Metabolism and Homeostasis quiz #1 Flashcards
Metabolism and Homeostasis quiz #1
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How does the surface area to volume ratio affect the physiology of animals as they increase in size?
As animals increase in size, their surface area to volume ratio decreases, making diffusion less efficient and reducing relative heat loss, which influences their metabolic needs and physiological adaptations. Why do larger animals require more energy in total but have lower metabolic rates per unit mass compared to smaller animals?
Larger animals require more total energy due to their greater mass, but their lower surface area to volume ratio means they lose less heat and thus have lower metabolic rates per unit mass than smaller animals. What are some strategies animals use to increase surface area for physiological processes?
Animals increase surface area by flattening, folding, and branching structures, such as the folds in the brain, villi and microvilli in the intestines, and branching in the vascular system. Define metabolism in the context of animal physiology.
Metabolism is the sum of all chemical processes in an organism that sustain life, including the breakdown of nutrients to produce energy. What is basal metabolic rate (BMR) and how does it differ from standard metabolic rate (SMR)?
Basal metabolic rate (BMR) is the minimum energy consumption of an endotherm at rest, while standard metabolic rate (SMR) is the minimum energy consumption of an ectotherm at rest. How do metabolic rates compare between endotherms and ectotherms?
Endotherms have higher metabolic rates than ectotherms because they generate body heat internally, requiring more energy. Explain the relationship between body size and relative metabolic rate in animals.
Smaller animals have higher relative metabolic rates than larger animals, meaning they use more energy per unit mass, largely due to greater heat loss. What are circadian rhythms and how do they affect hormone levels in animals?
Circadian rhythms are daily cycles that regulate physiological and metabolic processes, causing hormones like cortisol and melatonin to fluctuate throughout the day and night. Describe the typical daily pattern of cortisol and melatonin levels in humans.
Cortisol levels peak in the morning to promote alertness and decrease throughout the day, while melatonin levels are low during the day and rise at night to promote sleep. What is torpor and how does it differ from hibernation?
Torpor is a short-term state of decreased physiological activity and metabolic rate, while hibernation is a longer-term state, both helping animals conserve energy. Why is homeostasis important for enzyme function in animals?
Homeostasis maintains optimal conditions such as temperature and pH, which are crucial for proper enzyme function and overall survival. What is the difference between conformers and regulators in maintaining homeostasis?
Conformers allow their internal conditions to change with the environment, while regulators actively maintain stable internal conditions despite external fluctuations. List and briefly describe the four components of a generic homeostatic system.
The four components are: set point (the ideal value), sensor (detects changes), integrator (evaluates information and determines response), and effector (carries out the response to restore balance). How does negative feedback help maintain homeostasis in biological systems?
Negative feedback reduces the output of a system when it becomes excessive, helping to maintain stable internal conditions by counteracting deviations from the set point. Provide an example of negative feedback regulation in cellular metabolism.
In glycolysis, high levels of ATP inhibit the enzyme phosphofructokinase, slowing down the pathway to prevent excess ATP production. What is the HPA axis and how does it exemplify negative feedback?
The HPA axis (hypothalamic-pituitary-adrenal axis) regulates stress hormones; cortisol produced by the adrenal cortex inhibits the hypothalamus and pituitary, reducing further hormone release. Why is positive feedback less common than negative feedback in physiological systems?
Positive feedback amplifies changes and can quickly lead to uncontrolled responses, so it is less common and usually reserved for specific processes like childbirth. How do circadian rhythms and homeostatic mechanisms interact to regulate animal physiology?
Circadian rhythms provide daily timing cues for physiological processes, while homeostatic mechanisms maintain internal stability, together ensuring optimal function and adaptation.
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