Gas Exchange quiz #2 Flashcards
Gas Exchange quiz #2
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What gas enters plant cells through the stoma?
Carbon dioxide enters plant cells through the stoma. How do gases enter and exit the leaves of plants?
Gases enter and exit the leaves of plants through structures called stomata. Which structure of the plants is an opening that exchanges gas and water?
The stomata are the structures in plants that exchange gas and water. What is the name of the structure in plants that allows for gas exchange?
The structure in plants that allows for gas exchange is called the stomata. What gas enters the leaf?
Carbon dioxide enters the leaf. What gas enters the plant through the stomata?
Carbon dioxide enters the plant through the stomata. What is the primary function of hemoglobin in the blood?
The primary function of hemoglobin in the blood is to transport oxygen and facilitate its release to tissues. What is the Bohr effect in relation to hemoglobin?
The Bohr effect describes how lower pH and higher CO2 levels decrease hemoglobin's affinity for oxygen, enhancing oxygen release to tissues. How does the diaphragm contribute to breathing in humans?
The diaphragm contracts to create negative pressure in the thoracic cavity, drawing air into the lungs. What is the significance of the oxygen dissociation curve's sigmoidal shape?
The sigmoidal shape of the oxygen dissociation curve reflects cooperative binding, where hemoglobin's affinity for oxygen increases as more oxygen molecules bind. What is the primary function of gas exchange in animals?
The primary function of gas exchange is to supply oxygen for cellular respiration and remove carbon dioxide, a metabolic waste product. What are the three main factors that influence the rate of gas diffusion according to Fick's law?
The three main factors are surface area, distance (thickness of the membrane), and partial pressure differences. Why do small animals often rely on gas exchange across their body surfaces?
Small animals have a high surface area to volume ratio, allowing efficient gas exchange across their body surfaces. What is negative pressure ventilation and which animals use it?
Negative pressure ventilation involves expanding the thoracic cavity to pull air into the lungs; mammals, including humans, use this method. What is 'dead space' in the respiratory system?
Dead space refers to the portions of the respiratory tract (like the trachea and bronchi) where inhaled air does not participate in gas exchange. What is vital capacity?
Vital capacity is the maximum amount of air that can be exhaled after a maximum inhalation. Why is the air in the alveoli not completely 'fresh' with each breath?
Because each breath mixes fresh air with air left in the dead space from the previous breath, so alveolar air is a mix of new and stale air. How does altitude affect the partial pressure of oxygen?
At higher altitudes, the total atmospheric pressure is lower, so the partial pressure of oxygen is also lower, even though its percentage remains the same. What drives the movement of oxygen from the alveoli into the blood?
A higher partial pressure of oxygen in the alveoli compared to the blood drives oxygen into the blood. Why do metabolically active tissues receive more oxygen from hemoglobin?
Metabolically active tissues have lower partial pressure of oxygen and higher CO2, promoting oxygen unloading from hemoglobin. What is cooperative binding in hemoglobin?
Cooperative binding means that the binding of one oxygen molecule to hemoglobin increases its affinity for additional oxygen molecules. What shape does the oxygen dissociation curve of hemoglobin have and why?
The oxygen dissociation curve is sigmoidal (S-shaped) due to cooperative binding. What causes a rightward shift (Bohr shift) in the oxygen dissociation curve?
A rightward shift is caused by lower pH (higher acidity) and increased partial pressure of CO2. How does a decrease in blood pH affect oxygen delivery?
A decrease in blood pH (more acidic) reduces hemoglobin's affinity for oxygen, enhancing oxygen delivery to tissues. How is most carbon dioxide transported in the blood?
Most carbon dioxide is transported as bicarbonate ions after being converted from CO2 by carbonic anhydrase. How does the conversion of CO2 to bicarbonate in the blood affect CO2 diffusion?
Converting CO2 to bicarbonate lowers the partial pressure of CO2 in the blood, promoting further diffusion of CO2 from tissues into the blood. Why is monitoring blood pH an effective way for the body to regulate breathing?
Because CO2 forms carbonic acid in the blood, changes in pH reflect changes in CO2 levels, allowing effective regulation of breathing. What metabolic process produces carbon dioxide as a waste product?
The citric acid cycle (Krebs cycle) produces carbon dioxide as a waste product. How does the thickness of the respiratory membrane affect gas exchange?
A thinner respiratory membrane decreases diffusion distance, increasing the rate of gas exchange. What is the significance of the sigmoidal shape of the oxygen dissociation curve?
It allows hemoglobin to efficiently load oxygen in the lungs and unload it in tissues with low oxygen. What is the effect of high altitude on oxygen uptake?
Lower partial pressure of oxygen at high altitude reduces oxygen uptake by the blood. How does the respiratory system maintain homeostasis of blood gases?
By adjusting ventilation rate in response to changes in blood pH, which reflects CO2 levels.
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