Cell Membrane, Passive Transports, and Water Systems (copy)

 Dehydration Synthesis 

• Making something bigger, like a molecule

Hydrolysis

• Enzymes needed (adding water back is called hydrolysis)

Electronegativity 

• The affinity to gain elections

• Ability of an atom of an element to attract electrons when the atom is in a compound

• Noble gasses are not electronegative 

Why does ice float

• Solid water is less dense than liquid water

• When water freezes it expands, less dense 

• Hydrogen bond constantly break and reform in liquid

• kinetic energy is less in cold

• The structure of less moving water is a hexagon shape(Ice solid water), being less compact than the constant moving and structure of liquid water

CELL MEMBRANE AND TRANSPORT

• Concentration of water from high to low concentration is called osmosis

• Concentration of gasses from high to low concentration is called diffusion 

• Both are ways of passive transport (going with the flow, high to low)

• Both diffusion and osmosis work with the concentration gradient not against 

• No energy is needed (Passive transport) No ATP

• ATP stands for Adenosine Triphosphate 

• All cells have a cell membrane

• Controls what enters and exits the cell to maintain an internal balance called homeostasis

• Provides protections and support for the cell 

• It is a phospholipid bilayer (2 layers)

• Lipid bilayer - 2 layers of phospholipids

• Phosphate head is polar (water loving hydrophilic)

• Fatty acid tails (non polar) water fearing (hydrophobic )

• All contains 2 tails per 1 head 

• Proteins embedded in the membrane can be channels or carriers for molecules to move in and out of the cell

• Polar heads love water and dissolve

• Non polar tails hide from water

• Called fluid mosaic model of the membrane because its always moving 

• links/chains  are carbohydrates 

• Integral proteins go all the way through 1 end to the other(this is the channel or carrier protein)

• Peripheral proteins go partially through the membrane not all the way through 

• Cell membranes are selectively permeable only lets in certain substances through 

• Space between the fatty acid tails are called the intercellular space 

• Phospholipids are AMPHIPATHIC the liking of water Polar, non polar 

• Proteins can be called either channel proteins or carrier proteins 

• Cholesterol connects phospholipids together, keeps phospholipids from drifting away, like a glue holding the phospholipids together, in heat and cold 

• Glycoprotein is made up of a protein and a string of sugar 

• Glycolipid is made up of a fat and a string of sugar 

• Hydrocarbons are long trains of hydrogen with carbon attached to it

• Phospholipids are different from other lipids because the head has a charge and the tail does not have a charge.  Head is polar, tail is non-polar 

• Things with no charge can easily move through the bilayer

• Small molecules can too 

• Water moves into the cell through the aquaporin 

• When you use energy it goes from ATP adenosine triphosphate goes to ADP

• Adenosine diphosphate  (loses 1 phosphate)

• Channel proteins look like a tunnel 

• Carrier proteins look more round and like a klaw or clip 

• Proteins like these help bigger molecules WITH charges 

• Aquaporin (an pore that lets in water selectively into the cell) it is also a kind of protein because it is transferring water (a molecule with a charge)

• Cell wall gives structural integrity, helps hold water in more

• Bacteria also has a membrane and cell wall, sometimes also a capsule 

Passive transport

• Diffusion

• Osmosis

• Facilitated diffusion (through proteins, integral or aquaporin) 

• Uses no energy

• High to low concentration 

• When a cell bursts open its called lysis 

• Hypertonic - shrinks (water leaves)

• Isotonic - perfect (No movement)

• Hypotonic - expands and can explode (Water Enters)

• Plant cells never burst 

• When a plant cell goes through hypertonic the cell membrane pulls away and separates from a cell wall

In order to maintain osmotic pressure

• P;lants have a turgor pressure (plant cells will never burst or explode)

• Protists like paramecium has a contractile vacuole that collects water and can pump water in and out to prevent them from over expanding 

• Saltwater fish pump salt out of their specialized gills so that they do not dehydrate