The cell of the unicellular algae Ventricaria ventricosa is one of the largest known, reaching one to five centimeters in diameter. Like all single-celled organisms, V. ventricosa exchanges gases across the cell membrane. What adaptations would V. ventricosa likely have evolved related to its large size and ability to exchange materials with the outside environment?
- adaptations that would decrease cell metabolism to meet the needs of the large cell
- adaptations that would make the cell thicker, to reduce the loss of nutrients
- adaptations that make diffusion or nutrient passage across their cell membrane more efficient due to the large size of the cell
- adaptations that allow the cell to take in larger food objects using the components of its cell membrane
- evolve smaller size and flatter shape.
- evolve larger size and a pointy shape.
- evolve smaller size and a thicker shape.
- evolve larger size and a shorter shape.
Figure 30.10 shows a human alveolus, which is part of the respiratory system. What do arrows A and B represent in the diagram?
- A: inhaled air; B: blood travelling from the heart
- A: exhaled air; B: blood travelling from the heart
- A: inhaled air; B: blood travelling to the heart
- A: exhaled air; B: blood traveling from the heart
Intubation is a procedure used by ambulance crews that allows a person to breathe if part of the respiratory system is blocked by a foreign object (or otherwise injured). During intubation, a long, plastic tube is placed in the respiratory system so that air can bypass the obstructed area and reach the lungs. Typically, air is supplied artificially using a squeezable bag that connects to the top of the tube. The illustration shows the human respiratory system. The nasal cavity is a wide cavity above and behind the nostrils, and the pharynx is the passageway behind the mouth. The nasal cavity and pharynx join and enter the trachea through the larynx. The larynx is somewhat wider than the trachea and flat. The trachea has concentric, ring-like grooves, giving it a bumpy appearance. The trachea bifurcates into two primary bronchi, which are also grooved. The primary bronchi enter the lungs, and branch into secondary bronchi. The secondary bronchi in turn branch into many tertiary bronchi. The tertiary bronchi branch into bronchioles, which branch into terminal bronchioles. The diaphragm pushes up against the lungs. There is an intubation site indicated at the beginning of the pharynx. A patient has been surgically intubated in the location shown in the diagram. Based on this information, explain where the injury likely occurred in the patient’s respiratory system. Justify your answer.
- in the oral cavity, because it is above the injury
- in the oral cavity, because it is below the injury
- in the larynx, because it is above the injury
- in the larynx, because it is below the injury
Our body systems work to maintain homeostasis by adjusting when body cells need more oxygen or are experiencing a buildup of carbon dioxide. How would the body likely respond if some of its cells were experiencing the situation pictured?
- Generating neural signals that stimulate the heart to beat at a faster rate.
- Releasing hormones that stimulate body cells to undergo more active transport.
- Releasing red blood cells that can accept oxygen using diffusion as opposed to facilitated passive transport.
- Adjust blood pH to decrease the partial pressure of CO2 in the body cells.
The diagram shows a red blood cell in an alveolus and then in a body tissue. In which direction should the arrows point for the diffusion of oxygen and CO2? How should each partial pressure (body cell and RBC) be labeled as “high” or “low” to accomplish this diffusion?
- O2→ CO2←; Body cell PO2= low; RBC PO2= high; Body cell PCO2= high, RBC PCO2= low
- O2← CO2→; Body cell PO2= high; RBC PO2= low; Body cell PCO2= low, RBC PCO2= high
- O2← CO2→; Body cell PO2= low; RBC PO2= high; Body cell PCO2= high, RBC PCO2= low
- O2→ CO2←; Body cell PO2= high; RBC PO2= low; Body cell PCO2= low, RBC PCO2= high
The graph plots percent oxygen saturation of hemoglobin as a function of oxygen partial pressure in the alveoli. Oxygen saturation increases in an S-shaped curve, from 0 to 100 percent as the partial pressure of oxygen increases from 0 to 100. What happens as the curve levels off around a partial pressure of 60 mmHg?
- As the percent saturation of hemoglobin increases to its maximum, hemoglobin’s affinity for oxygen increases as the availability of oxygen increases.
- As the percent saturation of hemoglobin decreases (without all of the oxygen dissociating), hemoglobin’s affinity for oxygen decreases as the availability of oxygen decreases.
- As the percent saturation of hemoglobin increases to very high levels, hemoglobin’s affinity for oxygen decreases due to its decreasing ability to bind oxygen.
- As the percent saturation of hemoglobin decreases, hemoglobin’s affinity for oxygen increases as the availability of oxygen decreases.
The graph shows an oxygen dissociation curve for hemoglobin. Based on the graph, what would likely cause the curve to shift to the left, as shown by the dotted plot line?
- a decrease in carbon dioxide, increase in pH, or a decrease in temperature
- an increase in carbon dioxide, increase in pH, or a decrease in temperature
- a decrease in carbon dioxide, decrease in pH, or a decrease in temperature
- a decrease in carbon dioxide, increase in pH, or an increase in temperature
The graph shows an oxygen dissociation curve for hemoglobin. Based on the graph, what would likely cause the curve to shift to the right, as shown by the dotted plot line?
- decreasing carbon dioxide, increasing pH, or decreasing temperature
- decreasing carbon dioxide, decreasing pH, or decreasing temperature
- increasing carbon dioxide, increasing pH or increasing temperature.
- increasing carbon dioxide, decreasing pH, or increasing temperature.