (SER)
– Produce and store
lipids
Golgi Apparatus
Vesicles
• Flattened tubular
membranes
• Packaging plant
• Modify, sort,
package, and
transport
proteins
throughout the
cell
VACUOLES
• Storage sacs
Temporary storage
of materials
– Store food, enzymes,
waste
• Plant cells have one
large vacuole.
• Animal cells have
many small vesicles.
LYSOSOMES
• Contain digestive
enzymes
• Digest excess or
worn organelles, food
particles, viruses,
and bacteria
• Surrounded by
membrane that
prevents it from
destroying the cell
• Can burst causing
cell death
Chapter 4
Mitochondria
• Cellular respiration -converts food
into energy
• Cell “Powerhouse”
• Number of mitochondria depends upon the
function of the cell
– Ex: muscles cells have more mitochondria than fat
cells
Centriole
• Help with
cell
reproduction
• Only found in
animal cells
Plastids – Color pigments of cells
• Examples:
– Chloroplast – Located in plant cells, some
bacteria, and protists.
• Capture light energy to produce and store food
• Contain chlorophyll-green pigment that traps light
energy
Features Common to Cells:
• Cytoskeleton –
tiny
fibers that give structure
and support to the cell.
– Microfilament- thin and
tubular…support the cell
membrane.
– Microtubule- thick and
tubular also branched.
Act as “rails” on which
materials move through
the cell.
Cilia and Flagella
• Aid in movement
and feeding
• Composed of
microtubules
• Cilia-short,
numerous hair-like
projections that
move in a wavelike
motion
• Flagella-long,
whip-like
projections
Cell wall
• Rigid outer
covering PLANT
CELLS
• Located outside
the cell membrane
• Provides support
and protection
• Helps produce
turgor pressure
•
Animal Cell
Plant Cell
Plant cell vs. Animal Cell
Plant vs Animal cells
•
–
–
Animal Cell vs. Plant cell
•
•
•
•
Animal Cell
DO contain centrioles.
DO NOT contain a cell wall or plastids.
Plant Cell
DO contain a cell wall, plastids, and a
large central vacuole.
DO NOT contain centrioles