1 (A) Cell Theories

– Major subfield of biology, Cytology which is the study of the structures

and functions of plant & animal cells.
– Would not have progressed without the help of microscope.

Cyto Cell
Logy Study

Spontaneous Generation Theory - Spontaneous generation theory is an archaic

scientific theory which stated that living organisms could arise from nonliving
matter and that such a process was regular in nature.

Timeline
1665 Robert Hooke
1676 Antonie van Leeuwenhoek
1838 Matthias Jakob Schleiden
1839 Theodor Schwann
1858 Rudolf Virchow

Biologists

Robert Hooke

– first to illustrate & demonstrate cork cells

– 1665 book, Micrographia
– coined the word cell, comparing it to the cell in monastery. What he had
observed was actually the remains of dead plant cell.

Antonie van Leeuwenhoek

– first person to observe living cells ( blood & sperm cells )

– 1676, he introduced the first unicellular organisms, animalcules

Matthias Jakob Schleiden

– he discovered the plant cell out of the vegetative/ meristematic tissues &
embryonic plants

Theodor Schwann
 – he discovered animal cells
– muscle & nerve fiber tissues now called Schwann Cell in his honor

Rudolf Virchow

– physician
– proponent of the Cell Theory’s 3rd postulate, which states that all
cells come from pre-existing cells.

3 Postulates of Cell Theory

– All living organisms are composed of 1 or more cells.

– Cell is the basic unit of life.
– All cells come from pre-existing cells.

Cell - Tissue - Organs - Organ System

1 (B) Cell Structures & Functions

– Most cells are 10-20 minutes micrometers in diameter.

– One micrometer is one-thousandth of a millimeter, which is one
thousandth of a meter.

Microscope: used to visualize cells.

Light illuminate samples

Electron sample by bouncing electrons off
Transmission internal details by passing electron
through sample

Common Cells of the Human Body

Leukocytes white blood cells

Haematids red blood cells
Sarcomeres striated muscle tissue
Enterocytes intestinal cells
Thrombocytes platelets
Neurons nerve cells
Osteocytes bone cells
Ovum female sex cell
Sperm male sex cell
Hepatocytes liver cells

Cells

Prokaryotic Eukaryotic
No nucleus True nucleus
absence of other membrance-bound has other membrane-bound
organelles organelles
DNA is suspended in cytoplasm DNA is enclosed in the nucleus

3 Major Parts of the Cell

 Cell Membrane lipid bilayer, outer boundary of the
cell
Cytoplasm 90% of the cell, houses the
organelles, Jelly like
Nucleus Brain/Control center of the
Eukaryotic cell, enveloped by
nucleus membrane, contains DNA &
nucleoulus

Organelles - BOTH found in plant & animal cells

Mitochondrion
– powerhouse of the cell

Endoplasmic Reticulum
– interconnected thin folded membranes

Rough ER Smooth ER
attached ribosomes no presense ribosomes
site for protein synthesis lipids & break down drugs and
alcohol

Golgi Apparatus
– process, sort and packages proteins ( factory )
– layered stacks of flattened membranes

Ribosomes
– Attached to the Rough ER or floating in the cytoplasm
– site of protein synthesis
– large-small subunits made up of DNA & protein

Vacuole
– storage tank
– fluid-filled sank

Peroxisome
– enzymes in digesting fatty acids
– absorbs nutrients
– plays a part in the way organisms digest alcohol

Organelles - ONLY in Animal cells

Centriole
– cylinder shaped
– 9 groups of microtubules
– helps the cell to divide during mitosis & meiosis

Lysosome
– specialized vesicle containts a variety of enzymes
– digest waste materials & food
– defend the cell from bacteria/viruses

Organelles - ONLY in Plant cells

Cell Wall
– supports & protects the cell
– cellulose ( complex sugar )
– provides mechanical strength and accounts for the definite shapes of
plant cells

Chloroplast
– outer & inner membranes
– closed compartments of stacked membranes called grana
– each grana contains thylakoids ( chlorophyll )
1.1 (A) Prokaryotic & Eukaryotic Cells

Prokaryote Eukaryote
No nucleus Presence of nucleus
No other membrane bound Has other membrane bound
organelles organelles
Unicellular organisms Multicellular except for Euglana,
Paramecium and Amoeba

Commonalities: Cytoplasm, Cell Wall, Plasma membrane

Prokaryotic Kingdom

Archaebacteria

– Large class (250 species)

– Severe environment
– With no specific structure but are classified into 3 types based on the
substance they create and the environment they live in.

a. Methanogens

– Mostly thrive in sewege facilities, bogs and inside the intenstine of

ruminant animals like cows, goats & sheep.

Aerobic Anaerobic
- needs oxygen - can live without oxygen

b. Halophiles

– salty environment

c. Thermophiles

– Attracted to heat and hot places such as geothermal vents and hot
springs.

Eubacteria ( True Bacteria )

– Disease causing bacteria

 – Most number of species possess rigid cells with peptidoglycan that can
either be motile or non motile.

motile non motile

can move doesn’t move

Eukaryotic Kingdom

Euglena
– 800 species that is very intriguing as they exhibit both animal & plant
traits
– flagella tails for movement and presence of green chloroplasts for
photosynthesis.

Paramecium
– found in freshwater & marine
– Genus of the protozoa class known for its ciliated structure that has
become the favorite model organism of scientists for their researches.

Diatoms
– gems of the sea
– Transparent cell walls made of silicon dioxide hydrated in water which
gives them their very colorful and beautiful patters.

Fungi
– Very big family that consists of yeasts,molds and mushrooms.
– Digestive enzymes secretions are some of their distinct traits.

Plantae
– World of plants

a. Oryza Grass group

– blade like pointed leaves that grow very tall and primary source of
carbohydrated foods.

b. Angiospermae Group
– biggest phylum in the plant kingdom
– come from the greek words Angeion and Sperma, “ enclosed seeds “

c. Gymnospermae Group
– seed bearing plants but come in the form of cones
– Most of its 1,000 species are highly valuable lumber trees.
Animalia
– Largest group composed of millions of species that are characterized by
their motility, adaptation and survival mechanisms.
1.1 (B) Cell Modifications

Peptidoglycan unique and essential structural

element in the cell wall of most
bacteria
Chitin function: primarily to hydrate and
protect soft tissue
Flagella hair like structure that acts primarily
as organelle of locomotion

Other special cell

Cytoskeleton
– they help cell maintain their shape and form
– keeps organize the organelles intact in their proper places
– provide mechanical support (cell division and movement)

Cilia
– Microscopic hair like in eukaryotic cells
– 200 or 300 cilia per cell

Motile Non motile

Surrounded by mucus/fluid Antenna like role receiving sensory
substances to help cell move/ messages to be transmitted to other
dispose off materials. cells.

Microvilli
– Non motile membrane enclosed projectionss that increase secretion,
absorption and binding/adhesion on properties of cells.

Root hairs
– Hairy membrane enclosed projections in plant cells that increase
absorption/surface area for osmosis and nutrients.

Flagella
– Tail like projections in prokaryotic and eukaryotic that enable locomotion
of organisms.