Cells+Chap+3+JO

Chapter 3. Cell Structure. 1. What does the cell theory state? The cell theory states that a cell is the basic unit of life. Nothing smaller is alive.

2. Why are cells so tiny? The volume represents the needs of the cell.

3. What are the three main parts of a eukaryotic cell?

4. Explain how the eukaryotic cell gained mitochondria and chloroplasts. They have gained these items by engulfing prokaryotic cells.

5. What are glycoproteins, and what functions do proteins, including glycoproteins, have in the plasma membrane? Glycoproteins are short chains of sugars that are attached to outer surfaces of some protein and lipid molecules. In the plasma membrane they control substance flow in and out.

6. What is endocytosis and exocytosis, and how do they occur? Endocytosis: a portion of the plasma membrane invaginates, forms a pouch, to envelop a substance and fluid. Then the membrane pinches off and forms an endocytic vesicle inside the cell. Some white blood cells take up pathogens, this process is called phagocytosis. Exocytosis: The vesicle fuses with the plasma membrane as secretion occurs.

7. The nucleus, ribosomes, and rough endoplasmic reticulum make what contribution to protein synthesis? the nucleus: stores the genetic information ribosomes: are organelles composed of proteins, rRNA. protein synthesis occurs at the ribosomes and the are often attached to the endoplasmic reticulum or freely in cytoplasm. endoplasmic reticulum: a membranous system of saccules and channels, permits the passage of ribosomes.

8. The endoplasmic reticulum and the Golgi apparatus make what contribution to the processing of proteins? ER: here the proteins are synthesized and enter the ER interior where they are processed and modified. it also forms transport vesicles to the golgi apparatus. GA: where the modification of proteins occurs. Ex: chain of sugars may be added to proteins making them glycoproteins.

9. What is the function of smooth endoplasmic reticulum and lysosomes? the smooth ER synthesizes phospholipids that occur in membranes and has various other functions depending on the particular cell. the lysosomes fuse with an endocytic vesicle, its contents are digested by its own lysosomes into simpler subunits and enter the cytoplasm.

10. What is the function of the mitochondria? the function is to convert the chemical energy of glucose products into the chemical ATP molecules. cellular respiration is the name of this process.