Mitochondrion and ATP
-Both the inner and outer membranes of the mitochondrion have essentially the
same molecular structure as the cells plasma membrane.
-The fact that mitochondria generate most of the power for cellular work suggests
that the number of
Cilia and Flagella
-A flagellum produces wavelike movements, which propels a sperm cell forward,
like the tail of an eel.
-In humans, cilia found in groups on stationary cells beat in a coordinated oar like
pattern to push fluid and particles in the extra
-Microtubules are sometimes called the engines of the cell because they often
move things around in the cell or even cause movement of the entire cell.
-In addition to the bones and muscles that make up the cytoskeleton, there are
-Ideas about cell structure have changed considerably over the years.
-Early biologists saw cells as simple, fluid-filled bubbles.
-The inside of the cell is composed largely of a gel-like substance called
-The cytoplasm is made
-The cytoplasm is an amazingly rich network that is literally the bones and
muscles of the cell.
-It provides a variety of many different types of cell movement, both internal and
external; depend on the cell and the circumstances.
-Such movement can be used for intracellular transport or movement of the cells
-Other types of molecular motors can be used to generate power by converting
mechanical energy to chemical energy.
-In some cells, th
-A cell can control what moves through any section of membrane by means of
proteins embedded in the phospholipid bilayer.
-Many of these membrane proteins have openings that allow water-soluble
molecules to pass through the membrane.
-DNA molecules dictate both the structure and the function of cells.
-The most prominent structure visible in the nucleus is a small nonmembranous
body that contains densely when studied in the laboratory setting and is called
Recycling of Cells
-After entering the first cisterna of the Golgi apparatus, a protein molecule
undergoes a series of chemical modifications.
-When it is ready to exit, a molecule is packaged in a membranous secretory
vesicle that migrates to the surface
Organelles and its Functions
-Many types of organelles have been identified in various cells of the body.
-Membranous organelles are those that are described as sacs or canals made of
-Nonmembranous organelles are not made of membrane; they
-For example, in Parkinson disease, the proteasome system fails, and
consequently, the still intact improperly folded proteins kill nerve cells in the brain
that are needed to regulate muscle tension.
-In addition to lysosomes, another type of