Biology Chp 4

The sodium potassium pump uses energy in the form of what?

ATP - During active transport

What is an Ion Channel?

a transport protein with a polar pore through which ions can pass

What is facilitated diffusion?

is when carrier proteins are used to transport specific substances such as amino acids & sugars down their concentration gradient • Carrier Protein Binds to a specific molecule on one side of cell membrane • Change in shape of the protein exposes molecule to the other side of cell membrane • Carrier Protein shield molecule from interior lipid bilayer • Molecule is then released from carrier protein which returns to original shape

What are four examples of passive transport?

1. Diffusion 2. Osmosis 3.Ion Channels 4. Facilitated Diffusion

What type of protein is used during facilitated diffusion?

A Carrier Protein - they are used to transport specific substances Ex: Amino Acids & Sugars

Does Facilitated Diffusion require energy?

No it does not require energy. Moves substances down.

If a cell shrinks, what type of concentration was it put in-hypertonic or hypotonic?

Hypertonic

The random motion of particles of substance that causes a substance to move from an area of high concentration to an area of low concentration is what?

Diffusion or passive transport

What is the difference between endocytosis and exocytosis?

Endocytosis is the movement of a substance into the cell by a vesicle. Exocytosis is the movement of a substance by a vesicle out of the cell.

What are three examples of active transport?

1. Sodium Potassium Pump 2. Endocytosis 3. Exocytosis

Predict what would happen to a cell that is placed in hypertonic solution. Explain why this would occur.

A hypertonic solution would cause water to diffuse outside the cell and shrink the cell because the fluid outside the cell has a lower free water molecule concentration and higher concentration of dissolved particles than cytoplasm has. The water diffuses out making the cell smaller.

Be able to do a U-Tube problem

Be able to do a U-Tube problem

What is diffusion?

Diffusion is the movement of a substance from an area of high concentration to an area of lower concentration caused by random motion of particles of a substance.

What is the difference between diffusion and osmosis?

Diffusion is the movement of a substance from an area of high concentration to an area of lower concentration caused by random motion of particles of a substance. Osmosis is a special type of diffusion that involves water(moves from high-> low concentration)

Molecules that are too large to fit through the membrane are brought into the cell by what process?

Endocytosis makes it possible for large molecules to enter a cell. A small piece of the cell membrane wraps around the particle and is brought into the cell.

What doesn't a cell use (expend) during diffusion but does during active transport?

Energy

At the end of diffusion, the concentrations on both sides of the membrane are at what?

Equilibrium

What is the difference between diffusion and equilibrium?

Equilibrium is a condition in which concentration of a substance is equal throughout a space. Diffusion is the movement of a substance from a space of high concentration to an space of lower concentration caused by random motion of particles. If diffusion continues - equilibrium will eventually happen.

Molecules that are too large to fit through the membrane are brought out the cell by what process?

Exocytosis - the cell membrane extends to cover or "eat/swallow" the substances that are too big to pass through the cell membrane. Receptor proteins bind to signal molecules outside the cell.

Ion Channels are active or passive transport?

Passive Transport - No use of energy is needed.

Substances, without the input of energy, usually go from high to low concentration or from low to high concentration?

High to low concentration

If a cell swells, what type of concentration was it put in-hypertonic or hypotonic?

Hypotonic

What is the difference between isotonic, hypotonic and hypertonic? What does each do in the cell?

Isotonic is the equal movement in and out of the cell.(stays the same) Hypotonic is fluid outside the cell has low concentration of dissolved particles than the cytoplasm(inside cell has high concentration .(swells) Hypertonic is fluid outside cell has higher concentration of dissolved particles than the cytoplasm(outside has low concentration of water).(shrinks)

Explain how some substances cross the cell membrane by facilitated diffusion.

Most cells have a different kind of transport protein called a carrier protein that can bind to a specific substance on the one side of the cell membrane - carry the substance across the cell membrane and then release it on the other side. When carrier proteins are used to transport specific substances such as amino acids and sugars - down their concentration gradient it is facilitated diffusion.

What is the difference between Active & Passive Transport? Make sure to talk about energy and high/low or low/high.

Passive Transport is movement across the cell membrane that DOES NOT require energy from the cell. A difference in the concentration of a substance across a space is called concentration gradient. A concentration gradient exists across the cell membrane to diffuse down from an area of high concentration to an area of low concentration, a substance must be able to pass through the cell membrane. Active Transport requires energy from the cell. Molecules move against their concentration gradient from an area of low to high. To move molecules from an area of low concentration to an area of high concentration you Need Energy. This is the opposite of diffusion - these molecules flow against their concentration gradient. Most times ATP is the energy source. Some need a carrier protein

Why is the cell membrane selectively permeable?

The cell membrane is selectively permeable because it lets some substances go through the cell but does not let others.

In the sodium-potassium pump, how many sodium and how many potassium are moved against their concentration gradients? Which direction are they moved (into or out of the cell)?

Transports 3 Sodium Ions (Na+) out of the cell Transports 2 potassium ions (K+) into the cell Three sodium ions and two potassium ions are moved against their concentration gradient.

Is facilitated diffusion active or passive transport? It is passive.

passive

Osmosis is what type of transport

passive and does not require energy