Unit Test: Cellular Structure & Function, Cell Membrane Transport, and Cell Division

Accel 2015

Cell Transport Quiz Topics

READING:Text: ch.5.1-5.9, Class notes & Handouts (Membr. Prob Set, etc)

Activities:Diffusion Computer Models, MembraneStructureTutorial, GummiBear Osmosis Lab, Cell Transport Problem Set, Cell Membrane Problem Set, Cell Size Lab

REVIEW: How do ionic substances, polar molecules and non-polar molecules behave in water?

• Vocab: polar, ionic, non-polar (neutral), hydrophobic, hydrophilic

• General rules for dissolving:

• polar and charged things dissolve in water

• amphipathic things partially dissolve in water (tend to form micelle or bilayer)

• nonpolar things are excluded by water and do not mix with it

Structure of Cell Membrane (know how to label diagram)

• Parts of the cell membrane (What are each of the following for? What jobs do they do?)

• phospholipids / lipid bilayer

• proteins (various functions, be familiar with the range of these)

• cholesterol

• carbohydrates

• How/why do phospholipids form a bilayer in water?

• What would happen if you put a cell in a hydrophobic environment?

• How/why are membranes fluid?

• How can organisms, like plants, fish, & bacteria, which lack the ability to regulate their body temp:

• keep membranes fluid in cold temperatures?

• keep membranes together (less fluid) in hotter temperatures?

Transport Across the Cell Membrane

Cell membranes are selectively permeable (What does this mean?)

• What types of molecules can move freely across the lipid bilayer? Why can they get across?

• What types of molecules cannot cross the lipid bilayer? Why can’t they get across?

• How do these molecules cross the cell membrane?

• Vocab: concentration, diffusion, net diffusion, “random” motion, dynamic equilibrium

Passive Processes

• occur from areas of high concentration to areas of low concentration only(downconcentr. gradient)

• no extra energy use needed by cell

• include:

• Diffusion

• Osmosis (via lipid bilayer and Aquaporins)

• FacilitatedDiffusion (channel protein)

• Vocab: solution, solute, solvent, concentration gradient, hypotonic, hypertonic, isotonic

Active Processes

• allow for transport from areas of low concentration to areas of high concentration (againstconcentr. gradient)

• require energy use by cell, in form of ATP.

- ATP phosphorylates protein pump or motor protein, producing ADP & Pi

- ADP is “renewed” using energy from cell respiration: ADP & Pibonded again, forming ATP

• includes:

• Active Transport (protein pump)

• Endocytosis

• PhagocytosisOVER 

• Pinocytosis

• Receptor-mediated endocytosis

• Exocytosis

CELL SIZE and DIFFUSION: Why are cells so small?

• Relationship between SA:Vol ratio and rate of diffusion

Review resources:

The Biology Project (from the University of Arizona) has a MC “problem set” / quiz

BiologyMad topic notes on The Cell Membrane

Cell Defense Game: