AP Biology Topic 2: A Tour of the Cell

One of their hypotheses was that Fus3 kinase is required for the signal transduction pathway leading to shmoo formation. If this hypothesis is correct, what result should be observed in the ΔFus3 strain?

The ΔFus3 strain should NOT form shmoos, and the cells should NOT have a red zone in their walls

A model, like the diagram, helps scientists form testable hypotheses. What hypothesis was being tested with the Fus3 strain?

Fus3 is required for the signal transduction pathway leading to shmoo formation

The cell is carrying out its typical functions and is not engaged in producing molecules necessary for division

Gap 1

Look at the same figure but assume the membrane is not freely permeable to both glucose (C6H12O6) and sucrose (C12H22O11) but only to the smaller of the two sugars. Now what results would you predict?

Glucose will diffuse from side B to side A

Which of the following is a reasonable hypothesis describing what will happen next?

Glucose will diffuse from side B to side A

Earl Sutherland received the Nobel Prize for his discovery of cAMP as a second messenger. Which observation suggested to Sutherland the involvement of a second messenger in epinephrine's effect on liver cells?

Glycogen breakdown is observed only when epinephrine is administered to intact, living cells

Many signal transduction pathways use second messengers to

relay the message from the inside of of the membrane throughout the cytoplasm

Salivary glands produce a large quantity of enzymes that are transported out of the secretory cells. Which of the following organelles would be in abundance in these cells?

ribosomes

Which of the following uses passive transport without the help of proteins to move materials across the cell membrane?

the movement of carbon dioxide across the cell membrane

Using the same figure and assumption as for question 7, what effect will the movement of the sugar have on the water level in the tubes?

the water level will go up on side A

If you shut the system off and pressure was no longer applied to Tank A, you would expect

the water to reverse flow from Tank B to Tank A

In cell signaling, how is the flow of specific ions regulated?

through opening and closing of ligand-gated ion channels

In addition to testing shmoo formation in the two mutant strains of yeast, the scientists also tested shmoo formation in wild-type yeast. What is the purpose of including wild-type yeast cells in the experiment?

to show normal shmoo formation under the experimental conditions

Which two figures show a cell that is hypertonic to its environment

Cells A and D (both have water going into cell)

An organelle with a cis and trans face, which acts as the packaging and secreting center of the cell

Golgi Apparatus

Large membrane-bound structures that contain hydrolytic enzymes and are found predominantly in animal cells

Lysosomes

Organelles not found in red blood celss but present in large numbers in muscle cells

Mitochondria

What do you predict would happen if the yeast had a mutation that prevented the G protein from binding GTP?

No shmoo would form in response to a mating factor

An organelle that is characterized by extensive, folded membranes and is abundant in cells that detoxify poisons, such as liver cells

Smooth endoplasmic reticulum

Failure of this stage to occur prior to mitosis would result in daughter cells without sufficient DNA

Synthesis (S-phase)

The genetic material of the cell replicates to prepare for cell division

Synthesis (S-phase)

Which of the following statements regarding the cell-cycle. system is false?

The cell-cycle control system operates independently of the growth factors

Fus3 kinase and formin proteins are generally distributed evenly throughout a yeast cell. Based on the model in the diagram, why does the shmoo projection emerge on the same side of the cell that bound the mating factor?

The only formin molecules that get phosphorylated and thus activated are those near the G protein-coupled receptor binds the mating factor

What is a G protein?

a protein on the cytoplasmic side of a membrane that becomes activated by a receptor protein

By what process are H+ ions being moved from the cytoplasm to the extra cellular fluid in this figure?

active transport

Which of the following processes could result in the net movement of a substance into a cell if the substance is more concentrated in the cell than in the surroundings?

active transport

If the melanin production were not sufficient to prevent UV damage to the DNA, which of the following would you expect?

apoptosis and lysis of damaged cells

After the reverse osmosis system has been operating for 30 minutes, the solution in tank A would

be hypertonic to Tank B

Which of the following depicts an animal cell placed in a solution hypotonic to the cell

cell A ( H2O going in and it bursting)

If this did not occur, daughter cells would have two complete sets of chromosomes

cytokinesis

Based on the figure, how might the rate of sucrose into the cell be increased?

decrease the extracellular pH

The fluid mosaic model describes the plasma membrane as consisting of

diverse proteins embedded in a phospholipid bilayer

Small, nonpolar, hydrophobic molecules

easily pass through a membrane's lipid bilayer

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?

er - golgi apparatus - vesicles that fuse with plasma membrane

Large molecules are moved out of the cell by which of the following processes?

exocytosis

Based on their function, you would expect melanocytes in the skin to have a higher than usual number of

golgi bodies

Prokaryotic and eukaryotic cells have all the following in common EXCEPT

linear chromosomes

If the endosymbiont theory is supported by all of the following pieces of evidence except the fact that

mitochondria use ATP like prokaryotes

White blood cells (WBCs) are more resistant to lysis than are red blood cells (RBCs). When looking at a sample of blood for WBCs, what could you do to reduce interference from RBCs?

mix the blood in a hypotonic solution, which will cause the RBCs to lyse

Which of the following component molecules of the plasma membrane is most important in the reception phase of cell signaling?

protein

Which of the following can activate a protein by transferring a phosphate group to it?

protein kinase

Which of the following signal molecules pass through the plasma membrane and bind to intracellular receptors that move into the nucleus and function as transcription factors that regulate gene expression?

testosterone, a steroid hormone