Plasma Membrane
Describe what it means for the plasma membrane to be selectively permeable
Not everything a cross. Some things can, some can’t.
Which of the following are NOT plasma membrane proteins:
A) Channel and carriers
B) Receptors and identifiers (recognition)
C) Integrators and effectors
D) Enzymes and anchors
C) Integrators and effectors
True or False. Simple diffusion is when a substance is able to move directly through the plasma membrane without a carrier or channel
TRUE! Facilitated diffusion is when a carrier or channel helps assist a substance across the membrane
Which of the following describes the difference(s) between passive transport and active transport:
A) Active transport requires energy
B) Passive transport requires a carrier
C) Active substances move with their gradient
D) A & C
A) Active transport requires energy.
ACTIVE transport requires a carrier, and PASSIVE substances move with their gradient (active substances move against)
What is the term for receptors found inside the cell:
A) Cell surface receptors
B) Intracellular receptors
C) Extracellular receptors
D) Endocytosis receptors
B) Intracellular receptors
Which of the following describes the orientation of phospholipids in the plasma membrane:
A) The hydrophilic head is oriented towards the ECF, while the hydrophobic tails are oriented towards the ICF
B) There is a double layer in which the hydrophilic heads are oriented towards the ECF and ICF while the hydrophobic tails make up the core
C) There is a double layer in which the hydrophobic heads are oriented towards the ECF and ICF while the hydrophilic tails make up the core
D) None of the above
B) There is a double layer in which the hydrophilic heads are oriented towards the ECF and ICF while the hydrophobic tails make up the core
Which of the following accurately describes the differences between channels & carriers:
A) Channels are passive while carriers sometimes require energy
B) Carriers form a physical connection with substances while channels do not
C) Channels move nutrient molecules (like glucose and amino acids) while carriers move ions
D) A & B
E) B & C
F) All of the above
D) A & B. Not C because CARRIERS move nutrient molecules while CHANNELS move ions
Which of the following is an example of a substance that moves through the phospholipids via simple diffusion:
A) Sodium ion
B) Glucose molecule
C) Amino Acid
D) B and C
E) None of the above
E) None of the above. Some examples of substances that are able to move through the phospholipids without the help of a channel or carrier (via simple diffusion) would be: oxygen (O2), carbon dioxide (CO2), lipids
Primary active transport is when a carrier couples directly with _____. An example would be the ______.
A) ATP, Na-Ca exchanger
B) ATP, diffusion of CO2
C) ATP, Na-K pump
D) a G-Protein linked receptor, cAMP pathway
C) ATP, Na-K pump
Which of the following is NOT an example of a cell surface receptor?
A) Gene regulator
B) Chemically gated ion channel receptor
C) Enzyme receptor
D) G-protein linked receptor
A) Gene regulator (this would be an example of an intracellular receptor)
What four things make up the plasma membrane?
Phospholipids, proteins, cholesterol, carbs
Carriers that move one ion in the same direction across the membrane would best be described as _________.
Symport uniporters
Diffusion is a _____ process in which substances move with their concentration gradient from areas of ____ concentration to areas of ____ concentration
PASSIVE, ...from areas of HIGH concentration to areas of LOW concentration
A substance is packaged in a membrane bound sac and is transported out of the cell. This describes ______ and would be an example of _______ transport.
A) endocytosis, primary active transport
B) exocytosis, secondary active transport
C) endocytosis, passive transport
D) exocytosis, vesicular transport
D) exocytosis, vesicular transport. The membrane bound sac refers to vesicles. Vesicular transport is bulk transport.
Which of the following is true:
A) Chemically gated ion channel receptors have delayed, short lived responses
B) G-protein linked receptors have fast, long lasting responses
C) Chemically gated ion channel receptors have fast, long lasting responses
D) None of the above
D) None of the above. Chemically gated ion channel receptors have quick, short lived responses while G-protein linked receptors have a delay in response, but it's longer lasting
What is the role of cholesterol in the plasma membrane? The role of carbs? (not for points...but can you point them out?)
Cholesterol provides flexibility.
Carbs help with recognition.
If I were describing a protein that helps moves a substance across the plasma membrane and is open all of the time, I would most likely be describing a ______ _______.
Leak Channel
A hypotonic solution has _____ solutes outside of the cell than inside the cell. This means water would move ________ cell.
A) More, out of the
B) Fewer, out of the
C) More, into the
D) Fewer, into the
D) Fewer, into the. Water wants to move to wherever the hypertonic environment is at (in this case, it's inside the cell)
Which type of signaling describes the release and travel of hormones through the bloodstream to distant target cells?
Endocrine Signaling
What is the name of the enzyme that turns on to help make the second messenger, cyclic AMP?
Adenylyl Cyclase
What are 3 of the 4 functions of the plasma membrane
Combo of any of the following:
Barrier (provides physical isolation)
Structure & Support
Receptiveness (receives messages)
Control exchange (decides what can enter and leave)
Describe the role of a recognition protein (aka identifier protein).
Answer may vary. Something to the effect of 'helps with immunity by identifying cells - which cells are self-cells and which are foreign'
Where will water move in the following scenario:
You have a beaker of solution containing 7M glucose, 3M urea, 2M salt. In the solution is a cell that contains 6M glucose, 1M urea, 4M salt. The membrane is permeable to glucose and salt but not urea.
Water will move from inside the cell to outside the cell. It wants to go to where the party is at/the hypertonic environment which in this case is outside the cell (there is more urea outside the cell than inside).
What are the 3 steps in cell signaling?
Reception (signal molecule binding to receptor), Transduction (turning message into something the cell can understand in order to bring about specific response), Response (change in cellular activity)
What does the second messenger cyclic AMP do in the cAMP pathway?
Activates another enzyme (usually protein kinase) that generates cellular response