Structure and Function of the cell

What is the plasma membrane?

Is an outer cell boundary that separates the internal environment of the cell from the external environment

What is the nucleus?

Is the control center of a cell and contains DNA, which provides blue prints for everything that happens in a cell

• can be found either in the middle or the edge

What does the P.M regulate?

Regulates what gets in and out of the cell

What is the P.M composed of?

Its composed of lipids (fats), proteins, and carbohydrates (sugars)

What is the predominant lipids of the PM?

Phospholipids, which form the phospholipid bilayer

What provides stability to the p. bilayer?

Choloesteral

What do the proteins in the PM function as?

As markers, attachment sites, channels, receptors, enzymes, or carriers

What are marker proteins involved with?

involved with cell to cell recognition

What are most marker proteins?

Most are glycoproteins, with some being glycolipids

What are attachment proteins involved in?

Involved in the attachment of cells to other cells

What are channel proteins involved with?

Involved with transportation of substances in and out of a cell

• with some passing through the PM easily due to their size and biochemistry properties, while others need to use channels

What are receptor proteins?

Proteins that contain binding sites that can attach to specific substances

What are enzymes?

Molecules that catalyze chemical reactions on either the inner or outer surface of the PM

What are carrier proteins?

Proteins that move substances (ions or molecules) from one side of the PM to the other

What is the cytoplasm?

The site where most cellular activities take place and contains four major parts:

• Cytosol, cytoskeleton, inclusions, and organelles

What is the cytosol?

The fluid portion of the cytoplasm

What is the cytoskeleton?

Is the “cell skeleton” that provides support and structure

What is the cytoskeleton involved with?

involved with the movement of cellular structures

Where are microtubules located?

Located within cilia and flagella

where are actin filaments located?

Located abundantly in muscle cells and in microvilli

What do intermediate filaments provide?

Provides mechanical strength to cells

What are some examples of miscellaneous substances?

lipid droplets, hemoglobin, and melanin

What are organelles?

Machinery of the cell that each carry out a specific function

What are ribosomes?

Small structures where protein synthesis occurs

• two types: free ribosomes (which float freely in the cytosol) and fixed ribosomes (which are attached to the RER)

What does the RER contain?

Contains ribosomes on the external surface, which produces proteins

What does the SER function in?

Functions in lipid synthesis, storage of Ca ions in muscle cells and detoxification

• Reminder I guess: no ribosomes lol

What does the Golgi apparatus do?

It modifies and packages proteins produced by RER and lipids produced by SER, then figures out where to send them

What do lysosomes contain?

Contain acidic enzymes that can break down particles

• additionally, they are abundant in phagocytes

What is the mitochondria?

An organelle that produces ATP for energy

• two types: cross and long sectional

• lots of em can be found in tissue

What is cilia?

extensions of the PM that move materials over the cell surface

• Have a fluffy hair appearance

What is microvilli?

Finger like projections of the PM that increases the surface area where absorption occurs, resulting in more absorption

• Found in cells that absorb a lot

What are the four cell junctions?

Desmosomes, hemidesmosomes, tight junctions. and gap junction

What are desmosomes?

A type of cell junction that binds cells to one another

What are hemidesmosomes?

A type of cell junction that anchors an epithelial cell down to a basement membrane

What are tight junctions?

A type of cell junction that prevents stuff from moving between two cells

What are gap junctions?

A type of cell junction that allows cell to talk to each other