Cell Transports Study Guide

Carrier Protein

A transport protein that can change its shape to allow specific substances in and out of the cell. BOTH PASSIVE AND ACTIVE TRANSPORT (Depends).

Channel Protein

A transport protein that typically moves ions across the cell membrane - can be gated to open and close. PASSIVE TRANSPORT

Sodium-Potassium Pump

ACTIVE TRANSPORT Active transport of 3 sodium ions out of the cell and 2 potassium ions in the cell to maintain an electrical gradient in neurons - sodium-potassium moves against the gradient.

Exocytosis

ACTIVE TRANSPORT The active transport of very large molecules that need to be removed from the cell via vesicles.

Isotonic

A cell environment in which the number of solutes is equal on both sides of the cell membrane - no net water movement.

Hypertonic

A cell environment in which the number of solutes is higher on the outside of the cell membrane than the inside - water moves out of the cell.

Hypotonic

A cell environment in which the number of solutes is lower on the outside of the cell membrane than the inside - water moves into the cell. (HYPO - A LOT OF H2O!)

Concentration Gradient

A difference of concentration between two regions.

Equilibrium

A state in which the concentrations of a substance is equal on both sides of the membrane.

Simple Diffusion

Diffusion of nonpolar or non-charged molecules through the membrane. PASSIVE TRANSPORT With the concentration gradient going from high concentration to low concentration.

Osmosis

Diffusion of water through the membrane. PASSIVE TRANSPORT With the concentration gradient going from high concentration to low concentration.

Endocytosis and exocytosis are a type of active transport because these processes require ___ (___).

Endocytosis and exocytosis are a type of active transport because these processes require *energy (ATP).*

True or False: Active transport does not require energy.

FALSE! Active Transport DOES require energy.

True or False: Ion channels are used to move sugars during passive transport.

FALSE! Ion channels are used to move or transport IONS during passive transport.

True or False: Simple diffusion is the diffusion of water.

FALSE! OSMOSIS is the diffusion of water.

Endocytosis

The process in which molecules that are too large enter the cell. ACTIVE TRANSPORT Both, goes with and against the concentration gradient.

Passive Transport

Transport that moves with the concentration gradient.

Active Transport

Transport that requires energy.

True or False: Once equilibrium is reached, molecules diffuse at a net rate of zero. (If 2 go in, 2 go out, net = 0).

True! Once equilibrium is reached, molecules diffuse at a net rate of zero. (If 2 go in, 2 go out, net = 0).

Three cells each containing 98% water were soaked in different solutions. Cell #1 is soaked in a solution containing 100% water. Cell #2 is soaked in a solution containing 98% water. Cell #3 is soaked in a solution containing 80% water. Explain where water would move because of osmosis occurring within each cell. Use vocabulary words to describe each solution.

Cell#1 would expand because it is 98% water, and its surrounding solution is 100%; therefore, the water would move into the cell. Cell #2 would neither shrink nor expand because it is in an isotonic environment, where the percent of water inside and outside the cell are equal. Cell #3 would shrink because water would leave the cell, which is 98% water, to enter the solution, which is 100%.

Facilitated diffusion uses ion ___ or ___ proteins to move ions and other substances across the cell membrane from high concentrations to low concentrations.

Facilitated diffusion uses ion *channels* or *carrier* proteins to move ions and other substances across the cell membrane from high concentrations to low concentrations.

If a cell is in a hypotonic environment, the cell may be in danger of __.

If a cell is in a hypotonic environment, the cell may be in danger of *bursting.*

Diffusion

Moving substances from high concentrations to low concentrations.

Moving very large molecules into the cell using a vesicle from the cell membrane is known as ___.

Moving very large molecules into the cell using a vesicle from the cell membrane is known as *endocytosis.*

Moving very large molecules out of the cell using a vesicle from the cell membrane is known as ___.

Moving very large molecules out of the cell using a vesicle from the cell membrane is known as *exocytosis.*

Once equilibrium is reached, the net rate of diffusion is __ (___).

Once equilibrium is reached, the net rate of diffusion is *0 (ZERO).*

Osmosis

PASSIVE TRANSPORT The diffusion of water from high concentrations to low concentrations across a semipermeable membrane.

Facilitated Diffusion

PASSIVE TRANSPORT The diffusion of water, polar, or charged molecules across a semipermeable membrane using transport proteins.

Some substances that the cell needs are too large to fit through the cell membrane on their own. Describe how cells can get substances into the cells that are too large. Then describe how the cell can move substances out of the cell that are also too large.

Substances that are too large can enter the cell through a process called endocytosis. During this process, the cell creates a vesicle using its own membrane to enclose the molecules, and then brings them into the cell and disperses them. The opposite of this process is known as exocytosis. Molecules that need to leave the cell but are too large are enclosed within a vesicle, which surfaces at the cell membrane and the contents are dispersed into the extracellular matrix.

True or False: Active transport can be used to move substances from low concentrations to high concentrations.

TRUE! Active transport can be used to move substances from low concentrations to high concentrations.

True or False: Active transport is used to transport very large molecules.

TRUE! Active transport is used to transport very large molecules. Two example processes are endocytosis and exocytosis.

True or False: Facilitated diffusion uses transport proteins.

TRUE! Facilitated diffusion uses transport proteins.

True or False: Passive transport does not require energy.

TRUE! Passive Transport does not require energy.

The sodium potassium pump is a type of active transport that moves sodium and potassium ___ the concentration gradient.

The sodium potassium pump is a type of active transport that moves sodium and potassium *against* the concentration gradient.