cell membrane - the thin layer of protein and fat that
surrounds the cell, but is inside the cell wall. The cell membrane is
semipermeable, allowing some substances to pass into the cell and blocking
others.
cell wall - a thick, rigid membrane that surrounds a plant
cell. This layer of cellulose fiber gives the cell most of its support and
structure. The cell wall also bonds with other cell walls to form the
structure of the plant.
centrosome - (also called the "microtubule organizing
center") a small body located near the nucleus - it has a dense
center and radiating tubules. The centrosome is where microtubules are
made. During cell division (mitosis), the centrosome divides and the two
parts move to opposite sides of the dividing cell.
chloroplast - an elongated or disc-shaped organelle
containing chlorophyll. Photosynthesis (in which energy from sunlight is
converted into chemical energy - food) takes place in the chloroplasts.
cytoplasm - the jellylike material outside the cell nucleus
in which the organelles are located.
Golgi body - (also called the Golgi apparatus or Golgi
complex) a flattened, layered, sac-like organelle that looks like a stack
of pancakes and is located near the nucleus. The Golgi body packages
proteins and carbohydrates into membrane-bound vesicles for
"export" from the cell.
mitochondrion - spherical to rod-shaped organelles with a
double membrane. The inner membrane is infolded many times, forming a
series of projections (called cristae). The mitochondrion converts the
energy stored in glucose into ATP (adenosine triphosphate) for the cell. |
nuclear membrane - the membrane that surrounds the nucleus.
nucleolus - an organelle within the nucleus - it is where
ribosomal RNA is produced.
nucleus - a spherical body containing many organelles,
including the nucleolus. The nucleus controls many of the functions of the
cell (by controlling protein synthesis) and contains DNA (in chromosomes).
The nucleus is surrounded by the nuclear membrane
ribosome - small organelles composed of RNA-rich cytoplasmic
granules that are sites of protein synthesis.
rough endoplasmic reticulum - (rough ER) a vast system of
interconnected, membranous, infolded and convoluted sacks that are located
in the cell's cytoplasm (the ER is continuous with the outer nuclear
membrane). Rough ER is covered with ribosomes that give it a rough
appearance. Rough ER transports materials through the cell and produces
proteins in sacks called cisternae (which are sent to the Golgi body, or
inserted into the cell membrane).
smooth endoplasmic reticulum - (smooth ER) a vast system of
interconnected, membranous, infolded and convoluted tubes that are located
in the cell's cytoplasm (the ER is continuous with the outer nuclear
membrane). The space within the ER is called the ER lumen. Smooth ER
transports materials through the cell. It contains enzymes and produces
and digests lipids (fats) and membrane proteins; smooth ER buds off from
rough ER, moving the newly-made proteins and lipids to the Golgi body and
membranes.
vacuole - a large, membrane-bound space within a plant cell
that is filled with fluid. Most plant cells have a single vacuole that
takes up much of the cell. It helps maintain the shape of the cell. |