Biology 2A Test
phospholipid bilayer
A double layer of phospholipids that makes up plasma and organelle membranes.
enzyme-substrate complex
A temporary complex formed when an enzyme binds to its substrate molecule(s).
enzyme
A type of protein that speeds up a chemical reaction in a living thing
What energy molecule must be involved for active transport to happen?
ATP
what makes active transport necessary?
Active transport is a very important process enabling cells to accumulate molecules or ions from the environment against the concentration gradient
Pinocytosis
Cell drinking
Phagocytosis
Cell eating
Osmosis
Diffusion of water through a selectively permeable membrane
osmosis
Diffusion of water through a selectively permeable membrane
types of active transport
Endocytosis (phagocytosis and pinocytosis) Exocytosis, and Protein Pumps
how does protein denaturation relate to enzymes?
Enzymes work consistently until they are dissolved, or become denatured. When enzymes denature, they are no longer active and cannot function
when is facilitated diffusion necessary?
Facilitated diffusion is necessary when a membrane prevents the substance from diffusing on its own.
how does particle size contribute to diffusion?
Heavier particles will move more slowly and so will have a slower rate of diffusion. Smaller particles on the other hand will diffuse faster because they can move faster.
diffusion
Movement of molecules from an area of higher concentration to an area of lower concentration.
facilitated diffusion
Movement of specific molecules across cell membranes through protein channels
What happens when a cell is soaking in an isotonic solution?
No net water movement
how does polarity contribute to diffusion?
Nonpolar molecules such as CO₂ and O₂ can diffuse through the lipid bilayer in each direction. Polar molecules cannot diffuse through the bilayer. Polar molecules need polar protein channels to diffuse through the membrane.
exocytosis
Process by which a cell releases large amounts of material
how does the concentration gradient contribute to diffusion?
The bigger the difference, the steeper the concentration gradient and the faster the molecules of a substance will diffuse
Structure and components of a cell membrane
The cell membrane has lipids in it that let water in and out. Has protein channels that let protein in and out
What happens when a cell is soaking in an hypertonic solution?
The cell will gain water
What happens when a cell is soaking in an hypotonic solution?
The cell will lose water
products
The elements or compounds produced by a chemical reaction.
how does temperature contribute to diffusion?
The higher the temperature, the more kinetic energy the particles will have, so they will move and mix more quickly
active site
The part of an enzyme or antibody where the chemical reaction occurs.
peripheral proteins
The proteins of a membrane that are not embedded in the lipid bilayer; they are appendages loosely bound to the surface of the membrane.
Why is energy needed for the sodium-potassium pump?
The pump is moving both ions against the concentration gradient
What makes active transport "active"?
The use of energy
how do enzymes speed up reactions?
by lowering the activation energy
role of phospholipid bilayer
creates a selectively permeable barrier to the movement of ions and molecules important for cellular function.
Types of passive transport
diffusion, osmosis, facilitated diffusion
role of peripheral proteins
form temporary bonds with the cell membrane, allowing them to detach and reattach at specific times, with specific signals. This allows cells to coordinate and communicate using networks of proteins and reactions.
carbohydrate chains
found in the external surface of the plasma membrane for cell to cell recognition
integral proteins
penetrate the hydrophobic interior of the lipid bilayer
Endocytosis
process by which a cell takes material into the cell by infolding of the cell membrane
substrate
reactant of an enzyme-catalyzed reaction
catalyst
substance that speeds up the rate of a chemical reaction without itself undergoing the reaction
Factors that can affect the reaction rates of enzyme-catalyzed reactions
surface area/amount of enzyme, temperature, pH, enzyme/substrate concentration
role of carbohydrate chains
to recognize harmful cells (cell-cell recognition)
protein pumps
transport proteins that require energy to do work
role of integral proteins
transporting molecules or chemical messages into cell
Hypertonic
when comparing two solutions, the solution with the greater concentration of solutes
Hypotonic
when comparing two solutions, the solution with the lesser concentration of solutes
protein denaturation
when proteins are subject to heat, acid or other conditions that disturb their stability; protein uncoils, loses its shape, and loses its function
Isotonic
when the concentration of two solutions is the same
