3.1 and 3.2 Flashcards
What are cells?
Cells are the basic, living, structural, and functional units of the body.
What is cell biology?
The scientific study of cells
What are the three principal parts of a cell?
Plasma membrane, cytoplasm, nucleus
What is plasma membrane?
- forms the cell’s flexible outer surface, separating the cell’s internal environment (everything inside the cell) from the external environment (everything outside the cell).
- selective barrier that regulates the flow of materials into and out of a cell.
- plays a key role in communication among cells and between cells and their external environment
What is cytoplasm?
-consists of all the cellular contents between the plasma membrane and the nucleus.
What are the two compartment of cytoplasm?
cytosol and organelles
What is cytosol?
the fluid portion of cytoplasm, also called intracellular fluid, contains water, dissolved solutes, and suspended particles.
What is nucleus?
a large organelle that houses most of the cell’s DNA. Within the nucleus, each chromosome contains thousands of hereditary units called genes that control most aspects of cellular structure and function
What phrase is best described for plasma membrane?
fluid mosaic model
What is lipid bilayer?
The basic structural framework of the plasma membrane is the lipid bilayer
What are three types of lipid molecules?
phospholipids, cholesterol, and glycolipids
What are phospholipids?
About 75% of the membrane lipids are phospholipids, lipids that contain phosphorus.
What are cholesterol?
Present in smaller amounts are cholesterol (about 20%), a steroid with an attached-OH (hydroxyl) group
What are glycolipids?
(about 5%), lipids with attached carbohydrate groups
What is amphipathic?
the bilayer arrangement occurs because the lipids are amphipathic molecules, which means that they have both polar and non polar parts.
What region of cholesterol is polar?
The OH group
What region of cholesterol is non polar?
the stiff steroid rings and hydrocarbon tail of cholesterol
What are integral proteins?
Integral proteins extend into or through the lipid bilayer and are firmly embedded in it.
What are transmembrane proteins?
Most integral proteins are transmembrane proteins, which means that they span the entire lipid bilayer and protrude into both the cytosol and extracellular fluid.
What are peripheral proteins?
Peripheral proteins are not as firmly embedded in the membrane. They are attached to the polar heads of membrane lipids or to integral proteins at the inner or outer surface of the membrane.
What are glycoproteins?
Many integral proteins are glycoproteins, proteins with carbohydrate groups attached to the ends that protrude into the extracellular fluid.
What is glycocalyx?
The carbohydrate portions of glycolipids and glycoproteins form an extensive sugary coat
what are Ion channels?
pores or holes that specific ions, such s K+, can flow through to get into or out of the cell. Most ion channels are selective: they allow only a single type of ion to pass through
What are carriers?
selectively moving a polar substance or ion from one side of the membrane tot he other. Carriers also known as transporters.
What are receptors?
serves as cellular recognition sites. Each type of receptor recognizes and binds a specific type of molecule. For instance, insulin receptors bind the hormone insulin.
What are ligand?
A specific molecule that binds to a receptor.
What are enzymes?
catalyzes specific chemical reactions at the inside or outside surface of the cell
What are linkers?
actors proteins in the plasma membranes of neighbouring cells to one another or to protein filaments inside and outside the cell. Peripheral proteins also serve as enzymes and linkers.
What are cell-identify markers?
Membrane glycoproteins and glycolipids often serve as cell-identify markers. They may enable a cell to (1) recognize other cells of the same kind during tissue formation or (2) recognize and respond to potentially dangerous foreign cells. The ABO blood type markers are one example of cell-identify markers.
