Life120 Chapter 5

Cells utilize potential energy in the form of __________ to actively transport charged ions, like protons (H+), ___________ the concentration gradient. The movement of ions establishes a _____________ gradient. In a cotransporter protein, the difference in charge across the membrane represents a form of potential energy used to ___________ transport large solutes __________ their concentration gradient and transport the ions __________ their concentration gradient.

-ATP -against -concentration -actively -against -across

When a white blood cell engulfs a bacterium, this is an example of: A. phagocytosis B. exocytosis C. cotransport D. active transport

A. phagocytosis

Describe at least three different types of structures besides phospholipids that make up the fluid mosaic model of the plasma membrane (if you say membrane-associated protein, be specific--what kind of membrane-associated protein?). Be sure to include where in the plasma membrane they are found and how each interacts with the phospholipid bilayer.

Cholesterol is find next to phospholipids in the core of the membrane. Membrane proteins can be found on the interior of the lipid bilayer (integral proteins), partway in the interior (transmembrane proteins), and on the surface of the membrane (peripheral protein). Finally, carbohydrates are located on the outside of the plasma membrane and are connected to proteins or lipids.

TRUE/FALSE After ions are actively transported into the cell, water will be actively transported into the cell.

FALSE

TRUE/FALSE As ions move into the cell, it will create a hypertonic environment outside of the cell.

FALSE

TRUE/FALSE As ions move into the cell, it will result in an increase in osmolarity outside of the cell.

FALSE

TRUE/FALSE Water diffuses through the plasma membrane easily because it is it is a small, polar, charged molecule.

FALSE

Osmolarity

Number of moles of solute in a solution (the concentration of solute in a solution).

TRUE/FALSE As ions move into the cell, it will result in an increase in osmotic pressure inside of the cell.

TRUE

TRUE/FALSE Ions and other charged molecules cannot diffuse through the membrane without the aid of a carrier protein or channel protein.

TRUE

TRUE/FALSE Small, non-polar gasses easily move through the plasma membrane because they are hydrophobic.

TRUE

TRUE/FALSE Steroid molecules can pass more easily through the plasma membrane than a disaccharide.

TRUE

TRUE/FALSE The interior core of the intermembrane protein where ions are transported is likely hydrophilic.

TRUE

Tonicity

The measure of a solution's ability to change the volume of a cell by osmosis (e.g. a hypertonic solution outside of a cell will reduce the volume inside the cell).

Osmotic Pressure

The measure of a solution's tendency to take in water by osmosis (As the solute concentration inside of a cell increases, the osmotic pressure inside of a cell increases because the cell is more likely to take in water).

facilitated diffusion

a channel protein that allows calcium ions to move into a cell when the concentration of calcium outside of the cell is higher than inside

What is the definition of endocytosis? a. It is the transport of large molecules into the cell. b. The entire plasma membrane turns itself inside out. c. It is the transport of large molecules out of the cell. d. It is the digestion of larger molecules that were brought into the cell.

a. It is the transport of large molecules into the cell.

Which form of transport requires the expenditure of energy? a. Active transport b. Facilitated diffusion c. Osmosis d. Passive transport

a. active transport

Which of the following processes can move a solute against its concentration gradient? a. active transport b. facilitated diffusion c. osmosis d. passive transport

a. active transport

The presence of cholesterol in the plasma membranes of some animals a. enables the membrane to stay fluid more easily when cell temperature drops. b. enables the animal to add hydrogen atoms to unsaturated phospholipids. c. enables the animal to remove hydrogen atoms from saturated phospholipids. d. makes the animal more susceptible to circulatory disorders. e. makes the membrane less flexible, allowing it to sustain greater pressure from within the cell.

a. enables the membrane to stay fluid more easily when cell temperature drops.

The presence of cholesterol in the plasma membranes of some animals a. enables the membrane to stay fluid more easily when cell temperature drops. b. enables the animal to add hydrogen atoms to unsaturated phospholipids. c. enables the animal to remove hydrogen atoms from saturated phospholipids. d. makes the animal more susceptible to circulatory disorders. e. makes the membrane less flexible, allowing it to sustain greater pressure from within the cell.

a. enables the membrane to stay fluid more easily when cell temperature drops.

active transport

an intermembrane protein that transports protons out of the cell, against the gradient

Which of the following statements regarding membrane protein function is false? a. Membrane proteins serve as enzymes. b. Membrane proteins produce phospholipids. c. Membrane proteins form junctions between cells. d. Membrane proteins act as receptors to molecules like hormones.

b. Membrane proteins produce phospholipids.

Mammalian blood contains the equivalent of 0.15 M NaCl. Seawater contains the equivalent of 0.45 M NaCl. What will happen if red blood cells are transferred to seawater? a. NaCl will passively diffuse into the red blood cells. b. Water will leave the cells, causing them to shrivel and collapse. c. NaCl will be exported from the red blood cells by facilitated diffusion. d. The blood cells will take up water, swell, and eventually burst. e. The blood cells will expend ATP for active transport of NaCl into the cytoplasm.

b. Water will leave the cells, causing them to shrivel and collapse.

What kinds of molecules pass through a cell membrane most easily? a. small ionic b. small hydrophobic c. large polar d. large hydrophobic e. large and hydrophilic

b. small hydrophobic

Which of the following statements regarding active transport is false? a. Active transport can move a solute against its concentration gradient. b. Active transport uses ATP as an energy source. c. Active transport is driven by the concentration gradient. d. Active transport requires the cell to expend energy.

c. Active transport is driven by the concentration gradient.

Which of the following is one of the ways a species that lives in a cold environment would be able to have membranes that remain fluid when it is extremely cold? a. by decreasing the number of hydrophobic proteins in the membrane b. by cotransport of glucose and hydrogen c. by using active transport d. by increasing the percentage of unsaturated phospholipids in the membrane e. by decreasing the percentage of cholesterol molecules in the membrane

d. by increasing the percentage of unsaturated phospholipids in the membrane

Plasma membranes are selectively permeable. This means that a. glucose cannot enter the cell. b. plasma membranes must be very thick. c. anything can pass into or out of a cell as long as the membrane is intact and the cell is healthy. d. the plasma membrane allows some substances to enter or leave a cell more easily than others.

d. the plasma membrane allows some substances to enter or leave a cell more easily than others.

simple diffusion

movement of oxygen across mitochondrial and cell membranes

bulk transport

white blood cells engulf bacteria