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BIO 348 Chapter 11: membrane structure Questions with Correct Answers
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BIO 348 Chapter 11: membrane structure Questions with Correct Answers
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BIO 348 Chapter 11: membrane structure Questionswith Correct Answers
membrane functions Correct Answer--Barrier separating what's inside of
a cell from what's outside
-Selectively allows substances enter (e.g. nutrients) or leave (e.g. wastes)
the cell (through transport proteins)
-Compartmentalization within the cell (organellar membranes)
-Allows cell to sense and respond to external environment (receptor
proteins)
-Changes shape in response to cell needs (i.e. cell needs to grow or
change shape)
Internal cellular membranes Correct Answer--Eukaryotic cells contain
several of these that aid in surrounding and enclosing the various
organelles
-have essentially the same functions as PM
Selective barrier, etc.
membrane composition Correct Answer--fluid mosaic model
-lipid bilayer
-contain a combination of lipids and proteins
*phospholipids
*cholesterol
*glycolipids
*glycoproteins
,fluid mosaic model Correct Answer-model that describes the
arrangement and movement of the molecules that make up a cell
membrane (it moves around, contains different things)
Lipids and proteins present in the membrane Correct Answer-
Phospholipids
Cholesterol
Glycolipids
Glycoproteins
head of phospholipid Correct Answer-polar, hydrophilic
tail of phospholipid Correct Answer-nonpolar, hydrophobic
proteins of membrane Correct Answer-serve as channels
membranes are phospholipids composed of Correct Answer-
phospholipids
phospholipids are made of Correct Answer-glycerol, two fatty acids and
a "head" containing phosphate
Phospholipids are Correct Answer-amphipathic (hydrophobic and
hydrophilic)
, phospholipids spontaneously form Correct Answer-ilayers when placed
in aqueous environment (protects hydrophobic tails from water)
Phosphatidylcholine Correct Answer-Common phospholipid present in
abundance in most cell membranes; uses choline attached to a phosphate
as its head group.
*look at image**
amphipathetic components Correct Answer-Phospholipids, Glycolipids
and Sterols (cholesterol)
-look at image**
energetics of membrane function Correct Answer--When amphipathic
molecules are placed in an aqueous environment, the hydrophilic portion
wants to interact and dissolve in water, whereas the hydrophobic
portions want to avoid water
-The solution (for phospholipids): the lipid bilayer! Hydrophobic tails
hang out with each other, hydrophilic heads are oriented towards the
aqueous solutions
-Any edges are going to be energetically unfavorable (why?)
-Therefore, lipid bilayers automatically seal themselves to avoid edges
-Membranes are self-repairable, if there is a damaged end, they
automatically self-seal
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