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Membranes, transport processes & enzymes
Transcript of Membranes, transport processes & enzymes
Diffusion of water across a membrane. Water molecules from a higher concentration move to a lower concentration through a membrane,
A type of catalyst made out of PROTEINS
All enzymes ca
Fluid Mosaic Model
Definition: a model that describes the structure of a cell membrane. In this model, a flexible layer made of lipid molecules is interspersed with large protein molecules that act as channels through which other molecules enter and leave the cell.
Used to describe the features of biological membranes
Plasma membrane that surrounds the cells has a bilayer of phospholipids
Each phospholipid molecule has a hydrophilic head and a hydrophobic tail
-Receptors are protein molecules that are found in or on the surface of a cell
-Depending on what is passing through the membrane, it changes if the receptor is in or on the surface of the cell
-Part of the receptor is embedded into the membrane to send a signals to the inside or outside the cell
-The signals must be transmitted across the membrane to get to the cell, but sometimes the signal can go across the membrane its self
-Receptors bond different things outside of the membrane (ex: Dopamine receptors bind dopamine)
- The video below shows how receptors go through induced fit to bond with the hormone
A biological membrane is responsible for regulating the import and export of polymers and other molecules.
Catalysts that are made of PROTEINS
Molecules where the nonpolar ends will line an inner layer while the polar ends line the outside (and vice versa). They can form either micelles or vesicles.
All enzymes can both COMBINE substances and TAKE APART the same substances
In organisms, enzymes must be able to be TURNED ON AND OFF and only be used when a reaction needs to occur. This occurs when other molecules PLUG THE SPACES within the catalyst where the molecules that would react would go, or when regulatory substances attach to INACTIVE SITES OF THE CATALYST.
Activation Energy - the amount of energy needed to start a reaction.
The original cells with a single layer of lipids.
A vesicle is a type of organelle in the shape of a small bubble with a lipid bilayer. Initially, these layers were extremely leaky and they were larger.
C40 Membrane Spanning Lipid Molecule:
A 40 carbon membrane lipid which goes from end to end, it most likely has polar ends and is found on bacteria near ht springs.
A TYPE OF CATALYST MADE OF RNA
Made of RIBOSE, which is a SUGAR with 5 CARBONS
Definition of an aquaporin: integral membrane proteins from a larger family of major intrinsic proteins (MIP) that form pores in the membrane of biological cells.
Particles in an area of high concentration naturally go to an area of low concentration by moving and bouncing off of the other particles, therefore diffusing themselves.
ratio of amount of water to the amount of solute
here's how it works
Domain of Life:
Last universal common ancestor which was the first major split between archaea and bacteria.
The very first cells in existence.
How can catalysts lower the activation energy?
The active sites have shapes such that substances are pushed closer together upon entering.
The shapes of the active sites squeeze substances such that bonds are strained.
They donate or accept electrons so that reactions occur with more ease.
So, reactions occur more easily and require less energy.
Created By Josh and Sean
Evolution allowed for proto-cells' membranes to tighten and have a thicker linings.
Bilayer: two layers
Phospholipids: fats with
The Big Picture - Cell Membranes
Barriers that define living things.