cell (for edtech 213 class 2nd semester ay 2013-2014
DESCRIPTION
Lecture on Cell ( I made this for my Biology 1 class SY 2007-2012)TRANSCRIPT
CELL:ORGANIC UNIT OF LIFE
jrmguce2011
CELL basic unit of structure and function Can be:
Unicellular Multicellular
Bodies are cooperative of specialized cells Cannot survive for long on their own
How do we study cells? Invention of lenses (merchants of
Europe) Combination of lenses led to:
Telescope Microscope*
17th century: discovery and early study of cells thru*
Invention and Development of Microscopes
Anton von Leeuwenhoek Dutch biologist first to explore things: microscopic view
Pond water (detailed illustration)
ESSENTIAL SCIENTISTS Robert Hooke
English scientist Pieces of cork
Composed of thousands of chambers
After 200 years: cells were also found in other organisms
ESSENTIAL SCIENTISTS Robert Brown
(1833) Scottish Nucleus
Dark structure
Matthias Schleiden German STATED: all plants
are made up of cells
ESSENTIAL SCIENTISTS Theodor Schwann
STATED: all animals are made up of cells
Rudolf Virchow German 1855 Cells arise from the
division of pre-existing cells
The CELL THEORY
most fundamental discovery: nature of living things
forms basic framework formulated by Schwann,
Schleiden and Virchow
STATES that:
ALL LIVING THINGS ARE COMPOSED OF CELLS
CELLS ARE THE BASIC UNIT OF STRUCTURE AND FUNCTION
ALL CELLS COME FROM PRE-EXISTING CELLS
Prokaryotic VS Eukaryotic Cells
Pro- before Karyon- kernel NO NUCLEUS DNA: concentrated
in a NUCLEOID With cytoplasm w/ PM
Eu- true Karyon- kernel Has NUCLEUS With cytoplasm
Cytosol
w/ PM
ORGANELLES NUCLEUS
contains most of the genes averaging about 5µm in dm *Nuclear envelope
Encloses nucleus Double membrane (lipid bilayer with
proteins) 20 – 40 nm
Perforated by pores 100 nm in dm pore complex*
PARTS OF THE NUCLEUS *Nuclear lamina
netlike array of protein filaments maintains the shape of the nucleus
*Nucleolus Site: components of ribosomes are
synthesized and assembled Components pass through the nuclear pore
to the cytoplasm* Appears as a mass of densely stained
granules and fibers adjusting part of chromatin
FUNCTION of NUCLEUS information center of the cell
contains DNA
control protein synthesis By sending molecular messengers: mRNA
ORGANELLES RIBOSOMES
Protein factory cells with active protein synthesis
prominent nucleoli build proteins: two cytoplasmic locales
Free ribosomes: cytosol Bound ribosomes: for inclusion, transport,
packaging
ENDO-MEMBRANE SYSTEM
Membranes that are related either: direct physical continuity transfer of membrane segments
Includes: VAly PLAne GOer Nuclear Envelope ER Golgi Apparatus Lysosomes Vacuoles Plasma Membrane
Endoplasmic Reticulum
more than half the total membrane of cells
reticulum Greek word for network Two types:
Smooth ER Rough ER
Smooth ER Smooth walls of the sacs are not
studded with ribosomes Functions: SYLIP me car DE DRUP
Synthesis of lipidsMetabolism of carbohydratesDetoxification of drugs and poison
ROUGH ER studded with ribosomes FUNCTIONS:
synthesis of secretory protein membrane production (membrane factory) synthesis of proteins
Golgi Apparatus Center of: MWSS
Manufacturing Warehousing Sorting Shipping
Products from the ER are: SMS Modified Stored Sent to other destinations
flattened membranous sacs- CISTERNAE vicinity is concentrated with vesicles
Golgi apparatus- other ENDOMEMBRANE organelle CONNECTION
Parts of GA: Cis face
Receiving part (near ER) TV moves materials from ER to GA
Trans face Shipping (vesicles)
manufactures certain macromolecules Hyaluronic acid
glue animal cells together
dispatches products by Budding of vesicles
gives molecular tags (phosphate groups)
Vacuoles
membrane bound sacs in a cell food vacuole- formed by
phagocytosis Contractile vacuole
Pumps out water out
Central Vacuole- filled with liquid Tonoplast organic compounds (proteins in seed) Disposal sites for metabolic products
FUNCTIONRepository of inorganic ions
Storage of pigments
Helps to protect against predators
LYSOSOMES
membrane bounded sacs of hydrolytic enzymes
digestion of macromolecules
works best in acidic medium ~pH 5 maintains internal pH excessive leak of a large number
leads to AUTODIGESTION
hydrolytic enzymes and lysosomal membrane
by RER and Golgi Apparatus Ex. Lysosomes in an Amoeba
Exhibits PHAGOCYTOSIS Phagein Greek: to eat Kytos: vessel
Food vacuole + lysosome = digests food
AUTOPHAGY use of its own HE to digest its own
organelles Recyle its parts
happens when it engulfs an organelle after digestion
Organic monomers are returned to the cytosol
Absence of lysosomes accumulation of indigestible substrates Pompe’s Disease- glycogen Tay Sachs Disease- lipid
Other Membrane Organelles
not part of Endo-Membrane System membranes not made by ER
Free ribosomes and Ribomes of Mitochondria and Cytoplasm
contain small amounts of DNA semi- autonomous
Mitochondria
power house of the cell site of cellular respiration
Catabolic process that generates ATP* number related to cell’s metabolic
activity 1-10µm long enclosed by two membranes
Membranes*: Outer- smooth Inner**- convoluted with infoldings
(CRISTAE) Inter-membrane space Mitochondrial matrix
Chloroplast
found in plants and eukaryotic algae site of photosynthesis Solar energy – chemical energy member of plastids
Amyloplasts- colorless, stores starch Chromoplast- stores pigments
Chloroplast, xanthophyll, fucoxanthin
contains another membranous system THYLAKOIDS
flattened sacs forms GRANA bathed with stroma
Peroxisomes
specialized metabolic compartment bounded by a single membrane
sontains enzymes that produces* H2O2 as a by product
FUNCTION: use O2 to break Fatty acids detoxify alcohol
Transferring H2 from the poisons to oxygen
BUT…. H2O2 is toxic but peroxisomes have enzymes that
convert it to water grow by incorporation of proteins and
lipids made in the cytosol splits into two
Examples: Glyoxysomes
fat storing tissues of plant seeds has enzyme that initiates conversion of FA-
sugar food for the seedling