AP Biology Review: Cell Structure, Communication, and Division

Celery stalks that are immersed in fresh water for several hours become stiff and hard. Similar stalks left in a 0.15 M salt solution become limp and soft. From this we can deduce that the cells of the celery stalks are (think about the cells, not the environment)

• hypotonic to both freshwater and the salt solution

• hypertonic to both freshwater and the salt solution

• hypertonic to freshwater but hypotonic to the salt solution

• hypotonic to freshwater but hypertonic to the salt solution

• isotonic with fresh water but hypotonic to the salt

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?

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

• NaCl will be exported from the red blood cells by facilitated diffusion.

• The blood cells will take up water, swell, and eventually burst

• The blood cells will expend ATP for active transport of NaCl into the cytoplasm

Tags

NGSS.HS-LS1-3

The solutions in the arms of a U-tube are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride and water but not to glucose. Side A is filled with a solution of 0.4 M glucose and 0.5 M sodium chloride (NaCl), and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially, the volume in both arms is the same.

At the beginning of the experiment,

• side A is hypertonic to side B

• side A is hypotonic to side B

• side A is isotonic to side B

• side A is hypertonic to side B with respect to glucose

• side A is hypotonic to side B with respect to sodium chloride

The solutions in the arms of a U-tube are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride and water but not to glucose. Side A is filled with a solution of 0.4 M glucose and 0.5 M sodium chloride (NaCl), and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially, the volume in both arms is the same.

If you examine side A after three days, you should find

• a decrease in the concentration of NaCl and glucose and an increase in the water level

• a decrease in the concentration of NaCl, an increase in water level, and no change in the concentration of glucose

• no net change in the system

• a decrease in the concentration of NaCl and a decrease in the water level

• no change in the concentration of NaCl and glucose and an increase in the water level

Tags

NGSS.HS-LS2-3

A patient has had a serious accident and lost a lot of blood. In an attempt to replenish body fluids, distilled water–equal to the volume of blood lost–is transferred directly into one of his veins. What will be the most probable result of this transfusion?

• It will have no unfavorable effect as long as the water is free of viruses and bacteria

• The patient's red blood cells will shrivel up because the blood fluid has become hypotonic compared to the cells

• The patient's red blood cells will swell because the blood fluid has become hypotonic compared to the cells

• The patient's red blood cells will shrivel up because the blood fluid has become hypertonic compared to the cells

• The patient's red blood cells will burst because the blood fluid has become hypertonic compared to the cells

Based on the figure to the right, which of these experimental treatments would increase the rate of sucrose transport into the cell?

• decreasing extracellular sucrose concentration

• decreasing extracellular pH

• decreasing cytoplasmic pH

• adding an inhibitor that blocks the regeneration of ATP

• adding a substance that makes the membrane more permeable to hydrogen ions

Five dialysis bags, constructed from a semi-permeable membrane that is impermeable to sucrose, were filled with various concentrations of sucrose and then placed in separate beakers containing an initial concentration of 0.6 M sucrose solution. At 10-minute intervals, the bags were massed (weighed) and the percent change in mass of each bag was graphed.

Which line represents the bag that contained a solution isotonic to the 0.6 molar solution at the beginning of the experiment?

• A

• B

• C

• D

• E

Cells of the pancreas will incorporate radioactively labeled amino acids into proteins. This "tagging" of newly synthesized proteins enables a researcher to track their location. In this case, we are tracking an enzyme secreted by pancreatic cells. What is its most likely pathway through the cell? (Keep in mind that the pancreas secretes hormones and proteins)

• ER ^→ Golgi ^→ nucleus

• Golgi ^→ ER ^→ lysosome

• nucleus ^→ ER ^→ Golgi

• ER ^→ Golgi ^→ vesicles that fuse with plasma membrane

• ER ^→ lysosomes ^→ vesicles that fuse with plasma membrane

Which of the following is one of the ways that the membranes of winter wheat are able to remain fluid when it is extremely cold?

• by increasing the percentage of unsaturated phospholipids in the membrane

• by increasing the percentage of cholesterol molecules in the membrane

• by decreasing the number of hydrophobic proteins in the membrane

• by co-transport of glucose and hydrogen

• by using active transport

Tay–Sachs disease is a human genetic abnormality that results in cells accumulating and becoming clogged with very large, complex, and undigested lipids. Which cellular organelle must be involved in this condition?

• the endoplasmic reticulum

• the Golgi apparatus

• the lysosome

• mitochondrion

• membrane–bound ribosomes