Exam 3 content Flashcards
What are Cell membranes made up of?
It is made up of a phospholipid bilayer with carbs (for labeling), cholesterol to keep it fluid, and proteins (which can carry out common functions like transport).
What kinds of molecules can passively diffuse through a cell membrane?
Hydrophobic molecules like steroids can dissolve to pass through. Along with small uncharged molecules like O2 and C2.
What distinguishes active transport from passive transport?
Active transport requires ATP to occur
What are the characteristics of passive transport?
It requires no energy, and it moves molecules down a concentration gradient
Does the concertation gradient of diffusion move up or down?
Down
What occurs when dynamic equilibrium is established in diffusion?
There is still movement but not any net movement
Do two solutes in diffusion have any impact on each other?
No they move at thier own rate they are unaffected by eachother
What are some factors that influence the rate of diffusion?
Temperature, size of the molecule, polarity, and difference in the concentration gradient
What is osmosis?
The passive diffusion of water
What is “free water” in the context of osmosis?
“Free water” refers to water that is not connected to any of the other molecules in the solution
What does tonicity mean?
It refers to the ability of the cell to gain or lose water based on its own and the surrounding concentration levels.
What does is mean when a solution is hypertonic?
It means that the concertation of the solute it higher outside of the cell membrane.
What does it mean when a solution is hypotonic?
It means that concentration of the solution is higher inside the cell than outside the cell.
What does it mean when a solution is isotonic to the cell it surrounds?
It means that the concentration of the solute is equal inside and outside the cell
What happens to a human RBC when it’s in a hypertonic solution?
it to shrink/shrivel up (since it wants to reduce the concentration levels outside of it)
What happens to a human RBC when it’s in a hypotonic solution?
the cell is going to swell and burst due to the water coming in trying to dilute it
What happens to a human RBC when it’s in a isotonic solution?
It’s in an ideal solution and will be able to maintain a state of equilibrium
What do carrier proteins do?
They bind to molecules and modify their shape to help them get across the membrane
What does aquaporin do to help H2O diffuse across the membrane?
They support the diffusion of H2O by working with the gradient
What does it mean for an ion channel to ligand gated?
It means that in order for the channel to open a certain hormone or neurotransmitter needs to bind to the receptor for it to open
What does it mean for an ion channel to be voltage gated?
It means that when the potentials change inside/outside of the cell to a certain point it will trigger for the channel to open ex sodium potassium pump
What does it mean for an ion channel to be a leak channel?
It means that the channel is always open hence its a little leaky
What does it mean for an ion channel to be mechanically gated?
It means that there has to be physical pressure on the membrane for it to open
Is facilitated diffusion active or passive transport?
It is passive transport because it moves the ions down its concentration gradient and does not need ATP
What are the characteristics of active transport?
It requires energy (usually ATP) to occur and moves ions against its concentration gradient
In a sodium-potassium pump where is the NA+ concentration higher and lower?
higher- outside of the cell membrane
lower- inside the cell membrane
In a sodium potassium pump where the K+ concentration higher and lower?
higher- inside of the cell membrane
lower-outside of the cell membrane
What direction would NA+ move passively?
inside the cell
What direction would K+ move passively?
Outside of the cell
What direction would Na+ move actively?
outside of the cell
What direction would K+ move actively?
inside of the cell
What is the first step of the sodium-potassium pump?
Na+ on the inside of the cell binds to the sodium-potassium pump
What is the second step of the sodium potassium pump?
Phosphorylation occurs where ATP breaks down via hydrolysis to ADP and P to power the rest of the process
What is the third step to the sodium-potassium pump?
Phosphitylation leads to the pump to change its shape which expels the 3 NA+ outside of the cell and allows for 2 K+ inside the pump
What is the fourth step to the sodium-potassium pump?
The new shape has an affinity for the K+ ions bringing them into the cell and releasing the phosphate (activation) group as a result
What happens in the sodium potassium pump once the phosphorus is released from the pump?
It lets go of the K+ and has an increases affinity for NA+
What is cotransport?
It is when active transport of a solute indirectly causes the transport of other substances
How does it work?
The diffusion of the “uphill” solute is coupled with the “downhill” diffusion of another substance
How does cotransport work in the intestine?
it works in the intestine by coupling the uphill transport of sodium out of the cell with the downhill transport of glucose into the cell
What is bulk transport?
it is when a cell transports a lot of ions at once
What happens in exocytosis?
It is when a vacuole full of molecules fuses with the cell membrane and releases the molecules
What happens in endocytosis?
It is when takes in macromolecules by from vesicles from the plasma membrane
What is phagocytosis?
It is a form of endocytosis when the cell takes in molecules for its own consumption
What is pinocytosis?
It is a form of endocytosis when the cell drinks or takes in liquids do drink
What is receptor mediated endocytosis?
It is a type of endocytosis that is very specific in terms of only accepting certain solutes with known receptors
How is metabolism defined?
it is defined as the totality of an organism’s chemical reactions
What is an anabolic pathway?
It builds molecules and consumes energy (ATP)
How does anabolic and catabolic pathways influence metabolism?
They are the processes that define it
What is an example of an anabolic pathway?
cellular respiration
What is an example of a
catabolic pathway?
It breaks down molecules and releases energy to make ATP
What is an example of a catabolic pathway?
the sythesis of proteins from amino acids
How does hydrolysis affect ATP in metabolism?
It breaks down ATP into ADP and phosphate to power metabolic reactions
How does phosphorylation help chemical reactions occur?
It helps chemical reactions occur by giving them the energy that is needed to power uphill or anabolic reactions
What actions are a result of kinetic energy?
Actions that are associated with motion
What is a result of potential energy?
energy that matter posses because of its location or structure
What is the result of thermal energy?
kinetic energy that’s associated with the random movement of molecules that’s transferred as heat
What is chemical energy?
potential energy that can be used in chemical reactions
What is free energy?
It is a part of a system’s energy that do work in things like pressure and temperature are uniform similar to the atmosphere of a cell
Free energy is negative as a result of what kind of process?
a spontaneous process
Free energy is net 0 or positive for what kind of process?
all nonspontaneous processes
What is the effect of a spontaneous process on the free energy of a cell?
it decreases the cell’s free energy
When are reactions at their maximum stability?
When both reactions are at equilibrium
What does it mean when a reaction is exergonic?
It means that the reaction releases energy
What does it mean when a reaction is endergonic?
it means that reaction brings in energy
What is a catalyst?
It is a chemical agent that speeds up a reaction without being consumed by it
What are the reactants in a chemical equation?
The things that are being affected/ changed
What are the products in a chemical reaction?
The results of the changes that were made to the product
What is an enzyme?
it is a type of catalyst that lowers the rate of activation Ea which makes it happen faster
What is the substrate?
The substrate is what attaches to the enzyme for it to work
What ending in the name of an enzyme helps you know that it is an enzyme?
The ending of ase helps you know that it is an enzyme
What is an active site?
An active site is a site where the substrate will attach to the enzyme for it to work
What is an allosteric site?
It is a site that the non-competitive inhibitor will use to attach to an enzyme
What is a completive inhibitor?
An inhibitor that will share a similar shape to that of the substrate and will compete with it to get to the enzymes active site to inhibit it
How can a competitive inhibitor be stopped?
It can be stopped by increasing the substrate concentration which increases its competition
Are enzymes only used once?
No, they can be used over and over again to break down the same thing
Can increasing the temperature of the environment affect the enzyme?
If it’s increased by a bit it will speed up the reaction, if it’s increased by a lot the enzyme will become denatured and stop working
Can increasing the pH affect the enzyme/ reaction of the enzyme?
It would slow down the reaction of the enzyme
What are cofactors?
They are non-protein helpers that bind to the enzyme permanently or reversibly with the substrate
What is an organic cofactor?
They are also called coenzymes and most vitamins are cofactors or provide the raw materials to make them
What is an inorganic cofactor?
An inorganic cofactor is usually a form of metal atoms such as zinc, iron or copper in ionic forms
What will happen to the rate of reaction (ror) if the substrate concentration increases?
The reaction will speed up until the substrate concentration overwhelms the number of enzymes and then it will remain at the same rate
What does induced fit mean?
It is when the enzyme will adjust itself a bit to hold onto the substrate better
How could you increase the rate of an enzymatic reaction when a reversible inhibitor is present? How would this differ between a competitive and non-competitive inhibitor?
You can increase it by increasing the substrate concentration. Which is different from a noncompetitive inhibitor because for a non-competitive inhibitor you cannot reverse its effects
What is acetylcholine (ACh)?
it is a neurotransmitter that signals to the muscles when they need to contract
What is acetylcholinesterase (AChase)?
It is the enzyme that breaks down ACh and stops muscle contraction
What is Sarin?
Its a nerve gas blocks the acetylcholinesterase enzyme
What happens if sarin is added?
It will stop (Achase) from being activated
What does feedback inhibition mean?
It is when the product of a reaction shuts down the pathway to prevent other biological materials from being wasted
What is the equation for cellular respiration?
C6H12O6+6O–> 6CO2+6H2O+ATP+Heat
