Name ______Test Date______

UNIT 3 - THE WORKING CELL

A.Cell Wall (198)

  • ______&______the cell
  • Lies outside of the ______
  • Is made of ______&______
  • Plant cell walls are mainly ______
  • Fungi cell walls are mainly ______

I. CELL TRANSPORT

A cell is defined as the smallest ______unit of life. In order to maintain ______, ______must be moved into the cell and ______must be transported out of the cell. In addition, some cells produce ______and other materials designated for export. All materials moving in and out of the cell must pass through the ______, a ______

______boundary found in ______cells.

B.Cell Membrane in a Nutshell (187-190)

  • Made mainly of ______& ______
  • Hydrophobic tails of phospholipids make molecules line up as a ______with polar head facing ______and nonpolar tails facing ______.

C.Function

  • Membranes are ______=Semi-permeable, picky
  • Allow certain molecules to pass through; but keeps others out
  • ______what enters & leaves the cell
  • Helps maintain ______

D.Other components of the cell membrane

  • Proteins-
  • Peripheral- on the inside or outside surface. Can be partially embedded into the cell membrane or can be found attached to an integral membrane protein.
  • On the outside surface, ______to inside cell; “receptor proteins”
  • On inside surface, ______the cell membrane to cell’s internal support structure (cytoskeletal) giving cell its shape. “Anchor proteins”
  • Transport proteins (also called integral)- ______through the membrane; used as ______to move things in or out of the cell.
  • Cholesterol-only in ______cells.
  • Helps prevent fatty acid tails from ______together
  • Provides ______for ______cells (no cell wall)
  • Carbohydrates-in chain form; on outside surface
  • Used to ______; cell ID tags
  • If found on top of a protein the whole structure is called a ______
  • If found on top of a phospholipid the whole structure is called a ______

Label the following Cell Membrane

There are two basic mechanisms for transport of materials into and out of the cell:

A. Passive Transport (pgs. 201-205)

Does not require ______. Movement of substances from a ______concentration to

______. There are three types of passive transport:

1. Diffusion – Due to the random movement of molecules in a ______or ______. Many

substances move across the ______by diffusion, for example, ______.

2. Facilitated Diffusion – Diffusion of ______through a

______. Protein channels provide larger openings for larger molecules like

______. In addition, due to the ______fatty acid tails that make up most of the

phospholipid bilayer, ______molecules and ______utilize protein channels. This

includes ______, which utilizes specialized protein channels known as ______.

3. Osmosis – Diffusion of water from a______water concentration to a ______water concentration

through a ______membrane. There are comparative terms used to describe the

water versus solute concentration on either side of a membrane:

  • Hypertonic = ______solute; ______water
  • Hypotonic = ______solute; ______water
  • Water always moves from ______→ ______
  • Isotonic = Relative concentrations of ______and ______are ______
  • There will be ______net movement of water if two solutions are isotonic

Cells must have a mechanism for counteracting the pressure osmosis can create, otherwise a cell could swell &

burst or explode when it is placed in a ______environment.

  • Cell Wall - Rigid boundary found in ______, ______, and ______cells
  • Contractile Vacuole - Actively ______water out of cell in single-celled organisms without ______
  • Blood/Extracellular Fluid – Designed to be ______with cells

B. Active Transport – Requires energy in the form of ______(pgs. 205-207)

1. Protein Pumps – Energy-requiring process during which membrane proteins pump molecules across amembrane

against a concentrationgradient from a ______concentration to a ______concentration. An example

is the sodium-potassium pump.Its purpose is to establish an ______gradient in cells by

pumping ______sodium ions (______) into the cell for every ______potassium ions (_____) pumped out of the

cell. This slight ____ charge inside the cell relative to the outside is very important for ______

______and ______.

2. Endocytosis – “______”. Larger substances are moved into the cell from the exterior by

extending ______, forming a ______around thesubstance. Examples include

macrophages, amoeba, etc.

3. Exocytosis – “______”. Export of molecules from the inside of the cell to the exterior of the cell

by a ______fusingwiththe cellmembrane. Mechanism used to release ______from cells