Transcript Cell Structure and Function

Cell Structure and Function
Human Epidermis – Animal cells
Staphylococcus epidermis
Cardiac (heart) Muscle
Stems
Leaves
Amoeba proteus
Root tip
What are some similarities and differences
that you observed by looking at a variety
of cells?
History of the cell
 In 1665, Robert Hooke
was the first to view
cells from cork (dead
plant material). He
called them “cells”
because they looked like
tiny rooms.
 Anton van Leeuwenhoek
saw tiny living organisms
in water in 1675.
In 1838, Matthias Schleiden determined
that plants are made up of cells.
In 1839, Theodor Schwann determined
that animals are made up of cells.
In 1855, Rudolf Virchow concluded that
new cells are produced from the division
of existing cells.
The Cell Theory
All living things are composed of cells.
Cells are the basic units of structure
and function in living things.
New cells are produced from existing
cells.
Types of Cells
Two kinds of cells depending on whether
they have a nucleus
Eukaryote
Prokaryote
Genetic
material
Prokaryotes
 Usually small and simple
 Genetic material (DNA)
is not contained in a
nucleus
 The ONLY prokaryotes
in the world are
BACTERIA.
Prokaryotic Cells
Eukaryotes
 Usually larger and more
complex than
prokaryotes.
 May be unicellular like
an amoeba or
multicellular like a plant
 Contain dozens of
specialized structures
called organelles.
 Includes protists, fungi,
plants and animals.
Eukaryotic cell structure
Two major parts:
Nucleus
Cytoplasm-portion of the cell outside the
nucleus
Eukaryotic cells
Nucleus-The control center
Function:
Contains almost all of the cell’s DNA for
coding proteins and other molecules.
DNA is found on chromosomes which contain
genetic information.
Nucleus-The control center
 Structure:
 Surrounded by a double
membrane called a
nuclear envelope. It is
dotted with many pores
(holes) to allow materials
(RNA, proteins, etc) in
and out of the nucleus.
 Small internal region
called a nucleolus where
ribosomes are made.
Ribosomes
 Function:
Site of protein
assembly.
 Structure:
Small pieces of RNA
and protein found
throughout the cell.
Endoplasmic Reticulum
 Function:
 Site where lipid parts of
cell membrane are made,
along with proteins and
other materials to export
from the cell.
 Structure:
 Rough ER- has ribosomes
on surface to assemble
proteins
 Smooth ER-NO ribosomes
on surface
Golgi Apparatus
 Function:
Modify, sort, and
package proteins and
other materials from
the ER for storage in
the cell or release
from the cell. It puts
the finishing touches
on proteins.
 Structure:
Stack of closely
packed membranes
Lysosomes-The Clean Up Crew
 Function:
 Breakdown of lipids,
carbohydrates and
proteins into small
molecules to be used by
the rest of the cell
 Breakdown used up
organelles
 Get rid of all “stuff” in
the cell
 Structure:
 Small, filled with
enzymes
Vacuoles - Storage
 Function:
Stores water, salts,
proteins and
carbohydrates
 Structure:
Sac-like
Plant cells have one
large central vacuole
Animal cells have many
small vacuoles
Mitochondria - Energy
 Function:
 Convert chemical energy
in food into materials
easier for the cell to
use.
 Structure:
 Enclosed by two
membranes with the
inner membrane folded
up.
 Contains it’s own DNA
(unlike other organelles)
that is identical to your
mother’s!
Chloroplasts – Energy in Plants
 Function:
 Captures energy from the
sun (solar energy) and
changes it into food
(chemical energy) for plants
(photosynthesis)
 Structure:
 Surrounded by two
membranes
 Contains own genetic
information like
mitochondria
 Contains green pigment
called chlorophyll
 Not found in animal cells!
Cytoskeleton- structure and support
 Function:
Helps maintain cell
shape
Helps with movement
of the cell (i.e. flagella
and cilia)
 Structure:
Two types:
microfilaments and
microtubules
Cell Membrane
 Function:
 Regulates what enters
and leaves the cell
 Provides protection and
support
 Structure:
 Double membrane called
a lipid bilayer
 Flexible structure that
forms a strong barrier
between the cell and its
surroundings
CILIA/FLAGELLA
 Cilia are short & flagella are long
 Have a core of microtubules wrapped by plasma
membrane
 Have a 9 + 2 arrangement of microtubules
 The 9 + 2 arrangement extends to the basal body, where
the arrangement changes to 9 triplets of microtubules
 The microtubules bend when protein knobs called dynein
arms grab and adjacent doublet and “walk” along it
Cell Wall
 Function:
Provides support and
protection for the cell
 Structure:
Lies outside the cell
membrane
Found in plants, algae,
fungi and many
bacteria
NOT FOUND IN
ANIMAL CELLS!
Individually, write down 3 differences
between plant and animal cells.