BIO201 Connect 4

Indicate if the following statements about membrane proteins are true or false. 1. They can aid in the transportation of molecules across membranes. 2. They are used in DNA replication. 3. They can act as cell surface receptors. 4. They are totally water soluble. 5. They can be enzymes.

1. True 2. False 3. True 4. False 5. True

Describe the main components of a biological membrane by filling in the missing terms. Small amphipathic ______(1)______ are the most abundant molecules in a membrane. Larger ______(2)______ make up half of the mass of a membrane. Polar ______(3)______ are typically found attached to the outside of a membrane.

1. phospholipids 2. proteins 3. carbohydrates

Determine if each statement applies to facilitated diffusion, active transport, or both.

FACILITATED DIFFUSION: -Molecules move down their concentration gradient. ACTIVE TRANSPORT: -Molecules move against their concentration gradient. -Requires energy. -Transport proteins are specific for the structures of individuals molecules. BOTH: -Molecules move through a transport protein in the membrane.

Unlike simple diffusion, facilitated diffusion requires energy expenditure by the cell.

False

If a cell is placed in an isotonic medium, there will be no net movement of water.

True

Facilitated diffusion requires a. enzymes. b. carrier proteins. c. lipid carriers. d. carbohydrate carriers. e. lipid or carbohydrate carriers.

b. carrier proteins.

Exocytosis is a process by which cells a. release substances from the cell through pores in the cell membrane. b. release substances from the cell via vesicles. c. release substances from the cell via carrier proteins. d. bring in substances from the outside via vesicles. e. bring in substances from the outside via pores in the cell membrane.

b. release substances from the cell via vesicles.

Which of the following is the most direct source of energy for cotransport? a. the movement of one of the transported substances up its concentration gradient b. the movement of one of the transported substances down its concentration gradient c. ATP hydrolysis d. ATP formation e. cotransport requires no energy

b. the movement of one of the transported substances down its concentration gradient

Aquaporin allows water molecules to move very rapidly across a plasma membrane. What would be the best definition of this process? a. Facilitated diffusion using a transporter b. Active transport using a transporter c. Facilitated diffusion using a channel d. Active transport using a channel

c. Facilitated diffusion using a channel

Of the three basic types of endocytosis, what is a unique feature of receptor-mediated endocytosis? a. it is used to transport material into the cell b. it is non-specific c. it involves clathrin-coated pits d. it involves transport of material into e. the cell through pores in the cell membrane e. it can be used both to import and export materials

c. it involves clathrin-coated pits

Sea water is approximately 3% salt. Sea water is hypertonic to tissues of freshwater fish. Their tissue contain - a. 3% salt b. more than 3% salt c. less than 3% salt

c. less than 3% salt

Red blood cells put in a hypertonic solution will a. not be affected in any way. b. form linear edges. c. shrivel and become crenated. d. be destroyed by hemolysis.

c. shrivel and become crenated.

Sugars can be transported into cells against their concentration gradient because of a. osmosis. b. simple diffusion. c. facilitated diffusion. d. antiport with Na+. e. symport with Na+.

e. symport with Na+.

Which of the following molecules are most likely to pass through the membrane by facilitated diffusion? a. H2O and sucrose b. H2O and O2. c. CO2 and O2. d. CO2 and H2O.

a. H2O and sucrose

Simple diffusion is defined as the movement of a. molecules from areas of higher concentration to areas of lower concentration. b. molecules from areas of lower concentration to areas of higher concentration. c. water molecules across a membrane. d. gas molecules across a membrane. e. gas or water molecules across a membrane.

a. molecules from areas of higher concentration to areas of lower concentration.

When sugar is mixed with water, equilibrium is reached when Required information View the animation below, then complete the quiz to test your knowledge of the concept. Play Video When sugar is mixed with water, equilibrium is reached when a. molecules of sugar stop moving. b. water and sugar molecules are moving at the same speed. c. the dissolved sugar molecules are evenly distributed throughout the solution. d. there is the same number of water molecules as dissolved sugar molecules. e. water and sugar molecules are at an equal concentration.

c. the dissolved sugar molecules are evenly distributed throughout the solution.

A phospholipid will laterally diffuse in a plasma membrane faster than an integral membrane protein. What is the simplest explanation for this phenomenon? a. A phospholipid is more hydrophobic than an integral membrane protein b. A phospholipid has greater rotational movement than an integral membrane protein c. The enzyme Flippase can rapidly flip phospholipids across the bilayer but it cannot do the same for integral membrane proteins d. A phospholipid is smaller than an integral membrane protein

d. A phospholipid is smaller than an integral membrane protein

Which of the following is true of the fluid mosaic model of membrane structure? a. Membranes behave more like a solid than a liquid. b. Lipids can flip from one leaflet to another as easily as they can move laterally in a membrane. c. Proteins can easily move across membranes. d. Proteins can easily move laterally through membranes.

d. Proteins can easily move laterally through membranes.

Red blood cells put in a hypotonic solution will a. not be affected in any way. b. form linear edges. c. shrivel and become crenated. d. be destroyed by hemolysis

d. be destroyed by hemolysis

Certain white blood cells engulf microorganisms and digest them within the cell. A mutation that prevents this internalization would directly affect a. pinocytosis. b. osmosis. c. receptor-mediated exocytosis. d. phagocytosis. e. diffusion.

d. phagocytosis.

Osmosis is best defined as the movement of a. molecules from an area of high concentration to an area of lower concentration. b. molecules from an area of low concentration to an area of higher concentration. c. water molecules across a membrane from an area of low water to an area of higher concentration. d. water molecules across a membrane from an area of high water concentration to an area of lower concentration.

d. water molecules across a membrane from an area of high water concentration to an area of lower concentration.

The hormone insulin is a protein produced in the pancreas and then secreted into the blood stream after a meal to increase glucose uptake by tissues. Which of the following mechanisms would be used to secrete insulin from the pancreas? a. Active transport b. Facilitated diffusion c. Diffusion d. Endocytosis e. Exocytosis

e. Exocytosis