GCD 3033, Ch. 12.1 : Transport across cell membranes

Majority of ions are found at a high concentration __________the cell

OUTSIDE

The outside environment of a cell is generally _________ charged.

POSITIVELY

The inside environment of a cell is generally _________ charged.

NEGATIVELY

The lipid bilayer is impermeable to _______ and ____

solutes and ions

The lipid bilayer is permeable to ________________________ molecules.

small, hydrophobic or uncharged

The lipid bilayer is LESS permeable to ________________________ molecules.

large, polar, or charged

There are TWO types of ways molecules can pass through the lipid bilayer

transporters and Ion channels

transporters that transport down electrochemical gradients are _________ transporters.

PASSIVE

transporters that transport up electrochemical gradients are _________ transporters.

ACTIVE

active transport requires __________________ to function.

an input of energy

Ion channels are always a ____________ form of transportation.

PASSIVE

An electrochemical gradient is the….

The movement of charged molecules depends on the gradients' concentration and voltage.

typically, molecules want to move in the direction of ____to ___concentration.

high to low

Must water can diffuse passively or actively across the membrane?

PASSIVELY

transporters function by ….?

binding to a solute which changes its conformation to move the solute across the membrane

the active version of transporters are called _________?

pumps

transporter pumps function by ….?

requiring an input of energy to ‘pump’ a solute against its electrochemical gradient

transporter ‘coupled pumps’ function by …?

using the gradient of one solute, which is energetically favorable, to drive the active transport of a second molecule, which is energetically unfavorable.

There are 3 types of active transportation

1) Gradient driven pumps

2) ATP driven pumps

3) Light-driven pumps

The Glucose-Na⁺ pump is located in the ___________.

apical plasma membrane of kidney and intestinal cells.

The Glucose-Na⁺ pump uses an energy source of ___________.

Na⁺ gradient

Specifically, explain how the Glucose-Na⁺ pump functions.

Couples the transport of Na⁺, along its electrochemical gradient, to fund the transport of glucose, against its electrochemical gradient.

This decreases the net concentration of ions in the cell, and decreases osmotic pressure to prevent cell swelling.

The Glucose-Na⁺ pump functions to ______.

actively import glucose

The Na⁺- H⁺ pump is located in the _____.

plasma membrane of animal cells.

The Na⁺- H⁺ pump uses an energy source of _______.

Na⁺ gradient

The Na⁺- H⁺ pump functions to ______.

actively export H⁺ ions and regulate the pH.

The Na⁺- K^- pump is located in the __________.

plasma membrane of most animal cells.

The Na⁺- K^- pump uses an energy source of ______.

ATP hydrolysis

The Na⁺- K^- pump functions to __________.

actively export Na⁺ ions and import K^-.

Specifically explain how the Na⁺- K^- pump function.

Pumps 3 Na+ ions out, along its electrochemical gradient

Pumps 2 K+ ions in, consumes a ton of ATP and goes against its electrochemical gradient.

The Ca²⁺ pump(s) is located in the ___________.

plasma membrane of eukaryotic cells AND the sarcoplasmic reticulum membrane of muscle cells and the ER membrane of most animal cells.

The Ca²⁺ pump(s) use an energy source of

ATP hydrolysis

The Ca²⁺ pump in the plasma membrane functions to ________.

actively export Ca²⁺ ions.

The Ca²⁺ pump in the sarcoplasmic reticulum membrane of muscle cells and the ER membrane of most animal cells functions to _______________.

actively import Ca²⁺ ions into the sarcoplasmic reticulum or ER.

Specifically, explain how the Ca²⁺ pump(s) function.

Binds to 2X Ca²⁺ ions, pump becomes phosphorylated which causes a conformational change.

The H⁺ pump(s) are located in the ____________.

the plasma membrane of plant cells, fungi, and some bacteria AND the membranes of lysosomes in animal cells/vacuoles in plant and fungal cells.

The H⁺ pump(s) uses an energy source of ___.

ATP hydrolysis.

The H⁺ pump located in the plasma membrane of plant cells, fungi, and some bacteria functions to _______.

actively export H⁺ ions.

The H⁺ pump located in the membranes of lysosomes in animal cells/vacuoles in plant and fungal cells functions to __________.

actively export H⁺ ions from cytosol into lysosome or vacuole.

coupled pumps are also called _______.

gradient driven pumps

There are 2 types of coupled pumps.

symport and antiport

Symport Coupled Pumps function to ______________.

Use ion gradient to drive the active transport of two solutes in the same direction

Antiport Coupled Pumps function to ______________.

Use ion gradient to drive the active transport of two solutes in different directions

Uniports function to ____________.

mediate passive transport of one solute.

What ion has a strong electrochemical gradient that can be harnessed by coupled pumps?

Na⁺ Ions

What ions aren’t used in coupled pumps, have a weak electrochemical gradient that doesn’t generate the amount of energy needed for a couple pump.

K^- ions.

glucose is an example of a _________________.

passive uniport