Bio 1303 Exam 2

Phospholipids

Forms bilayer

Cholesterol

Stabilizes bilayer

Integral membrane proteins

• Their a.a. interact with hydrophobic lipids to anchor in membrane

• Many functions

glycoproteins + glycolipids

• carbohydrates

• Creates hydrophilic coating that attracts water

• “fluids” bc lipids + proteins not covalently attracted to each other

• Move laterally

Passive transport

Movement of materials that does Not require energy

Diffusion

• Solutes move from high concentration to lower concentration

• “Down” their concentration gradient

“Selectively permeable”

The plasma membrane is

Facilitated transport

• Type of passive transport involves use of carrier molecule to move molecules across plasma membrane

• Channel/ carrier proteins

Channel/ carrier proteins

• Allow for movement of solutes across plasma membrane, down their concentration gradient

• Can be always open or gated by specific mechanisms

• All very specific for atom/ molecule they transport

• Ex. Aquaporin

Osmosis

Movement of water through a selectively permeable membrane from an area of low solute concentration to an area of higher concentration

Aquaporins

Due to ____, plasma membrane allows movement of water via osmosis in or out of cell

Solutes

Movement depends on amount of ____ in surrounding solution

• Hypotonic

• Hypertonic

• Isotonic

3 types of solutions

Hypotonic solution

• Solution/ surroundings have fewer solutes than inside of cell

• Water moves into cell

• Cell swells, can burst

• Bad for animal cells, good for plant cells

Hypertonic solution

• solution/ surroundings have more solutes than inside of cell

• Water moves out of cells

• Cells shrivel

• Bad for cells

Isotonic solution

• solution/ surroundings have some amount of solutes as inside of cell

• NO net movement of water

• Good for animal cells, bad for plant cells

Active transport

• movement of of materials that require energy

• Moves materials “against” concentration gradient

• From low to high concentration

• Can be one/ few atoms/ molecules at a time

• bulk transport

Bulk transport

Active transport of large structures or large quantities

Endocytosis

Exocytosis

2 types of active/ bulk transport

Endocytosis

• enters in vesicles/ vacuoles

• “Phagocytosis” for large structures

• “Pinocytosis” for small particles

Exosytosis

Exits from particles

Solutes

Substance that dissolves in another substance to form a solution

(Solid,liquid,gas)

Fluid mosaic model

Plasma membrane is described by the _____

Energy

Ability to do work

Potential

Kinetic

2 types of energy

Potential energy

• stored energy

• Includes “chemical energy”

• Energy in chemical bonds

Releases

Breaking chemical bonds ____ energy

Kinetic energy

• energy of motion

• Includes heat

First law of thermodynamics

• energy cannot be created nor destroyed

• Only converted from one form to another

Exergonic

Endergonic

2 types of chemical reactions

Exergonic

• products are at lower energy than reactants

• Release energy

Endergonic

• products are at a higher than reactants

• Require input of energy

CAN

Exergonic and Endergonic ___ be coupled

Heat energy

_____ can be used to overcome activation energy

Catalysts

Activation energy can be lowered by ____

Catalysts

• hold reactant (s) and strain chemical bonds to lower activation energy

• Can facilitate Exergonic or Endergonic reactions

Biological catalysts

(Most are proteins) are called enzymes