Chapter 3 -- The Cell Flashcards
List General Parts of a Cell
1- plasma membrane
2- cytoplasm– contains organelles
3- nucleus
Relate and explain the 4 main functions of cells
- Cell metabolism and energy use
- Synthesis of molecules (proteins, lipids, etc.)
- Communication: produce and receive electrical and chemical signals
- Reproduction and Inheritance: each cell contains DNA. Some cells called gametes transmit DNA during sexual intercourse.
Aquaporins
Water channel proteins
Osmotic Pressure
Force required to prevent water from moving by osmosis across a selectively permeable membrane
Hydrostatic Pressure
Prevents net movement of water into the tube
Osmotic vs. Hydrostatic
Pressures
Osmotic has to do with concentration gradient
Hydrostatic has to do with weight –>pressure that the water
Endocytosis and Exocytosis are included in what broader transport category?
Vesicular transport
Endocytosis
The uptake of material through the plasma membrane by the formation of a vesicle.
(Ingested)
Three types of endocytosis:
- phagocytosis
- pinocytosis
- mediated endocytosis
Phagocytosis
“Cell eating”–> solid particles are ingested and phagocytic vesicles are formed
(Important to eliminate harmful substances from body. Ex. White blood cells phagocytize bacteria)
Pinocytosis
“Cell drinking”–> smaller vesicles form and contain molecules dissolved in liquid rather than particles
(Pinocytotic vesicles form on the internal side of a capillary, are transported across the cell, and open by exocytosis outside the capillary)
Receptor-mediated endocytosis
The receptors combine only with certain molecules (ex. Cholesterol)
Hypercholesterolemia
Common genetic disorder characterized by the reduction or absence of low-density lipoprotein (LDL) receptors on cell surfaces resulting in inadequate cholesterol uptake, cholesterol synthesis within these cells is not regulated, and too much cholesterol is produced. The excess cholesterol accumulates in blood vessels, resulting in atherosclerosis which can cause hart attacks or strokes
Exocytosis
Secretions are expelled from the cell
Ex. Digestive enzymes, mucous by salivary gland, milk by mammary glands
Cytoplasm
Material outside nucleus but inside cell
