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