Question

briefly describe 3 important parts of cells

Answer 1

1. PLASMA MEMBRANE/ CELL MEMBRANE

• Structure- a bilipid membraneous layer composed of proteins and carbohydrates.  It is fluid like.
• Function - the cell membrane separates the cell from its external environment, and is selectively permeable (controls what gets in and out).  It protects the cell and provides stability.
• Proteins are found embedded within the plasma membrane, with some extending all the way through in order to transport materials.
• Carbohydrates are attached to proteins and lipids on the outer lipid layer.

2. "ER" OR ENDOPLASMIC RETICULUM

• The Endoplasmic Reticulum is a network of membranous canals filled with fluid.  They carry materials throughout the cell.  The ER is the "transport system" of the cell.

• There are two types of ER: rough ER and smooth ER.
• Rough Endoplasmic Reticulum is lined with ribosomes and is rough in appearance and smooth endoplasmic reticulum contains no ribosomes and is smooth in appearance.

3. MITOCHONDRIA

The mitochondria are round "tube-like" organelles that are surrounded by a double membrane, with the inner membrane being highly folded.  the mitochondria are often referred to as the "powerhouse" of the cell.  the mitochondria releases food energy from food molecules to be used by the cell.  This process is called respiration.  Some cells( muscle cells)  require more energy than other cells and so would have many more mitochondria.