AP Bio Unit 2 Quiz 1

What is hypotonic?

Low solute concentration (will make a cell expand because of high to low principle) (pay attention to what the word hypotonic is attached to)

What is diffusion?

The movement of particles from an area of high concentration to an area of low concentration.

What effects diffusion?

1. Distance 2. High concentration differences (gradient => fast diffusion) 3. High temperature => faster diffusion

Mold can withstand the properties of salt and sugar because they have what?

A cell wall

Because the tails of a phospholipid are hydrophobic and they bind together to make a bilayer, they repel what?

Anything that is hydrophilic. They create a hydrophobic barrier

How is osmosis different from diffusion?

Diffusion refers to the movement of any particles from a region of high concentration to a region of low concentration. Osmosis only refers to movement of water molecules.

What is the role/function of peripheral proteins?

Enzymes. These interact with the phospholipid head. There IMFs are dipole-dipole and hydrogen bond force. They are hydrophilic and it is a fairly weak interactions because of their IMFs (they are on the outside of the membrane and it is very easy for them to become detached since they are hydrophilic)

What is the net travel of molecules?

High to low

Be able to label the parts of a cell membrane

Ok

Molecules travel in what kind of directions?

Random directions called random walk

What are the two substances that cause a decrease in water concentration?

Salt and Sugar (this is why they are use preservatives)

What is the role/function of glycoproteins?

Signal and recognition. Glycolipids are made of sugars, more specifically oligosaccharides. These are only on the outside of the membrane and they are attached to proteins.

What is the role/function of glycolipids?

Signal and recognition. Glycolipids are made of sugars, more specifically oligosaccharides. These are only on the outside of the membrane.

What is the role/function of integral proteins?

Signaling, recognition and attachment. These interact with the phospholipid tails. There IMF is London. They are hydrophobic and there have a strong interaction because they are hydrophobic and cannot move to any place with water

What is the role/function of transmembrane proteins?

Signaling, recognition, attachment, and channels for hydrophilic nutrients. These are a type of integral proteins. They go from one side of the membrane to the other (they must touch the phospholipid tails as well)

What is signal transduction?

Taking information from the outside and bringing it inside

What will happen when a plant cell is placed in a hypotonic solution?

The plant cell will expand until it hits the cell wall. This is called turgent and it makes the cell very stiff and rigid

What will happen when a plant cell is placed in a hypertonic solution?

The plant cell will shrink. This is called plasmolysis and this the cause of death of a plant cell

A dialysis tube with a membrane permeable to sucrose is filled with a sucrose solution and placed in another sucrose solution. What happens to the tubing if it is filled with a .1M sucrose solution and is put into a .2M sucrose solution? Will the tubing shrink or expand?

The tubing will expand because the higher concentration of sucrose (.2M) will pass through the membrane (because it is permeable to sucrose) to the lower concentration of sucrose inside the tubing (.1M)

A dialysis tube with a membrane permeable to sucrose is filled with a sucrose solution and placed in another sucrose solution. What happens to the tubing if it is filled with a .5M sucrose solution and is put into a .7M sucrose solution? Will the tubing shrink or expand?

The tubing will expand because the higher concentration of sucrose (.7M) will pass through the membrane (because it is permeable to sucrose) to the lower concentration of sucrose inside the tubing (.5M)

A dialysis tube with a membrane permeable to water is filled with a sucrose solution and placed in another sucrose solution. What happens to the tubing if it is filled with a .1M sucrose solution and is put into a 0M sucrose solution? Will the tubing shrink or expand?

The tubing will expand because there is a higher water concentration outside of the tubing (0M) than inside the tubing (.1M)

A dialysis tube with a membrane permeable to sucrose is filled with a sucrose solution and placed in another sucrose solution. What happens to the tubing if it is filled with a .1M sucrose solution and is put into a 0M sucrose solution? Will the tubing shrink or expand?

The tubing will shrink because there is a higher concentration of sucrose (.1M) inside the tubing and it will pass through the membrane (because it is permeable to sucrose) to the lower concentration of sucrose (0M) on the outside of the tubing

A dialysis tube with a membrane permeable to water is filled with a sucrose solution and placed in another sucrose solution. What happens to the tubing if it is filled with a .1M sucrose solution and is put into a .2M sucrose solution? Will the tubing shrink or expand?

The tubing will shrink because there is a higher water concentration inside the tubing (.1M) than outside the tubing (.2M)

A dialysis tube with a membrane permeable to water is filled with a sucrose solution and placed in another sucrose solution. What happens to the tubing if it is filled with a .5M sucrose solution and is put into a .7M sucrose solution? Will the tubing shrink or expand?

The tubing will shrink because there is a higher water concentration inside the tubing (.5) than outside the tubing (.7)

What will happen when an animal cell is placed in a hypertonic solution?

The water from the inside of the cell will go out to the surrounding solution. The cell will shrink

What will happen when an animal cell is placed in a hypotonic solution?

The water from the outside solution will go into the cell. The cell will expand

What is the role/function of gap junctions?

These allow molecules to travel through "holes" to another cel. Ex. Heart muscle cells. These are the opposite of tight junctions

What is the role/function of aquaporines?

These are channels for water

What is the role/function of plasmodesmata?

These are the plant version of gap junctions

What is the role/function of tight junctions?

These create a water proof layer. Ex. Stomach epithelial cells. These are the opposite of gap junctions

What is the role/function of adhesion junctions?

These hold the cells together against stress. The cytoskeleton attaches these (ex. Skin epithelial cells) these are made of many proteins

What is the role/function of cholesterol?

This adds rigidity

What is the role/function of phospholipids?

To create a hydrophobic barrier. They only allow small, uncharged molecules and lipids through (CO2, O2, N2, estrogen and testosterone)

Animal cells are very permeable to what?

Water

What is osmosis?

diffusion of water across a selectively permeable membrane

What is hypertonic?

high solute concentration (will shrink a cell because of the high to low principle) (pay attention to what the word hypertonic is attached to)

What is a selectively permeable membrane?

membrane that only allow certain substances to cross

Cell membranes are made of what?

phospholipid bilayer

What is isotonic?

same solute concentration

What is the fluid mosaic model?

states that a membrane is a fluid structure with a "mosaic" of various proteins embedded in it