Practice BS Zoology Semester Exam questions with answers and explanations.
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Internal chemoreceptors can detect gases or pH changes and help regulate breathing and circulation. This supports homeostasis.
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Steroid hormones are lipid-soluble and can pass through cell membranes. Their receptor complexes often regulate transcription in the nucleus.
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Photoreceptors in the retina detect light and initiate neural pathways that control pupil size. This protects the retina and improves visual focus.
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Effectors are organs or cells that carry out responses, including muscles and glands. They respond to neural or hormonal commands.
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Rods are retinal photoreceptors specialized for low-light vision. Cones support color and high-acuity vision in many vertebrates.
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The thyroid produces thyroxine, which influences metabolic rate, growth, and development. Low thyroxine commonly slows metabolism.
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Sensory receptors convert one form of stimulus energy, such as light, pressure, or chemicals, into electrical signals the nervous system can interpret.
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Nerve signals are fast and precise, making them suitable for immediate responses such as withdrawal, escape, and coordinated movement.
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Cones are photoreceptors that detect different wavelengths of light, allowing color vision where multiple cone types are present.
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Thyroid hormones are essential for amphibian metamorphosis and vertebrate development. Deficiency can delay or prevent normal transformation.
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Resting membrane potential depends on unequal ion distribution and selective membrane permeability. Sodium-potassium pumps help maintain these gradients.
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Hormones often travel through blood or body fluids and can produce longer-lasting effects than brief nerve impulses. Their effects depend on target cell receptors.
