HOMEOSTASIS
What is homeostasis, and why is it important for the body?
Homeostasis is the process by which organisms maintain stable internal conditions, despite changes in the external environment. It is crucial for keeping various physiological parameters (like body temperature, blood pressure, and glucose levels) within a certain range, allowing the body to function properly. For example, the body maintains an internal temperature of about 98.6°F regardless of external temperatures.
What are the three subatomic particles that make up an atom, and what are their charges?
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What are the three main components shared by all cells?
All cells share the following three components:
What is diffusion, and what is the general direction of molecule movement during this process?
Diffusion is the random motion of molecules, and the net movement is from a region of high concentration to a region of low concentration.
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What is the difference between negative and positive feedback mechanisms in homeostasis? Give an example of each.
Negative Feedback: This mechanism stabilizes a condition by bringing it back to the set point. An example is body temperature regulation: when the body gets too hot, it sweats to cool down.
Positive Feedback: This amplifies a change, pushing the system further away from the set point. It is less common and typically associated with processes that need to reach a climax, such as childbirth. For example, during labor.
What is the difference between ionic and covalent bonds?
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What is the role of the plasma membrane, and how is its structure described by the fluid mosaic model?
The plasma membrane acts as a barrier between the intracellular and extracellular environments, regulating the movement of substances. The fluid mosaic model describes the membrane as a dynamic structure where proteins and phospholipids move laterally, allowing for flexibility and function.
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What factors affect the rate of diffusion?
The rate of diffusion depends on several factors:
Explain the roles of the sensor, integrating center, and effector in regulating homeostasis. How do they interact to maintain dynamic equilibrium?
Sensor: Detects changes in the internal or external environment, like a temperature sensor detecting body heat.
Integrating Center: Often the brain or spinal cord, it processes information from the sensor and determines the appropriate response.
Effector: Carries out the action to correct deviations from the set point, such as muscles or glands. For example, when body temperature rises, sensors detect this change, the brain (integrating center) processes the information, and sweat glands (effectors) are activated to cool the body down.
What is a polar covalent bond, and why does water (H₂O) form a polar molecule?
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A polar covalent bond occurs when electrons are shared unequally between atoms, leading to a partial positive charge on one side and a partial negative charge on the other. In water (H₂O), the oxygen atom pulls the shared electrons more strongly than the hydrogen atoms, creating a partial negative charge near the oxygen and partial positive charges near the hydrogens. This makes water a polar molecule.
If confused about the concept look up electronegitivity
Explain the process of phagocytosis and its importance in cellular function.
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Phagocytosis is a form of bulk transport, often referred to as "cell eating," where a cell engulfs large particles, such as debris or microorganisms, into vesicles. This process is vital for immune responses and cellular maintenance, helping to remove harmful materials from the body.
What is osmosis, and how does osmotic pressure relate to solute concentration?
Osmosis is the diffusion of water across a selectively permeable membrane, where water moves down its concentration gradient. Osmotic pressure is the force that would need to be exerted to stop osmosis and is directly proportional to solute concentration.
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Describe how antagonistic effectors help maintain homeostasis. Provide an example that shows how opposing effectors work together to regulate a specific body condition.
Antagonistic effectors are mechanisms that work in opposition to each other to maintain homeostasis. For example, when body temperature rises, the body sweats to cool down. Conversely, when body temperature drops, the body shivers to generate heat. These opposing actions help maintain body temperature within a narrow range, ensuring stable conditions.
What is the normal pH range of human blood, and what conditions arise if the blood's pH falls outside this range? How does the body maintain blood pH within this range?
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The normal pH range of human blood is 7.35 to 7.45.
The body maintains blood pH through buffer systems, particularly the bicarbonate buffer system, which either releases or absorbs hydrogen ions (H⁺) to neutralize changes in acidity or alkalinity. This buffering action helps maintain homeostasis and prevent harmful shifts in pH.
What are the roles of lysosomes and peroxisomes in the cell, and how do they differ?
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Explain the difference between primary and secondary active transport, giving an example of each.
Explain how positive feedback contributes to negative feedback loops using the clotting process or uterine contractions as an example. Why can't positive feedback loops function independently?
Positive feedback INCREASES changes, which helps processes like blood clotting or childbirth reach a critical endpoint. For instance, when a blood vessel is damaged, platelets begin to form a clot. The initial action of clotting releases chemicals that attract more platelets, amplifying the process. Once the vessel is repaired, negative feedback stops the clotting process to prevent excess clotting. Positive feedback loops cannot function independently because they would lead to an uncontrolled process; they rely on negative feedback to eventually halt the amplification and restore stability. REMEMBER POSITIVE FB LOOPS ARE RARE AND ALWAYS FOLLOWED UP BY NFL
Describe the structural levels of proteins and explain how they contribute to the protein’s function. What can cause proteins to denature?
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Proteins have four structural levels:
Denaturation can occur due to heat, pH changes, or chemicals, disrupting the protein's structure and causing it to lose its function.
Describe the two stages of gene expression and explain the difference between transcription and translation. page 12
Describe how blood osmolality is regulated in the body, and what happens when dehydration occurs.
Blood osmolality is maintained around 300 mOsm. When dehydration occurs, osmoreceptors in the hypothalamus detect the increase in blood osmolality. This stimulates the release of ADH (antidiuretic hormone), which causes the kidneys to conserve water and triggers thirst, helping to restore normal blood osmolality.
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