Ch, 5 + 6 Quiz Flashcards
Membranes are _______ permeable, some molecules _____ pass and some ______
selectively;can;cannot
______ molecules, ____, and ______ molecules cannot pass through a lipid bilayer
Charged;ions;large
_____ non-polar or ______ molecules can pass through a lipid bilayer
small;uncharged
which of these can and which cannot pass through a lipid bilayer?
O2, Na+, Co2, Cl-, H2o, Glucose
CAN: O2, Co2, H2O CANNOT: Na+, Cl-, Glucose
What is diffusion?
The movement of molecules of a substance across a semi-permeable membrane, often from higher concentration to lower concentration
One gram of table salt is placed at the bottom of 200mL of water. If left alone for several hours, what will happen to the sodium and chlorine ions as they dissolve in water?
The sodium and chlorine ions will dissipate/diffuse and evenly disperse themselves within the water.
200mL of water is placed on one side of a two chambered beaker – labeled “start” in the diagram below. A lipid bilayer seperates the two chambers. What will eventually happen to the water? Use the box labeled “finish” to diagram your answer and include the volume of water you expect to see on each side of the membrane.
By way of osmosis, the water will evenly diffuse across the bilayer, going from high concentration to low concentration until it is 100mL and 100mL.
This time the two chambers are seperated by a piece of impermeable plastic. We start with a 1% NaCl solution on one side and a 2% NaCl solution on the other side (diagram labeled ‘start’). If we remove the plastic what will eventually happen to the solutions? Use the box labeled ‘finish’ to diagram your answer.
ASK CAHOON THIS Q
This time the two chambers are seperated by a semi-permeable membrane that is left in place. We start with 1% NaCl solution on one side and a 2% NaCl solution on the other side (diagram labeled ‘start’). What will eventually happen to the solutions? Use the box labeled ‘finish’ to diagram your answer. Include water volumes and salt percentages on each side.
Diffusion would occur from left to right, being that the salts cannot pass through the semi-permeable membrane, the water would diffuse from the left (higher concentration) to the right (lower concentration)
What is osmosis, and how is it related to the problem above?
Osmosis is the process by which molecules of a solvent (typically water) pass through a semipermeable membrane from high concentration to low concentration. ASK CAHOON IF THIS IS ALWAYS LIKE THIS.
The two chambers are still separated by a semi-permeable membrane that is left in place. We start with a 1% NaCl solution on one side and a 2% NaCl solution on the other side. What could you add to either side to prevent osmosis from occurring?
Make both sides even
What is a hypertonic solution?
High solute concentration, low water concentration, in a hypertonic solution, the net movement of water will be out of the body and into the solution.
What is a hypotonic solution?
Low solute concentration with high water concentration. Net movement of water from solution into the body
What is an isotonic solution?
Solution that has the same solute concentration and water concentration, no net movement.
A vesicle containing a 3% solution of sucrose is placed into a solution of 1% sucrose. Are the solutions inside the vesicle and in the surrounding solution hypertonic, hypotonic, or isotonic? What do you predict will happen to the vesicle?
Solution inside vesicle is hypertonic compared to the surrounding solution, surrounding solution is hypotonic compared to vesicle. Vesicle will likely shrink due to movement of solution to the outside of the vesicle.
A vesicle containing a 5% solution of sucrose is placed into a solution of 5% sucrose. Are the solutions inside the vesicle and in the surrounding solution hypertonic, hypotonic, or isotonic? What do you predict will happen to the vesicle?
The vesicle is isotonic compared to the surrounding solution, surrounding solution is isotonic. Altogether the solution is isotonic, no movement will take place.
What category of amino acids would you expect to find on the parts of a membrane protein that are in contact with the interior of the lipid bilayer?
Hydrophobic
What category of amino acids would you expect to find on the parts of a membrane protein that are in contact with the exterior of the lipid bilayer?
Hydrophilic
How does a cell transport molecules across its plasma membrane?
Diffusion, primarily passive diffusion/transport
What is the difference between passive transport and active transport across a cell’s plasma membrane?
Passive Transport - no energy high to low concentration with the gradient, Active - requires ATP, low to high against the gradient
Define passive transport
The passage of a molecule across a membrane that DOES NOT require energy expenditure by the cell
3 methods of passive transport
Diffusion;Ion protein channels; Glucose carrier protein, Aquoporins
Define diffusion
Movement of molecules across a semipermeable membrane, typically high to low concentration
Define Ion protein channels
Ion protein channels span across the membrane and allow for the passage of ions from one side to the other. ex. Calcium channel
Define glucose carrier protein/glucose transporter
Transporter proteins that facilitate the diffusion of glucose
Define Active Transport
The passage of a molecule across a membrane that DOES require energy expenditure by the cell
2 methods of Active Transport
Pump Carrier Protein; Coupled Transport
Define Bulk Transport
Movement of large materials/amounts across the membrane.
2 Methods of Bulk Transport
Endocytosis;Exocytosis
Define endocytosis
movement rom exterior to interior
Define exocytosis
movement from interior to exterior
3 methods of endocytosis
Phagocytosis;Pinocytosis;Receptor Mediated
2 methods of exocytosis
Constitutive; - constant Regulated, - on/off switch, signaled
Define Phagocytosis
Movement of large particles (food) into the cell
Define Pinocytosis
Similar process as phagocytosis, movement of liquids
Define Receptor Mediated Endocytosis
A molecule fits into a membrane embedded protein which then begins the process of endocytosis - anticipated signals - how viruses “trick” cells
Define Constitutive Exocytosis
Secretion of molecules, involvs the formation of a newly synthesized membrane and proteins. ASK CAHOON.
Define Regulated Exocytosis
Secretion of molecules, involves a signal and receptor to form a vesicle. On/off switch
Glucose is an essential source of energy for most cells, yet it cannot efficiently diffuse through the outer plasma membrane surrounding the cell. How do glucose molecules get into a cell?
Facilitated Transport by way of glucose transport protein
It is essential that a cell control the concentration of sodium ions (Na+ ) in its interior. Ions cannot diffuse through the outer plasma membrane surrounding the cell. How do cells move sodium across its outer membrane?
Ions move across the membrane by way of ion channel proteins via facilitated diffusion
What are the differences and similarities of protein channels and protein carriers?
Both form protein pathways across the membrane, carriers can transport either active or passive, channels can only transport via passive.
What are the differences and similarities of pumps and coupled transport mechanisms? Both are active transport but make sure you consider how they utilize energy differently.
Protein pumps expand cellular energy to move molecules against the concentration gradient.
Coupled Transport is the process by which the transmembrane protein moves one molecules with the concentration gradient, essentially sacrificing it. The energy of this diffusion is then used to transport an unwanted molecule against the gradient.
How does bulk transport differ from channel protein style transport?
Channel proteins are specialized and specific where as bulk transport is the process of transporting large substances or bulk amounts, not as specialized. ASK CAHOON bulk active transport passive
What is a membrane embedded glycoprotein?
A molecule made of a sugar (carbohydrate) attached to a protein molecule
A phospholipid bilayer may also be called a…
Membrane
Which cannot pass through a phospholipid bilayer?
Glucose