Passive and Active Transport

Active transport goes from_____ to _____

low; high

Which method moves against the concentration gradient

Active transport

What are the requirements of active transport

1. the input of energy (ATP)

2. always occurs across a cell membrane

3. requires carrier proteins to move the molecules

What is required to transport macromolecules?

endocytosis and exocytosis

Endocytosis

moves cell inside, cell membrane takes in macromolecules by folding in on itself and forming new vesicles derived from the membrane

Exocytosis

Internal vesicles containing macromolecules move to the cell surface and fuse with the cell membrane. The macromolecules are released into the extracellular space

Example of active transport

A plant absorbing mineral ions into its roots in low quality soil so it is against the concentration gradient

Sodium-potassium pump is a _____ in the ______

protein; cell membrane

Whats it called when the sodium potassium pump continues to repeat?

electrochemical gradient

Whats the purpose of the sodium-potassium pump?

to maintain the resting potential of the cell membrane by helping establish an electrochemical gradient

Why is the sodium-potassium pump active transport?

Sodium ions are pumped out of the cell AGAINST their concentration gradient from low to high concentration. Potassium ions are pumped into the cell also moving AGAINST their concentration gradient.

What is diffusion?

the movement of a substance from high to low concentration

Molecules in diffusion do not move randomly

false

is the net movement of molecules in diffusion up or down?

down

When the concentration is equal there is

equilibrium

Is diffusion passive or active

passive; no energy required

Whats required of cells to function correctly?

many molecules and ions

What are the types of diffusion?

simple and facilitated

Examples of diffusion

Nutrients from digested foods diffuse into small intestines into the blood stream

What controls when can and cant enter the cell membrane?

the properties of the cell

Simple diffusion

when molecules can pass directly through the cell membrane, small

In simple diffusion molecules must be able to fit through the gaps between the ______

phospholipids

The middle of the cell membrane is ____ so only ____ can easily pass through

hydrophobic; nonpolar

Facilitated diffusion

when proteins have to help transport larger, polar molecules

What are the types of channel proteins?

Channel and carrier

Whats the interior of channel and carrier proteins?

hydrophilic

What does increasing the concentration gradient do?

It increases the rate of diffusion

Does increasing the surface area of a cell increase or decrease its rate of diffusion?

increase

Does a thinner or thicker exchange surface slow down diffusion?

Thicker

Increasing the temp, ____ the rate of diffusion

increases

Osmosis is a passive process

true

Osmosis is the diffusion of _____ from a ___ to ____ concentration

water; high; low

Semi/partially/selectively permeable membrane

only specific molecules can pass through

osmosis

Increasing the solute concentration of a solution ____ the concentration of water

lowers

Hypotonic

the solution has a lower concentration of solute, water will move into the cell

What happens when an animal cell is hypotonic

It swells and bursts called lysis

What happens when a plant cell is hypotonic

there is pressure against the cell wall and is “turgid”, normal

Isotonic

the solution has the same concentration of solute as the cell, no net movement

What happens when an animal cell is isotonic

red blood cells didn’t lose or gain water and is normal and concaved

What happens when a plant cell is isotonic

The cell hasn’t gained or lost water, no pressure on cell wall, cell is flaccid

Hypertonic

Solution has a higher concentration of solute than the cell. Water moves out of the cell

What happens to an animal cell when it is Hypertonic

red blood cells loses water and appears shriveled and spikey

What happens to a plant cell when it is hypertonic

The cell lost water so cytoplasm pulls away from the cell wall and vacuole shrinks, cell is plasmolyzed