Page 3 - Chapter 3: Cells and Tissues



a) The nucleus is the control center of the cell; it stores the genetic
information in the form of DNA.

b) The plasma membrane is made up of two layers of phospholipids. The
membrane is very selective of the substances that can go inside and outside
of the cell.

c) The cytoplasm is a gel-like substance inside the cell membrane but
outside of the nucleus.
Many different organelles (little organs) are in the cytoplasm.
d) The mitochondria are the power plants of the cell. Enzymes within the
mitochondria carry out the reactions in which oxygen is used to break down
foods. As the foods are broken down, energy is released. Some of that
energy is captured and is used to form ATP molecules. ATP provides the
energy for all cellular work.
e) Ribosomes are concerned with protein synthesis. Some ribosomes float
free in the cytoplasm,others attach to membranes in the rough endoplasmic
reticulum.
f) Endoplasmic Reticulum is a network of fluid-filled canals that coil and
twist through the cytoplasm. It serves as a minicirculatory system of the cell.
The rough ER is so called because is studded with ribosomes. The ER is the
cell membrane factory. The smooth endoplasmic reticulum function in lipid
metabolism, detoxification of drugs and pesticides.

g) The Golgi apparatus appears as a stack of flattened membranous sacs. It
is close to the nucleus. Its major function is to modify and packages proteins.