Unit 2 AP Bio

The following data was collected by observing subcellular structures of three different types of eukaryotic cells. Identify a function of Cell Z.

• Detoxification

• Secretion of Proteins

• Motility

• Storage

Where is the mRNA (used for synthesis of proteins) made?

• Nucleus

• Ribosome

• Rough ER

• Smooth ER

The sodium-potassium (Na+/K+) pump functions like an anti-porter transporting Na+ and K+ across membranes using ATP. This protein spans the membrane with intracellular and extracellular domains. It has a binding site for Na+, K+, and ATP. An experiment was conducted to determine the locations of these binding sites. Artificial cells were created and incubated in buffers containing ATP, ouabain (or oubain), Na+, and K+ in varying combinations inside and outside of the cell as indicated in the chart. The transport of Na+ and K+ was measured to determine activity of the Na+/K+ pump. Which of the following conclusions is supported by the data?

• Ouabain does not disrupt ATP binding to the Na+/K+ pump.

• ATP is required for transport of Na+ and not for transport of K+.

• The ATP binding site of the Na+/K+ pump is located on the intracellular domain of the pump.

• The ATP binding site of the Na+/K+ pump is located on the extracellular domain of the pump.

Tags

NGSS.HS-PS1-5

Paramecia are unicellular protists that have contractile vacuoles to remove excess intracellular water. In an experimental investigation, Paramecia were placed in salt solutions of increasing osmolarity. The rate at which a Paramecium's contractile vacuole contracted to pump out excess water was determined and plotted against osmolarity of the solutions, as shown in the graph. Which of the following is the correct explanation for the data?

Tags

NGSS.HS-LS1-3

An experiment was set up to determine the movement of molecules through a dialysis-tubing bag into water. A dialysis-tubing bag containing 5% lactose and 5% fructose was placed in a beaker of distilled water, as illustrated. After four hours, fructose is detected in the distilled water outside of the dialysis-tubing bag, but lactose is not. What conclusions can be made about the movement of molecules in this experiment?

• Fructose, being a monosaccharide, diffused through the dialysis bag into the distilled water. However, lactose, being a disaccharide, could not diffuse through the dialysis bag.

• Fructose was homogenized by lactose, allowing the fructose to diffuse through the dialysis bag and into the distilled water. Lactose is not homogenized, so it could not pass through the dialysis bag.

• Fructose and lactose are oppositely charged and separated out due to the force of repulsion.

• Fructose diffused because of the pore specificity of the semipermeable membrane, not because of its concentration gradient.

Which characteristic of a phospholipid, shown here, increases the fluidity of the membrane?

• cholesterol

• its head

• saturated fatty acid tail

• double bonds in the fatty acid tail

How would an organism maintain membrane fluidity in an environment where temperatures fluctuated from very high to very low?

• 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.

According to the fluid mosaic model of the plasma cell membrane, what is the location of carbohydrates in the cell 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.

Identify the principal driving movement in diffusion, such as depicted here.

• concentration gradient

• membrane surface area

• particle size

• temperature

Water moves via osmosis across plasma cell membranes in which direction?

• 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