Download Cell Parts _ Function

The Parts of a Cell
How did scientists first discover
the different cell parts?
History of the Cell
•  Hooke - the first person to see cells (1665)
•  van Leeuwenhock - observed living cells in
pond water (1673)
•  Schwann - observed animals had cells (1839)
•  Schleiden - observed plants had cells (1845)
•  Virchow - predicted all cells come from other
cells. (1850)
The Cell Theory
1.  Every living organism is made of one
or more cells.
2.  The cell is the smallest living unit that
can perform life functions.
3.  All cells arise from pre-existing cells.
Endosymbiosis Theory
•  Eukaryotic cells evolved from a larger cell
engulfing smaller bacteria cells
•  Evidence: Mitochondria and Chloroplasts have
their own separate proteins & DNA
The Prokaryotic Cell:
Identify Animal Cell Parts
vacuole
centrioles
mitochondria
cytoplasm
nucleolus
cilia
nucleus
rough ER
smooth
ER
Golgi
apparatus
ribosomes
microtubules
Cell Membrane
•  protects cell
•  semi-permeable; controls what goes in
and out of cell
Cytoplasm
•  contains everything inside the cell: salts,
organic molecules, organelles, etc.
Nucleus
•  contains DNA
•  makes RNA in the nucleolus
Nucleolus
•  large dark spot within nucleus
•  makes ribosomes
Nuclear Membrane
•  protects DNA
•  its pores control what goes in/out of nucleus
•  connected to endoplasmic reticulum (ER)
Cytoskeleton
•  supports shape and movement
•  help anchor and transport of vesicles,
organelles, etc
•  made of microtubules and microfilaments
Ribosomes
•  NOT an organelle
•  makes proteins
•  can be free floating, or bound to rough ER
.
Endoplasmic Reticulum
(ER)
•  make and transport materials for cell
•  connected to nuclear membrane
Smooth ER vs Rough ER
•  makes lipids &
vesicles; storage for
detoxifying chemicals,
etc
•  transports secretory
proteins (used in cell
membrane)
Golgi apparatus
•  stack of membrane-bound vesicles
•  packages molecules for transport
Vacuole
•  stores food and water, waste
•  bigger than vesicles
Lysosome
•  digest food
•  remove waste
Mitochondrion
•  powerhouse - makes energy for the cell
•  size and DNA similar to bacteria
Centrioles (animal)
•  helps divide the cell
Cilia & Flagella
•  moving the cell itself (flagella)
•  moves objects outside the cell (cilia)
Chloroplast (plant)
•  contains the pigment chlorophyll
•  where photosynthesis occurs
Cell Wall (plant)
•  supports and shapes the cell
Cell Wall (bacteria)
•  peptidoglycan
Capsule (bacteria)
•  surrounds and protects the cell
Are all cells the same?
Animal vs. Plant
• cell wall
• central vacuole
• plastids (chloroplasts,
leucoplasts, etc)
• centrioles
• lysosomes*
Prokaryote vs. Eukaryote
•  no membrane-bound
organelles; no nucleus
•  DNA in single loop;
plasmid DNA
•  cell wall of
peptidoglycan
•  capsule for protection
•  pili for sex
•  has membrane bound
organelles; has nucleus
•  DNA in linear
chromosomes
•  cell wall of cellulose
•  compartmentalization
Nucleus
•  nuclear pores
•  nucleolus
Nucleolus
•  makes ribosomes (2 rRNA subunits)
prokaryote
(70S ribosome)
eukaryote
(80S ribosome)
Vacuole
•  stores food, ions, water, waste; buds off
Golgi apparatus
*food vacuoles
*central vacuole in plants
*contractile vacuoles in protozoa
Golgi apparatus
•  cis face (toward nucleus)
•  trans face (toward cell membrane)
Lysosome
•  buds off Golgi
The Endomembrane system:
•  Related through direct continuity or by
transfer on membrane segments
through vesicles.
•  Structure of membranes is not identical
•  Includes:
•  Nuclear envelope --> Endoplasmic
reticulum --> Golgi apparatus -->
lysosomes --> vacuoles -->plasma
membrane
Peroxisome
•  produces H2O2; contains
catalase
•  detoxifies alcohols and
other poisons (liver cells)
•  self-replicating vesicle;
NOT formed from Golgi
Plastids
•  chloroplast – contain chlorophyll
•  amyloplast (also leucoplast in
potatoes) - store starch, in roots
and tubers
•  chromoplast – contains nonchlorophyll pigments
*carrots, tomatoes
Cytoskeleton
•  microfilaments
(actin)
•  intermediate
filaments
•  microtubules
(tubulin)
Cilia
•  moves the cell; moves things around
the cell; respiratory & digestive tract
•  made of microtubules
Pork vs Euk Flagella
•  spinning motion
•  flagellin proteins
•  waving motion
•  9+2 arrangement of
tubulin proteins
•  Cell-Cell Connections
channels connect cytoplasm between cells
•  plasmodesmata (plants)
•  gap junctions (animals)
Animal Cell Surface
•  desmosome - rivets cells together with space in
between
•  tight junction - holds cells together
Extracellular Matrix
•  fluids, carbohydrates and proteins
The Plasma Membrane:
Cell Membrane
& Cell Transport
Phospholipid
Phospholipids in Water
Cholestrol in Fluidity
Cholesterol inside animal cell membranes:
•  At high T°, decreases fluidity by restrict movement of
phospholipids
•  At low T°, increases fluidity by preventing close
packing of phospholipids
*plant cells do not have cholesterol
Polar areas
of protein
Nonpolar areas of protein
Membrane Proteins
•  glycocalyx - markers, glycoproteins or
glycolipids enable cell-cell recognition
•  transport – active transport *Na-K pump
•  receptors – receive, transmit ECM signals
•  ion channels – passage of polar molecules
•  adhesion – attachment sites for proteins
•  electron transport chain – chemical reactions
*photosynthesis
Factors Affecting Movement
•  size – larger molecules, slower rate
•  concentration – increase [ ], increase
rate
•  temperature – higher T°, faster rate
Membrane Permeability
•  semi-permeable to small nonpolar molecules,
small polar & uncharged molecules and
gases (water, oxygen, carbon dioxide)
•  NOT permeable to large or charged
molecules (glucose, ions like H+ or Na+)
Diffusion & Osmosis
--movement of water
and other molecules
Diffusion
•  movement of molecules from areas of higher
concentration to areas of lower concentration
Osmosis
•  diffusion of a solvent through a semipermeable membrane
Osmosis in Living
Systems
hypertonic–
solution with
more solute
isotonic - both
have the same
amount of solute
hypotonic–
solution with
less solute
Isotonic
Hypotonic Hypertonic?
Plasmolysis
Plasmolysis
•  net loss of water from a cell to a
hypertonic environment; the plasma
membrane pulls away from the cell wall