Cell Structure & Function
 Robert

Viewed cork, noted “cellulae” (monk’s cells)
 Anton

Hooke, 1665
van Leeuwenhoek, 1676
First visualized “animalcules”
 Theodore
Schwann, Matthias Schleiden,
1830s

Described cell division, nuclei, all living things
made of cells
 Rudolf

Virchow, 1858 & later
All cells arise from pre-existing cells
 Every
living organism is composed of one or
more cells
 A cell is the smallest unit having the
properties of life
 The continuity of life directly arises from the
growth and division of single cells
 Plasma


membrane
Lipid bilayer
Regulates transport in/out of cell
 Genetic


material
Nucleus
Nucleoid
 Cytoplasm
 Metabolic
activity related to cell volume and
surface area
 Volume increases faster than surface area
 The speed and amount of “stuff” (waste &
nutrients) across a cell membrane is
determined by the surface area
 Larger cell volume needs more nutrients and
produces more waste
 Eventually the cell becomes big enough that
the membrane can’t transport “stuff” fast
enough
 Prokaryotes
 Eukaryotes
 “Before
the nucleus”—no nucleus or
membrane-covered structures (organelles)
 True bacteria
 Archaebacteria
 Very small
 Simplest cells
 Nucleoid
region
 DNA (single loop)
 Cell membrane
 Cell wall (in some)
 Capsule (in some)
 Cytoplasm
 Ribosomes
 Pili
 Flagellum
 Nucleus
and other complex organelles
 Organelle—internal membrane-bound
compartment that serves specialized
functions. “Little organs”
 Protozoans
 Algae
 Fungi
 Plants
 Animals
 Complex
systems
 Nucleus



Control center
Houses DNA (6 feet!!!)
Nuclear envelope/membrane



Regulates transport of molecules
Receptors for signaling
Nucleolus

Constructs ribosomes
 Endoplasmic

Rough



Reticulum (ER)
Ribosomes attach
Protein synthesis
Smooth


No ribosomes
Lipid synthesis
 Ribosomes

Synthesize proteins
 Golgi

Bodies
Package and process proteins & lipids
 Vesicles—sacs


containing enzymes
Lysosomes—intracellular digestion
Peroxisomes—break down fatty acids & proteins
 Vacuoles—large
vesicles for storing food &
water

Only some eukaryotes
 Mitochondria




Forms ATP (energy)
Requires oxygen
H+ stored in outer compartment, controlled flow
into inner
Similar to bacteria: have their own DNA &
ribosomes
 Plastids



Chlorloplasts—Photosynthesis (energy from light)
Chromoplasts—color
Amyloplasts—store starches
 Central

Vacuole
Storage (amino acids, sugars, ions, wastes)
 Centrioles—produce
cell division.
microfilaments during
 Cell
membrane—regulates movement of
“stuff” in and out of cell
 Cell wall—strong, gives permanent shape to
cell
 Protein
filaments between nucleus & plasma
membrane
 Microtubules—keep organelles & cell
structures in place or move them


Can fall apart in controlled ways (amoebas)
Some poisons can affect
 Microfilaments




Thin filaments
Help in cell division (contracts midsection)
Anchor membrane proteins
Muscle contraction
 Motor
proteins move things within cells
 Flagella—long outer structures for movement

Usually only a few
 Cilia—short

outer structures for movement
Usually many
 Pseudopod

“False foot”
 Plant




cells
Have cell walls & cell membranes
Have plastids such as chloroplasts
Have a central vacuole
Do not have centrioles
 Animal




cells
Have cell membrane but no cell wall
Do not have plastids
Do not have a central vacuole
Have centrioles