AP Biology - Unit 2: Cell Transport & Size

cell transport

cell transport

___________ is required to maintain homeostasis in the cell.

transport of waste

importance of cell transport: ____________ out of the cell helps maintain pH and salt balance

maintain pH and salt balance

importance of cell transport: transport of water out of the cell helps _____________

transport signal proteins

importance of cell transport: _______________ out of the cell helps cells communicate, like in the nervous system

absorption of nutrients

importance of cell transport: __________ into the cell

respiration

importance of cell transport: allow oxygen into the cell for ____________

CO2

importance of cell transport: allows for _____ to leave cells

apoptosis

importance of cell transport: can assist in _______________ in infected cells
(hint... cell death)

concentration gradient

A difference in the concentration of molecules across a space
(one area will have a higher concentration of molecules than the other)

difference

biological concentration gradients occur when there is a ______________ in the concentration of biomolecules, water, or ions across the cell membrane

high, low

molecules moving with the concentration gradient are moving from an area of ____ concentration to an area of ___ concentration

inherent energy

atoms/molecules have _____________________ that causes them to vibrate and move around

random

the direction in which the molecules move is _____________

net movement

the overall direction that MOST of the molecules move

concentration gradient

net movement of molecules generally follow the __________________________________

cell transport

process by which cells exchange nutrients, waste, and other materials with the extracellular environment

extracellular environment

cell transport is the process by which cells exchange nutrients, waste, and other materials with the ___________________

passive transport

net movement of molecules with the concentration gradient until the system reaches dynamic equilibrium

passive transport

relies on the inherent energy of the concentration gradient. does not require the input of the metabolic energy (ATP) to occur

active transport

requires a net input of metabolic energy (ATP) to occur

active transport

net movement of molecules against the concentration gradient. system will not reach dynamic equilibrium.

dynamic equilibrium

occurs when molecules moving with the concentration gradient reach the same net concentration on both sides of the membrane

dynamic equilibrium

molecules are still moving, but the net movement is zero

reset

cells will remain in dynamic equilibrium unless work (using ATP energy) is done to ______ the concentration gradient

passive transport processes

simple diffusion, facilitated diffusion, osmosis

simple diffusion

net movement of small, non-polar molecules with the concentration gradient without the aid of a channel protein

simple diffusion

only occurs with O2, N2, CO2, and small amounts of water

facilitated diffusion

net movement of molecules with the concentration gradient that requires the use of a channel protein to occur

facilitated diffusion

occurs for any molecules that are large, polar, charged, or some combination thereof

active transport

-requires the use of ATP energy
-moves from low to high concentration

membrane potential

created by the separation of charge across the membrane

electrical potential energy

in membrane potential, the membrane is acting like a battery and stores _________________________

polarized

when ions change concentrations on both sides of the membrane through transport, the membrane can become ___________________ and fire an electrical signal

endocytosis

process by which cells take in molecules into the intracellular space. requires formation of a vesicle for bulk import of substances

exocytosis

process by which cells release molecules into the extracellular space. requires formation of a vesicle for bulk export of substances

metabolic energy (ATP)

both endocytosis and exocytosis require the input of ______________________________________ to occur

fluid

unsaturated hydrocarbon tails with kinks

viscous

saturated hydrocarbon tails (no kinks)

cell size

cells can be anywhere from 10 micrometers to 1 mm in range

big

cells have to be ___ enough to fit all the DNA and organelles

small

cells have to be ______ enough to efficiently exchange nutrients, oxygen, and waste

homeostasis

cells have to be big enough to fit all the DNA and organelles, but also have to be small enough to efficiently exchange nutrients, oxygen, and waste with the extracellular environment to maintain ____________

surface area (SA)

the amount of space covering the outside of the cell. materials are exchanged with the environment here. more _________ = better

volume

the amount of space inside the cell. affects time for molecules to move through the cell. less ____________ = better

surface area to volume ratio

cells need to have a large ___________________________ to be efficient at transport.

high surface area

= more places for materials to enter/exit

small volume

= less space to cross for materials to get where they need to be

projections

having ______________ (like villi) on a cell will increase the surface area to volume ratio.
cells with ______________ will be more efficient at transporting materials compared to other cell shapes

less ATP

mitochondria has folds inside the membrane: if the mitochondrion did not have a double membrane, it would be unable to efficiently produce ATP (cellular energy). they would not be able to fit as many ETCs and ATP Synthases, and consequently would produce _________________

smaller

what size cells are the most efficient? smaller or larger?
(hint... the ones that have greater surface area to volume ratio)