Term
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Definition
| Maintenance of a relatively constant environment within the body |
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Term
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Definition
V- cell conditions such as temp, concentration, volume.
SP - Variable's Normal ranges fluctuate around what is called the SP |
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Term
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Definition
| Homeostatic mechanism that regulates the body's variables, by bringing variable back towards the set point |
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Term
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Definition
| NON-homeostatic response that involves increasing the deviation from the setpoint when a deviation occurs from the normal range of values |
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Term
| Integral/transmembrane proteins |
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Definition
| Protein in lipid bilayer that runs through the entire membrane. Has a non-polar center, and polar ends |
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Term
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Definition
| Protein in lipid bilayer that runs halfway through the membrane. Has a non-polar end (in the membrane), and a polar end (outside the membrane) |
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Term
Gated vs. Nongated channel
Gated include ? |
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Definition
| Gated channels open/close. Non Gated channels are always open. Gated channels include: Chemically gated, Thermally gated, mechanically gated, and voltage gated. |
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Term
| What do protein channels (gap junctions) allow ? |
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Definition
| Communication between adjacent cells. Causes all adjacent cells to activate; all or none (like heart muscles activating together) |
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Term
| In cell responses to receptors, what is considered the primary messenger ? |
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Definition
| The Ligand eg. acetylcholine |
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Term
| Secondary messengers allow alterations to the cell in response to a stimuli. These alterations include: (4) |
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Definition
1) change in conformation of receptors
2) change in permeability of ions
3) activate enzyme cascade
4) change in transcription/translation |
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Term
| Concerning receptors and ligands, what determines the specificity of the response? |
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Definition
| The protein. The same ligand can be used in many places, but the response elicted is determined by the protein to which the receptor is attached. |
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Term
| The Plasma membrane is selectively permeable. What two factors determine the permeability ? |
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Definition
| The solute, and the protein transporters present on the cell |
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Term
| The selective permeability is important for these reasons (3) |
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Definition
1) The unequal distribution of ions
2) Concentration gradient
3) Signaling events |
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Term
Define :
-Intercellular
-Extracellular
-Intracellular |
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Definition
-Intercellular: Between cells
-Extracellular: Outside a cell
-Intracellular: Inside a cell |
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Term
| The cells' ability to recognize and communicate with other cells takes place through this. |
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Definition
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Term
| Define Membrane potential |
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Definition
| Membrane potential: The Charge difference across the plasma membrane |
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Term
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Definition
| The collection of glycolipids, glycoprotein, and carbohydrates on the OUTER surface of the plasma membrace |
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Term
| What are phospholipids, and what to they form? |
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Definition
| Lipids of the plasma membrane include phospholipids and cholesterol. Phospholipids for the lipid bilayer. Each one has a polar head, and nonpolar tail. |
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Term
| Rigidity of the lipid bilayer? |
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Definition
| Plasma membrane is not rigid or static, but highly flexible. |
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Term
| Lipid bilayer's Important functions as a liquid: |
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Definition
- distributes molecules through the membrane
- repairs damage to the membrane because the phospholipids can gather round and tend to the broken area. |
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Term
| How is Cholesterol oriented ?Cholesterol's function in the plasma membrane is ? |
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Definition
Cholesterol's hydrophilic OH group is runs through the phospholipid heads, and its hydrophobic tail lies in the center of the membrane.
Cholesterol determinds the fluid nature of the plasma membrane, and limits the movement of phospholipids, providing stability |
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Term
| What determines the functions of the plasma membrane? |
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Definition
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Term
| What are Carrier Proteins and how do they function ? |
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Definition
| Carrier proteins are proteins that allow molecules to bind to them at specific binding sites, then change shape to transport the protein to the other side of the plasma membrane. They can then change back to their original shape and transport more molecules. |
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Term
What are ATP powered pumps, and how do they work ?
What binding sites do they contain ? |
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Definition
| ATP powered pumps are transport proteins that use the breakdown of ATP as fuel. They have specific binding sites to which specific molecules/ions can bind, and they contain an ATP binding site. The breakdown of ATP to ADP releases energy, changing the shape of the protein, which moves the molecule accross the membrane. |
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Term
| What are Receptor proteins ? Fuction ? Specificity ? |
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Definition
| Proteins/glycoproteins with an exposed receptor site on the surface, which can attach to specific chemical signals. Used to communicated intercellularly. Chemical signal has no effect on cells that lack the specific receptor molecule. |
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Term
| Acetylcholine released by nerve cells causes what to occur? |
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Definition
| Acetylcholine binding to membrane bound receptors of skeletal muscle cells causes the ligand-gated channel to open, allowing Na+ into the cell, causing events that lead to muscle contraction |
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Term
| What makes up a G protein complex ? Where is it located |
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Definition
| Consists of 3 proteins, alpha, beta, and gamma proteins. It is located on the inside surface of the plasma membrane. |
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Term
| How does a G protein complex work? |
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Definition
| A G protein complex works when it is bound to a membrane bound receptor. When the chemical signal binds to the receptor, GDP is released from the alpha protein and a GTP takes its place. The complex then breaks off from the membrane bound receptor, and the alpha protein stimulates a response in the cell. |
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Term
| What four ways can substances move across the plasma membrane ? |
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Definition
The Four ways to move a substance across the plasma membrane include:
- Diffusion
- Vesicles
- Transport proteins (Carriers)
- Membrane Channels |
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Term
| Movement of substance in solution is by these 3: |
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Definition
- Diffusion
- Osmosis
- Active Transport |
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Term
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Definition
| Osmosis works by WATER movement. It moves High water conc, to low water conc. This causes the movement of water to go from low solute concentration to to high solule conc. |
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Term
| How does diffusion work ? |
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Definition
| Diffusion is the movement of SOLUTES from high to low concentration. At Eq, the net movement stops although random motion continues. |
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Term
What is a concentration gradient ?
What increases the gradient? |
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Definition
| The concentration difference between 2 points, divided by distance between the 2 points. The gradient is increased by a increasing the concentration difference, or by decreasing the distance between the regions in the solvent. |
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Term
| What is the driving force in osmosis? |
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Definition
| Osmotic Pressure (gradient). |
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Term
What is Osmolarity ?
What is the value of 1 osmole? units? |
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Definition
Osmolarity is the measure of the # of solutes in a solution.
1 Osmole = 6.022*10^23 molecules/L |
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Term
| What does increasing the osmolarity difference, do to the osmotic pressure? |
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Definition
| Increasing the osmolarity difference will INCREASE the osmotic pressure |
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Term
Define these tonicities of solution:
- Hypertonic
- Hypotonic
- Isotonic
Which way is water moving in each of these? |
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Definition
- Hypertonic: The solution has a high solute concentration, causing water to flow out from the cell.
- Isotonic: The solution has the same concentration as that of the cell, so water moves in and out (Eq)
- Hypotonic: The solution has a low solute concentration, causing water to rush into the cell, which could burst it (lyses). |
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Term
| What three terms define the osmolarity of solutions? |
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Definition
- hyperosmotic (more solute than other solution)
- hyposmotic (less solute than other solution)
- isosmotic (same solute conc as other solution) |
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Term
| Define a the Diffusion coefficient with words, and mathematically (what is fick's law of diffusion?) . |
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Definition
The Diffusion coefficient represents the diffusive potential of an individual substance.
Fick's Law of Diffusion:
D= [(C1-C2)T*S*A] / X
D - Diffusion coefficient
C1&C2- concentrations
T - Temperature
S - Solubility of solute
A - Area over which to diffuse
X - Distance over which to diffuse |
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Term
1)What is Simple Diffusion?
2)How does simple diffusion of lipid soluble molecules occur?
3)How does simple diffusion of hydrophilic molecules occur? |
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Definition
1) The movement of materials down their concentration gradient through the membrane, or through pores in the membrane.
2) Lipid soluble molecules can easily move across the membrane because they are non-polar.
3)Through channels or pores in the membrane |
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Term
| What is the rate limiting step of simple diffusion? |
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Definition
| The Concentration Difference (C1-C2) |
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Term
| Describle Facilitated Diffusion |
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Definition
Facilitated Diffusion is carrier/channel mediated diffusion that carries materials from high to low concentration.
- Used in POLAR transport
- Requires a change in conformation for each transport event
- It does not require metablic energy
- The rate at which molecules or ions are transported is directly proportional to their concentration gradient, UP TO the point of saturation |
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Term
1)What is mediated transport?
2)What three types of transport are included in mediated transport? |
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Definition
1)Mediated transport is the process by which transport proteins assist in the transport of large, water soluble molecules, or ions across the plasma membrane.
2)Mediated transport includes, carriers, channels, and active transport |
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Term
| What are the three characteristics of mediated transport? |
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Definition
1) Specificity
2) Competition
3) Saturation |
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Term
| What are the rate limiting steps in Active transport? |
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Definition
| The rate limiting steps are the amounts of ATP, and ATP-powered pumps present. |
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Term
| What is the function of active transport? |
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Definition
The purpose of active transport is to move polar solutes from low to high concentrations. AGAINST their gradient.
It CAN also transport from high to low concentrations. |
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Term
| What does secondary active transport involve? What does it require? |
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Definition
Secondary active transport involves moving an ion or molecule down its concentration gradient, which provides energy to move another ion/molecule up its concentration gradient.
Secondary active transport requires a transport protein that will move both ions/molecules.
Both an item that is moving down its concentration gradient (which provides energy), and an item moving up its concentration gradient(which requires energy( are required. |
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Term
What happens in these types of Secondary active transport:
- Symport/Co-transport
- Antiport/counter-port |
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Definition
- Symport/Co-transport: The 2 items move in the same direction through the transport protein
- Antiport/counter-port: The 2 items move in opposite directions through the protein. |
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