The organelle that contains enzymes for intracellular digestion is the:
A. Lysosome
B. Peroxisome
C. Chloroplast
D. Mitochondria
Answer: Option A
Solution (By JKSSB Mock Tests)
Lysosomes are membrane-bound vesicles packed with hydrolytic enzymes (proteases, lipases, nucleases) that digest macromolecules, old organelles, and engulfed pathogens. They maintain an acidic pH (about 5.0) for optimal enzyme activity. Peroxisomes detoxify peroxides, mitochondria generate ATP, chloroplasts perform photosynthesis.
Consider the following statements regarding mitochondria:
1. They are double-membrane organelles.
2. They have their own 80S ribosomes.
3. They are the site of aerobic respiration.
Which of the statements is/are correct?
Explanation:
Mitochondria have two membranes (outer and inner) and are the site of Krebs cycle and oxidative phosphorylation. They possess 70S ribosomes, not 80S. Hence, statements 1 and 3 are correct.
Explanation:
The heart is myogenic because the heartbeat originates in the SA node within the heart itself, not from brain signals. The brain can modulate the rate but not initiate. Thus, A is true, but R is false.
Explanation:
The Competitive Exclusion Principle, formulated by G.F. Gause based on his experiments with Paramecium, states that two species with identical ecological niches (competing for the exact same limited resources) cannot coexist indefinitely in the same habitat. One species will inevitably have a slight reproductive advantage and will outcompete the other, leading to the local extinction or evolutionary shift (resource partitioning) of the inferior competitor.
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