Zoology Module Two

Exam One

Passive transport

small molecules move across cell with concentration gradient, no input of energy

Active transport

needs energy (ATP) and transport protien (carrier), against concentration gradient (ex: sodium potassium pump)

Bulk transport

movement of large molecules, exocytosis or endocytosis needed

Endocytosis

large molecule taken in when plasma membrane pinches inward, forming a vesicle, three types: phagocytosis, pinocytosis, receptor-mediated endocytosis

Exocytosis

large molecule secreted out when vesicle fuses with plasma membrane

Cell membrane components

lipids and protiens, mainly of phospholipids (carbohydrates included but not main)

Fluid mosaic model

protiens bobbing in fluid bilayer of phospholipids

Membrane protiens

peripheral and integral

Peripheral protien

bound to membrane surface

Integral protien

penetrate hydrophobic core

Transmembrane protiens

integral protiens that span the membrane

Cell surface membrane functions

transport, enzymatic activity, signal transduction, cell-cell recognition, intercellular joining, attachment to cytoskeleton and extracellular matrix

Glycolipids

carbohydrates bonded to lipids

Glycoprotiens

carbohydrates bonded to protiens

Transport protiens

channel protiens and carrier protiens

Channel protiens

have hydrophilic channel that certain molecules/ions use

Carrier protiens

bind to molecules and change shape to transport them across membrane

Osmosis

diffusion of free water across selectivly permeable membrane from lower solute conc to higher solute conc, done till equal conc on both sides

Tonicity

ability of surrounding solution to cause cell to gain/lose water

Isotonic solution

when solut conc is same as that inside the cell, water diffuses across membrane at same rate in both directions

Hypertonic solution

conc of solute is greater than that inside the cell, net diffusion of water from inside the cell into surrounding solution

Hypotonic solution

conc of solute less than that inside cell, net diffusion water from solution into cell

Osmoregulation

control of solute conc and water balance, through pumps

Facilitated diffusion

transport protiens (channel and carrier) speed up passive transport or molecules across plasma membrane

Gated channels

ion channels that open/close due to stimulus

Membrane potential

voltage across membrane, maintained by ion pumps

Voltage

from dif of positive and negative ions across membrane, inside of cell is negative relative to outside

Electrochemical gradient

dives diffusion of ions across membrane

Electrogenic pump

transport protien that generates voltage across membrane (ex: sodium potassium pump in animal cells)

Cotransport

active transport that indirectly drives transport of other substances

Phagocytosis

cellular eating, cell absorbs molecule and packs into food vacule

Pinocytosis

cellular drinking, molecules taken up when extracellular fluid is absorbed into tiny vesicles

Receptor-mediated endocytosis

vesicle formation triggered by solute binding to receptors