- carbohydrates
- cholesterol
- glycolipid
- protein
- The proportion of phosphate within the phospholipids will vary.
- Only certain membranes contain phospholipids.
- Only certain membranes are selectively permeable.
- The proportions of proteins, lipids, and carbohydrates will vary.

- cholesterol
- its head
- saturated fatty acid tail
- unsaturated fatty acid tail
- Greater proportion of unsaturated phospholipids in membranes.
- Greater proportion of saturated phospholipids in membranes.
- Greater proportion of carbohydrates in membranes.
- Greater proportion of proteins in membranes.
- Carbohydrates are in contact with the aqueous fluid both inside and outside the cell.
- Carbohydrates are present only on the interior surface of a membrane.
- Carbohydrates are present only on the exterior surface of a membrane.
- Carbohydates span only the interior of a membrane.

- the fluidity of membranes
- the hydrophobic nature of membranes
- the hydrophilic nature of membranes
- preventing high temperatures from increasing fluidity of membranes

- concentration gradient
- membrane surface area
- particle size
- temperature
- the movement of into a thylakoid disc during photosynthesis
- the uptake of glucose in the intestine
- the uptake of mineral ions into root hair cells of plants
- the movement of water from the descending loop of a nephron into the interstitium
- from an area with a high concentration of other solutes to a lower one
- from an area with a high concentration of water to one of lower concentration
- from an area with a low concentration of water to one of higher concentration.
- throughout the cytoplasm
- They will have higher concentrations of body solutes.
- Without compensating mechanisms, their bodies tend to take in too much water.
- They have no way of controlling their tonicity.
- Their bodies tend to lose too much water to their environment.
Which of the following questions can be asked about organisms that live in fresh water?
- Will their bodies take in too much water?
- Can they control their tonicity?
- Can they survive in salt water?
- Will their bodies lose too much water to their environment?
Which of the following explains why active movement of molecules across membranes must function continuously?
- Diffusion cannot occur in certain cells.
- Diffusion is constantly moving solutes in opposite directions.
- Facilitated diffusion works in the same direction as active transport.
- Not all membranes are amphiphilic.
- by expelling anions
- by pulling in anions
- by expelling more cations than it takes in
- By taking in and expelling an equal number of cations.
- Primary active transport is indirectly dependent on ATP, while secondary active transport is directly dependent on ATP.
- Primary active transport is directly dependent on ATP, while secondary active transport is indirectly dependent on ATP.
- Primary active transport does not require ATP, while secondary active transport is indirectly dependent on ATP.
- Primary active transport is indirectly dependent on ATP, while secondary active transport does not require ATP
- It leaves the cell.
- It is disassembled by the cell.
- It fuses with and becomes part of the plasma membrane.
- It is used again in another exocytosis event.
- It transports only small amounts of fluid.
- It does not involve the pinching off of membrane.
- It brings in only a specifically targeted substance.
- It brings substances into the cell, while phagocytosis removes substances.