Chapter 5 Biology
Which of the following is not one of the four main components of all plasma membranes?
Extracellular matrix
When a channel protein or carrier protein assists in diffusion, which of the following is observed?
Facilitated diffusion
Which method of microscopy is illustrated in this drawing?
Freeze-fracture microscopy
When the concentration of a substance varies from one region to another, this substance is said to exhibit a concentration _______ .
gradient
An aqueous solution with a lower concentration of solutes will have a ______ concentration of free water molecules.
higher
An aqueous solution with a lower concentration of solutes will have a ________concentration of free water molecules.
higher
Water is attracted to charged or polar solutes, forming _______ shells around them.
hydration
Which structure surrounds all cells?
plasma membrane
What is the name of carrier proteins that transport a single type of molecule or ion?
uniporters
In an aqueous solution the solvent is
water
The cytoplasm contains ions and molecules dissolved in ______
water
The diffusion of which molecules across a selectively permeable membrane is called osmosis?
water
The most abundant molecule in the cytoplasm is the molecule.
water
When 10 grams of sugar are dissolved in 1 L of water, ______ is the solvent and ______ is the solute.
water, sugar
Net movement of a substance from a region where it has a higher concentration to a region where it has a lower concentration is called which of the following?
Diffusion
If two solutions have unequal concentrations of solutes, which one will be considered hypertonic?
The solution with the higher solute concentration
Select the statements that are true about ions.
-They interact well with polar molecules. -They are repelled by the hydrophobic interior of the lipid bilayer
Which of the following describes the sodium-potassium pump?
-It uses energy from ATP to alter the conformation of the carrier protein. -It is an active transport mechanism. -It moves sodium ions and potassium ions across the membrane in opposite directions.
Which statements are true regarding endocytosis?
-Once materials enter the cell they are still separated from the cytoplasm by the membrane of a vacuole or vesicle. -The plasma membrane envelops food particles and fluids.
Which of the following statements about endocytosis are true?
-Phagocytosis, pinocytosis, and receptor-mediated endocytosis are 3 different types of endocytosis. -During endocytosis, a segment of the plasma membrane pinches off to form a vacuole or vesicle inside the cell. -Virtually all eukaryotic cells carry out endocytosis.
Which of the following are key functions carried out by membrane proteins?
-Receive external chemical messages -Connect adjacent cells and hold them together -Attach the membrane to the cytoskeleton
Which of the following are the three main types of endocytosis?
-Receptor-mediated endocytosis -Pinocytosis -Phagocytosis
Which processes require the cell to expend some of its own energy, usually from ATP?
-Receptor-mediated endocytosis -Pinocytosis -Phagocytosis
Which of the following statements about ion channels are true?
-Some can be opened or closed in response to a specific stimulus. -They are used to transport ions across the membrane.
How does lipid composition affect membrane fluidity?
-Sterols, such as cholesterol, can either increase or decrease membrane fluidity depending on temperature. -Saturated fatty acids tend to make the membrane less fluid because they pack together well.
Select the true statements about cell membranes.
-The degree of membrane fluidity varies depending on the composition of the membrane. -Individual lipids and unanchored proteins are relatively free to move around laterally within the lipid bilayer.
select the accurate statements concerning membrane fluidity.
-The degree of membrane fluidity varies depending on the composition of the membrane. -Individual lipids and unanchored proteins are relatively free to move around laterally within the lipid bilayer.
Select the accurate statements concerning membrane fluidity.
-The degree of membrane fluidity varies depending on the composition of the membrane. -Phospholipids are relatively free to move around laterally within the membrane. -Unanchored proteins are relatively free to move around laterally within the membrane.
The two solutions shown in this diagram are separated by a selectively permeable membrane that allows water to pass through freely but prevents the passage of urea. Before equilibrium is reached, which of the following statements are true?
-The solution on the left is hypertonic. -The water level will rise on the left side of the U-tube -Net movement of water across the membrane is toward the left.
Which of the following are key functions carried out by membrane proteins?
-Transport specific ions and molecules across the membrane -Function as cell-surface identity markers -Receive external chemical messages -Catalyze specific chemical reactions on the surface of the membrane
Water is attracted to which kinds of solutes, forming hydration shells around them? Choose all that apply.
-charged -polar
during coupled transport
-energy released as one substance moves down its concentration gradient is used to move another substance up its concentration gradient. -energy from ATP is used to create a concentration gradient.9
Which of the following are true of the plasma membrane?
-it is selectively permeable -it is fluid
Which of the following describes the sodium-potassium pump?
ATP and Carrier proteins
Transport that requires a cell to expend some of its own energy, typically from ____ is called ______ transport.
ATP, active
Compared to the ER membrane, the plasma membrane contains more of which of the following (choose all that apply)?
Cholesterol, Phosphatidylcholine, Sphingomyelin
How do carrier proteins differ from channel proteins?
Only carrier proteins actually bind to the substance being transported.
Plasma membranes allow some substances to pass through easily while other substances only pass through very slowly or not at all. For that reason, plasma membranes are considered which of the following?
Selectively permeable
Substances that cannot easily cross the lipid bilayer can still diffuse across the plasma membrane with the help of which of the following?
Specific channel proteins or carrier proteins
Choose the three groups of lipids found in eukaryotic cells.
Sterols, Glycerol phospholipids, sphingolipids.
The ER membrane is typically more fluid than the plasma membrane and it contains more curvature. Why?
The ER membrane contains mainly unsaturated phospholipids.
When phospholipids are placed in water, they spontaneously form a bilayer with which of the following?
The polar heads on the surface and the nonpolar tails in the interior
This diagram shows two solutions separated by a membrane that allows water to pass through freely but prevents the passage of urea. Before equilibrium is reached, which statement is true?
The solution on the right has a higher concentration of free water molecules.
Select the statement that is true of transmembrane domains.
Transmembrane domains are composed of hydrophobic amino acids.
When phospholipids are placed in water, they spontaneously form which of the following?
a bilayer
If you compare two aqueous solutions which differ in the amount of solutes dissolved, the aqueous solution with a higher concentration of solutes will have
a lower concentration of free water molecules.
While _______transport requires the cell to expend some of its own energy, ________ transport does not.
active, passive
A solution where water is the solvent is called a(n) _______ solution.
aqueous
Why do ions need membrane transport proteins to help them cross the plasma membrane?
because of their charge
The two main categories of ______ ________are endocytosis and exocytosis.
bulk transport
Of the 2 types of transport proteins that mediate facilitated diffusion, _______ only proteins actually bind with the substance being transported while _______ proteins simply provide a hydrophilic space for the substance to move through.
carrier, channel
Many substances that are repelled by the hydrophobic interior of the lipid bilayer can readily diffuse across the plasma membrane with the help of specific _______ proteins or _______ proteins. These transporter proteins are typically transmembrane proteins.
channel, carrier
Ion ______ have a hydrated interior that spans the membrane and allows ions to diffuse through.
channels
Ion _______ have a hydrated interior that spans the membrane and allows ions to diffuse through.
channels
When the concentration of a substance varies from one region to another, this is called which of the following?
concentration gradient
During _____transport, carrier proteins use the energy in one substance's concentration ________to actively transport another substance.
coupled, gradient
Due to the constant random motion of its atoms and molecules, a substance will exhibit net movement from a region where it has a higher concentration to a region where it has a lower concentration. This net movement is called ________ .
diffusion
Each membrane-spanning region of a transmembrane protein is called a transmembrane _______ .
domain
What type of microscope can be used to see the two phospholipid layers in a plasma membrane?
electron
During _______, the plasma membrane surrounds and envelopes smaller cells, solid particles, or liquids.
endocytosis
Phagocytosis is one of the mechanisms of which of the following?
endocytosis
The fusion of a secretory vesicle with the plasma membrane in order to discharge the contents of the vesicle is called ________.
endocytosis
What is the name of the process during which the plasma membrane surrounds and envelopes smaller cells, solid particles, or liquids.
endocytosis
Based on the direction of movement, bulk transport can be divided into two main categories: _______and ________.
endocytosis. exocytosis
The reverse of endocytosis is
exocytosis
This diagram illustrates which of the following processes?
exocytosis, bulk transport
Diffusion that is assisted by a channel protein or carrier protein is called ________diffusion.
facilitated
If two solutions contain equal concentrations of solute, they can be described as _________ in terms of their respective osmotic concentrations.
isotonic
The lack of double bonds in saturated fats allow them to pack together tightly, and therefore the membrane is _______ fluid. The presence of double bonds in unsaturated fats prevent them from packing together tightly, and therefore the membrane _____ is fluid.
less, more
Which of the following are typical components of biological membranes?
lipids, proteins
Cellular ______ are said to be selectively ________ because they allow some substances to pass through easily while other substances pass through very slowly or not at all.
membrane, permeable
The diffusion of water across a selectively permeable membrane is called _______.
osmosis
The combined concentration of all solutes in a solution determines ______ _______ the of the solution.
osmotic concentration
The plasma membrane can best be described as which of the following
selectively permeable.
When 10 grams of NaCl are dissolved in 1 L of water, NaCl _______ is called the and water is called the _______ .
solute, solvent
The combined concentration of all ______ in a solution determines the osmotic concentration of the solution.
solutes
Although a eukaryotic cell membrane can contain many different lipids, they can be classified in three groups: glycerol phospholipids, ________ , and _______ . When answering the question think about the lipids found in membranes, not about all the lipids that an organism makes!
sphingolipids, sterols
Carrier proteins that transport 2 different types of molecules or ions may be either ______ or antiporters.
symporters
