Bio Study

Graphs representing enzymes sensitive to changes in pH include which of the following?

A) 1 only

Intact cells of two unknown cell types were placed into solutions with different concentrations of NaCl. Type I cells swelled and burst in the solution with the lowest concentration of NaCl. Type II cells swelled but did not burst in the solution with the lowest concentration of NaCl. Which of the following descriptions of cell type I and cell type II are most consistent with the data?

A) Cell 1-Animal cell surrounded by a plasma membrane only Cell 2-Plant cell surrounded by a plasma membrane and a cell wall

The most likely explanation for the results shown about in Graph 1 is that

A) pH affects the shape of active site of the enzyme

Enzymes with their highest activity at an alkaline (basic) pH are represented by which of the following graphs?

B) 2 only

Bacteriophages are virus that infect bacteria

B) Amino Acid

In the figure, why does the reaction plateau at higher reactant concentrations?

B) Most enzyme molecules are occupied by substrate at high reactant concentrations

Which of the following best explains how small molecules move between adjacent cells in a plant shoot?

B) The molecules pass freely through plasmodesmata, which are cytoplasmic strands connecting two cells.

A cell with a predominance of free ribosomes is most likely

B) producing primarily cytoplasmic proteins.

Which of the following can be used to determine the rate of enzyme catalyzed reactions?

B) rate of disappearance of the substrate

Enzymes have similar responses to both changes in temperature and pH. The effect of both is on the

C) Three dimensional shape of the enzyme

In order for a protein to be an integral membrane protein it would have to be

C) amphipathic, with at least one hydrophobic region

Increasing the substrate concentration in an enzymatic reaction could overcome which of the following?

C) competitive inhibition

Feedback inhibition is an efficient way to control a metabolic pathway because the?

C) first enzyme in a pathway is inhibited by the end-product of the pathway

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

C) hypertonic to fresh water but hypotonic to the salt solution.

The volume enclosed by the plasma membrane of plant cells is often much larger than the corresponding volume in animal cells. The most reasonable explanation for this observation is that...

C) plant cells confain a large vacuole that reduces the volume of cytoplasm

For the enzyme-catalyzed reaction shown in the figure, which of these treatments will cause the greatest increase in the rate of the reaction, if the initial reactant concentration is 1.0 micromolar?

D) doubling the enzyme concentration

If radioactive deoxythymidine triphosphate (dTTP) is added to a culture of rapidly growing bacterial cells, where in the cell would you expect to find the greatest concentration of radioactivity?

D) nucleoid region

The phosphate transport system in bacteria imports phosphate into the cell even when the concentration of phosphate outside the cell is much lower than the cytoplasmic phosphate concentration. Phosphate import depends on a pH gradient across the membrane-more acidic outside the cell than inside the cell. Phosphate transport is an example of

E) Cotransport