Mastering Biology - Cellular membranes

An isotonic solution

A cell that neither gains nor loses water while sitting in a solution is probably sitting in

Take up water through osmosis

A human cell placed in a hypotonic environment would -shrivel up. -have no change in net water balance. -take up water through osmosis. -lose water through osmosis.

Lose water by osmosis

A human cell placed into a hypertonic solution is likely to -burst as a result of osmosis. -lose water by osmosis. -increase in size. -remain unchanged.

Passive transport

Diffusion across a biological membrane is called ______.

free water, solute, free water, solute

During osmosis, water diffuses across a selectively permeable membrane from the region of higher _______concentration and lower _______ concentration to the side with lower _______concentration and higher ______ concentration.

Passive transport

Facilitated diffusion is a type of _______.

Lipids are mostly non polar.

How can a lipid be distinguished from a sugar?

Hypotonic

If a red blood cell is placed in a salt solution and bursts, what is the tonicity of the solution relative to the interior of the cell?

A hypotonic solution such as tap water

If you are going to bake potatoes, and your potatoes are soft and dehydrated, they can be soaked in __________ to make them more firm before baking. -a hypotonic solution such as tap water -a hypertonic solution made with distilled water and a tablespoon of salt -an isotonic solution -a hypertonic solution such as distilled water

that the salt in the food creates a hypertonic environment for the bacteria and fungi.

Many bacteria and fungi have a difficult time surviving on our food if the food is very salty. The best explanation for this is -that bacteria and fungi cannot survive in an isotonic environment. -that bacteria and fungi cannot survive in a hypotonic environment. -that the salt in the food creates a hypotonic environment for the bacteria and fungi. -that the salt in the food creates a hypertonic environment for the bacteria and fungi.

Freshwater lakes and ponds

Paramecium is a genus of protists that lives in water. It has organelles called contractile vacuoles that continually eliminate the excess water gained through osmosis. Knowing that Paramecia gain water through osmosis, we can deduce that they normally live in -freshwater lakes and ponds. -the ocean. -very salty environments. -ice and very cold environments.

Osmosis is the diffusion of water molecules across a selectively permeable membrane.

Select the correct statement about osmosis. -If a dead cell is placed in a solution hypotonic to the cell contents, osmosis will not occur. -Osmosis is the diffusion of water molecules across a selectively permeable membrane. -Osmosis is strictly water moving through the lipid membrane. -Osmotic equilibrium cannot be reached unless solutes move across the membrane.

True

True or false? Osmosis is a type of diffusion.

True

True or false? The water-soluble portion of a phospholipid is the polar head, which generally consists of a glycerol molecule linked to a phosphate group.

The cell becomes turgid, and the cell wall prevents it from bursting.

What happens to a cell surrounded by a cell wall when it is placed in a hypotonic solution?

Water molecules move between the two solutions, but there is no net movement of water across the membrane.

What happens when two solutions separated by a selectively permeable membrane reach osmotic equilibrium? -Water molecules continue to move from the hypertonic solution to the hypotonic solution. -Water molecules move between the two solutions, but there is no net movement of water across the membrane. -Water molecules no longer move between the solutions. -Water molecules continue to move from the hypotonic solution to the hypertonic solution.

Osmosis

What name is given to the process by which water crosses a selectively permeable membrane?

Amphipathic nature

What property of dishwashing liquid (detergent) makes it useful to wash grease from pans? -Hydrophobic nature -Amphipathic nature -Solubility in water -Permeability

should be isotonic, because either a hypertonic or hypotonic IV would damage red blood cells.

When a person is dehydrated, his or her IV fluids -should be isotonic, because either a hypertonic or hypotonic IV would damage red blood cells. -should be hypertonic, because if dehydrated, he or she probably needs salt as well. -should be hypotonic, because if dehydrated, he or she needs as much water as possible. -are not necessary, since a dehydrated person would not require IV fluids.

more concentrated, less concentrated

When molecules move down their concentration gradient, they move from where they are _____ to where they are _____.

The polarity of membrane phospholipids

Which of the following factors does not affect membrane permeability? The polarity of membrane phospholipids The saturation of hydrocarbon tails in membrane phospholipids Temperature The amount of cholesterol in the membrane

When a plant cell is placed in concentrated salt water, water moves out of the cell.

Which of the following molecular movements is due to diffusion or osmosis? -The sodium-potassium pump pumps three sodium ions out of a neuron for every two potassium ions it pumps in. -When a plant cell is placed in concentrated salt water, water moves out of the cell. -Cells of the pancreas secrete insulin into the bloodstream. -Cell engulfs extracellular content.

Oxygen (O2)

Which of the following particles could diffuse easily through a cell membrane? -Glucose -Sodium ion (Na+) -Oxygen (O2) -Hydrogen ion (H+)

-the similarity of the drug molecule to other molecules that are transported into the target cells

Which of the following would be a factor that determines whether the molecule selectively enters the target cells? -the concentration of the drug molecule that is transported in the blood -the similarity of the drug molecule to other molecules that are transported into the target cells -the phospholipid composition of the target cells' plasma membrane -the nonpolar, hydrophobic nature of the drug molecule

The contents of a red blood cell are hypertonic to distilled water.

Which statement is correct? -A solution of seawater is hypertonic. -The contents of a red blood cell are hypertonic to distilled water. -The red blood cell has a greater solute concentration than distilled water, which means that its contents are hypotonic to distilled water. -A solution of distilled water is hypotonic.

-Because membranes are fluid, membrane proteins and phospholipids can drift about in the membrane. -The diverse proteins found in and attached to membranes perform many important functions. -The framework of a membrane is a bilayer of phospholipids with their hydrophilic heads facing the aqueous environment inside and outside of the cell and their hydrophobic tails clustered in the center.

Which statements about the fluid mosaic structure of a membrane are correct? Select the three correct statements. -Because membranes are fluid, membrane proteins and phospholipids can drift about in the membrane. -The diverse proteins found in and attached to membranes perform many important functions. -The kinky tails of some proteins help keep the membrane fluid by preventing the component molecules from packing solidly together. -Membranes include a mosaic, or mix, of carbohydrates embedded in a phospholipid bilayer. -The framework of a membrane is a bilayer of phospholipids with their hydrophilic heads facing the aqueous environment inside and outside of the cell and their hydrophobic tails clustered in the center.