Paul A Forever Exam #3

Based on the information presented, which of the following genetic changes in an individual without diabetes is most likely to result in a disrupted cellular response to insulin signaling similar to that of an individual with type 2 diabetes?

(A) A deletion in the gene encoding the insulin receptor that removes only the cytoplasmic domain of the protein

The figure above illustrates the similarities between ATP Synthesis in the mitochondria and chloroplast. The figure can bets assist in answering which of the following questions?

(A) Do electron transport chains create a gradient so that ATP Synthase can generate ATP molecules?

Epinephrine is a protein hormone found in many animals. Epinephrine stimulates a signaling pathway that results in the breakdown of glycogen to glucose in the liver cells. Which of the following describes the initial steps in the process whereby epinephrine stimulates glycogen breakdown?

(A) Epinephrine binds to a cell-surface receptor, the activated receptor stimulates production of the second messenger, cAMP

To investigate whether an organism in the study is capable of both photosynthesis and respiration, a comparison of which treatment groups is most appropriate?

(A) I and II

According to the data, the mice at 10 C demonstrated greater oxygen consumption per gram of tissue than did the mice at 25 C. This is most likely explained by which of the following statements?

(A) The mice at 10 C had a higher rate of ATP production than the mice at 25 C.

Two nutrient solutions are maintained at the same pH. Actively respiring mitochondria are isolated and placed into each of the 2 solutions. Oxygen gas is bubbled into one solution. The other solution is depleted of all available oxygen. Which of the following best explains why ATP Production is greater in the tube with oxygen than in the tube without oxygen?

(A) The rate of proton pumping across the inner mitochondrial membrane is lower in the sample without oxygen

Which of the following is a valid interpretation of the experimental results that explains how individuals with type 2 diabetes differ from individuals without diabetes?

(A) The relatively low levels of glucose uptake in individuals with type 2 diabetes indicate that mobilization of GLUT4 to the cell surface is reduced in muscle cells of those individuals

To test the hypothesis that a particular plant synthesizes storage lipids by using glyceraldehyde 3-phosphate (G3P) from photosynthesis, a researcher plans to use radio-labeled precursors to track the molecules through the bio-synthetic pathway. Which of the following radio-labeled precursors is most appropriate for the researcher to use?

(B) 14C-labeled CO2, because atmospheric carbon is fixed to carbohydrates by photosynthesis

The mechanism of action of many common medications involves interfering with the normal pathways that cells use to respond to hormone signals. Which of the following best describes a drug interaction that directly interferes with a signal transduction pathway?

(B) A medication enters the target cell and inhibits an enzyme that normally synthesizes a second messenger

Experimental evidence shows that the process of glycolysis is present and virtually identical in organisms from all 3 domains, Archaea, Bacteria, and Eukarya. Which of the following hypotheses could be best supported by this evidence?

(B) Glycolysis is a universal energy-releasing process and therefore suggests a common ancestor for all forms of life.

Why is apoptosis potentially threatening to the healthy "neighbors" of a dying cell?

(B) Lysosomal enzymes exiting the dying cell would damage surrounding cells.

During aerobic respiration, electrons travel downhill in which sequence?

(B) food-->NADH--> electron transport chain--> oxygen

Which of the following describes a metabolic consequence of a shortage of oxygen in muscle cells?

(C) A buildup of lactic acid in the muscle tissue due to fermentation

Theodor W. Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He noted that the largest groups were found in the areas illuminate by the red and blue light. What did Engelmann conclude about the congregation of bacteria in the red and blue areas?

(C) Bacteria congregated in these areas because these areas had the most oxygen being released

Which of the following is characterized by a cell releasing a signal molecule into the environment, followed by a number of cell sin the immediate vicinity responding?

(C) Paracrine signaling

To identify the molecule that accepts CO2, Calvin and Benson manipulated the carbon-fixation cycle by either cutting off CO2 or cutting off light from cultures of photosynthetic algae. They then measured the concentrations of various metabolites immediately following the manipulation. How would these experiments help identify the CO2 acceptor?

(C) The CO2 acceptor concentration would increase when the CO2 is cut off, but decrease when the light is cut off.

Which of the following observations provides the best evidence that photosynthesis occurred in treatment group 1?

(C) The mean pH of the samples increased after one hour

One approach to treating patients with pancreatic cancer and other cancers in which Hedgehog protein is detected is to modify the hedgehog signaling pathway. Which of the following is the most useful approach?

(C) Treating patients with a membrane-soluble compound that can bind to Smo and block its activity.

During aerobic cellular respiration, oxygen gas is consumed at the same rate as carbon dioxide gas is produced. In order to provide accurate volumetric measurements of oxygen gas consumption, the experimental setup should include which of the following?

(D) A substance that removes carbon dioxide gas

If water taken in by a plant is labeled with a radioactive isotope of oxygen, 18 O, then the oxygen gas released as photosynthesis proceeds is also labeled with 18 O. Which of the following is the most likely explanation?

(D) During the light reactions of photosynthesis, water is split, removing electrons and protons, and oxygen gas is released.

At puberty, an adolescent female body changes in both structure and function of several organ systems, primarily under the influence of changing concentrations of estrogen and other steroid hormones. How can one hormone, such as estrogen, mediate so many effects?

(D) Estrogen binds to specific receptors inside many kinds of cells, each of which have different responses to its binding

Based on the experimental results, which of the following describes the most likely defect in the muscle cells of patients with type 2 diabetes?

(D) IRS-1 activation is reduced at high insulin concentrations

Which of the following is the best explanation for the fact that most transduction pathways have multiple steps?

(D) Multiple steps provide for greater possible amplification of a signal.

Which of the following statements describes the primary function of the Calvin Cycle in green plants?

(E) Synthesize simple sugars from carbon dioxide

Which of the following best describes the function of the coenzymes NAD+ and FAD in eukaryotic cellular respiration?

(E) They accept electrons during oxidation-reduction reactions

GRID IN: What would you predict the mean absorbance to be for a treatment solution that contains 60% acetone and 40% water?

.24 Steps: (.215 +.274)/2= .2445

GRID IN: According to the data below, what is the deepest water level at which light penetration is expected to be at least 200 micrometers (Light)

1.5 meters

GRID IN: The effect of temperature on the respiration of heterotrophic bacteria in a shallow, slow moving freshwater stream was investigated by performing the following experiment. The water temperature of the stream was monitored over a continuous 24 hour period (Starting at time=0 hours). The respiration rates of bacteria living in the streambed were determined at 6 hours and at 9 hours. The results are presented below. Based on the information provided, what was the change in (C) in water temperature associated with the change in respiration rate?

5 C. Steps: 18 C- 15 C= 13 C