Exam 5: Lifes Border: the Plasma Membrane

An accident victim lost a lot of blood and was rushed to the emergency room.In the emergency room,the first thing the doctors did was replace lost fluids by giving an IV of pure water.But this caused the patient to die.Propose a reason why the patient died.

Osmosis refers to the diffusion of ________ across a membrane.

Facilitated diffusion occurs through membrane-bound transport proteins.

What are two major differences between active transport and passive transport? Please give a specific example of each that occurs within a eukaryotic cell.

How does glucose enter a cell if levels of blood glucose are high?

Small,nonpolar molecules easily pass through the phospholipid bilayer because the molecules:

Yeast cells take up glucose (a sugar)to use as their primary source of energy.Typically,glucose concentrations outside yeast cells are far lower than glucose concentrations inside the cells.Therefore,for yeast to take up glucose,the cells must use:

Some integral proteins can span the entire phospholipid bilayer.

Which of the following is an accurate description of the plasma membrane?

Facilitated diffusion occurs down a concentration gradient.

It seems that bacteria and molds should grow well in jam.It's extremely high in sugar,a substance many cells can use for energy,and contains enough other nutrients to support cell growth.Yet jam can be left unrefrigerated for a very long time without contamination by microorganisms.How can this be?

The functioning of the immune system depends on recognition proteins.

You have lost a lot of blood in an accident.In the emergency room the first thing the doctors will need to do is replace lost fluids.The fluids they give you should be:

Transport proteins are integral plasma membrane proteins.

A component of the plasma membrane that helps to maintain its fluidity is:

The most up-to-date explanation of the structure of the plasma membrane is called the fluid-mosaic model.

Having defective proteins in the cell membrane can cause disease.

The hydrophilic region of the phospholipid bilayer faces to the interior of the plasma membrane.

Which of the following would be least likely to diffuse through a phospholipid bilayer?

A woman suffering from severe dehydration goes into the hospital.The doctor tells the woman that her blood has far too much solute in it and not enough water.Explain how this condition could affect the cells of her body and why.