Histology - exam 1 The Cell - Plasma Membranes

Compartmentalizes the cell and acts as a selectively permeable barrier.

Describe the function of the cell membrane

Fatty acids, proteins, & lipids

What does the cell membrane consist of?

Hydrophobic fatty acid tails and hydrophilic polar heads

What do fatty acids consist of in the plasma membrane?

It prevents most charged particles from crossing the membrane & sets up a concentration gradient

What is unique about the anatomy of cellular membranes?

Integral proteins (embedded) & peripheral proteins (attached to inner surface)

What two types of proteins are associated with the cell membrane?

Carbohydrate-rich Glycocalyx/Cell coat: functions in cell recognition, acts as hormone receptors, helps in cell adhesion, and protects from chemical injury.

What is the arrow pointing to and how does that structure function

Transmembrane proteins & integral monotropic proteins

What are the two categories of integral proteins

Pumps, Channels, Receptors, Transducers, Enzymes, & Structural Proteins

What are the 6 different types of integral monotropic proteins

Active transporters of ions across the membrane. Ex: Na+/K+ pump

Describe the function of pumps and give an example

Protein "tunnels" in the membrane allowing passive diffusion of ions

Describe the function of Channels

Recognize and bind substances important to cell functions (hormones, ect)

Describe the function of Receptors

Link receptors to cell enzymes which activate cellular processes

Describe the function of Transducers

Assist in cellular activities

Describe the function of Enzymes

Form cell to cell junctions such as gap junctions

Describe the function of Structural Proteins

Simple diffusion, osmosis, mediated transport, facilitated diffusion, active transport, & vesicular transport

List 6 ways molecules can move in and out of the cell

Flow of molecules down their concentration gradient. Typically small polar and ionic molecules

Define simple diffusion

Diffusion of water from high concentration to a low concentration across the membrane

Define osmosis

Substance binds to a carrier protein causing a conformation change which passively moves the substance across the membrane

Define mediated transport

Carrier mediated transport that moves molecules from higher concentration to lower concentration with no energy required

Define facilitated diffusion

A carrier mediated transport process that moves molecules against its concentrated gradient, requiring energy.

Define active transport

Involves the formation of vesicles through endocytosis and exocytosis

Define vesicular transport

Invagination of the plasma membrane forming vesicles enclosing a small volume of extracellular material. There are two types: phagocytosis and pinocytosis

Define endocytosis

Cellular eating: involves ingestion of particulate matter such as bacteria or other cells

Define Phagocytosis

Cellular drinking: the internalization of fluids and proteins

Define Pinocytosis

Fusion of membrane covered vesicles with the cell membrane & release of substance into the extracellular space

Define Exocytosis

Membrane channels between adjacent cells allowing the passage of small molecules & ions from cell to cell without entering the extracellular space. Also allows the flow of electrical current in heart cells

Define Gap Junctions