Biology

Biology Multiple Choice Questions and Answers (MCQ) PDF: Quizzes & Practice Tests with Answer Key. This section Biology basic concepts, theory and objective tests.

This section covers following topic MCQs: Bioenergetics, biological molecules, cell biology, coordination and control, enzymes, fungi, recyclers kingdom, gaseous exchange, growth and development, kingdom Animalia, kingdom plantae, kingdom prokaryotae, kingdom protoctista, nutrition, reproduction, support and movements, transport biology, variety of life, and homeostasis etc.

    Cell Cycle
    Which of following should be attached for activation of cell cycle kinases?
    Author: rikazzz Comment
    Coordination and Control
    The movement of plant part in the direction of light is:
    Phototrophic movement is the growthof a plant in response tolight. If the plant part growstowards light, it is called positive phototropism, and if the plant part growsaway from light, it is called negative phototropism. The shoot of a plant shows positive phototropism and the root of a plant shows negative phototropism.
    Author: rikazzz Comment
    Biology
    The structural and functional unit of nervous system is called a
    Neurons, or nerve cell, are the main structural and functional units of the nervous system. Every neuron consists of a body (soma) and a number of processes (neurites).
    Author: rikazzz Comment
    Homeostasis
    During the delivery of a baby, the baby’s head is pushing against the cervix causing the cervix wall to stretch. This stretching causes nerve impulses to be sent to the hypothalamus which directs the posterior pituitary to release oxytocin in the blood. Oxytocin stimulates the uterus to contract which pushes the baby’s head deeper into the cervix, stretching it further. This situation is a description of which of the following?
    The stimulus (cervical stretching) causes the integrating centre (the hypothalamus) to respond by enhancing the stimulus – releasing oxytocin so that the uterus contracts. Enhancing the stimulus is an example of positive feedback. The feedback stops when the cervix is no longer being stretched, that is, when the baby is delivered.
    Author: rikazzz Comment
    Life Processes
    What could be the possible explanation for the evolution of four-chambered heart in mammals as opposed to two-chambered heart in fishes?
    In fishes and reptiles, the heart is two-chambered and there is mixing of oxygenated and deoxygenated blood. They are cold blooded (the body temperature varies according to the surrounding temperature), so energy is required only for locomotion and hence less amount of oxygen is sufficient in them. Birds and mammals are warm blooded, so more energy is required to keep up the body temperature. To maintain high energy requirements of the body, more oxygen supply is required. Therefore, the heart has four chambers and oxygenated blood and deoxygenated blood is kept strictly separated. Also, complexities in the body structure and different mechanisms have increased with evolution. Therefore the mechanism of circulation has also evolved.
    Author: rikazzz Comment
    Homeostasis
    Choose one answer below that completes the sentence so that it makes a true statement. Positive feedback:
    “Positive” feedback will reinforce the stimulus, making it greater or more insistent.
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    Homeostasis
    When peripheral chemoreceptors detect an increase in the concentration of dissolved carbon dioxide in arterial blood above 45 mmHg (the upper limit of normal), which of the following homeostatic responses would occur?
    The homeostatic response opposes the stimulus, so if blood pCO2 is rising, the response must produce a decrease in pCO2. If respiratory rate increases, the increase in lung ventilation will blow off more CO2 (not less). This will lead to a decrease in the gas dissolved in arterial blood and a restoration of the healthy dissolved carbon dioxide concentration.
    Author: rikazzz Comment
    Biology
    The Chipko Andolan was basically started against
    In the 1970s, an organized resistance to the destruction of forests spread throughout India and came to be known as the Chipko movement. The name of the movement comes from the word “embrace”, as the villagers hugged the trees, and prevented the contractors from felling them.
    Author: rikazzz Comment
    Coordination and Control
    Nodes of Ranvier are present at:
    The Nodes of Ranvier, also known as myelin sheath gaps, are the gaps (approximately 1μm in length) formed between the myelin sheaths generated by Schwann cells. Electrical impulses jump from these nodes.
    Author: rikazzz Comment
    Biology
    The process of removal of metabolic waste from the body is known as:
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