art 2

1. The Cell Membrane
Cell Membrane (1) & (Pg.75-77)
Madison, Nicole, Courtney, Marchelle
Each cell has various membrane organelles.
Membranous organelles are sacs and canals made of
The A & P Journal
the same membrane material as the plasma
membrane. The concept of a cell membrane is called
the fluid mosaic model. The fluid mosaic model is
where the molecules of the membrane are bound
tightly enough to form a continuous layer but
loosely enough so molecules can slip past one
another. Chemical attractions hold a cell membrane
together. The primary structure of a cell membrane
is a double layer of phospholipids. Phospholipid
molecules have heads that are water soluble and
double tails that are lipid soluble. Their “heads” are
hydrophilic which means water loving and their
“tails” are hydrophobic which are water fearing.
Phospholipids naturally arrange themselves into
double layers, or bilayers, in water. Membrane
proteins are proteins embedded in the phospholipid
bilayer of the membrane; contributes to cell
transport, cell-cell recognition, and other cell
functions. Membrane proteins have many different
structural forms that allow them to serve various
other functions. Other membrane proteins are
receptors that can react to the presence of hormones
Flower Power!
or other regulatory chemicals and thereby trigger
metabolic changes in the cell. Signal transduction is
when cells translate the signal received by a
membrane receptor into a specific chemical change
in the cell.
Volume: 7 Issue: 21

2. Inorganic Molecules
Water is the “cradle of life”; the molecules are polar and interact with each oth-
er. It plays as a solvent that permits the transportation of many essential mate-
rials within the body. The 4 properties of water are high specific heat, heat of
vaporization, cohesion and polarity. High specific heat is when water can lose
and gain large amounts of heat with little change in temperature and both ab-
sorbs and gives up heat slowly. Heat of vaporization requires absorption of sig-
nificant amounts of heat to change water from a liquid to a gas and cools the
body down. Cohesion is when water works as a lubricant or cushion to protect
against damage from friction or trauma. (1) (pg. 44)
Oxygen and Carbon Dioxide is the second inorganic molecule. Oxygen is re-
quired to complete the decomposition reactions required for the release of ener-
gy from nutrients burned by the cell. Carbon dioxide produces as a waste prod-
uct during the breaking down of complex nutrients and serves an important
role in maintaining the appropriate acid-base balance in the body. (1) (pg. 45-
46)
The last inorganic molecule is electrolytes. Electrolytes are substances that
break up in solution to form charged particles, called ions. Acids are any sub-
stance that will release a hydrogen ion when in solution. Bases are electrolytes
that, when dissociated in solution, shift the H+/OH- balance in favor of OH-.(1)
(pg. 46-47)
© (7)
Volume: 7 Issue: 21

3. Organic Molecules
• Organic Molecules
Organic is used to describe the enormous number of compound that contain car-
bon (C-C or C-H) (page 47)
• Major groups of organic substances: carbohydrates, proteins, lipids, nucleic acids.
(page 48)
• Carbohydrate compounds contain the elements carbon, hydrogen, and oxygen with
carbon atoms linked to one another to form chains of varying lengths. (page 48)
• Sugars and starches (page 48)
• Divided into three types of classes classified by length of their carbon chains: Mon-
osaccharaides (simple sugars), Disaccharides (double sugars), Polysaccharides
(complex sugars). (page 48)
• Monosaccharides: short carbon
chains, glucose most important sim-
ple sugar, hexoses (6 carbon simple
sugars) include fructose and galac-
tose. (page 48-50)
• Disaccharides: Sucrose, maltose,
and lactose, each consist of two
monosaccharides linked together,
hydrogen atom from a glucose mole-
cule combines with a hydroxyl group
from the fructose molecule to form
water. (page 50)
• Polysaccharides: Monosaccharides
may be bonded together to form long
© (7)
Volume: 7 Issue: 21

4. Organelles
Centrosome – Area of the cytoplasm near the nucleus that coordinates the
building and breaking of microtubules in a cell.
Cytoplasm - The cytoplasm (of both eukaryotes and prokaryotes) is where
the functions for cell expansion, growth, metabolism, and replication are car-
ried out.
Endoplasmic Reticulum- The endoplasmic reticulum or ER is an extensive
membranous network in eukaryotic cells, continuous with the outer nuclear
membrane. The ER modifies proteins; makes macromolecules, and transfers
substances throughout the cell. Endoplasmic means "within the cytoplasm",
and reticulum means "little net".
Golgi apparatus - The Golgi apparatus is often considered the distribution
and shipping department for the cell's chemical products. It modifies proteins
and lipids (fats) that have been built in the endoplasmic reticulum and pre-
pares them for export outside of the cell or for transport to other locations in
the cell.
Lysosome- Lysosomes hold enzymes that were created by the cell. The pur-
pose of the lysosome is to digest food or break down the cell when it dies.
Mitochondria- the Mitochondria is the “power house” of the cell which is re-
sponsible for converting food to energy.
Nucleus- The nucleus is a membrane bound structure that contains the cell's
hereditary information and controls the cell's growth and reproduction
Plasma membrane- the plasma membrane is the outermost covering of the
cell where in plants, fungi, and some bacteria it is located beneath the cell
wall
Ribosome- ribosomes are the protein builders of the cell, the also connect
amino acids to make a chain.
© (6)
Volume: Issue: 21