cell membrane

Fluid mosaic model

Idea that the plasma membrane is made of proteins, carbohydrates, phospholipids, and cholesterol which give it a fluid characteristic

Glycoprotein

when a carb attaches to a protein

Glycolipid

Carb attached to a phospholipid or cholesterol

Amphiphilic molecules

A molecule that has a hydrophobic and hydrophilic part organizes itself in a way that the hydrophilic part faces out when bonded to other amphiphilic molecules

Integral protein

A protein that is embedded in the plasma membrane, has hydrophobic segments that interact with the hydrophobic segments of the membrane

Peripheral protein

A protein that is attached to either the outer or inner layer of the membrane, can act as an enzyme, as part of the cytoskeleton, or as part of the cell’s recognition system

Glycocalyx

Carbs attached to the exterior surface of the cell as glycoproteins/lipids, help the cell’s recognition system

Membrane fluidity

The extent to which a membrane can bend due to the nature of the double bonds of the fatty acids that make it up

Selective permeability

Cell membranes only allow certain substances to pass through it, vital to cell survival

Passive transport

A form of Ep where a substance moves from an area where it is highly concentrated to one where it is less concentrated

Concentration gradient

The range of concentration of a certain substance over a space

Diffusion

The movement of a substance across a membrane due to its concentration gradient which expends no energy

Factors that affect diffusion

Concentration gradient, mass of molecule, temperature, solvent density, and solubility

Facilitated transport

Polar molecules diffuse across a membrane with the help of transport proteins

Transport protein

A protein that helps molecules diffuse through the membrane by binding it

Channel protein

Protein that has part exposed to both the ICF and ECF and has a tunnel through it that allows polar molecules to pass through it into the cell

Carrier protein

A protein that binds to a molecule, changes its own shape, and then pulls the molecule into the cell

Osmosis

The diffusion of water through semi-permeable membranes from areas with high [h2o] to areas with less [h2o]

Tonicity

How an extracellular substance can make water enter/exit a cell through osmosis

Osmolarity

The total concentration of all substances dissolved in a solvent

Hypotonic solution

When the osmolarity of the ECF is less than the osmolarity of the fluid inside the cell so water enters the cell

Hypertonic solutions

When the osmolarity of the ECF is higher than the osmolarity of the fluid inside the cell so water exits the cell

Isotonic solution

When the osmolarity of the ECF and the fluid inside the cell are equal so there is no net movement of water

Electrochemical gradient

The combined concentration and charge that affects an ion

Active transport

The process of a substance moving against a gradient which expends ATP

Primary active transport

When an ion moves across the membrane and causes a change in the charge across the membrane, costs ATP

Secondary active transport

When molecules move according to the change in gradient caused by primary transport

Transporters

Proteins that help in active transport

Uniporter

Protein that carries one specific ion/molecule in one direction

Symporter

Protein that carries two different ions/molecules in the same direction

Antiporter

Transporter that moves 2 different ions/molecules in opposite directions

Endocytosis

Active transport that moves large molecules into the cell

Phagocytosis

The process of a cell taking in a large particle by engulfing it in its clathrin-coated membrane and forming a vesicle

Pinocytosis

The process of a cell taking in water an other molecules from the ECF, results in a small vesicle formation

Receptor Modified Endocytosis

Receptor proteins in the protein that targets certain molecules aids the endocytosis and a clathrin-coated vesicle forms

Exocytosis

When a cell pushes a vesicle to its surface and expels fluid into the ECF