General Biology 1 :Topic: Cell Theory dense spot which he termed as the nucleus.

A
few years later, German botanist Matthias
Schleiden (1838) concluded that all plant parts
are made of cells. Theodor Schwann (1839), also
What is Cell ? a botanist and a close friend of Schleiden, stated
-Cell is what we called “the basic unit of life” that all animal tissues are composed of cells, too.
Cells are the basic building blocks of all living things. In 1858, Rudolf Virchow concluded that all cells
The human body is composed of trillions of cells. come from pre-existing cells.
They provide structure for the body, take in nutrients
from food, convert those nutrients into energy, and
carry out specialized functions. Cells also contain the
body’s hereditary material and can make copies of REMEMBER
themselves. Cells have many parts, each with a
different function. Some of these parts, called All cells come from pre-existing cells (1858).
organelles, are specialized structures that perform -Rudolf Virchow
certain tasks within the cell.
All animals are made up of cells (1839)
PLANT CELL ANIMAL CELL -Theodor Schwann
All plants are made up of cells (1838)
-German Botanis Matthias Schleiden

Tiny living organisms are observed (1676).

-Anton van Leeuwenhoek

Thousands of tiny empty chambers in cork are called

cells (1665)
-Robert Hooke

Cell Theory
-The cell theory states that all biological Cell Functions and Structures
organisms are composed of cells; cells All living organisms are made up of one or many
are the unit of life and all life come from cells. The cells are the building block of life just
preexisting life as atoms are the basic building blocks of all
matter. Each cell contains materials that carry
Prior to the invention of the very first microscope,
out basic life processes.
everything that could not be seen by the naked
eye was unexplainable. In 1665, English
physicist Robert Hooke used of the first light Cell structures can only be observed under high
microscopes to look at thin slices of plant tissues. magnification electron microscope and are
One of these, a slice of cork, especially caught separated internally into numerous
his eye. Under the microscope, cork seemed to
membranous compartments called organelles
be made of thousands of tiny chambers. Hooke
called this chambers ―cells‖ because they (little organs).
reminded him of a monastery‘s tiny rooms, which
were also known as cells. Until 1676, Anton van These organelles perform a variety of functions
Leeuwenhoek published his observations on tiny like production of proteins, storage of important
living organisms which he named animalcules. It materials, harvesting energy, repairing cell parts,
was believed that Leeuwenhoek was the first to
digestion of substances, and maintaining the
observe under his microscope the structure of a
red blood cell of different animals as well as a shape and structure of the cell.
sperm cell. One of the leading botanists in his
time, Robert Brown in 1831 was able to compare
diverse kinds of plant specimens under the
microscope. He markedly indicated that there is
a common thing about them-they are all
composed of cells, and inside the cell is a dark
 hereditary information. Nucleoli are small
Cell Membrane bodies often seen within the nucleus. The
gel-like matrix in which the nuclear
-the cell components are suspended is the
membrane (also nucleoplasm.
known as
the plasma Ribosomes
membrane (PM) Ribosomes can
or cytoplasmic be found floating
membrane, and within the
historically referred to as the plasmalemma) cytoplasm or
is a biological membrane that separates attached to the
the interior of all cells from the outside endoplasmic
environment  which protects the cell from its reticulum.A
environment.They are the controls passage ribosome functions as a micro-machine for
of organic molecules, ions, water, oxygen making proteins. Ribosomes are composed
and wastes into and out of the cell of special proteins and nucleic acids.

Cytoplasm
Mitochondria
 Cytoplasm is a Mitochondria are
thick solution that often referred to as
fills each cell and is the “powerhouses of
enclosed by the cell the cell.” They help
membrane..Provide turn the energy we
s structure to cell; take from food into
site of many metabolic reactions; medium in energy that the cell
which organelles are found. can useThe main
job of mitochondria is to perform
Nucleolus cellular respiration. This means it takes
is the in nutrients from the cell, breaks it down,
largest
and turns it into energy. ... The more
structure in
the nucleus energy a cell needs the more
of
eukaryotic
mitochondria that will be present..  
cells. It is
best known
as the site of ribosome biogenesis. ... Peroxisomes
Nucleoli are made of proteins, DNA and Peroxisomes are
RNA and form around specific chromosomal organelles that sequester
regions called nucleolar organizing regions. diverse oxidative
reactions and
Nucleus play important roles in
metabolism, reactive
oxygen species
The nucleus controls
detoxification, and signaling. Oxidative
and regulates the
pathways housed in peroxisomes include
activities of the cell
fatty acid β-oxidation, which contributes to
(e.g., growth and
embryogenesis, seedling growth, and
metabolism) and carries
stomatal opening.
the genes, structures
that contain the
 damaged beyond repair, lysosomes can help
it to self-destruct in a process called
programmed cell death, or apoptosis.

Vescicles and Vacuoles Cell Wall

Vesicles and vacuoles

are membrane-  cell wall is a
bound sacs that structural
function in storage layer
and transport. surrounding
Vacuoles are some types
somewhat larger than of cells, just
vesicles, and the outside the
membrane of a vacuole does not fuse with cell membrane. It can be tough, flexible, and
the membranes of other cellular sometimes rigid. It provides the cell with both
components. Vesicles can fuse with other structural support and protection, and also
membranes within the cell system  acts as a filtering mechanism.

Centrosomes
The Chloroplast
centrosome
is considered
to be the Chloroplasts
main are plant cell
microtubule- organelles
organizing that convert
center light energy
(MTOC) therefore regulating cell adhesion, into relatively
motility, and polarity. It also promotes the stable
spindle pole organization in an animal cell chemical
during mitotic replication. energy via
the photosynthetic process. By doing so,
they sustain life on Earth. ... Chloroplasts are
Lysosomes plant cell organelles that convert light energy
into relatively stable chemical energy via the
A lysosome photosynthetic process.
is a
membrane- Endoplasmic Reticulum
bound cell
organelle The endoplasmic
that reticulum is a network
contains digestive enzymes. Lysosomes of sacs that
are involved with various cell processes. manufactures,
They break down excess or worn-out cell processes, and
parts. They may be transports chemical
used to destroy compounds for use
inside and outside of
invading viruses and
bacteria. If the cell is the cell They .Modifies proteins and
synthesizes lipids
Golgi Apparatus
A Golgi body, also known as a Golgi Flagellum, plural flagella, hairlike
apparatus, is a cell organelle that helps structure that acts primarily as an
process and package proteins and lipid organelle of locomotion in the cells of
molecules, especially proteins destined to many living organisms. ..
be exported from the cell. 

Cytoskeleton

The
cytoskeleton
is a structure
that helps
cells maintain
their shape
and internal
organization, Cilia
and it also provides mechanical support that
enables cells to carry out essential functions
like division and movement. are small hair-like protuberances on the
outside of eukaryotic cells. They are
primarily responsible for locomotion, either of
Flagella the cell itself or of fluids on the cell
surfaceThe function of cilia is to move water
relative to the cell in a regular movement
of the cilia