Tiara
The Cell Theory States:
• The cell is the basic unit of life.
• All living organisms are composed of cells, they may
multicellular or unicellular.
• Cells arise from pre-existing cells.
More Modern Concepts State:
• Energy flow occurs within the cells.
• DNA is passed from cell to cell.
• All cells have the same basic chemical composition.
.
Actually, intracellular
is really called
Cytosol. Cytosol
contains dissolved
nutrients, ions, waste
products, and soluble
and insoluble
proteins.
The cell membrane
keeps the intracellular
fluid away from the
extracellular fluid.
Extracellular fluid is
what our cell floats
around and about
in. It’s a watery
substance, and like
it was previously
stated, the cell
membrane
separates the
extracellular from
the intracellular
fluid.
STRUCTURE: The cell membrane is basically a
wall that separates the interior of cells, from
the outside atmosphere. It is selectively
permeable to organic molecules and ions.
It protects the cell from the outside forces,
and consists of the lipid bilayer with
embedded proteins/
IMPORTANCE: The cell membrane anchors
the cytoskeleton to provide a shape to the
cell. It also attaches to the extracellular
matrix and other cells to form tissues.
Cells interact with their environment through
many ways. The cells needs to obtain nutrients
from the environment, maintain water balance
with their surroundings and to remove the waste
materials from within the cell. The plasma
membrane keeps a boundary between any cell
and its environment.
The non-membranous organelles are the
following:
Cytoskeleton, microvilli, centrioles, cilia, flagella,
and ribosomes.
CYTOSKELETON: is an internal protein
framework that gives the cytoplasm
strength, and flexibility.
MICROVILLI: small, finger-shaped
projections of the cell membrane.
CENTRIOLES: are cylindrical structures
composed of short microtubules.
CILIA: contain nine pairs of microtubules
that surround a central pair.
FLAGELLA: resemble cilia, but larger, they
move a cell through surrounding fluid.
RIBOSOMES: small, dense structures that
cannot be seen clearly with the light
microscope.
The membranous organelles are listed below:
Mitochondria, Nucleus, endoplasmic reticulum,
Golgi apparatus, lysosomes, and peroxisomes.
MITOCHONDRIA: small organelles that
have an unusual double membrane.
NUCLEUS: the control center for cellular
operations.
ENDOPLASMIC RETICULUM: a network of
intracellular membranes.
GOLGI APPARATUS: consists of flattened
membrane discs, called saccules, and
contains of five to six of them.
LYSOSOMES: vesicles that are filled with
digestive enzymes.
PEROXISOMES: are smaller than lysosomes
and carry a different group of enzymes.
The nucleus is the control center for cellular
operations. The nucleus directs processes that take
place in the cytosol and must receive information
about the conditions and activities in the cytosol.
The nucleus has many parts surrounding itself,
including: the nuclear envelope, nuclear space,
nuclear pores, nucleoplasm, nucleoli, and
nucleosome. Most cells have one nucleus, but some
are an exception and have many nuclei.
INTERPHASE
G1: a cell that is going to divide first.
S-Phase: cell duplicates its chromosomes for
next 6-8 hours.
G2: last minute protein synthesis.
MITOSIS
Prophase: begins when chromosomes coil
tightly together and become visible as
individual structures.
Metaphase: chromosomes move to a narrow
central zone called metaphase plate.
Anaphase: chromatid pairs separate and
daughter chromosomes move toward opposite
ends of cell.
Telophase: Nuclear membranes form, nuclei
enlarge, and chromosomes gradually uncoil.
Cytokinesis: separation of daughter cells.
Cells divide through a process
called Mitosis and Meiosis. People
know cell division, and they mean
mitosis, which is the process of
making new body cells. Meiosis is
the cell division that makes sperm
and egg cells.
Transmembrane
potential is the
difference in
voltage between
the interior and
exterior of a cell.