bio transport test

what is simple diffusion?

• Type of passive transport

• move from high to low concentration (down the concentration gradient)

• no energy or membrane required

why is simple diffusion considered a passive process?

no energy is used to make the molecules move, they have a natural kinetic energy.

explain what happens to a drop of food coloring put into a beaker of water.

It’s diffused from higher to lower concentration.

What does moving down the concentration gradient mean?

When solutes moving through a membrane from high to low concentration.

Give & explain 2 examples of simple diffusion.

Oxygen moving out of the lungs (high concentration) into the red blood cells (low concentration).

CO2 moving out of erythrocytes (high concentration) into the lungs (low concentration).

what is osmosis?

the diffusion of water through a selectively permeable membrane.

if water potential is HIGH, what is solute concentration?

low

if water potential is LOW, what is solute concentration?

high

how does water potential move?

from high water potential to low water potential

what do aquaporins do?

speed up the diffusion of water osmosis

how are aquaporins formed?

by channels/pores in integral proteins (channel proteins).

are aquaporins closed or open?

they’re always open

sketch pictures of cells in isotonic, hypotonic, and hypertonic environments & show the direction of water movement

:)

what is the net movement of water & what happens to HYPOTONIC cells?

net movement: water enters the cell

cell expands & eventually bursts

what is the net movement of water & what happens to HYPERTONIC cells?

net movement: water leaves cell

cell shrinks

what is the net movement of water & what happens to ISOTONIC cells?

no net movement

cell stays the same size

what is plasmolysis?

when water moves out of a cell & the cell shrinks in size

what is cytolysis?

when water moves into a cell & the cell swells and bursts

what is hemolysis?

when erythrocytes (red blood cells) are placed in distilled water & they swell and burst

what is crenation?

when erythrocytes (red blood cells) are placed in salty water & they shrivel

what happens when erythrocytes are placed in an isotonic solution?

they will maintain normal shape with no net movement of water.

which environments do plants prefer?

hypotonic

which environments do animals prefer?

isotonic

why don’t plant cells burst in hypotonic solutions?

because of their cell wall

when do plants have high osmotic pressure?

in hypotonic environments

what is facilitated diffusion?

• type of passive transport

• moves materials down the concentration gradient (high to low) using transport proteins

• doesn’t require energy

what is active transport?

• requires ATP

• uses transport proteins to move against the concentration gradient (low to high concentration)

• often uses carrier proteins/pumps

what are the 4 passive transport mechanisms?

1. simple diffusion

2. osmosis

3. facilitated diffusion

4. filtration

what is filtration?

• the movement from high pressure to low pressure.

• one way that your kidneys process/filter your blood.

what does a pump do?

moves things from low to high concentration (active transport)

name 3 materials that move into or out of cells by facilitated diffusion.

glucose, amino acids, and ions

name 2 categories of transport proteins found in cell membranes

channel proteins & carrier proteins

where are channel proteins found & explain their pore?

they’re embedded in the cell membrane & have a pore for materials to cross passively through facilitated diffusion.

are channel proteins open or closed?

some are always opened, while others are gated & require a stimulus to open them

what are channel proteins used for?

used to move ions like Na+, Cl-, and K+

what are some properties of channel proteins?

• they’re integral/specific

• they include aquaporins used in osmosis

how do carrier proteins help move materials across a cell membrane?

They bind to the substance & drag the molecule through the membrane and release it on the other side. They may change shape.

do all carrier proteins extend across the cell membrane?

No, they can go part of the way through the membrane.

are carrier proteins specific or not specific?

carrier proteins used in facilitated diffusion & active transport are specific

what are all pumps?

proteins involved in active transport

give an example of an antiport & what does it do?

sodium-potassium pump is an antiport that returns sodium ions to outside the cell membrane (where it’s concentrated) & return potassium ions to inside the cell membrane (where it’s concentrated)

give an example of a uniport & what does it do?

proton pumps are uniports that move H+ ions & are very important in plants

what is the rate at which the sodium-potassium pump moves ions?

it moves 3 sodium ions out of the cell for every 2 potassium ions moved into the cell.

what is resting membrane potential?

the voltage across the cell that is created by the sodium-potassium pump’s movement.

what is the RMP of the cell membrane?

-70mv

what is systic fibrosis?

Thickened mucus due to a channel protein problem.

how do local anesthetics work?

they block sodium from entering the cell to there is no nerve impulse.

OR

negative ions go in to make it harder for nerves to respond.

what is phagocytosis?

“cell eating”

involves extension of cell membrane to form “pseudopods”

what is pinocytosis?

“cell drinking”