Exam Questions and CORRECT Answers
What is diffusion? - CORRECT ANSWER - the spontaneous movement of molecules
away from areas of highest density
One area in a cell has a higher density of a certain type of molecule compared to a neighboring
area. This situation describes: - CORRECT ANSWER - a concentration gradient
The highest rates of diffusion are associated with (choose all that are correct!!): - CORRECT
ANSWER - -high temperatures
-large diffusion surface area
-steep concentration gradient
After molecules have moved around until there is no longer a concentration gradient, how do the
molecules behave? - CORRECT ANSWER - they continue moving, but their density
remains relatively even throughout the space
How does facilitated transport differ from diffusion? - CORRECT ANSWER - in
facilitated transport, the substance passes through a pore, or tunnel, inside other molecules in the
membrane
Which three of the following are types of transport proteins? - CORRECT ANSWER --
aquaporins
-channel proteins
-carrier proteins
What benefit do cells obtain by using facilitated transport instead of simple (=unfacilitated)
diffusion to move material across a membrane? - CORRECT ANSWER - Some molecules
have positive and negative regions (i.e. polarity) that prevent them from moving easily through
the membrane; facilitated transport overcomes this problem
, What does it mean if a channel is gated? - CORRECT ANSWER - sometimes the channel
allows molecules to pass through, and sometimes it doesn't
What is the difference (or relationship) between the terms diffusion and osmosis? - CORRECT
ANSWER - they both function in the same way, but osmosis refers specifically to the
diffusion of water molecules
Which of the following are the four categories of organic molecules? Note: the question asks for
the 4 categories, not for specific examples of organic molecules, and not for the building blocks
of organic molecules - CORRECT ANSWER - -carbohydrates
-lipids
-proteins
-nucleic acids
If a molecule is described as 'organic,' then which of the following statements must be true? -
CORRECT ANSWER - it contains carbon
Which of the following are examples of carbohydrates? Choose 3 answers from the list below. -
CORRECT ANSWER - -glucose
-cellulose
-chitin
Which of the following are examples of lipids - CORRECT ANSWER - -olive oil
-bees wax
-bacon fat
When a fat is described as 'saturated,' what is it saturated with? - CORRECT ANSWER -
hydrogen